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Maximum likelihood decoder or viterbi decoder

Subclass of:

375 - Pulse or digital communications

375316000 - RECEIVERS

375340000 - Particular pulse demodulator or detector

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DocumentTitleDate
20130044841WIRELESS RECEIVING APPARATUS AND METHOD - According to one embodiment, a wireless receiving apparatus includes a receiver, a phase rotation module and a demodulator. The receiver receives a first signal, the first signal being processed a bit conversion, a scramble and an M-phase shift keying modulation processes. The phase rotation module multiplies a first symbol obtained from the first signal with an amount of phase rotation determined by a scramble sequence used for the scramble, to obtain a second symbol. The demodulator demodulates the second symbol by referring to signal points of N-PSK replica signal generated based on a data rate and the bit conversion process and calculates a likelihood obtained from demodulation as a soft decision value.02-21-2013
20090016470TARGETED MAXIMUM LIKELIHOOD ESTIMATION - A method for obtaining an estimator for a distribution pertaining to a dataset is provided. In an illustrative embodiment, the method includes obtaining a dataset; determining a question pertaining to the data; determining an initial estimator descriptive of a distribution of the data; and selectively modifying the initial estimator based on the question, yielding a targeted estimator in response thereto. In a more specific embodiment, selectively modifying the initial estimator includes applying an additional equation and/or a fluctuation function to the initial estimator to yield the targeted estimator, wherein the additional equation or fluctuation function parameter (ε) causes the initial estimator to fluctuate or change as a function of the parameter. The fluctuation function is chosen so that when the parameter ε is set to zero, the initial estimator is not fluctuated. The targeted estimator and a fluctuation function may be employed in an accompanying targeted Bayesian method that involves mapping a prior distribution of a target feature to a posterior distribution of the target feature.01-15-2009
20120163513METHOD AND APPARATUS OF ADAPTIVE TRANSMISSION SIGNAL DETECTION BASED ON SIGNAL-TO-NOISE RATIO AND CHI-SQUARED DISTRIBUTION - Disclosed are a method and apparatus of adaptive transmission signal detection based on a signal-to-noise ratio and a Chi-squared distribution for decoding a reception signal in the form of multi-streams into a transmission signal, the method comprising: receiving a reception signal vector; estimating a channel matrix of a channel that the reception signal vector experienced; performing QR decomposition based on the estimated channel matrix; calculating dimensions of divisional spaces adaptively on the basis of a signal-to-noise ratio (SNR) or a signal-to-interference noise ratio (SINR); detecting a maximum likelihood point having a maximum likelihood value among lattice points within each divisional space optained on the basis of results from performing the QR decomposition and calculating dimension of the divisional spaces; and recovering a transmission signal vector based on the detected maximum likelihood points.06-28-2012
20090074114Method and System for Approximate Maximum Likelihood (ML) Detection in a Multiple Input Multiple Output (MIMO) Receiver - Aspects of a method and system for approximate maximum likelihood (ML) detection in a multiple input multiple output (MIMO) receiver may comprise computing soft decision values for bits that may be decoded from a received signal vector by utilizing approximate ML detection. The soft decision values may be computed for at least a portion bits carried within a received signal vector by decomposing a candidate constellation vector into segments, with each dimension representing a spatial stream signal. After decomposition, soft decision values for at least a portion of the bits may be computed by selecting values in a search dimension and computing values in a plurality of slice dimensions. Values within the search dimension may be determined by selecting constellation points within a constellation map for the search dimension. Values within each slice dimension may be computed for each selected constellation point.03-19-2009
20100061490Timing Phase Detection Using a Matched Filter Set - Various embodiments of the present invention provide systems and methods for phase identification in data processing systems. As one example, a circuit is disclosed that includes a bank of matched filters with two or more matched filters tuned to detect patterns corresponding to a timing pattern sampled using different phases of a sample clock. In particular, the bank of matched filters includes at least a first matched filter tuned to detect a first pattern corresponding to the timing pattern sampled using a first phase of a sample clock, and a second matched filter tuned to detect a second pattern corresponding to the timing pattern sampled using a second phase of the sample clock. The circuits further include a logic circuit operable to determine whether the sample clock is closer to the first phase or the second phase based on an output of the first matched filter and an output of the second matched filter.03-11-2010
20090196381INFORMATION REPRODUCING DEVICE - In an information reproducing device for performing maximum likelihood decoding using asynchronous sample data, data from the recording medium 08-06-2009
20090196380METHOD FOR GENERATING SOFT DECISION SIGNAL FROM HARD DECISION SIGNAL IN A RECEIVER SYSTEM - A receiver system, which generates a soft decision signal from a hard decision signal, includes a hard output receiver for determining a received bit to generate a hard decision signal. A hard input soft output receiver determines an estimated probability of symbol data corresponding to the received bit based on the hard decision signal and generates a soft decision signal represented by a log-likelihood ratio from the estimated probability.08-06-2009
20090041164APPARATUS AND METHOD TO GENERATE CONVOLUTION ENCODED DATA - An apparatus and method are disclosed to generate convolution encoded data. The method supplies a convolution encoder. The method receives original data and generates convolution encoded original data. The method receives revised data. The method generates an XOR data stream by Exclusive OR'ing the original data with the revised data, forms a convolution encoded XOR data stream using the convolution encoder, and Exclusive ORs the convolution encoded XOR data stream with the convolution encoded original data to generate convolution-encoded revised data.02-12-2009
20110188615APPARATUS AND METHOD FOR DETECTING SIGNAL IN A SPATIAL MULTIPLEXING MULTIPLE INPUT MULTIPLE OUTPUT COMMUNICATION SYSTEM - A Spatial Multiplexing Multiple Input Multiple Output (SM-MIMO) communication system, which generates a Q matrix and an R matrix through QR decomposing a channel matrix in an array order corresponding to an order of transmission antennas of a signal transmission device, determines a detection order of transmission symbols included in a transmission symbol vector, QR decomposes a reception signal vector and generates the QR decomposed reception signal vector as a transformed reception signal vector, substitutes all of transmittable candidate symbols for a transmission symbol corresponding to a first detection order among the transmission symbols and sequentially removes interference in the transformed reception signal vector, detects candidate symbols of transmission symbols corresponding to a remaining detection order from the interference-removed transformed reception signal vector, combines the detected candidate symbols, detects candidate symbol vectors, and calculates Log-Likelihood Ratio values of bits included in the transmission symbols by using the detected vectors.08-04-2011
20110194655METHODS AND APPARATUS TO PERFORM RESIDUAL FREQUENCY OFFSET ESTIMATION AND CORRECTION IN IEEE 802.11 WAVEFORMS - Methods and apparatus are provided for performing and utilizing residual frequency offset estimation and correction in Institute of Electrical and Electronics Engineers (IEEE) 802.11 waveforms. Certain aspects of the present disclosure provide a technique for enabling one to perform good channel estimation with a signal-to-noise ratio (SNR)>33 dB, even in the presence of residual frequency errors. Further, certain aspects may enable one to support uplink Spatial Division Multiple Access (UL-SDMA), even in the presence of residual frequency offsets at the client side.08-11-2011
20090122925Viterbi slicer for turbo codes - A method for synchronizing receivers that receive turbo encoded signals to a received signal. Turbo encoding may enable signals to be decoded at a much lower signal to noise ratio than previously practical. A traditional method of synchronizing a receiver to an incoming signal is to use a slicer to determine a received symbol and then to compare the determined symbol to the incoming waveform, in order to adjust the phase of the slicer with respect to the incoming signal. At signal low levels, at which turbo encoded signals may be decoded, this slicing method may be prone to errors that may disrupt the synchronization of the receiver to the incoming signal. By replacing the slicer by a Viterbi decoder with zero traceback (i.e., one which does not consider future values of the signal only past values) a prediction as to what the incoming signal is can be made. Because the Viterbi decoder can consider past signal values it can predict the present symbol being received with higher reliability than by using a slicer, which considers only the present value of the incoming signal.05-14-2009
20090122924DIGITAL BROADCASTING TRANSMISSION/RECEPTION SYSTEM HAVING IMPROVED RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcasting transmission/reception system having improved receiving performance and signal processing method thereof. A digital broadcasting transmitter according to the present invention includes a data pre-processor which processed robust data and generates robust data packet of predetermined format, a TS stream generator which combines robust data packet with a normal data packet to generate a TS stream of a predetermined format, a randomizer which randomizes the TS stream output from the TS stream generator, a convolution encoder which performs convolution encoding with respect to the robust data of the data output from the randomizer, and a RS encoder which performs RS encoding with respect to the data output from the convolution g encoder. Accordingly, digital broadcasting receiving performance can be improved in a poor multipath channel, while maintaining compatibility with existing transmission/reception system.05-14-2009
20090122922DIGITAL BROADCASTING TRANSMISSION/RECEPTION DEVICES CAPABLE OF IMPROVING A RECEIVING PERFORMANCE AND SIGNAL PROCESSIGN METHOD THEREOF - Disclosed is a digital broadcasting transmission/reception system having an improved reception performance and in a signal-processing method thereof. A digital broadcasting transmitter comprises a TS stream generator for inputting robust and normal packets having stuff bytes in predetermined positions and generating dual TS stream by inserting the robust packets between the normal packets; a randomizer for randomizing the dual TS stream; a stuff byte exchanger for replacing the stuff bytes of a randomized data streams from the randomizer to a predetermined known data; and an encoder for encoding a data streams to which the known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization, so that the digital broadcasting reception performance can be improved at poor multipath channels.05-14-2009
20090122921METHOD AND APPARATUS OF DECODING ENCODED DATA FRAME HAVING DUMMY BIT SEQUENCES INCLUDED THEREIN - A method of decoding an encoded data frame including dummy bit sequences each generated from encoding a predetermined bit pattern is provided. The method includes: determining a boundary of dummy bit sequences in the encoded data frame; and generating a decoded data frame according to a partial decoding result and a plurality of predetermined bit patterns each corresponding to one of the dummy bit sequences within the boundary, wherein the partial decoding result is generated by decoding encoded bits beyond the boundary according to the predetermined bit pattern.05-14-2009
20100074378Method and System for Estimating a Signal and Computer Program Product - A method for estimating a signal transmitted via a communication channel from a signal received via the communication channel, is described comprising carrying out a channel-dependent transformation of the received signal; and iteratively determining, channel-independently, an estimate for the transmitted signal on the basis of the transformed received signal.03-25-2010
20130039448MULTI-CHANNEL SEQUENTIAL VITERBI DECODER - A multi-channel sequential Viterbi decoder includes: an input buffer, a “Read Data from Input Buffer” signal driver, a processing unit selector, a decoder channel parameters registers unit, a processing unit for a “Reset Path Metrics” command, a processing unit for a “Set Path Metric Value for the Given Path Number” command, a processing unit for a “Get Single Bit from the Path with Given Number” command, a processing unit for a “Process Input Samples” command, a memory for storing decoding paths and path metrics, a unit for generating an address for the memory, and data buffers for decoder channels output.02-14-2013
20130039447SYMBOL VECTOR-LEVEL COMBINING RECEIVER FOR INCREMENTAL REDUNDANCY HARQ WITH MIMO - Techniques are provided for transmitting and receiving a mother code in an incremental redundancy hybrid automatic repeat-request protocol. Each bit position of the mother code may be mapped to an output symbol, and each output symbol may be mapped to an antenna for transmission. One or more transmissions of symbols contained in the output symbols may be performed, where each transmission may include puncturing the mother code by selecting one or more symbols from the of output symbols, and transmitting each symbol in the one or more symbols on an antenna corresponding to that symbol. The mother code may be decoded, in part, by determining combinable bits contained within a set of received symbols, and computing one or more log-likelihood ratio values corresponding to each symbol in the set of received symbols.02-14-2013
20100034323Signal decoding systems - We describe an ultra wideband (UWB) orthogonal frequency division multiplexed (OFDM) modified dual carrier modulation (MDCM) decoder comprising: first and second inputs to input first and second signals for first and second OFDM carriers; third and fourth inputs for respective third and fourth signals comprising channel quality estimates for the OFDM carriers; a set of integer arithmetic units coupled to said first, second, third and fourth inputs to form a set of intermediate terms; a first set of adders to form first and second sets of combinations of said intermediate terms, one for each MDCM coded bit value; a compare-select stage to select a first and second minimum valued said combination of said intermediate terms from said first and second set; and a subtracter to determine a log likelihood ratio (LLR) value for said bit from said first and second minimum valued combinations.02-11-2010
20130077721METHODS AND APPARATUS FOR MIMO DETECTION - A transmitted signal estimate based on signals received in a layer i within a multiple input, multiple output transmission system and based upon selected constellation points for other, previously processed layers is quantized to a nearest constellation point. A list of candidates headed by the nearest constellation point and with remaining candidates presorted by proximity to the head is selected, for each such quantized estimate based on constellation point selections for previously processed layers. To select K best candidates for the transmitted signal estimates of the current layer i, the proximity of the candidates at the head of each list to the signal estimate for the current layer are compared, and the closest candidate is selected. The list containing the selected candidate is advanced, and proximity of the transmitted signal estimate to all list heads is again evaluated and the closest candidate selected.03-28-2013
20100046676DIGITAL BROADCAST TRANSMITTER/RECEIVER HAVING AN IMPROVED RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcast transmitting/receiving system, and a signal processing method thereof, includes a randomizer for randomizing a transport stream into a specified position of which stuff bytes are inserted, a stuff-byte exchanger for replacing the stuff bytes included in data output from the randomizer with specified known data, an RS encoder for performing an RS-encoding of data output from the stuff-byte exchanger, an interleaver for interleaving data output from the RS encoder, a trellis encoder for performing a trellis encoding of data output from the interleaver, an RS parity generator for generating a parity by performing an RS encoding of data output from the RS encoder, and outputting the generated parity to the trellis encoder, and a modulator/RF converter for modulating data output from the trellis encoder and performing an RF up-converting of the modulated data. The digital broadcast receiving performance can be improved even in an inferior multi-path channel by detecting the known data from the received signal and using the known data for synchronization and equalization in a digital broadcast receiver.02-25-2010
20090274247Detection of synchronization mark from output of matched filter upstream of viterbi detector - Embodiments of the present invention relate to the detection of synchronization marks in data storage and retrieval. According to one embodiment, synchronization marks are detected from the output of a matched filter, upstream of the Viterbi detector. This approach avoids the delay associated with the latency of the Viterbi output, thereby allowing time to align parity framing and to properly start the time-varying trellis. Certain embodiments disclose 34- and 20-bit primary synchronization marks located at the beginning of a data region. Other embodiments disclose 16-, 20-, and 24-bit embedded synchronization marks located within a data region.11-05-2009
20130077720MULTI-STAGE TURBO EQUALIZATION AND INTERFERENCE CANCELLATION RECEIVER FOR WIRELESS SYSTEMS - In a receive node of a wireless network, an iterative multi-user multi-stage interference cancellation receiver is used. The receiver performs code-averaged equalization and chip chip-level code-specific interference over-cancellation on the received signals. This can result in a unified interference cancellation processing, and can avoid cumbersome calculations of code cross correlations that is required in symbol-level interference cancellation. A symbol-level code-averaged desired signal add-back is performed to address the over-cancellation of some desired signals.03-28-2013
20080310560Apparatus for Estimating Phase Offset of Multiple Survival Paths and Digital Wired/Wireless Communication System Using the Same - Provided is an apparatus for estimating phase offsets of multiple survival paths and a satellite communication system using the same. The apparatus includes: upper/lower decoding units for obtaining a phase offset estimation value and estimating phase offsets of each survival path based on a stored parameter estimation value of a previous state inputted from an external device; an interleaving/de-interleaving unit for minimizing correlation between data used to estimate a parameter according to the estimated phase offset value from the upper/lower decoding means; and a phase offset outputting unit for outputting the phase offset value estimated through the upper decoding unit and the de-interleaving unit.12-18-2008
20130136214SCALING DECISION DEVICE AND METHOD FOR DECIDING SCALING VALUE USED IN NORMALIZATION OF SIGNAL - According to one embodiment, a scaling decision device includes a first decision unit and a second decision unit. The first decision unit decides, based on a plurality of input signals, a K-th smallest signal of the plurality of input signals or a range to which the K-th smallest signal belongs of a plurality of ranges which classify the plurality of input signals by intensities. The second decision unit decides, based on a decision result of the first decision unit, a scaling value which prevents the K-th smallest signal from being submerged in quantization errors by normalization.05-30-2013
20100104050SYSTEM AND METHOD FOR ENHANCED SYMBOL GENERATION - According to some embodiments, an input symbol may be received, and a hard symbol may be generated from the input symbol. A probability associated with the hard symbol may be calculated along with a probability associated with a previous hard symbol. An enhanced symbol may then be determined as a function of a comparison between the probability associated the hard symbol and the previous hard symbol.04-29-2010
20090154608RECEIVING APPARATUS AND METHOD FOR MIMO SYSTEM - Provided are a receiving apparatus for a multiple input multiple output (MIMO) system and a method thereof. The receiving apparatus includes a QR decomposing unit for calculating a single (Q) matrix vector and an upper triangle (R) matrix vector for a receiving signal vector; a first symbol estimation unit for estimating predetermined symbols using the calculated Q matrix vector and R matrix vector; a log likelihood ratio (LLR) calculating unit for calculating log likelihood ratios of unit bits for the estimated symbols; an interference removing unit for receiving a decoded signal that is decided using the calculated log likelihood ratios and removing interference from the receiving signal vector; and a second symbol estimation unit for linearly estimating remaining symbols for the interference removed signal.06-18-2009
20090154606Combining soft decisions in a weather band radio - According to one aspect of the present invention, an apparatus is provided to enable weather band radio signals to be received and processed using a digital signal processor (DSP). The DSP can include functionality to implement both frequency modulation (FM) demodulation and weather band data demodulation, i.e., specific area encoding (SAME) demodulation. In one such embodiment, soft decision samples of a SAME message can be combined, and based on a combined result, a hard decision unit can generate a bit value of weather band data.06-18-2009
20090154605SYSTEM AND METHOD FOR PERFORMING DIRECT MAXIMUM LIKELIHOOD DETECTION - A method, wireless device, and wireless communication system perform Maximum Likelihood Detection. At least one data signal is accepting on at least one communication channel (06-18-2009
20100040177MIMO Symbol Detection for SNR Higher and Lower than a Threshold - A system detects symbols communicated from multiple transmitting antennas to multiple receiving antennas. A first detector determines the symbols from respective partial distances of potential choices for symbols from a constellation. A second detector determines the symbols from respective partial distances of more potential choices. The first and second detectors determine their partial distances from signals received at the receiving antennas. The second detector has a lower bit error rate than the first detector. The potential choices for the second antenna are smaller than the potential choices for the first antenna in response to a signal-to-noise ratio (SNR) being higher than a threshold. An evaluator estimates the SNR of the signals received at the receiving antennas. The evaluator enables the first detector in response to the SNR being lower than the threshold, and the evaluator enables the second detector in response to the SNR being higher than the threshold.02-18-2010
20090129519METHOD AND APPARATUS FOR JOINT EQUALIZATION AND DECODING OF MULTILEVEL CODES - A method and apparatus are disclosed for joint equalization and decoding of multilevel codes, such as the MLT-3 code, which are transmitted over dispersive channels. The MLT-3 code is treated as a code generated by a finite-state machine using a trellis having state dependencies between the various states. A super trellis concatenates the MLT-3 trellis with a trellis representation of the channel. Joint equalization and decoding of the received signal can be performed using the super trellis. A sequence detector is disclosed that uses the super trellis or a corresponding reduced-state trellis to perform joint equalization and decoding of the received signal to decode the MLT-3 coded data bits. The sequence detector may be embodied using maximum likelihood sequence estimation that applies the optimum Viterbi algorithm or a reduced complexity sequence estimation method, such as the reduced-state sequence estimation (RSSE) algorithm.05-21-2009
20130083873INFORMATION REPRODUCTION APPARATUS AND INFORMATION REPRODUCTION METHOD - An information reproduction apparatus includes a generator of a channel clock synchronized to input data, an analog/digital converter for converting the input data with an 1/N clock which is in frequency one Nth (N: a positive real number) of the channel clock, and a Viterbi decoder including a unit for calculating a branch metric based on a difference between an output of the converter and a reference value, an ACS unit responsive to input of data corresponding to one time point of the 1/N clock, for adding the branch metric for one time point to an old path metric, comparing addition results, selecting a smaller result, and outputting a new path metric and a path selection signal, according to state transitions with N bits as a unit, a unit for determining a maximum likelihood path based on the selection signal, and a decoder for outputting a decoding result.04-04-2013
20130083871ITERATIVE DETECTION AND DECODING DEVICE FOR SELECTING SOFT INFORMATION ACCORDING TO AT LEAST ONE PREDETERMINED CONSTRAINT RULE, AND RELATED ITERATIVE DETECTION AND DECODING METHOD - An iterative detection and decoding device includes a signal detector, an error-correction decoder and an SI selector. The signal detector is utilized for generating a set of soft information (SI). The error-correction decoder is coupled to the signal detector, for iteratively decoding the set of SI and accordingly updating the set of SI to generate a set of updated SI. The SI selector is coupled between the signal detector and the error-correction decoder, for selecting at least one SI from the set of updated SI when each SI satisfies at least one predetermined constraint rule. The signal detector further selectively generates a new set of SI according to a selection result generated from the SI selector.04-04-2013
20130083872METHOD FOR COHERENT AND NON COHERENT DEMODULATION - Methods for coherent and non-coherent demodulation are disclosed. Embodiments herein relate to wireless communication systems, and more particularly, to demodulating block orthogonal codes in wireless communication systems. Coherent detection of signals provides improved performance at higher complexity of implementation, but it can be difficult to keep the frequency errors in a wireless communications receiver within the required limits for coherent detection. Embodiments disclosed enable means of using coherent demodulation for block orthogonal codes in the presence of high frequency errors, through the use of techniques of frequency prediction, estimation and correction. Further, it enables a low complexity frequency estimator which provides high estimation range and accuracy.04-04-2013
20100034324REDUCED COMPLEXITY VITERBI DECODING - A system includes a Viterbi decoder. The Viterbi decoder includes add compare select logic. The add compare select logic determines path metrics for an encoded signal. The add compare select logic also is shared to determine a best state by which trace-back procedure gets started, resulting in hardware saving.02-11-2010
20090316840METHODS AND SYSTEMS FOR STC SIGNAL DECODING USING MIMO DECODER - Space time coding (STC) may be applied at the transmitter adding redundant information in both space and time dimensions. At the receiver, the received STC signal may be decoded using a spatial multiplexing MIMO decoding, for example, based on either Minimum Mean Square Error (MMSE) or maximum-likelihood (ML) algorithms. A selective STC decoder may incorporate both the conventional maximum ratio combining (MRC) decoding scheme and a MIMO decoding scheme. One of the STC decoding schemes may be selected, for example, based on estimated channel conditions in order to achieve a trade-off between error rate performance and computational complexity. Components used for a non-selected scheme may be powered down.12-24-2009
20090304125ITERATIVE RECEIVER AND METHOD FOR DETECTING TRANSMITTED SIGNAL THEREOF - In an iterative receiver, a signal detector estimates interference from an estimated transmitted signal, and cancels the estimated interference from a signal received through an antenna. A decoder performs channel decoding by using the interference cancelled received signal. A soft decision unit performs a soft decision process on the transmitted signal by using the channel decoded signal. A channel estimator estimates a channel by using the soft decision applied transmitted signal and the received signal. A covariance estimator estimates covariance on the sum signal of the interference and noise by using the soft decision applied transmitted signal, the received signal, and the estimated channel. A hard decision unit determines the transmitted signal by using the channel decoded signal after interference cancellation, channel decoding, estimated transmitted signal updating, channel estimation, and covariance estimation are iterated a number of times.12-10-2009
20090304124REDUCED-COMPLEXITY MULTIPLE-INPUT, MULTIPLE-OUTPUT DETECTION - A wireless receiver detects signals generated with a multiple-input, multiple-output (MIMO) transmitter. The receiver applies maximum-likelihood detection (MLD) for soft-output signal detection, where an MLD exhaustive search across all candidate vectors is performed recursively by computing and accumulating the differences between, for example, the Euclidean metrics of consecutive candidate tests. Difference terms used for the accumulation are also calculated recursively. An ordering of candidates, such as by a triangular-waveform shaped ordering, is employed such that only one candidate variable is changed between any two consecutive candidate evaluations, leading to a reduced set of computations.12-10-2009
20090304123APPARATUS AND METHOD FOR DETECTING SIGNAL IN MIMO SYSTEM - An apparatus and method for detecting a signal in a Multiple-Input Multiple-Output (MIMO) system are provided. The method includes filtering each stream of a received signal, acquiring a new search space by acquiring a set of candidates having reliability greater than a threshold with respect to each filtered stream, and detecting a signal for each stream of the new search space.12-10-2009
20090304122RECEIVER ARCHITECTURE - A receiver adaptively selects between a joint detection Viterbi demodulator and a second Viterbi demodulator to demodulate a received signal based on at least one characteristic of the received signal. The joint detection Viterbi demodulator jointly demodulates a desired signal component and an interference signal component of the received signal, and the second Viterbi demodulator demodulates the desired signal component without demodulating the interference signal component.12-10-2009
20090304121RECEIVER ARCHITECTURE - A wireless receiver uses a joint detection Viterbi (JDV) algorithm to demodulate a signal that has a desired signal component and an interference signal component. The desired signal component includes a training sequence and at least one data field. The training sequence and a corresponding portion of the interference signal component is demodulated using the JDV algorithm to evaluate possible transmitted training sequences and interference signal sequences, and channel estimations for the desired signal component and the interference signal component are generated. The at least one data field is demodulated according to the JDV algorithm using the channel estimations as initial channel estimates for the JDV algorithm.12-10-2009
20090103666CHANNEL ESTIMATION FOR RAPID DISPERSIVE FADING CHANNELS - This invention addresses the problem of channel estimation in fast fading communications channels, particularly for OFDM systems. It finds wide application in existing and future systems such as WLAN and WiMax. In particular, the invention involves a method of channel estimation and data detection for rapid dispersive fading channels due to high mobility. The invention involves decoding a symbol of the received transmission by retrieving pilot tones from it and using these to estimate variations in the channel frequency response using an iterative maximum likelihood channel estimation process, in which the estimation process comprises the following steps: In a first iteration, deriving soft decoded data information, that is information having a confidence value or reliability associated with it, from the estimates of the channel frequency response for the symbol obtained from pilot tones. And, in at least a second iteration using the soft decoded data information as virtual pilot tones together with the pilot tones to re-estimate the channel frequency response for the symbol. In other aspects the invention concerns a receiver and software designed to perform the method.04-23-2009
20120219097TWO-STEP JOINT DEMAPPING ALGORITHM FOR LLR COMPUTATION OF MIMO SIGNAL BASED ON SPHERE DECODING - Certain aspects of the present disclosure relate to a technique for two-step joint demapping based on sphere decoding for log-likelihood ratio (LLR) computation related to a received multiple-input multiple-output (MIMO) signal. The first step of the proposed algorithm comprises a linear minimum mean square error (LMMSE) based detection to form soft symbol estimates of symbols being transmitted. Then, the LMMSE-based soft symbol estimates can be utilized to form a set of constellation points of a stream interfering to a stream of interest. These candidate constellation points can be then subtracted (canceled) from the received signal to improve the LLR computations of the stream of interest. After the cancellation, the maximum ratio combining (MRC) can be applied to each individual stream to form more refined soft symbol estimates as well as an effective signal-to-noise ratio (SNR) estimate. The refined outputs of the MRC can be utilized to compute LLRs of transmitted bits based on the effective SNR and the refined soft symbol estimates associated with all the candidate constellation points from the set. The LLRs of transmitted bits may be employed by a channel decoder.08-30-2012
20120219096Method and Arrangement Related to Blind Detection - Method and arrangement for use in a receiving node, for determining whether received data is encoded with a certain channel code candidate. The method involves obtaining baseband data encoded with an unknown channel code and calculating the respective posterior probabilities that a set of syndrome checks are satisfied, given the obtained data, which syndrome checks are associated with the channel code candidate. The method further involves combining the posterior probabilities and determining whether the channel code candidate was used for encoding the obtained data, based on the combined posterior probabilities.08-30-2012
20090041165RECEIVER APPARATUS - A receiving apparatus includes: a transmission-channel estimating unit that estimates a transmission-channel response matrix; a hard-decision sequence estimating unit that estimates a hard decision sequence and outputs the hard decision sequence and likelihood information α corresponding to the hard decision sequence; and a soft-decision value creating unit that creates likelihood information β corresponding to a sequence that a specific bit in the hard decision sequence is inversed by using the received signal vector, a transmission-channel response matrix reconstructed by reducing the dimension of the transmission-channel response matrix, and the hard decision sequence, and that creates a soft decision value of the hard decision sequence based on the likelihood information β and the likelihood information α.02-12-2009
20130058441Signal Demodulation Method - A signal demodulation method is disclosed, which includes: obtaining a complete transmission code word; calculating estimated values of three non-differential phases of the transmission code based on a majority logic; identifying a most unreliable phase among three non-differential phases and determining the other two reliable phases to obtain their determination values; calculating determination values of the rest two phases based on the two determined phases; and looking up in tables based on determination values of the four phases to obtain incoming bits. The demodulation method of the present invention is capable of sufficiently reducing the effect of noise on signal and effectively improving the signal demodulation performance.03-07-2013
20090268854METHOD AND APPARATUS FOR MULTIPLE ANTENNA COMMUNICATIONS, AND RELATED SYSTEMS AND COMPUTER PROGRAM - A method of detecting sequences of multi-level encoded symbols. The multi-level encoded symbols are mapped and modulated with a modulation scheme having a number of constellation points identified by a sequence of bits arranged in at least a first and a second group. The first group is encoded with a first encoding scheme, and the second group is encoded with a second coding scheme, and the multi-level encoded symbols are transmitted by multiple transmitting sources and received as a received vector by multiple receiving elements.10-29-2009
20100091914Iterative Decoding - This invention provides an iterative process to maximum a posteriori (MAP) decoding. The iterative process uses an auxiliary function which is defined in terms of a complete data probability distribution. The auxiliary function is derived based on an expectation maximization (EM) algorithm. For a special case of trellis coded modulators, the auxiliary function may be iteratively evaluated by a combination of forward-backward and Viterbi algorithms. The iterative process converges monotonically and thus improves the performance of any decoding algorithm. The MAP decoding minimizes a probability of error. A direct approach to achieve this minimization results in complexity which grows exponentially with T, where T is the size of the input. The iterative process avoids this complexity by converging on the MAP solution through repeated maximization of the auxiliary function.04-15-2010
20100091913APPARATUS AND METHOD FOR ESTIMATING PHASE ERROR BASED ON VARIABLE STEP SIZE - Disclosed is a phase error estimating an apparatus and a method which provides improved convergence speed and tracking speed even in mobile channel environment by variably applying the step size for phase error estimation according to channel status. The apparatus for estimating a phase error includes: a posterior probability (APP) average calculating unit for calculating an APP average value from a soft decision result of a currently received symbol; a step size determining unit for determining a step size variably according to channel status; and a phase error estimating unit for estimating a phase error of the currently received symbol from a phase error of a previously received symbol and the APP average value by using the variably determined step size.04-15-2010
20100091912METHODS AND SYSTEMS USING NORM APPROXIMATION FOR MAXIMUM LIKELIHOOD MIMO DECODING - Certain embodiments of the present disclosure provide techniques for approximate computation of l04-15-2010
20120224660Method and Apparatus for Performing Demapping in Wireless Communication System - A method and apparatus for performing demapping in a wireless communication system utilizing a modulo operation are disclosed. The demapping method of a receiver in a wireless communication system includes receiving an input signal and first information indicating whether a first modulo operation is performed on the input signal from a transmitter; if the first information indicates execution of the first modulo operation, performing a second modulo operation of the input signal, and acquiring a reception signal; generating a maximum function value having a highest probability that the reception signal corresponds to a candidate constellation point of an extended constellation; and generating a log-likelihood ratio (LLR) using the generated maximum function value.09-06-2012
20130064332METHOD AND APPARATUS FOR GENERATING SOFT BIT VALUES IN REDUCED-STATE EQUALIZERS - A demodulator is provided that functions as a reduced-state equalizer and produces reliable soft bit values. According to an embodiment, soft bit values are generated for a sequence of transmitted symbols using a demodulator by updating an M-state trellis managed by the demodulator responsive to a transition from symbol time n−1 to symbol time n, where M is a function of the number of bits per symbol in the sequence of transmitted symbols. Survivor metrics associated with the M states of the trellis are saved each symbol time so that the demodulator can calculate soft bit values with regard to transitions from symbol time n+D−1 to symbol time n+D. The trellis is traced back through to calculate soft bit values for a symbol detected at symbol time n−D based on survivor metrics saved for the M states at symbol time n−D.03-14-2013
20130064331METHOD AND APPARATUS FOR DECODING A REPEATED MESSAGE - Techniques for decoding repeated messages sent from a transmitter are improved with information obtained from the decoding of the first transmission and by augmenting Chase combining techniques with a voting-based combining method. In an example method, first encoded bits corresponding to a first instance of the repeated message and demodulated to obtain first soft bits, which are decoded to obtain first decoded bits. Second encoded bits corresponding to a second instance of the repeated message are demodulated to obtain second soft bits. The first decoded bits are re-encoded to obtain re-encoded bits. Sign values for modified soft bits are determined from sign values for the first soft bits, the sign values for the second soft bits, and the sign values for the re-encoded bits. The modified soft bits are combined with the first soft bits and decoded.03-14-2013
20090213966System and Method for Generating Soft Output in Hybrid MIMO Systems - A hybrid soft output MIMO detector uses a QR decomposition detector followed by a Markov chain Monte Carlo detector. The QRD-M generates initial candidate decision vectors, which are used as input for the Markov chain Monte Carlo detection to generate the soft output.08-27-2009
20090034662Unified multi-mode receiver detector - In general, in one aspect, the disclosure describes a unified simplified maximum likelihood detector to be utilized with multiple input multiple output (MIMO) receivers to estimate transmitted signals. The unified detector includes a common framework capable of being utilized for multiple spatial operational modes and multiple MIMO configurations.02-05-2009
20090232257METHOD AND SYSTEM FOR IMPACT MITIGATION OF SUDDEN CARRIER FREQUENCY SHIFTS IN OFDM RECEIVERS - This disclosure relates to a method and system for impact mitigation of sudden carrier frequency shifts in OFDM receivers that transforming a received complex digital baseband signal and decoding data from the transformed signal.09-17-2009
20090232256ITERATIVE DECODING FOR LAYER CODED OFDM COMMUNICATION SYSTEMS - A modified classical Viterbi decoder which can take extrinsic information and output hard decisions. A modified Viterbi decoder is provided comprising a branch metric unit, the unit having a calculator; and a processor adapted to compute a revised branch metric by combining the initial branch metric and an additional weight parameter. The modified classical Viterbi decoder computes a branch metric by summing an initial branch metric and the additional weight parameter.09-17-2009
20090010365Repetition coding for a wireless system - A system and method are disclosed for transmitting data over a wireless channel. In some embodiments, transmitting data includes receiving convolutionally encoded data and enhancing the transmission of the data by further repetition encoding the data.01-08-2009
20120269303Branch Processing of Search Tree in a Sphere Decoder - Sphere decoding of signals for MIMO detection involves a first distance processor arranged to determine a distance between symbols of a received symbol vector and possible transmit symbols, in a search sequence according to a search tree. A line from root to leaf of the search tree represents a possible transmit symbol vector and the sequence of processing root level symbols can be ordered with respect to increasing distance without explicit sorting of the root level symbols based on distance calculations. A next symbol in the sequence is determined, based on a symbol currently being processed by the first distance processor, and a second distance processor determines the distance in respect of the next symbol in the search sequence for the same possible transmit symbol vector, in parallel with the determining of the distance in respect of the current symbol by the first distance processor. By looking ahead to the next symbol in the sequence and determining its distance in parallel, without waiting to see if the sequence jumps away from that next symbol, the processing can be speeded up or use less resources such as silicon area on an integrated circuit.10-25-2012
20090034663Tone Ordered Discrete Multitone Interleaver - A tone ordered discrete multitone interleaver system and method, including a tone ordered interleaver and deinterleaver, are provided for efficiently communicating data despite noise affecting a Discrete Multitone modulation (DMT) system. The tone ordered discrete multitone interleaver forces interleaving of trellis encoded information by assigning a different number of bits to adjacent tones or adjacent tone pairs.02-05-2009
20090022251MAXIMUM LIKELIHOOD DETECTION APPARATUS AND METHOD IN A WIRELESS COMMUNICATION SYSTEM - A Maximum Likelihood (ML) detection apparatus and method in a wireless communication system are provided, in which a Euclidean distance are calculated using at least one of channel matrix information, noise power information and modulation order information of each stream, Pairwise Error Rate (PER) are calculated using the Euclidean distance, an error probability of the each stream is calculated using the PER, the error probability of the each stream is ordered and sorted, and ML detection is performed using a result of the ordering and sorting.01-22-2009
20100014616Detection of Wideband Interference - A method of detecting interference in a received sample vector using hidden Markov modelling by first estimating noise variance, where estimating noise variance comprises the steps of receiving a sample vector of noise and interference, sorting the sample vector in the frequency domain by order of increasing magnitude to produce an ordered vector, finding a sub-vector of the ordered vector that minimises the distance from a noise measure, and estimating the noise variance.01-21-2010
20110280345TAIL-BITING CONVOLUTIONAL DECODING - Methods and apparatuses for enhanced processing of received channels in a mobile communications system is described. Particularly, convolutionally encoded tail biting data in a mobile communications system is efficiently decoding by replicating the received encoded signal N times, where N equals a number of iterations. A Viterbi decoding algorithm is applied and a most likely survivor path is obtained. The ensuing decoding window is set as a fixed decoding window and placed at a mid-section of the most likely survivor path. Simulations have shown codeword accuracy to be comparable to MLSE with less complexity. A high degree of accuracy has been obtained for N=3.11-17-2011
20110280347Method for demodulating signals from a multi-access system able to collide and equipment for implementing same - A method for demodulating time-multiplexed signals able to mutually collide, in particular in the case of an AIS (Automatic Identification System), being a communications system between ships allows collisions between these ships to be limited and allows the maritime traffic in view from the coasts to be monitored thanks to coastal stations that listen to the communications. When these colliding signals are sufficiently “distinct” (in frequency, in power or in time), algorithms exist for discriminating between them. The demodulator offers the possibility of demodulating two colliding signals, whose collision parameters (difference in frequency, in power or their non-synchronization) are sufficiently small to make them virtually inaccessible otherwise. The method and equipment allow the satellite AIS system to utilize cases of signal collisions that were hitherto detrimental in order to improve the overall performance.11-17-2011
20110280346METHOD AND APPARATUS FOR FACILITATING TRI-STATE DECODING ON A SHARED UPLINK CHANNEL - Methods, apparatuses, and computer program products are disclosed for facilitating decoding a communication received from a wireless terminal. Encoded bits are received from the wireless terminal via a shared uplink channel, and a plurality of acknowledgment tones are identified within the encoded bits. A correlation value is ascertained corresponding to a correlation between detected bits within the plurality of acknowledgment tones and valid bits corresponding to any of a plurality of valid acknowledgment codewords. A determination is then made as to whether the plurality of acknowledgment tones includes information corresponding to a discontinuous transmission by comparing the correlation value to a threshold value.11-17-2011
20110129042METHOD AND APPARATUS FOR DETECTING A PLURALITY OF SYMBOL BLOCKS USING A DECODER - Teachings presented herein offer a technique for using a demodulator to improve a demodulation process. For example, a demodulation unit according to an embodiment of the present invention may be a multi-stage demodulator and may include: a demodulator configured to receive a baseband signal and configured to produce modem bit likelihood values based on the received baseband signal; a decoder configured to receive and process the modem bit likelihood values to produce improved modem bit likelihood values; a candidate value generator configured to produce, based on the improved modem bit likelihood values, candidate symbol values for a group of one or more symbols; and a detector configured to receive the baseband signal and the candidate symbol values and configured to produce one of (a) final modem bit estimates and (b) candidate symbol values for a group of symbols.06-02-2011
20120288039APPARATUS AND METHOD FOR SOFT DEMAPPING - Provided are a soft demapping apparatus and method that may cancel interference included in a rotated quadrature amplitude modulation (QAM) signal, using at least one interference cancellation unit, and may perform one-dimensional (1D) soft demapping of the interference-cancelled rotated QAM signal.11-15-2012
20120294395CANCELLING INTERFERENCE BY DETERMINING MODULATION AND CODING INFORMATION EMBEDDED IN A RECEIVED SPATIAL STREAM - Data-directed interference cancellation involves detecting the modulation and coding embedded in an interfering spatial stream and using the detected modulation and coding for interference cancellation in conjunction with decoding another spatial stream. In an 802.11ac-based system, the modulation and coding scheme of a spatial stream is specified by a SIGB value. Upon detecting the SIGB value of an interfering spatial stream in a received signal, the modulation and coding indicated by the SIGB value is used to identify the information transmitted in the interfering spatial stream. Once this information is known, the interference caused by the transmission of this information is canceled from the received signal to improve the decoding of the other spatial stream (or streams) in the received signal.11-22-2012
20110299637Message Decoding for Discretized Signal Transmissions - Methods, devices and systems for sensor-based wireless communication systems using compressive sampling are provided. In one embodiment, the method for sampling signals comprises receiving, over a wireless channel, a user equipment transmission based on an S-sparse combination of a set of vectors; down converting and discretizing the received transmission to create a discretized signal; correlating the discretized signal with a set of sense waveforms to create a set of samples, wherein a total number of samples in the set is equal to a total number of sense waveforms in the set, wherein the set of sense waveforms does not match the set of vectors, and wherein the total number of sense waveforms in the set of sense waveforms is fewer than a total number of vectors in the set of vectors; and transmitting at least one sample of the set of samples to a remote central processor.12-08-2011
20090103663DIGITAL BROADCAST TRANSMISSION AND RECEIVING SYSTEM HAVING AN IMPROVED RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcast transmitter comprising: a randomizer to receive a data stream of which stuff bytes are inserted into a specified position and to randomize the received data stream; a stuff-byte exchange unit to generate known data having a predefined pattern and to insert the known data into the specified position of the data stream into which the stuff bytes are inserted; an encoder to encode the data stream output from the stuff-byte exchange unit for an error correction; and a modulator and RF converter to modulate the encoded data stream, RF-convert the modulated data stream and transmit the RF-converted data.04-23-2009
20080273630DECODING SYMBOLS OF A SIGNAL DISTRIBUTED ACCORDING TO FREQUENCY AND TIME DIMENSIONS - A signal of OFDM type received in a radio receiver via a propagation channel includes symbols distributed according to frequency and time. The receiver determines likelihoods of the symbols, decodes the received signal to yield a decoded signal as a function of the likelihoods of the symbols, and estimates an instantaneous noise power of the received signal as a function of a difference between the received signal and a reconstructed noise-free signal derived from the decoded signal. A filtering module determines a bounded distribution of the instantaneous noise power as a function of frequency and/or time, and filters the distribution to yield a filtered noise variance as a function of a frequency and/or time parameter of the propagation channel. A corrector weights the likelihoods of the symbols of the received signal to be decoded as a function of the filtered noise variance.11-06-2008
20120236972SIGNAL SEPARATING DEVICE AND SIGNAL SEPARATING METHOD - A signal demultiplexing method and apparatus are provided, for determining a likelihood of each bit included in a second signal, which is spatially multiplexed with and received with a first signal, based on a maximum likelihood detection (MLD) method using QR decomposition, wherein the first signal excludes the second signal to be calculated only in a final stage of the MLD method.09-20-2012
20100034322Method and apparatus for layer cancelling in a multiple antenna system supporting space multiplexing - A method and apparatus for layer canceling in a multiple antenna system supporting space multiplexing are provided. The method includes determining a Log Likelihood Ratio (LLR) for each layer of signals received through a plurality of receive antennas and ordering each layer, and performing layer canceling using the ordering result.02-11-2010
20100034325LOW-POWER PREDECODING BASED VITERBI DECODING - In at least some disclosed embodiments, a system includes a Viterbi decoder and predecoding logic coupled to the Viterbi decoder. The predecoding logic decodes encoded data. The system further includes detection logic coupled to the predecoding logic. The detection logic tests decoded data, and the detection logic produces a binary result. The Viterbi decoder is enabled if the binary result is a first value, and the Viterbi decoder is disabled if the binary result is a second value.02-11-2010
20100034321Sharing Logic Circuitry for a Maximum Likelihood MIMO Decoder and a Viterbi Decoder - A receiver system for receiving and decoding modulated communications signals in a multiple-input, multiple-output (MIMO) environment, where the signals are modulated according to Orthogonal Frequency Division Modulation (OFDM). The receiver system includes shared decoder logic circuitry that executes a maximum-likelihood (ML) estimation algorithm in deriving the signals transmitted from the multiple transmitting antennae, as those signals were received over all of the receiving antennae. For a control channel portion of the data frame, the shared decoder logic circuitry applies Viterbi decoding to the transmitted datastreams estimated by the ML estimation algorithm. This sharing of decoder logic reduces the integrated circuit chip area, and also power dissipation, otherwise required in performing these complex decoding functions.02-11-2010
20090122923DIGITAL BROADCASTING TRANSMISSION/RECEPTION DEVICES CAPABLE OF IMPROVING A RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - Disclosed is a digital broadcasting transmission/reception system having an improved reception performance and in a signal-processing method thereof. A digital broadcasting transmitter comprises a TS stream generator for inputting robust and normal packets having stuff bytes in predetermined positions and generating dual TS stream by inserting the robust packets between the normal packets; a randomizer for randomizing the dual TS stream; a stuff byte exchanger for replacing the stuff bytes of a randomized data streams from the randomizer to a predetermined known data; and an encoder for encoding a data streams to which the known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization, so that the digital broadcasting reception performance can be improved at poor multipath channels.05-14-2009
20090147889DIGITAL BROADCASTING TRANSMISSION/RECEPTION DEVICES CAPABLE OF IMPROVING A RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - Disclosed is a digital broadcasting transmission/reception system having an improved reception performance and in a signal-processing method thereof. A digital broadcasting transmitter comprises a TS stream generator for inputting robust and normal packets having stuff bytes in predetermined positions and generating dual TS stream by inserting the robust packets between the normal packets; a randomizer for randomizing the dual TS stream; a stuff byte exchanger for replacing the stuff bytes of a randomized data streams from the randomizer to a predetermined known data; and an encoder for encoding a data streams to which the known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization, so that the digital broadcasting reception performance can be improved at poor multipath channels.06-11-2009
20100124301METHOD FOR RE-ORDERING MULTIPLE LAYERS AND DETECTING SIGNAL OF WHICH THE LAYERS HAVE DIFFERENT MODULATION ORDERS IN MULTIPLE INPUT MULTIPLE OUTPUT ANTENNA SYSTEM AND RECEIVER USING THE SAME - Disclosed are a method for re-ordering multiple layers and detecting signals and a receiver using the same to be able to exert performance approaching a maximum likelihood scheme while having lower complexity than that of the maximum likelihood scheme in a multiple input multiple output (MIMO) antenna system in a form where each layer is modulated and transmitted with different modulation orders.05-20-2010
20090147890Apparatus and method for canceling interference in multi-antenna system - An apparatus and a method for canceling interference based on Maximum Likelihood (ML) at a receiver of a multi-antenna system are provided. The method includes estimating a channel using a signal received over one or more receiver antennas; generating one or more weights using the estimated channel to cancel interference; detecting a candidate symbol having the shortest Euclidean distance through Maximum Likelihood using a first weight; and soft-decoding the candidate symbol using a second weight. Therefore, by receiving the signal based on the ML under the interference, the system capacity can be increased and the reception performance can be enhanced.06-11-2009
20080267323SLIDING BLOCK TRACEBACK DECODING OF BLOCK CODES - Sliding block traceback decoding of block codes. Block by block basis decoding is performed in which a single block, and its corresponding overlap portion, are processed during a given time. The traceback saves a record of decision (e.g., among possible trellis branches between various trellis stages) and constructs only the surviving paths through each individual block. Since only one block (by also employing its corresponding overlap portion) is decoded per time, the traceback through the coded block signal is short. One block of the coded block signal is decoded at a time, and certain resulting information (e.g., bit estimates and/or states) of a first decoded block can be leveraged when decoding a second/adjacent block.10-30-2008
20100054375SYSTEM AND METHOD FOR FORWARD AND BACKWARD RECURSIVE COMPUTATION - A system and method is provided for improved and efficient forward and backward recursive computations that may be used, for example, with turbo code decoding applications. The invention performs the forward computations using a full length of a sequence to be decoded and performs the reverse computations using a sliding window over the sequence.03-04-2010
20090141834RECEIVER AND RECEIVING METHOD FOR RF SIGNALS - An rf signal receiver of the present invention includes: a replica signal generating unit for generating on the basis of a received signal a replica of a transmission signal a delayed arriving signal removing unit for removing the delayed arriving signal from the received signal through the use of the replica signal at the timing of a predetermined timing pattern; a signal combining unit for combining the output of the delayed arriving signal removing unit, whose output represents the results of the removal of the delayed arriving signal from the received signal at the timing of a predetermined timing pattern; and a demodulation unit for demodulating the output of the signal combining unit.06-04-2009
20100266074METHOD FOR DETERMINING CHARACTERISTICS OF SIGNAL AND APPARATUS USING THE SAME - A method of determining characteristics of a signal and an apparatus using the method. The apparatus for determining characteristics of a signal includes: a level detector receiving sample values of a radio frequency (RF) signal and binary data obtained by binarizing the RF signal, generating selection signals based on the binary data, classifying each of the sample values of the RF signal into one of a plurality of levels using the selection signals, and outputting average values of sample values of each level; and a signal characteristics determiner determining a characteristics value that indicates the characteristics of the RF signal using the average values of the sample values belonging to each level.10-21-2010
20090310720EQUALIZING STRUCTURE AND EQUALIZING METHOD - An equalizing structure and method for a wireless communication system receiving device. Two or more transmit signals transmitted in parallel from one or more transmitters are received in received signal vectors representing two or more received data streams, the signals including information modulated onto carrier signals according to a modulation scheme, all possible transmit signals being represented by candidate constellation values in the signal constellation of the modulation scheme. A processor calculates an estimate for a constellation value of a received signal and determines a number of candidate constellation values in the vicinity of the estimated constellation value in the signal constellation. A metric value calculator calculates metric values based on the received signal vectors and the product of channel estimation values with candidate signal vectors. A maximum likelihood detector detects one of the candidate signal vectors having a minimum Euclidean distance to a respective received signal vector as a most likely transmit signal vector based on the metric values.12-17-2009
20090310719EQUALIZING STRUCTURE AND EQUALIZING METHOD - An equalizing structure and method for a wireless communication system receiving device, in which two or more transmit signals transmitted in parallel from one or more transmitters are received in received signal vectors representing two or more received data streams, the signals including information modulated onto carrier signals according to a modulation scheme, all possible transmit signals being represented by candidate constellation values in the signal constellation of the modulation scheme. A metric value calculator calculates metric values based on the received signal vectors and the product of channel estimation values with candidate signal vectors using absolute value calculations, each candidate signal vector including a candidate constellation value for each of the two or more transmit signals. A maximum likelihood detector detects one of the candidate signal vectors having a minimum Euclidean distance to a respective receive signal vector as a most likely transmit signal vector based on metric values.12-17-2009
20090168927BROADCAST CHANNEL SIGNAL, APPARATUS AND METHOD FOR TRANSMITTING AND DECODING BROADCAST CHANNEL INFORMATION - The present invention provides a broadcast channel signal, a wireless communication device and method for transmitting broadcast channel information, where an invariant subportion of a variant portion of the broadcast channel information is separated from the variant subportion of the variant portion and combined with the invariant portion, and encoded separately from the variant subportion. Both encoded portions are transmitted and decoded by a wireless communication device, which uses subsequent transmissions of the broadcast channel information to assist in the decoding in the event the broadcast channel information for a particular transmission frame of a transmission interval cannot be decoded. If the variant subportion cannot be decoded, then using one or more of a set of prestored possible matches defining anticipated bit differences, between multiple successive transmissions, based upon the relative transmission sequence, which can be negated as part of attempting to decode and combine the received information for the multiple received frames.07-02-2009
20090046818RECEPTION DEVICE - It is possible to demodulate a plurality of modulated signals transmitted from a plurality of antennas by using a comparatively small-size circuit with a preferable error ratio characteristic. Partial bit judgment units (02-19-2009
20090274248METHOD AND APPARATUS FOR CONTENTION-FREE INTERLEAVING USING A SINGLE MEMORY - A method and apparatus for contention free interleaving are disclosed. A single memory configured to use an address scheme wherein the most significant bits (MSBs) indicate which word in memory stores an interleaved piece of data. The least significant bits (LSBs) are used to calculate an index that identifies a specific soft-in/soft-out (SISO) decoder associated with a sub-word of the retrieved data. Using an interleaved address generator, the extrinsic data may be written into the memory in sequential order, but read out from the memory in interleaved order, effectively de-interleaving the data so it may be decoded. The generated interleaved address is used by SISO selector circuit which controls a multiplexer that routes the sub-word to its appropriate SISO decoder. The same address generator may be used to write interleaved extrinsic data from SISOs by reordering the sub-words, allowing the extrinsic data to be read in sequential order.11-05-2009
20090274246APPARATUS AND METHOD FOR PHASE RECOVERY USING INDEPENDENTLY DECODABLE COMPONENT CODES OF CHANNEL CODE IN WIRELESS COMMUNICATION SYSTEM - An apparatus and method for phase recovery in a wireless communication system employs independently decodable component codes. The apparatus includes a decoding unit for decoding the input signal to thereby output the decoding value; an estimation unit for estimating phase errors of the received signal by estimating phase errors of the each component codeword in the received signal to thereby generate phase error estimation values; and a correction unit for correcting the phase of received signal using the phase error estimation values to thereby generate the phase corrected signal in an effective manner.11-05-2009
20090262871Receiver and method for detecting signal in multiple antenna system - Provided are a receiver and a method for detecting a signal in a multiple antenna system. The receiver includes a filter coefficient calculator and a signal detector. After separating a first signal portion and a second signal portion, the filter coefficient calculator calculates an MMSE filter coefficient using a Matrix Inversion Lemma such that an inverse matrix of the first signal portion has a predetermined constant value regardless of a repetition signal detection process. The signal detector detects a relevant transmission signal from an interference-removed reception signal using the MMSE filter coefficient.10-22-2009
20090262870TUNING SYSTEM AND METHOD USING A SIMULATED BIT ERROR RATE FOR USE IN AN ELECTRONIC DISPERSION COMPENSATOR - A system and method is disclosed for controlling signal conditioning parameters and a sampling parameter controlling conversion of a received signal to digital sampled values prior to decoding. The sampled values are decoded according to a comparison with expected values calculated according to a model of a transmission channel. The model is also updated from time to time by comparing the expected values with actual sampled values. Variation of the expected values over time is calculated. One or more of the signal conditioning parameters and the sampling parameter are adjusted according to a numerical minimization method such that the system BER is reduced.10-22-2009
20080260075SYSTEMS AND METHODS FOR LOW-COMPLEXITY MAX-LOG MIMO DETECTION - Embodiments provide novel systems and methods for multiple-input multiple-output (MIMO) Max-Log detection. These systems and methods enable near-optimal performance with low complexity for a two-input two-output channel. Some embodiments comprise using a Max-Log detector to compute a set of log-likelihood ratio (LLR) values for a channel input by minimizing cost function while computing only one instance of the cost function for each value of each bit in a symbol. Other embodiments comprise using a Max-Log detector to compute a set of log-likelihood ratio (LLR) values for a channel input by computing all instances of a cost function for each value of each bit in a symbol and selecting the minimum cost from all computed instances of the cost function for each value of each bit.10-23-2008
20090103665DIGITAL BROADCAST TRANSMISSION AND RECEIVING SYSTEM HAVING AN IMPROVED RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcast transmitter comprising: a randomizer to receive a data stream of which stuff bytes are inserted into a specified position and to randomize the received data stream; a stuff-byte exchange unit to generate known data having a predefined pattern and to insert the known data into the specified position of the data stream into which the stuff bytes are inserted; an encoder to encode the data stream output from the stuff-byte exchange unit for an error correction; and a modulator and RF converter to modulate the encoded data stream, RF-convert the modulated data stream and transmit the RF-converted data.04-23-2009
20090103661DIGITAL BROADCAST TRANSMISSION AND RECEIVING SYSTEM HAVING AN IMPROVED RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcast transmitter comprising: a randomizer to receive a data stream of which stuff bytes are inserted into a specified position and to randomize the received data stream; a stuff-byte exchange unit to generate known data having a predefined pattern and to insert the known data into the specified position of the data stream into which the stuff bytes are inserted; an encoder to encode the data stream output from the stuff-byte exchange unit for an error correction; and a modulator and RF converter to modulate the encoded data stream, RF-convert the modulated data stream and transmit the RF-converted data.04-23-2009
20090103660DIGITAL BROADCASTING TRANSMISSION CAPABLE OF IMPROVING RECEIVNG AND EQUALIZING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcast transmitting system and a signal processing method thereof that improves the receiving performance of the system. A digital broadcast transmitter includes a randomizer to receive and randomize a transport stream into a specified position of which stuff bytes are inserted, a replacement sequence generator to generate known data including a predefined sequence, a stuff-byte exchange unit to insert the known data into the specified position of the transport stream into which stuff bytes are inserted, an encoder to encode the transport stream output from the stuff-byte exchange unit for an error correction, and a transmission unit to modulate the encoded transport stream, RF-convert the modulated transport stream and transmit the RF-converted data. The digital broadcast receiving performance is improved even in an inferior multi-path channel by detecting the known data from the received transmission and using the known data for synchronization and equalization.04-23-2009
20090103659REDUCED-COMPLEXITY DECODING ALGORITHMS FOR TAIL-BITING CONVOLUTIONAL CODES - A decoder is provided which is configured to operate upon an input encoded sequence using a wrap around Viterbi procedure, and a decoding method which employs the decoder. The decoder/method is configured to output a selected path as a decode sequence, and to avoid storing, for a current iteration of the wrap-around Viterbi procedure other than a first iteration, a best path up to the current iteration.04-23-2009
20090129514Accurate data-aided frequency tracking circuit - A frequency compensation circuit for compensating for a frequency offset in a received signal, the received signal including a periodically repeated pilot sequence for phase locking. The circuit comprises a phase estimator for estimating a phase of the received signal; a phase compensator, associated with the phase estimator, for compensating for the phase; a frequency estimator, comprising a maximum likelihood estimator comprising a first modification for estimating a frequency offset which is small relative to a symbol time, from the pilot sequence, the frequency estimator being connected downstream of the phase compensator; and a frequency compensator for applying a compensation to the signal, thereby to compensate for the frequency offset. The compensator is suitable for the exacting conditions of the DVB-S2 standard.05-21-2009
20090196382EQUALIZING STRUCTURE AND EQUALIZING METHOD - An equalizing structure and method for a wireless communication system receiving device, in which two or more transmit signals transmitted in parallel from one or more transmitters are received in received signal vectors representing two or more received data streams, the signals including information modulated onto carrier signals according to a modulation scheme, all possible transmit signals being represented by candidate constellation values in the signal constellation of the modulation scheme. A metric value calculator calculates metric values based on the received signal vectors and the product of channel estimation values with candidate signal vectors, each candidate signal vector including a candidate constellation value for each of the two or more transmit signals. A maximum likelihood detector detects one of the candidate signal vectors having a minimum Euclidean distance to a respective receive signal vector as a most likely transmit signal vector based on the metric values. A soft decision value calculator calculates a soft decision value for the most likely candidate signal vectors based on the candidate signal vectors of at least some of the metric values.08-06-2009
20090041166Method and apparatus to improve information decoding when its characteristics are known a priori - The present invention provides systems and methods for decoding received messages using a priori characteristics of selected message portions. A message which has been encoded in a particular format, such as a tail-biting convolutional coding, is received and decoded by utilizing the a priori information about the message. In one case, static-type receive bits in a portion of the message, such as a Frame Control Header, are used to reduce the number of trellis states at particular stages of the decoding process. A Viterbi-type decoding process may be employed in either a soft or hard decision mode. Reducing the number of trellis states improves the success rate for message decoding and improves receiver throughput. Power consumption may also be reduced.02-12-2009
20100111234SYSTEM FOR SOFT SYMBOL DECODING MIMO LOG-MAP DETECTION - A soft symbol decoder for use in a multiple input multiple output (MIMO) and OFDM (orthogonal frequency division multiplexing) system. The decoder generates soft symbol values for a digital signal that represents a number of source bits. The source bits are transmitted as symbols in corresponding to points in a signaling constellation. Soft metrics are determined by searching for all possible multi-dimensional symbols that could have been transmitted. The method includes transmitting a sample of the multi-dimensional symbol using K transmit antennas. The multi-dimensional symbol is represent-able as a complex, K-dimensional vector x. Each vector component of vector x represents a signal transmitted with one of the K transmit antennas. After transmission through a communication channel, a sample corresponding to the transmitted sample is received. The received sample is represented by a complex, N-dimensional vector y, where N is the number of receive antennas in the MIMO system. After the sample is received, a soft metric L(b05-06-2010
20110200149PREPROCESSING APPARATUS AND METHOD FOR GROUP-BASED DECODING - Provided are a preprocessing apparatus and a method thereof for group-based decoding. The preprocessing apparatus includes a log likelihood ratio (LLR) calculator for calculating LLRs of received signals, a signal sorter for sorting the received signals based on the calculated LLRs; and a grouping unit for grouping the sorted signals.08-18-2011
20080212720Maximum likelihood decoder for pulse position modulation multi-source system - The present invention concerns a sphere decoder for a maximum likelihood receiver intended to receive PPM symbols at M modulation positions from a plurality P of sources. The sphere decoder uses a Schnorr-Euchner type enumeration adapted to classify the points of a multidimensional PPM modulation.09-04-2008
20080212721LOW COMPLEXITY MAXIMUM LIKELIHOOD SEQUENCE DETECTION SYSTEM AND METHODS - A system and method implement low complexity maximum likelihood sequence detection. A decision feedback algorithm computes x(M+D+L−1). Optimality examination is performed for x(M), and state values and values of Markov states along paths from states in x(M) to x1(M+L) are computed.09-04-2008
20100278287List Output Viterbi Deconder with Blockwise ACS and Traceback - A Viterbi decoder for decoding convolution-coded data blocks has a memory region (11-04-2010
20100135438SIGNAL DETECTION METHOD AND RECEIVER - Disclosed is a method of detecting signals at a receiver of a communication system with a multiple input multiple output antenna. With the signal detection method, a square of the distance between a received signal vector and a channel status-considered transmission symbol vector is calculated first, and the square of the distance is then classified into first and second components. The first component is minimized to calculate a plurality of first soft symbol estimates. A solution set of the first component is calculated on the basis of the plurality of first soft symbol estimates. The second component is minimized to calculate a plurality of second soft symbol estimates. A solution set of the second component is calculated on the basis of the plurality of second soft symbol estimates. A final solution set is calculated by doing the sum of the first component solution set and the second component solution.06-03-2010
20110206166METHOD AND DEVICE FOR QUANTIZING LIKELIHOOD QUOTIENTS - The invention relates to a method in signal processing for quantizing likelihood quotients of binary random variables for transmitting between at least two signal processing units. Decision levels and reconstruction levels of a quantization of likelihood quotients are thereby determined by maximizing (08-25-2011
20100150282APPARATUS FOR DECODING CONVOLUTIONAL CODES AND ASSOCIATED METHOD - A decoding device may include a sequential convolutional code decoder, and a parallel convolutional code decoder. The decoding device may further include a controller for selectively processing a convolutionally encoded input signal via at least one of the sequential convolutional code decoder and the parallel convolutional code decoder. The selection of decoder may be based upon a signal-to-noise ratio or the passage of time, for example.06-17-2010
20080273632Estimation of Log-Likelihood Using Constrained Markov-Chain Monte Carlo Simulation - Log likelihood ratios for data bits transmitted in a multi-dimensional signal are estimated using multiple Markov chain Monte Carlo simulations (MCMC). The MCMC simulations can include constraining symbols based on a most-likely symbol to improve the likelihood of finding distances for non-most-likely symbols. The log likelihood ratios can be calculated based on distances of the most-likely symbol and the non-most-likely symbols.11-06-2008
20080285688Method and a Device for Decoding Turbo Codes - A method and a device (11-20-2008
20080292031POWER MANAGEMENT METHOD AND CORRESPONDING DEVICE - A device for receiving a radio frequency signal including consecutive bursts of data, the device includes a demodulating unit (11-27-2008
20080292029Method and Apparatus For Carrier Recovery Using Multiple Sources - A receiver comprises a multiple source phase estimator. The latter comprises a pilot-phase estimator, a data-driven average phase estimator, a selector and a common interpolation controller. The selector selects either the pilot-phase estimator or the data-driven average phase estimator as the source of determined phase estimates at particular times. At other times, the common interpolation controller provides interpolated phase estimates as a function of a linear interpolation based on a respective determined phase estimate.11-27-2008
20080292030APPARATUS AND METHOD FOR DECODING SPACE-TIME BLOCK CODED (STBC) SIGNAL - Apparatus and method for decoding a Space-Time Block Coded (STBC) signal. The decoding apparatus includes a channel estimator for estimating a real equivalent channel based on a coded signal; a channel converter for decomposing the real equivalent channel to a unit matrix and a subchannel; a receive signal converter for converting the coded signal to a real equivalent receive signal and converting the real equivalent receive signal to a converted receive signal based on the unit matrix; and a detector for detecting an estimate of a transmit signal by performing a maximum likelihood decoding using the converted receive signal and the subchannel. Since the transmit signal candidates are independent of each other, the complexity of the maximum likelihood decoding can be decreased. With the lowered complexity of the receiver, the power consumption for the decoding can be reduced and the high-speed data can be transmitted more easily in the actual mobile communication environment.11-27-2008
20110007852RECEIVING APPARATUS AND METHOD - Disclosed is a MIMO receiving apparatus in which a residual interference calculation unit (01-13-2011
20080298513Adaptive Sliding Block Viterbi Decoder - An adaptive sliding block Viterbi decoder (ASBVD) includes forward and backward Viterbi processors, a state estimator and a control unit. The processors generate metrics of states and of transitions between the states associated with an encoder, based on encoded input information symbols received via a communications channel. Each processor includes a plurality of buffers for storing information symbols so that a number of the encoded input information symbols can be concurrently decoded. The state estimator estimates a current state of a code trellis based on the generated metrics, and the processors decode the stored information symbols based on the estimated current state. The control unit adapts the number of encoded input information symbols to be concurrently decoded based on a condition of the communications channel, and selectively controls the number of buffers that are enabled in accordance with the number of encoded input information symbols to be concurrently decoded.12-04-2008
20130216006LOW-LATENCY VITERBI SURVIVOR MEMORY ARCHITECTURE AND METHOD USING REGISTER EXCHANGE, TRACE-BACK, AND TRACE-FORWARD - In various aspects, the disclosure describes systems and methods for decoding of convolutionally encoded signals representing, for example, telecommunications signals such as command or content signals used in digital telecommunications. In various embodiments such aspects of the disclosure provide systems and methods for improving the efficiency, speed, and power consumption of such processes by providing architectures and methods for processing various parts of the encoded data records in parallel, using multiple and optionally specially-designed, dedicated memory registers and multiplexers.08-22-2013
20090052595Method of evaluating a readout signal, and optical disc apparatus - A method and optical disc apparatus for evaluating a quality of a read signal adapted to the PRML method by evaluating a binary code decoded from the read signal obtained by a head, in which an error bit sequence having one bit edge shift from the binary code is generated, a Euclidian distance is calculated on both a correct bit sequence and the error bit sequence with respect to a predetermined target signal level, assuming that the binary code is the correct bit sequence, a Euclidian distance difference between the Euclidian distance on the correct bit sequence and the Euclidian distance on the error bit sequence is calculated, an average Euclidian distance from the target signal level is calculated, a normalized sequence error is calculated, the binary code is evaluated using the normalized sequence error.02-26-2009
20080240304APPARATUS AND METHOD FOR INTERFERENCE CANCELLATION IN A BROADBAND WIRELESS COMMUNICATION SYSTEM - An apparatus and a method for interference cancellation in a broadband wireless communication system are provided. A receiving apparatus includes an estimator, a channel compensator, and a demodulator. The estimator estimates channels of a desired signal and at least one interference signal, estimates noise, calculates a mean interference power of each interference signal, and calculates a mean noise power. The channel compensator channel-compensates burst data. The demodulator calculates a noise variance value by adding the mean noise power to the at least one mean interference power and creates Log Likelihood Ratio (LLR) by demodulating the channel-compensated data.10-02-2008
20080240305Message Decoding With Apriori Information and Soft Combining - A method and arrangement for improving channel decoding performance in a radio receiver. Data bits from previously decoded messages are analyzed to provide a priori information to a channel decoder which is decoding a currently received message of the same type. The invention may analyze both the header and data fields of the previously decoded message frames to detect fields that are unchanging or rarely changing from one frame to the next. Probabilistic knowledge (a) of the bits in these unchanging or rarely changing fields is then used to improve the decoding performance for the current message. If a message cannot be successfully decoded, soft values of the bits are stored and then soft-combined with selected bits in the next message received prior to decoding. The invention is applicable to any type of message that has data components that are repeated with varying degrees of probability in successive transmissions.10-02-2008
20090135965Flexible rate matching - Flexible rate matching. No constraints or restrictions are placed on a sending communication device when effectuating rate matching. The receiving communication device is able to accommodate received transmissions of essentially any size (e.g., up to an entire turbo codeword that includes all systematic bits and all parity bits). The receiving communication device employs a relatively small-sized memory to ensure a lower cost, smaller sized communication device (e.g., handset or user equipment such as a personal wireless communication device). Moreover, incremental redundancy is achieved in which successive transmissions need not include repeated information therein (e.g., a second transmission need not include any repeated information from a first transmission). Only when reaching an end of a block of bits or codeword to be transmitted, and when wrap around at the end of such block of bits or codeword occurs, would any repeat of bits be incurred within a later transmission.05-28-2009
20090190697DECODING TECHNIQUES FOR MULTI-ANTENNA SYSTEMS - In one embodiment, a wireless device for a wireless data communication system including the wireless device and a base station. The base station includes a plurality of first groups and a signal-processing unit. Each first group includes a receiver and at least one antenna connected to the receiver. The signal-processing unit includes memory and a processor adapted to process signals received by the first groups using a Maximum Likelihood Detection (MLD) method. The wireless device includes a plurality of second groups, each second group adapted to transmit a wireless signal to at least one first group via a corresponding communication channel. Each second group further includes a transmitter and at least one antenna connected to the transmitter. The signal-processing unit is adapted to store, in the memory, information corresponding to one or more transfer functions, each transfer function corresponding to transmission of a wireless signal from an antenna of the second groups to an antenna of the first groups. The transmitters and receivers are adapted to operate at essentially the same frequency or frequency band. Two or more of the communication channels are generated simultaneously. Each transmitter is adapted to modulate an information signal on a radio-frequency signal according to a Quadrature Amplitude Modulation (QAM) method to transmit QAM symbols. Each receiver is adapted to demodulate information signals from a received radio-frequency signal according to the QAM method.07-30-2009
20100142656APPARATUS AND METHOD FOR SIGNAL DETECTION USING LOG LIKELIHOOD RATIO - A method for signal detection using a log likelihood ratio in a multi-input multi-output communication system includes reconfiguring the signals received through the reception antennas on the basis of channel characteristics and acquiring candidate groups for each transmission symbol by acquiring a signal constellation of one quadrant with respect to signals generatable for each transmission symbol and signal constellations for the remaining quadrants on the basis of the reconfigured signals.06-10-2010
20090168926METHODS, APPARATUS, AND SYSTEMS FOR DETERMINING 1T PATH EQUIVALENCY INFORMATION IN AN nT IMPLEMENTATION OF A VITERBI DECODER - Methods, apparatus, and systems for generating bit-wise path equivalency information corresponding to 1T decision nodes in a soft output Viterbi algorithm (“SOVA”) decoder operating with an nT clock signal. An add, compare, select circuit (ACS) of the SOVA generates decision data for decision nodes 1T through nT responsive to each nT clock signal pulse. The decision data is applied to corresponding 1T through nT path equivalency detector circuits to generate 1T through nT path equivalency information for generation of soft output signals corresponding to the 1T through nT decision data.07-02-2009
20090161799DECODING COMMUNICATION SIGNALS - A method includes identifying a soft decision from a constellation point of a modulated signal. The identification is based upon a logical combination of data representing a first and second portion of the constellation point, data representing an arrangement of the first and second portions of the constellation point, and data representing a scrambling of the first and second portions of the constellation point.06-25-2009
20090185643Methods and Apparatus for Map Detection with Reduced Complexity - Methods and apparatus are provided for high-speed, low-power, high-performance channel detection. A soft output channel detector is provided that operates at a rate of 1/N and detects N bits per 1/N-rate clock cycle. The channel detector comprises a plurality, D, of MAP detectors operating in parallel, wherein each of the MAP detectors generates N/D log-likelihood ratio values per 1/N-rate clock cycle and wherein at least one of the plurality of MAP detectors constrains each of the bits. The log-likelihood ratio values can be merged to form an output sequence. A single MAP detector is also provided that comprises a forward detector for calculating forward state metrics; a backward detector for calculating backward state metrics; and a current branch detector for calculating a current branch metric, wherein at least two of the forward detector, the backward detector and the current branch detector employ different trellis structures.07-23-2009
20090022250Conditionally Input Saturated Viterbi Detector - Various embodiments of the present invention provide systems and methods for decoding encoded information. For example, a decoder including a branch metric calculator that conditionally calculates a branch metric based on either an actual input or a saturated input. Such a branch metric calculator is operable to receive an actual input, and to compare the actual input with an expected range. At times, the aforementioned comparison yields a comparison result indicating that the actual input is outside of the expected range. A first branch metric associated with a first branch is calculated. Where the first branch has an expected value representing a boundary of the expected range, calculating the first branch metric is done using the saturated input. Further, a second branch metric associated with a second branch is calculated. Where the second branch has an expected value representing something other than a boundary of the expected range, calculating the second branch metric is done using the actual input.01-22-2009
20110142181COMMUNICATION SYSTEM - A communication system having a program of machine-readable instructions for solving an ILS problem, tangibly embodied on a computer readable memory and executable by a digital data processor, to perform actions directed toward outputting a set of a-posteriori probability vectors.06-16-2011
20090052594ROBUST JOINT ERASURE MARKING VITERBI ALGORITHM DECODER - Joint erasure marking Viterbi algorithm (JEVA), decoder schemes, methods, and systems are provided which perform robust trellis decoder techniques. The provided JEVA decoding schemes are shown to be maximum likelihood decoding schemes that find the most likely transmitted code sequence with a set of symbol erasures, without knowledge of the impulsive noise probability distribution function, and can be implemented sequentially such that they are well suited for dynamically changing impulsive noise channels. In addition, the disclosed details enable various refinements and modifications according to decoder and system design considerations. For example, truncated JEVA is provided for continuous transmission and long frame applications.02-26-2009
20110142180APPARATUS FOR RECEIVING SIGNALS IN A COMMUNICATION SYSTEM BASED ON MULTICARRIER TRANSMISSION AND METHOD FOR INTERFERENCE CANCELLATION - Provided are an apparatus and method of receiving signals in a communication system based on multicarrier transmission. The receiving apparatus cancels Inter-Symbol Interference (ISI) in a time domain from a received signal having a delay time above a guard interval, and cancels Inter-Carrier Interference (ICI) in a frequency domain from the received signal.06-16-2011
20110142179METHOD AND APPARATUS FOR GENERATING SOFT-DECISION INFORMATION BASED ON NON-GAUSSIAN CHANNEL IN WIRELESS COMMUNICATION SYSTEM - A method and apparatus for generating soft-decision information based on non-Gaussian channel in a wireless communication system is provided. A receiver receives a decision variable, models an interference or noise distribution in the decision variable as a non-Gaussian probability density function and estimates a number of parameters of the non-Gaussian probability density function, and determines a log likelihood ratio (LLR) of the decision variable using the results of the estimation, wherein the parameters of the non-Gaussian probability density function comprise a shape parameter for determining the shape of the non-Gaussian probability density function.06-16-2011
20110228883COMBINING DECISION METRICS FOR DECODING BASED ON PAYLOAD DIFFERENCE - Decision metrics used to decode wireless communication payloads are combined for successive frames to improve decoding of the later received frames. A bitwise payload difference between successive frames is encoded in the same manner the payloads are encoded. Decision metrics determined for the earlier received frame are combined with the encoded payload difference to generate adjusted decision metrics. The adjusted decision metrics are combined with decision metrics determined for the later received frame. The combined decision metrics are decoded to generate a payload for the later received frame. If the decoding is not successful the combined decision metrics are carried forward and the process is repeated based on the payload difference between the following frames.09-22-2011
20130121447Parallel Execution of Trellis-Based Methods - A receiver system and method for recovering information from a symbol data sequence Y. The symbol data sequence Y corresponds to a symbol data sequence X that is transmitted onto the channel by a transmitter. The symbol data sequence X is generated by the transmitter based on associated information bits. At the receiver, a set of two or more processors operate in parallel on two or more overlapping subsequences of the symbol data sequence Y, where each of the two or more overlapping subsequences of the symbol data sequence Y corresponds to a respective portion of a trellis. The trellis describes redundancy in the symbol data sequence Y. The action of operating in parallel generates soft estimates for the associated information bits. The soft estimates are useable to form a receive message corresponding to the associated information bits.05-16-2013
20080317173METHOD AND SYSTEM FOR RATE>1 SFBC/STBC USING HYBRID MAXIMUM LIKELIHOOD (ML)/MINIMUM MEAN SQUARED ERROR (MMSE) ESTIMATION - Aspects of a method and system for rate>1 SFBC and/or STBC using hybrid maximum likelihood (ML)/minimum mean squared error (MMSE) estimation are presented. Aspects of an exemplary system may enable rate 5/4 coding in diversity communication systems that utilize SFBC and/or STBC. A transmitting station may utilize SFBC or STBC to generate and/or concurrently transmit a plurality of signals symbols, which are encoded to enable rate 5/4 transmission. A receiving station may decode rate 5/4 encoded signals utilizing a hybrid decoding method. The hybrid decoding method may result from application of a plurality of decoding methods when decoding the rate 5/4 encoded signals. In an exemplary aspect of the invention, the hybrid method may utilize ML/MMSE estimation in combination with zero forcing (ZF) interference cancellation. The combination may be referred to as hybrid ML/MMSE estimation.12-25-2008
20090103664DIGITAL BROADCAST TRANSMISSION AND RECEIVING SYSTEM HAVING AN IMPROVED RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcast transmitter comprising: a randomizer to receive a data stream of which stuff bytes are inserted into a specified position and to randomize the received data stream; a stuff-byte exchange unit to generate known data having a predefined pattern and to insert the known data into the specified position of the data stream into which the stuff bytes are inserted; an encoder to encode the data stream output from the stuff-byte exchange unit for an error correction; and a modulator and RF converter to modulate the encoded data stream, RF-convert the modulated data stream and transmit the RF-converted data.04-23-2009
20090245433Systems and Methods for Approximating Log Likelihood Ratios in a Communication System - Systems and methods for computing log likelihood ratios in a communication system are described. A demodulated symbol may be received. A set of scalars may be determined based on a modulation order, a signal-to-noise ratio for the symbol, and a bit of the symbol. At least one log likelihood ratio for the bit may be approximated using a piecewise linear process based on the scalars and the symbol.10-01-2009
20090220034LAYERED RECEIVER STRUCTURE - A method and apparatus is disclosed herein for receiving a layered transmission of data in a wireless communication system using an iterative layered receiver structure. In one embodiment, a receiver comprises a layer 1 demapper and a layer 1 outer decoder to iteratively decode layer 1 of the coded data, and a layer 2 demapper and a layer 2 outer decoder to iteratively decode layer 2 of the coded data, wherein the layer 1 demapper generates a layer 1 set of likelihood estimates only for bits of the first information layer of received signal data in each of one or more iterations and where the layer 1 set of likelihood estimates are generated in response to the received signal data and, in at least one of the one or more iterations, also in response to one or more of the likelihood estimates generated by the outer decoders in decoding schemes for at least one layer other than layer 1; the layer 1 outer decoder updates the layer 1 likelihood estimates from the layer 1 demapper and feedbacks the updated layer 1 likelihood estimates to the layer 1 demapper for use in another iteration of iterative decoding; the layer 2 demapper generates a layer 2 set of likelihood estimates only for information bits of the layer 2 of received signal data in each of one or more iterations, and where the layer 2 set of likelihood estimates are generated in response to the received signal data and, in at least one of the one or more iterations, also in response to one or more of the likelihood estimates generated by the outer decoders in decoding schemes for at least one layer other than layer 2; and the layer 2 outer decoder updates the layer 2 likelihood estimates from the layer 2 demapper and feedbacks the updated layer 2 likelihood estimates to the layer 2 demapper for use in another iteration of iterative decoding.09-03-2009
20090220033METHOD AND APPARATUS FOR BIT DEMULTIPLEXING IN A WIRELESS COMMUNICATION SYSTEMS - A method and apparatus of bit demultiplexing for a rate 1/3 convolutional encoder in a wireless communication system, the method comprising, receiving bits from the rate-1/3 convolutional encoder, demultiplexing the received bits by distributing the bits sequentially into 3 sequences denoted as V09-03-2009
20090052591GMSK-receiver with interference cancellation - A GMSK receiver with interference cancellation includes a linear equalizer configured to be coupled to a received signal from a first antenna and to provide first soft bits, an adaptive estimator, e.g., adaptive MLSE coupled to the first soft bits and configured to provide second soft bits; a quality assessor coupled to the first soft bits and configured to provide a quality indication; and a switching function coupled to the linear equalizer and the adaptive MLSE and controlled in accordance with the quality indication to provide output soft bits corresponding to at least one of the first soft bits and the second soft bits. The GMSK receiver can be extended to multiple antennas and corresponding methods for interference cancellation in a GMSK signal are discussed.02-26-2009
20090245434APPARATUS AND METHODS FOR TILE AND ASSIGNMENT PROCESSING - Disclosed are methods and apparatus for synchronizing tile processing and assignment processing in a communication device. In particular, the methods and apparatus utilize a tile processing scorecard with a number of assertable bits corresponding to a number of tiles to be tile processed. As each tile is tile processed, the scorecard or bit indicators are asserted to indicate that the tile has been processed. Assignment jobs, which involve codewords having information from symbols in multiple tiles are processed after all of the pertinent tiles are tile processed. The scorecard information is accessible for assignment processing to determine which tiles have been processed, thus affording synchronization of tile processing with assignment processing, while maximizing the independence of these two processing operations. Tile processing operations may further use the scorecard information to prioritize or order tile processing in relation to known queued assignment jobs.10-01-2009
20090245435ARCHITECTURE TO HANDLE CONCURRENT MULTIPLE CHANNELS - An apparatus and method for enhanced downlink processing of received channels in a mobile communications system is described, containing a buffer for control data and traffic data, a demapper engine with at least two independently operating demappers for demapping the control and traffic data, a log-likelihood-ratio (LLR) buffer for supporting memory segments accessible by the demapper engine, a decoder engine containing decoders, each of the decoders operating on data from selected memory segment(s) of the LLR buffer, and an arbitrator providing control of at least one of the demapper engine, LLR buffer, and decoder engine. At least one of the decoders is suited for decoding control data and another one of the decoders is suited for decoding traffic data. By partitioning the decoding as such, an increase in downlink throughput can be obtained.10-01-2009
20120195399APPARATUS, METHOD AND RECEIVING TERMINAL FOR LDPC DECODING - An apparatus and a method for Low-density parity-check (LDPC) decoding are provided. The apparatus for LDPC decoding comprises a post effective noise variance estimation unit for estimating a post effective noise variance based on a preamble in a received signal, an LLR calculation unit for calculating an LLR based on the estimated post effective noise variance, and a decoding unit for performing LDPC decoding based on the calculated LLR. The post effective noise variance estimation unit comprises a channel frequency response estimation unit for estimating a channel frequency response based on the preamble in the received signal, a noise variance estimation unit for estimating a noise variance based on the preamble in the received signal, and a post effective noise variance calculation unit for calculating the post effective noise variance based on the channel frequency response and the noise variance.08-02-2012
20090129518DIGITAL BROADCASTING TRANSMISSION/RECEPTION SYSTEM UTILIZING SRS AND TRS CODE TO IMPROVE RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcasting transmission and/or reception system having an improved reception performance and a signal-processing method thereof. A digital broadcasting transmitter comprises a TRS encoder for to TRS-encode an MPEG-2 transmission stream having null data for inserting an SRS data and a TRS parity at predetermined positions, randomizer to input and randomize data stream from the TRS encoder, a SRS exchanger to replace the null data for inserting the SRS data to the known data, and an encoder for encoding a data streams to which the Known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization and further uses the TRS parity for correcting error of the received signal, so that the digital broadcasting reception performance can be improved at poor multipath channels.05-21-2009
20100183101TECHNIQUES FOR INCREASING DECODING RELIABILITY IN AN ADAPTIVE MINIMUM MEAN SQUARED ERROR WITH SUCCESSIVE INTERFERENCE CANCELLATION (MMSE/SIC) DECODER - A technique for increasing decoding reliability in an adaptive minimum mean squared error with successive interference cancellation (MMSE/SIC) decoder in a channel-coded multiple-input multiple-output (MIMO) communication system. A code block selector evaluates reliability metrics and determines whether the reliability metric of the decoded symbols of a particular indexed code block of a first code word satisfies a quality threshold. Depending upon this determination, a composite second code word is formed at each indexed code block using a previously calculated MMSE-LLR output of a second code word or a SIC-LLR output using the indexed symbols of a first code word. Composite second code word is decoded with increased accuracy.07-22-2010
20090052592Method and Arrangement for Recovering a Binary DC-Free Code From a Frequency Modulated Signal - The invention is related to a method and an arrangement for recovering a binary DC-free code from a frequency-modulated signal, without any analog signal demodulation of the frequency-modulated signal. The invention relates more particularly to an ATIP bi-phase channel bit and timing recovery in a deteriorated wobble channel as e.g. required for high speed recording on optical storage media. The arrangement comprises a digital phase lock loop and a phase detector uses a phase trellis and a maximum likelihood detection is applied to the phase trellis for providing a bi-phase channel bit signal and a bi-phase clock signal, which is in time with the sampling point for the bi-phase channel bit signal for recovering said binary code. The invention is also applicable for further data transmission systems based on frequency modulation as e.g. modem or wireless data communication systems.02-26-2009
20100189201Method and System for Decoding SACCH Control Channels in GSM-Based Systems with Partial Combining - Methods and systems for signal processing are disclosed herein and may include storing bit sequences for a plurality of previously received control channels. A bit sequence for a currently received control channel may be correlated with at least one of the bit sequences for the plurality of previously received control channels. One of the bit sequences for the plurality of previously received control channels may be selected to represent the bit sequence for the currently received control channel, based on the correlating. The selected one of the stored bit sequences for the plurality of previously received control channels may include a maximum correlation. The maximum correlation may be higher than a threshold value. The bit sequence for the currently received control channel may include slow associated control channel information. The bit sequence for the currently received control channel may be decoded using Viterbi decoder and/or fire code decoder.07-29-2010
20100189199Log-likelihood ratio algorithm for use in reducing co-channel interference in wireless communication systems - In one embodiment, an apparatus includes a receiver configured to receive a transmission from a wireless communication device, the transmission associated with resource units, a detector configured to generate log-likelihood ratio data from the received transmission, and a controller configured to calculate noise and interference for each of the resource units and modify the generated log-likelihood ratio data based on the calculated noise and interference.07-29-2010
20100183102RADIO COMMUNICATION DEVICE AND RADIO COMMUNICATION METHOD - A radio receiver which performs iterative decoding of a received signal is provided. The radio receiver comprises: a receiving unit receiving a signal on a symbol-by-symbol basis; a demodulation unit (07-22-2010
20090116590APPARATUS AND METHOD FOR DETECTING SIGNAL IN MULTI-ANTENNA SYSTEM - A method and an apparatus for detecting a signal in a multi-antenna system using a spatial multiplexing are provided. The apparatus includes at least one antenna for receiving a signal, a channel estimator for estimating a channel using the received signal, a detector for calculating multiplication values commonly used to determine a Euclidean distance using the receive signal and channel information and for detecting a transmitted signal by calculating Euclidean distances of one or more candidate symbols using the receive signal and the determined multiplication values and a decoder for demodulating and decoding the detected signal. Hence, the computational complexity of the signal detection can be mitigated.05-07-2009
20090116589Performance-based link adaptation techniques - A multiple carrier wireless communications system includes a channel predictor, a performance predictor, and a link adapter. The channel predictor is configured to predict channel state information for a next packet based on channel state information for the current packet. The performance predictor includes an uncoded performance predictor configured to predict system performance at an input of a decoder based on a modulation type and the predicted channel state information for the next packet, and a decoder input-output performance mapper configured to determine a required coding rate based on a requested system performance and the predicted system performance at the input of the decoder. The link adapter includes a modulation and coding scheme (MCS) updater configured to identify a MCS based on the required coding rate.05-07-2009
20100189200DECODING DEVICE AND METHOD FOR MIMO SYSTEM - The present invention relates to a decoding device and method for a MIMO system. A linear process is applied to a received signal vector by using a channel matrix estimated from the received signal vector and a poly-diagonalized matrix, and a soft decision value is acquired through a trellis decode by using the linear process result. Since the linear preprocess is performed by using the poly-diagonalized matrix, it is possible to receive a MIMO signal having good packet error rate performance and less complexity. Also, since the tail-biting trellis decoding method is used based on the poly-diagonalized matrix that is generated by poly-diagonalizing the effective channel matrix during the process for eliminating the signal interference, the soft decision value for the symbol can be generated with a simple hardwired device and less operation complexity.07-29-2010
20100150280METHODS, APPARATUS, AND SYSTEMS FOR UPDATING LOGLIKELIHOOD RATIO INFORMATION IN AN nT IMPLEMENTATION OF A VITERBI DECODER - Methods and circuits comprising a reliability measurement unit (RMU) for generating log-likelihood ratio (LLR) values corresponding to 1T for use in a soft output Viterbi algorithm (“SOVA”) decoder. The RMU operates with an nT clock signal. 1T signals generated by an add, compare, select circuit (ACS) of the SOVA generates 1T decision data and a path equivalency detector generates 1T path equivalency information for 1T SOVA decoding and applies the 1T data to the RMU operating with an nT clock frequency (1/n'th that of the 1T clock signal). The nT RMU receives a plurality of 1T inputs on each nT clock signal pulse and generates 1T LLR information for use by the SOVA decoder. Other components of the SOVA may also operate using the nT clock signal pulse or may operate using a 1T clock signal.06-17-2010
20100150281APPARATUS AND METHOD FOR RECEPTION IN MULTI-INPUT MULTI-OUTPUT SYSTEM - Provided are an apparatus and method for reception in a MIMO system. An apparatus for calculating a signal weight, includes: at least two multiplexers configured to receive, a data stream corresponding to a weight inputted and multiplex the received data stream prior to output; a multiplexing control unit configured to control the outputs of the respective multiplexers and provide a clock of a predetermined rate and a clock of a double rate two times higher than the predetermined rate; a first multiplier configured to receive multiplexed data outputted from the respective multiplexers and multiply the multiplexed data; a first storage unit configured to latch the multiplication result of the first multiplier by the double-rate clock prior to output; an adder configured to add the output of the first storage unit and the output of the first multiplier; and a second storage unit configured to latch the addition.06-17-2010
20100158162QR DECOMPOSITION DETECTION DEVICE AND METHOD SUPPORTING INTERFERENCE WHITENING - Disclosed is a QR decomposition device supporting interference whitening. The QR decomposition device supporting interference whitening may calculate a whitening matrix based on an interference channel matrix. The QR decomposition device supporting the interference whitening may simultaneously support interference whitening and detection of a transmission symbol vector through QR decomposition. A vector manufactured during the whitening and a result of the QR decomposition may be used for detecting the transmission symbol vector.06-24-2010
20100266071METHOD AND APPARATUS FOR GENERATING SOFT BIT VALUES IN REDUCED-STATE EQUALIZERS - A demodulator is provided that functions as a reduced-state equalizer and produces reliable soft bit values. According to an embodiment, soft bit values are generated for a sequence of transmitted symbols using a demodulator by updating an M-state trellis managed by the demodulator responsive to a transition from symbol time n−1 to symbol time n, where M is a function of the number of bits per symbol in the sequence of transmitted symbols. Survivor metrics associated with the M states of the trellis are saved each symbol time so that the demodulator can calculate soft bit values with regard to transitions from symbol time n+D−1 to symbol time n+D. The survivor metrics indicate the probability that each respective state represents the transmitted symbol associated with symbol time n+D−1. The trellis is traced back through to calculate soft bit values for a symbol detected at symbol time n−D based on survivor metrics saved for the M states at symbol time n−D.10-21-2010
20120033767SELECTIVE QUANTIZATION OF DECISION METRICS IN WIRELESS COMMUNICATION - A method for quantizing decision metrics (e.g., log likelihood ratios (LLRs)) for reduction of memory requirements in wireless communication is described. The method includes selecting a quantization algorithm. The quantization algorithm may be selected as a function of a characteristic of a decision metric representative of a transport block received over a communication channel, a characteristic of the transport block, or a condition of the communication channel. The method further includes quantizing the decision metric using the selected quantization algorithm to generate at least one quantized decision metric representative of the transport block. The method further includes storing the quantized decision metric and an indicia of the selected quantization algorithm to enable recovery of the decision metric representative of the transport block prior to decoding.02-09-2012
20090074116Iterative decoding - This invention provides an iterative process to maximum a posteriori (MAP) decoding. The iterative process uses an auxiliary function which is defined in terms of a complete data probability distribution. The auxiliary function is derived based on an expectation maximization (EM) algorithm. For a special case of trellis coded modulators, the auxiliary function may be iteratively evaluated by a combination of forward-backward and Viterbi algorithms. The iterative process converges monotonically and thus improves the performance of any decoding algorithm. The MAP decoding minimizes a probability of error. A direct approach to achieve this minimization results in complexity which grows exponentially with T, where T is the size of the input. The iterative process avoids this complexity by converging on the MAP solution through repeated maximization of the auxiliary function.03-19-2009
20090074115Soft Bit Viterbi Equalizer Using Partially Collapsed Metrics - A system and method of decoding data are provided. A particular method includes determining a first partially collapsed metric value for each bit in a symbol transition, where each first partially collapsed metric value is a cumulative metric of starting in a first state and ending in a second state in L transitions. The first partially collapsed metric value is equal to the cumulative metric value for each of the states plus first minimum sum of branch metric values.03-19-2009
20090074113Wireless receiver supporting multiple algorithms and algorithm selection method thereof - Provided is a method of selecting an algorithm in a wireless receiver which supports a plurality of algorithms, more particularly, a method of selecting a suitable algorithm which is adaptive to changes in channel environment and satisfies requirements of applications, using information which is available in the wireless receiver. The algorithm selection method includes: calculating a measure value for selecting an algorithm on the basis of information obtained from the wireless receiver; comparing the measure value with at least one threshold value, and selecting an algorithm that is to be applied to a received packet, from among the plurality of algorithms, according to the result of the comparison; and decoding the received packet using the selected algorithm, wherein the at least one threshold value is adaptively updated on the basis of the information obtained from the wireless receiver.03-19-2009
20100266073ACCELERATED TURBO TRANSCEIVER AND METHOD FOR MIMO SYSTEM - A reception apparatus including: a detection unit detecting extrinsic information based on a tentative symbol decision signal, a channel estimation signal, a noise variance estimation signal, and a received signal that are obtained from a previous iteration process; a Cyclic Redundancy Check (CRC) aided channel decoding unit outputting an interleaved bit or a posteriori information thereof based on the extrinsic information; a tentative symbol decision unit determining a tentative transmission symbol based on an output of the CRC aided channel decoding unit; a channel estimation unit estimating a channel based on an output of the tentative symbol decision unit; and a noise variance estimation unit estimating a noise variance based on the output of the tentative symbol decision unit and an output of the channel estimation unit is provided.10-21-2010
20100266072METHOD AND APPARATUS FOR RECEIVING SIGNAL FOR MIMO SYSTEM - Provided is a method and apparatus for receiving a signal for a MIMO system. The receiving apparatus includes: a QR decomposer for calculating a unitary matrix Q, an upper triangle matrix R, and a vector size for a received signal; a multiple dimension detector for calculating a first LLR for an output of the QR decomposer through multiple dimension detection; an inverse matrix and weight calculator for calculating an inverse matrix for the upper triangle matrix R and a weight; an interference remover for regenerating a symbol for a demodulated data stream using the fist LLR and removing interference from an output vector of the QR decomposer using the regenerated symbol; and a weight zero forcing unit for performing zero forcing on the interference removed output vector from the interference remover using the inverse matrix of the upper triangle matrix R and the weight and calculating a second LLR.10-21-2010
20090207948RECEIVING APPARATUS - For each of a plurality of control channels, a likelihood indicated by a state metric of each state at the last point which is obtained at the time of Viterbi decoding is obtained. This Viterbi decoding is not cut off and performed to convolutionally coded data of the corresponding control channel. The ranking of the likelihood is obtained as a possibility ranking SM08-20-2009
20090110125MAXIMUM A POSTERIORI PROBABILITY DECODER - A method is provided for performing a MAP probability decoding of a sequence R(n) including N bits of encoded data. The method includes the steps of: (a) generating a sequence r04-30-2009
20090110124Soft decision enhancement - A Viterbi trellis processing technique in which soft decisions and hard decisions are derived from a received signal and the soft decisions are enhanced by being modified using the hard decisions. A log likelihood ratio for a bit of the received signal can be derived by grouping candidate metrics associated with the decision that the bit has a first state, grouping candidate metrics associated with the decision that the bit has a second state, applying respective functions to the groups and calculating the difference of the function values.04-30-2009
20090103662DIGITAL BROADCAST TRANSMISSION AND RECEIVING SYSTEM HAVING AN IMPROVED RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcast transmitter comprising: a randomizer to receive a data stream of which stuff bytes are inserted into a specified position and to randomize the received data stream; a stuff-byte exchange unit to generate known data having a predefined pattern and to insert the known data into the specified position of the data stream into which the stuff bytes are inserted; an encoder to encode the data stream output from the stuff-byte exchange unit for an error correction; and a modulator and RF converter to modulate the encoded data stream, RF-convert the modulated data stream and transmit the RF-converted data.04-23-2009
20100310020DATA RECOVERY SYSTEM AND METHOD THEREOF - A data recovery system and method is disclosed. Said data recovery system comprises a maximum-likelihood detector, a non-maximum likelihood detector, signal-length calculator, a determining unit and a selecting unit. The maximum-likelihood detector transforms a digital signal into a first binary signal. The non-maximum likelihood detector transforms the digital signal into a second binary signal. The signal-length calculator calculates a length of the first binary signal and a length of one previous to the first binary signal. The determining unit generates a selecting signal when the length of the first binary signal and the length of one previous to the first binary signal meet a criterion. The selecting unit coupled to the maximum-likelihood detector and the non-maximum likelihood detector, selectively outputs the first binary signal or the second binary signal based on the selecting signal.12-09-2010
20100310019RFID RECEIVER - RFID data signals from RFID tags may be recovered by determining the probabilities of transitions between data states between a series of a pairs of signal samples using a set of predetermined probabilities related to data, timing, baud rate and/or phase variables affecting the received signal and processing those determined probabilities to determine the sequence of such transitions that has the highest probability of occurrence. A second set of predetermined probabilities related to transitions in the opposite direction may be used to sequence in a reverse direction. The determination of the sequence representing the RFID tag data may be iterated in both directions until further iterations do not change the determined probabilities.12-09-2010
20130136215CHANNEL DECODING METHOD AND TAIL BITING CONVOLUTIONAL DECODER - The disclosure provides a channel decoding method and a tail biting convolutional decoder. The method comprises: the tail biting convolutional decoder performs add-compare-select processing on metric values of 205-30-2013
20100303176METHODS AND APPARATUSES FOR MIMO DETECTION - Methods and apparatuses are provided for MIMO detection. A method may include considering a symbol vector received over MIMO system. The method may further include generating a list comprising a predefined number of candidate transmit symbol vectors based at least in part upon the received symbol vector using a trellis comprising a plurality of nodes that apply distributed list decoding to generate the list, wherein the list of the predefined number of candidate transmit symbol vectors comprises the predefined number of candidate transmit symbol vectors derived from the set of all possible trellis paths as determined based at least in part upon the respective cumulative trellis path weights. Corresponding apparatuses are also provided.12-02-2010
20100303177Doppler frequency estimation system and method - A Doppler frequency estimation system includes a basis projector, a polynomial generator and an extreme value determinator. The basis projector receives and projects multiple channel sampling signals to a set of orthogonal bases to thereby generate multiple channel correlation vectors. The polynomial generator is connected to the basis projector in order to produce a target polynomial based on the channel correlation vectors, an estimated channel-envelope-to-noise-plus-interference power-ratio and a channel-envelope power. The extreme value determinator is connected to the polynomial generator in order to determine an extreme value of the polynomial and output a frequency corresponding to the extreme value as an estimated Doppler frequency.12-02-2010
20110110469APPARATUS OF MAXIMUM LIKELIHOOD SIGNAL DETECTION - An apparatus for maximum likelihood signal detection comprises a reference data unit, a branch metric unit, an add-compare-select unit, a path metric unit and a path memory, and is used for detecting maximum likelihood signal. The reference information unit, the branch metric unit, the add-compare-select unit or the path metric unit can further comprise a multiplexer to removing unnecessary paths according to a control signal. The control signal is adjusted according to channel response, coding constraint or channel memory length.05-12-2011
20100322357METHOD AND APPARATUS FOR ENHANCED CHANNEL ESTIMATION IN WIRELESS COMMUNICATION SYSTEMS - A method and apparatus for channel estimation based on extracting channel information, including noise spectral density, from a received signal, and advantageously exploiting that information for improved channel estimation accuracy. One embodiment is directed to a method of generating channel estimates in a wireless communication receiver, for processing a received communication signal. The method includes generating first channel estimates from a set of pilot observations obtained from the received communication signal, using a first channel estimation process that is not dependent on knowledge of channel statistics. The method further includes estimating channel statistics and a noise variance from the first channel estimates, and generating second channel estimates from the set of pilot observations, the estimated channel statistics, and the estimated noise variance, using a second channel estimation process that is dependent on knowledge of the channel statistics.12-23-2010
20100322359METHOD AND APPARATUS FOR A DATA-DEPENDENT NOISE PREDICTIVE VITERBI - An improved Viterbi detector is disclosed in which each branch metric is calculated based on noise statistics that depend on the signal hypothesis corresponding to the branch. Also disclosed is a method of reducing the complexity of the branch metric calculations by clustering branches corresponding to signals with similar signal-dependent noise statistics. A feature of this architecture is that the branch metrics (and their corresponding square difference operators) are clustered into multiple groups, where all the members of each group draw input from a single, shared noise predictive filter corresponding to the group. In recording technologies as practiced today, physical imperfections in the representation of recorded user data in the recording medium itself are becoming the dominate source of noise in the read back data. This noise is highly dependent on what was (intended to be) written in the medium. The disclosed Viterbi detector exploits this statistical dependence of the noise on the signal.12-23-2010
20100322358Parallel Execution of Trellis-Based Methods - A receiver system and method for recovering information from a symbol data sequence Y. The symbol data sequence Y corresponds to a symbol data sequence X that is transmitted onto the channel by a transmitter. The symbol data sequence X is generated by the transmitter based on associated information bits. At the receiver, a set of two or more processors operate in parallel on two or more overlapping subsequences of the symbol data sequence Y, where each of the two or more overlapping subsequences of the symbol data sequence Y corresponds to a respective portion of a trellis. The trellis describes redundancy in the symbol data sequence Y. The action of operating in parallel generates soft estimates for the associated information bits. The soft estimates are useable to form a receive message corresponding to the associated information bits.12-23-2010
20110007853Method For Selecting Transmitting Points In A Communication System - The present invention provides a method for identifying a specific number of communicating points having relatively smallest accumulated path values from a plurality of transmitting points for a receiving point in a communication system. The method includes steps of: (a) defining a first coordination of each of the plurality of transmitting points and the receiving point on a complex plane; (b) transferring the first coordination of the receiving point to a second coordination thereof, in which the second coordination of the receiving point is near an origin of the complex plane; and (c) identifying the specific number of transmitting points having relatively smallest accumulated path values based on the second coordination of the receiving point.01-13-2011
20090067554High throughput and low latency map decoder - In digital communication systems forward error correction coding techniques are typically used to improve the bit error rate performance. The receiver of the digital communication systems employs a decoding apparatus which may use Maximum A posteriori Probability (MAP) algorithm and its variations such as Logarithmic-MAP (Log-MAP), Maximum-Logarithmic-MAP (Max-Log-MAP). MAP decoding apparatus is commonly used as a key component in of decoder for error correcting codes such as convolutional codes and turbo codes. The MAP decoding apparatus computes likelihood estimates as the output. The present invention performs faster MAP decoding by computing likelihood estimates in parallel.03-12-2009
20090067553JOINT SYMBOL, AMPLITUDE, AND RATE ESTIMATOR - The system in one embodiment relates to tightly integrating parameter estimation, symbol hypothesis testing, decoding, and rate identification. The present invention provides Turbo-decoding for joint signal demodulation based on an iterative decoding solution that exploits error correction codes. The system iteratively couples an initial amplitude estimator, a symbol estimator, a bank of decoders, and a joint amplitude estimator to produce the symbol estimates.03-12-2009
20090067552Method for the Detection of Symbols and Associated Receiver - Method for the detection of symbols by a receiver, each symbol (S03-12-2009
20110129043METHOD AND APPARATUS FOR DETECTING A PLURALITY OF SYMBOL BLOCKS USING A DECODER - Teachings presented herein offer improved symbol block detection by including a decoder unit in a demodulation system. Utilizing a decoder unit in a demodulation system can significantly enhance symbol block detection because the decoder can produce bit likelihood values (soft bit values), and these bit likelihood values can be used to construct a set of candidate symbol values. Advantageously, this set of candidate symbol values is more likely to contain the actually transmitted symbol(s) than if the decoder unit was not used in the demodulation system.06-02-2011
20110019781DEVICE AND METHOD FOR CALCULATING BACKWARD STATE METRICS OF A TRELLIS - A method for calculating backward state metrics of a trellis, the method includes: performing a radix-K calculation of backward state matrices of multiple states of at least one time instance of a trellis; and performing a radix-J calculation of backward state matrices of multiple states of at least one other time instance of the trellis; wherein K differs from J.01-27-2011
20110026647SOFT BIT VALUE GENERATION IN A SEQUENCE ESTIMATOR - Teachings presented herein offer reduced computational complexity for symbol sequence estimation, and also provide for the generation of soft bit values representing the reliability of that estimation. A demodulator is configured to generate these soft bit values by identifying a candidate value for each symbol in the sequence which is more likely than at least one other in a defined set of candidate values. Based on the candidate value identified for each symbol, the demodulator forms a reduced set of candidate values for the symbol by selecting as many additional candidate values from the defined set as are needed to have complementary bit values for each bit value in that identified candidate value. The demodulator calculates soft bit values for the symbol sequence based on a sequence estimation process whose state space for each symbol is constrained to the corresponding reduced set.02-03-2011
20090034664MAXIMUM LIKELIHOOD DECODING METHOD AND RECEIVER - Provided is a maximum likelihood decoding method that includes the steps of; firstly arranging channel impulse responses corresponding to the received signals in a plurality of different orders; secondly specifying the same number of parts as the plurality of different orders in which the channel impulse responses are arranged, so that the received signals are placed in each of the parts; thirdly generating channel matrices each having the channel impulse responses as matrix elements, by using the channel impulse responses arranged in the plurality of different orders, obtaining triangular matrices by applying QR decomposition to the generated channel matrices, and determining at least one combination candidate for each of the parts of the plurality of transmission signals by using the obtained triangular matrices; and fourthly selecting the combination candidates so that a Euclidean distance between the combination candidates determined in the third step is shortest.02-05-2009
20090034661COORDINATE-ASCENT METHOD FOR LINEAR PROGRAMMING DECODING - A decoder is operable to decode data transmitted on a noisy communication channel. The decoder includes a memory storing bits of encoded data received over the communication channel. The decoder also includes a processor estimating a transmitted codeword from the received bits. The processor is operable to determine a linear program (LP) for decoding the received data, wherein the linear program includes a cost function. A solution to the LP is calculated using a coordinate-ascent method that varies multiple variables associated with the cost function in one iteration. A transmitted codeword is estimated from the received encoded data using the solution to the LP.02-05-2009
20090213967POWER-SAVING METHOD FOR VITERBI DECODER AND BIT PROCESSING CIRCUIT OF WIRELESS RECEIVER - A power-saving method for Viterbi decoder and bit processing circuit of wireless receiver is provided. In response to various computational load of bit processing circuit and/or Viterbi decoder of a wireless receiver, the method is used for adjusting duty cycle of the bit processing circuit and/or the Viterbi decoder so as to save power in addition, in response to various data rates of the wireless receiver, the Viterbi decoder and the bit processing circuit are provided with power based on various duty cycles of related time pulse signals, thereby preventing the Viterbi decoder and/or the bit processing circuit from consuming power while being idle (during time segments of idle operation), so as to reduce power consumption.08-27-2009
20090213965MIMO MULTIPLEXING COMMUNICATION SYSTEM AND A SIGNAL SEPARATION METHOD - A disclosed receiver in a MIMO multiplexing communication system, in which plural signals are simultaneously transmitted from plural transmitting antenna branches using the same frequency, and the transmitted signals are retrieved by receiving signals at plural receiving antennas, separating the received signals and searching for proper symbol metrics for each branch, comprises a QR decomposer for QR decomposing the received signals to orthogonalize the transmitted signals; a symbol replica candidate ranking unit for subtracting surviving symbol replica candidates from the QR decomposed received signals to get remaining received signals and rank the remaining signals in the increasing order of expected branch metrics of the remaining received signals; a symbol replica candidate selector for selecting symbol replica candidates in the ranked order; a branch metric calculator for calculating the branch metrics of the selected symbol replica candidates; and a threshold comparator for comparing the calculated branch metrics with a predetermined threshold; wherein if a calculated branch metric is larger than the predetermined threshold, the branch metric and successive branch metrics are deleted without further searching.08-27-2009
20110129044APPARATUS AND METHOD FOR IMPROVING ERROR CORRECTION CAPABILITY USING STUFFING BYTE - A decoding circuit and method for improving error correction capability using a stuffing byte, in which in the decoding method, an input data packet is decoded. When it is determined that error correction is impossible based on a decoding result, a stuffing byte section is detected in the input data packet. A level value of data in the stuffing byte section is converted into a stuffing byte level value. A data packet having the converted level value is decoded and output. The decoding circuit includes a decoder decoding an input data packet and a control block detecting a stuffing byte section in the input data packet, converting the input data packet, and decoding a converted data packet when the decoder fails in error correction of the input data packet.06-02-2011
20110116581COMMUNICATION SYSTEM, RECEPTION DEVICE, AND COMMUNICATION METHOD - A reception device, which communicates with a transmission device having multiple transmission antennas, includes: at least one reception antenna which receives multiple transmission signals that are transmitted from the multiple transmission antennas by the transmission device; a Fourier transform unit which transforms the signals received by the reception antenna from a time domain into a frequency domain; a propagation channel estimating unit which calculates propagation channel estimation values by estimating propagation channels between the multiple transmission antennas and the reception antenna; and a signal detecting unit which detects the multiple transmission signals by dividing multipaths from the signals that are transformed into the frequency domain by the Fourier transform unit.05-19-2011
20110051859SYMBOL ESTIMATION METHODS AND APPARATUSES - A novel symbol estimation method produces intersymbol interference free symbols by detecting interfering symbols in an interfering channel. A channel estimate is refined for additional improvements. The method can lends itself as a serial or parallel algorithm implementation. The symbol estimation method includes using an initial estimate of received symbols and calculating a refined estimate of the received symbols using a channel estimate. The refined estimate is calculated by performing parameterization of intersymbol interference by symbols other than the symbol being refined and selecting a refined value for the symbol being refined by evaluating an optimization function. Symbol estimates are refined in multiple iterations, until a predetermined iteration termination criterion is met. Parameterization of ISI contribution of other symbols results in reduced computation by reducing total number of unknown variables in the refinement operation.03-03-2011
20110243282Method of Estimating the Symbols of a Digital Signal and Receiver for Implementing Said Method - The invention relates to a method of estimating symbols carried by a digital signal that is received by a receiver over a communication channel (10-06-2011
20110243281PIPELINED DECISION-FEEDBACK UNIT IN A REDUCED-STATE VITERBI DETECTOR WITH LOCAL FEEDBACK - A pipelined decision feedback unit (DFU) is disclosed for use in reduced-state Viterbi detectors with local feedback. The disclosed pipelined decision feedback unit improves the maximum data rate that may be achieved by the reduced state Viterbi detector by the pipelined computation of partial intersymbol interference-based estimates. A pipelined decision feedback unit is thus disclosed that computes a plurality of partial intersymbol interference based estimates, wherein at least one partial intersymbol interference-based estimate is based on a selected partial intersymbol interference-based estimate; and selects the selected partial intersymbol interference-based estimate from among partial intersymbol interference-based estimates for path extensions into a state.10-06-2011
20130156139WIRELESS COMMUNICATION SYSTEM WITH INTERFERENCE FILTERING AND METHOD OF OPERATION THEREOF - A method of operation of a wireless communication system includes: receiving a desired input signal and an interference input signal; activating a first symbol detector for generating a desired log-likelihood ratio from the desired input signal; activating a second symbol detector for generating an interference log-likelihood ratio from the interference input signal; and jointly decoding a decoded bit by iteratively refining the interference log-likelihood ratio for negating the interference input signal and iteratively refining the desired log-likelihood ratio for enhancing the desired input signal.06-20-2013
20120243644RECEPTION APPARATUS AND RECEPTION METHOD - The present invention provides a reception apparatus and reception method that reduce the amount of operation processing, reduce the processing delay and allow high signal separation performance. The reception method of the present invention is characterized by receiving signals including a plurality of codewords transmitted by a plurality of streams and performing maximum likelihood detection-based signal separation in the same codeword in the received signals while performing continuous interference canceller-based signal separation between different codewords.09-27-2012
20100254495TREATING CARRIER-SPECIFIC INTERFERENCE - A receiver for receiving data carried by multiple carriers, the receiver having: estimation means for forming an estimate of the reliability with which data from one or more of the carriers is received as distinct from the reliability with which data from one or more other of the carriers is received; and a decoder arranged for forming an estimate of the symbols represented by the data received from the carriers in dependence on the estimate of reliability.10-07-2010
20090129517DIGITAL BROADCASTING TRANSMISSION/RECEPTION SYSTEM UTILIZING SRS AND TRS CODE TO IMPROVE RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcasting transmission and/or reception system having an improved reception performance and a signal-processing method thereof. A digital broadcasting transmitter comprises a TRS encoder for to TRS-encode an MPEG-2 transmission stream having null data for inserting an SRS data and a TRS parity at predetermined positions, randomizer to input and randomize data stream from the TRS encoder, a SRS exchanger to replace the null data for inserting the SRS data to the known data, and an encoder for encoding a data streams to which the Known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization and further uses the TRS parity for correcting error of the received signal, so that the digital broadcasting reception performance can be improved at poor multipath channels.05-21-2009
20090129516DIGITAL BROADCASTING TRANSMISSION/RECEPTION SYSTEM UTILIZING MULL PACKET AND TRS CODE TO IMPROVE RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcasting transmission and/or reception system having an improved reception performance and a signal-processing method thereof. A digital broadcasting transmitter comprises a TRS encoder for to TRS-encode a MPEG-2 transmission stream having null data for inserting a Known data and a TRS parity at predetermined positions, randomizer to input and randomize data stream from the TRS encoder, a null packet exchanger to replace the null data for inserting the Known data to the known data, and an encoder for encoding a data streams to which the Known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization and further uses the TRS parity for correcting error of the received signal, so that the digital broadcasting reception performance can be improved at poor multipath channels.05-21-2009
20110211660MULTI -CHANNEL SEQUENTIAL VITERBI DECODER - A multi-channel sequential Viterbi decoder includes: an input data buffer, a “Read Single Data Word from Input Data Buffer” signal driver, a processing unit selector, a decoder channel parameters registers unit, a processing unit for the “Reset Path Metrics” command, a processing unit for the “Set Path Metric Value for the Given Path Number” command, a processing unit for the “Get Single Bit from the Path with Given Number” command, a processing unit for the “Process Input Samples” command, a decoding paths and path metrics RAM, a unit for generating current decoder channel base address for the decoding paths and path metrics RAM, a unit for generating cell address for the decoding path and path metric RAM, and a data buffers unit for decoder channels output.09-01-2011
20110085624CODED POLARIZATION-MULTIPLEXED ITERATIVE POLAR MODULATION - Systems and methods for optical communication that use a transmitter/receiver. The systems and methods include receiving a modulated, encoded input stream. Channel memory is reduced using coarse digital backpropagation and other channel impairments are removed using turbo equalization. Symbols are detected in the input stream that conform to a non-uniform, polar constellation having a Gaussian source distribution to produce a stream of encoded data. The stream of encoded data is decoded with one or more low density parity check (LDPC) decoders.04-14-2011
20100054376DIGITAL BROADCAST TRANSMITTER/RECEIVER HAVING AN IMPROVED RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcast transmitting/receiving system, and a signal processing method thereof, includes a randomizer for randomizing a transport stream into a specified position of which stuff bytes are inserted, a stuff-byte exchanger for replacing the stuff bytes included in data output from the randomizer with specified known data, an RS encoder for performing an RS-encoding of data output from the stuff-byte exchanger, an interleaver for interleaving data output from the RS encoder, a trellis encoder for performing a trellis encoding of data output from the interleaver, an RS parity generator for generating a parity by performing an RS encoding of data output from the RS encoder, and outputting the generated parity to the trellis encoder, and a modulator/RF converter for modulating data output from the trellis encoder and performing an RF up-converting of the modulated data. The digital broadcast receiving performance can be improved even in an inferior multi-path channel by detecting the known data from the received signal and using the known data for synchronization and equalization in a digital broadcast receiver.03-04-2010
20100054374Method and Arrangement Relating to Telecommunications - The present invention relates to a method and arrangement for providing a reliability information on information bits (bk) transmitted in a communications network, said bits constituting a transmitted vector (s) comprising elements selected by a transmitter from finite alphabet (S), wherein said transmitted vector is detected from an observed vector received symbols (y) providing a log-likelihood (L). Thus, the approximation is done by defining a number of bit terms having constant size and selecting a subset of bits and marginalizing over a selected part of said subset of bits.03-04-2010
20100067621Feed Forward Detector for Pattern Dependent Noise Prediction - Various embodiments of the present invention provide systems and methods for processing data. As one example, a circuit is disclosed that includes a digital input signal that is provided to a pre-detector that detects an estimated pattern in the digital input signal. In addition, the digital input signal is provided to a summation element that subtracts the estimated pattern from the digital input signal to yield a noise estimate. The noise estimate is provided to a data dependent noise prediction filter that is statically tuned to detect a highly correlated noise pattern, and provides a filtered noise estimate. In some cases, the circuit further includes a post-detector that performs a data detection process on the digital input signal reduced by the filtered noise estimate.03-18-2010
20110075769 METHOD AND APPARATUS FOR GENERATING SOFT BIT VALUES - Teachings presented herein offer reduced and stable computational complexity for symbol block detection using multi-stage assistance, and also provide for the generation of soft bit values. A demodulator generates these soft bit values by forming from a set of candidate symbol combinations, for each group of symbols in a symbol block, a subset of candidate symbol combinations for that group. The demodulator selects from the set the most likely combination, at least one combination that has a complementary bit value for a respective bit value in the most likely combination, and as many of the next most likely combinations not already selected as are needed for the size of the subset to conform to a pre-determined size. The demodulator generates soft bit values by limiting the candidate combinations of symbols considered for a symbol block according to the subsets formed for the groups of symbols in that symbol block.03-31-2011
20110075770RADIO COMMUNICATION APPARATUS AND ERROR CORRECTING METHOD - A radio communication apparatus includes a receiving unit configured to receive signals, an obtaining unit configured to obtain a reference amplitude that depends on a modulation scheme for a received signal received by the receiving unit, and on amplitude fluctuations of the received signal in a propagation path, a demodulating unit configured to demodulate the received signal to obtain an in-phase component and a quadrature component of each received symbol included in the received signal, a calculating unit configured to calculate a likelihood ratio for each of bits mapped to each received symbol using the reference amplitude and the in-phase or quadrature component, and a decoding unit configured to perform error correction decoding on the received signal using the calculated likelihood ratios.03-31-2011
20110069791Parallel Viterbi Decoder with End-State Information Passing - A parallel implementation of the Viterbi decoder becomes more efficient when it employs end-state information passing as disclosed herein. The improved efficiency enables the usage of less area and/or provides the capacity to handle higher data rates within a given heat budget. In at least some embodiments, a decoder chip employs multiple decoders that operate in parallel on a stream of overlapping data blocks, using add-compare-select operations, to obtain a sequence of state metrics representing a most likely path to each state. Each decoder passes information indicative of a selected end-state for a decoder operating on a preceding data block. Each decoder in turn receives, from a decoder operating on a subsequent data block, the information indicative of the selected end-state. The end-state information eliminates any need for post-data processing, thereby abbreviating the decoding process.03-24-2011
20120201334DECODING APPARATUS, DECODING METHOD AND RECORDING MEDIUM - Provided is a decoding apparatus capable of reducing the error rate of the decoding results and also the circuit scale. A computing unit computes a plurality of distances only for a number of code word candidates of code words from demodulated data, the number being smaller than a number of values the code words can express, the code words having a possibility of being transmitted. A decoding unit decodes the code words from the plurality of computed distances. This invention is applicable to a decoding apparatus for Long Term Evolution (LTE).08-09-2012
20100098194Method and Apparatus for Simplified Expected Symbol Value Computation and Interference Cancellation in Communication Signal Processing - A computationally-simplified approach to expected symbol value determination is based on classifying soft bit information corresponding to symbols in a received communication signal as being reliable or unreliable, and computing expected symbol values for the symbols based on the classified soft bit information. Classification can be carried out by “quantizing” the soft bit information to coarsely indicate whether individual symbol bits are known with high or low probability. Using quantized soft bit information greatly simplifies expected symbol value calculation, yet the calculated values still reflect a scaling corresponding to the underlying reliability of the soft bit information. Where the expected symbol values are computed for interfering symbols in a composite signal that also includes desired signals, preserving the underlying reliability knowledge in this manner effectively scales the amount interference cancellation applied to the composite signal in dependence on the reliability to which the interfering signal values are known.04-22-2010
20100054373Method and Apparatus for Low-Complexity Interference Cancellation in Communication Signal Processing - The teachings herein disclose interference cancellation processing that uses hard decision logic for simplified estimation of interfering signals, in combination with soft scaling of the hard decisions for better interference cancellation performance, particularly in low signal quality conditions. In one aspect, the soft scaling may be understood as attenuating the amount of interference cancellation applied by a receiver, in dependence on the dynamically changing received signal quality at the receiver. More attenuation is applied at lower signal quality because the hard decisions are less reliable at lower signal qualities, while less (or no) attenuation is applied at higher signal qualities, reflecting the higher reliability of the hard decisions at higher signal qualities. Signal quality may be quantized into ranges, with a different value of soft scaling factor used for each range, or a soft scaling factor may be calculated for the continuum of measured signal quality.03-04-2010
20110211661Metrics Calculations Utilizing Pre-Stored Values - A trellis processing technique for estimating a transmitted signal from a received signal acquired through a channel achieves a reduced computational structure when implementing a DDFSE-like branch metrics calculation by pre-storing computed values, which can be re-used. The technique involves storing differences between a received symbol and different products, each of which is a product of a channel coefficient corresponding to a least time delay and a different possible transmitted symbol. A summation of products is calculated, each product being a product of a possible transmitted signal symbol and a channel coefficient other than the channel coefficient corresponding to the least time delay, the summation being specific to a branch-start state in a trellis. The summation is combined with different stored differences in a calculation of branch metrics leading to different branch-end states in the trellis.09-01-2011
20090245432Communication system - A communication system receives a signal that is coded using a repetition encoder (10-01-2009
20080247493METHODS, APPARATUS, AND SYSTEMS FOR DETERMINING 1T STATE METRIC DIFFERENCES IN AN nT IMPLEMENTATION OF A VITERBI DECODER - Methods, apparatus, and systems for generating bit-wise reliability information using a soft output Viterbi algorithm (“SOVA”) in an nT Viterbi decoder implementation devoid of 1T metric information. At each nT clock pulse 1T equivalent metric values are determined from the current nT metric information. 1T equivalent metric information is determined as values that sum to the corresponding nT metric information. Subtraction is then used to determine state metric difference information from the 1T equivalent metric values. The state metric difference information may then be used to estimate log likelihood ratio information for use in the SOVA algorithm to determine bit-wise reliability information.10-09-2008
20110150147DEVICE, SYSTEM AND METHOD OF MULTIPLE-INPUT-MULTIPLE-OUTPUT WIRELESS COMMUNICATION - Some demonstrative embodiments include devices, systems and/or methods of multiple-input-multiple-output (MIMO) wireless communication. For example, a device may include a MIMO decoder to decode a MIMO transmission encoded over a constellation scheme including a first number of constellation points; wherein, the decoder is to determine at least one initial constellation point corresponding to at least one received value of the MIMO transmission, and to select a set of selected constellation points including the initial constellation point, wherein the selected set of constellation points includes a second number, lesser than the first number, of the constellation points, and wherein, for each bit-location of the initial constellation point, the selected set of constellation points includes at least one constellation point having, at the bit location, a bit value opposite to the bit value of the initial constellation point at the bit location; and wherein the decoder is to decode the MIMO transmission using the set of selected constellation points. Other embodiments are described and claimed.06-23-2011
20090185644Soft Decision Processing - A method of producing soft decisions for a signal, wherein a model provides an expression for an LLR for the signal, the LLR expression is dependent on noise power in the signal and can be rendered in a form independent of the noise power, wherein the method comprises evaluating the noise power independent expression using values from the signal to produce soft decisions, calculating a weight expressing the noise power affecting a soft decision relative to the noise power affecting at least one other soft decision and applying the weight to its respective soft decision.07-23-2009
20080240303MAP DETECTOR WITH A SINGLE STATE METRIC ENGINE - A MAP detector includes a single state metric engine that performs forward and backward processing to produce forward and backward state metrics. The state metric engine includes a plurality of processes that each perform both the forward and the backward processing operations. The system further includes memory that stores the forward and backward state metrics that are produced by the engine in appropriate orders for the forward and backward processing. A number of multiplexers provide the appropriate branch metrics and apriori values to adder strings in each of the processors in accordance with an associated decoding trellis.10-02-2008
20080267322SYSTEM AND METHOD FOR TRELLIS CONSTRUCTION FOR GOUP CODES - A method and system constructs a minimal trellis for decoding a block group code. A generator matrix of the code is obtained and converted into a row-reduced echelon matrix form. Vertices are determined from the row-reduced echelon matrix form at a first time. Further vertices at later times are also determined to obtain a minimal trellis for the block group code C for storing or use in decoding received codes.10-30-2008
20110164707UTILIZATION OF A KNOWN PORTION OF A PAYLOAD TO DECODE A PAYLOAD HAVING A KNOWN AND AN UNKNOWN PORTION - A method, an apparatus, and a computer program product for wireless communication are provided in which a payload is received, the payload having a known portion and an unknown portion. The payload is decoded through correlation, where correlation includes the generation of a plurality of payload hypothesis based on possible combinations of the unknown portion and using the known portion and the generation of a metric value based on each of the plurality of payload hypothesis. The received payload is selected through a determination of the payload hypothesis having a largest generated metric value.07-07-2011
20110085623METHOD AND APPARATUS FOR EQUALIZATION OF RECEIVED SIGNALS - A receiver for a mobile communication device comprises an primary detector for generating an initial sequence estimate comprising a plurality of initial symbol estimates from a received symbol sequence corrupted by intersymbol interference, and a secondary detector to receive said initial sequence estimate and to output a final sequence estimate comprising a plurality of final symbol estimates. The secondary detector comprises a sequence generator configured to generate one or more revised sequence estimates by replacing at least one initial symbol estimate in said initial sequence estimate with a corresponding nearest neighbor symbol in each of said revised symbol estimates; an error calculator to compute error metrics for said revised sequence estimates; and a selection circuit to compare error metrics for said initial and revised sequence estimates and to output one of said initial or revised sequence estimates as said final sequence estimate based on said error metrics.04-14-2011
20100329395METHOD AND APPARATUS FOR SYMBOL DECODING USING TREE PRUNING BASED SPHERE SEARCH - An apparatus and method for symbol decoding comprising selecting a degree of freedom (DOF) parameter for a noise vector; selecting a delta probability value; computing a cost function for a lattice point that is one of a discrete set of nominal codeword positions in a hypersphere; selecting a sphere decoding radius based on the DOF parameter, the delta probability value and the cost function; and decoding a symbol using the sphere decoding radius. And, the apparatus and method comprising setting pre-defined threshold probabilities; computing threshold radii based on the pre-defined threshold probabilities; setting an initial sphere radius square to the value of a first threshold radii; finding the Lattice point based on the initial sphere radius square; computing an updated sphere radius square as the minimum of either a cost function or a second threshold radii; and finding a next lattice point based on the updated sphere radius square.12-30-2010
20110135041RECEIVER AND METHOD FOR RECEIVING - A procedure of receiving includes estimating a phase offset of a received signal and calculating one or more phase offsets which result in the estimated phase offset of the received signal and which have different phase rotation directions and/or different phase rotation amounts from one another; compensating for the phase offset of the received signal, using each of a plurality of phase offsets that are the estimated phase offset and the calculated phase offsets, and demodulating and decoding the plurality of compensated received signals; and selecting a decoding result that is the most likely to be the received signal among a plurality of results of the decoding corresponding one for each of the plurality of phase offsets.06-09-2011
20100202572LLR COMBINING METHOD AND APPARATUS FOR HARQ IN WIRELESS COMMUNICATION SYSTEM - A Log-Likelihood Ratio (LLR) combining method and apparatus for Hybrid Automatic Repeat Request (HARQ) in a wireless communication system for reducing a number of the LLR bits of previous packet stored for LLR combining are provided. The LLR combining apparatus includes an LLR combiner for combining a first LLR of a currently received packet and a second LLR of a previously received packet, an LLR buffer for storing the second LLR and a first packet exponent for recovering the second LLR in the same size as the first LLR, and an HARQ controller for determining whether the currently received packet is a retransmission packet or an initial transmission packet, and for controlling the LLR combiner to generate a third LLR by combining the first and second LLRs for the retransmission packet and to bypass the initial transmission packet.08-12-2010
20100166119MIMO SYMBOL DECODER AND METHOD FOR DECODING SPATIALLY MULTIPLEXED SYMBOLS USING COMBINED LINEAR EQUALIZATION AND MAXIMUM LIKELIHOOD DECODING - Embodiments of MIMO symbol decoders and methods for decoding spatially multiplexed symbols using combined linear equalization decoding and maximum likelihood decoding are generally described herein. In some embodiments, one group of symbols (y) received through two or more spatial channels is decoded using a linear equalization decoding technique and another group of symbols is decoded using a maximum likelihood decoding (MLD) technique to generate a soft-bit output. The symbols may be grouped for either linear equalization decoding or MLD based on channel orthogonality or signal-to-interference and noise ratios (SINRs).07-01-2010
20110051861METHOD AND APPARATUS FOR RECEIVING IN MULTIPLE-INPUT MULTIPLE-OUTPUT SYSTEM - A receiving method and apparatus in a Multiple-Input Multiple-Output (MIMO) communication system are provided. The method includes receiving reception signals through a plurality of reception antennas, grouping symbols corresponding to the reception signals, respectively, into a preset number of groups, and rearranging symbols of the respective groups, transforming the reception signals by applying QR decomposition to the reception signals, sequentially canceling interference due to each of total possible candidate symbols for a first symbol based on an order of the rearranged symbols in the transformed reception signals, determining a portion of the total possible candidate symbols to be a candidate symbol set for each remaining symbol, except for the first symbol, using the interference-canceled reception signal, and determining log-likelihood ratio values of the first symbol, which are to be used upon decoding the received signals, using candidate symbols for the first symbol and each remaining symbol.03-03-2011
20110051860ITERATIVE DECODING ARCHITECTURE WITH HARQ COMBINING AND SOFT DECISION DIRECTED CHANNEL ESTIMATION - Certain aspects of the present disclosure relate to a method for iterative decoding with re-transmissions of data and to a method for iterative decoding with soft decision directed channel estimation.03-03-2011
20110051858HARDWARE SIMPLIFICATION OF SIC-MIMO DECODING BY USE OF A SINGLE HARDWARE ELEMENT WITH CHANNEL AND NOISE ADAPTATION FOR INTERFERENCE CANCELLED STREAMS - Certain aspects of the present disclosure relate to a method and an apparatus for simplified serial interference cancellation in multiple-input multiple-output (MIMO) and non-MIMO wireless systems by using a single hardware element for multiple interference cancelled streams.03-03-2011
20110051857METHOD AND SYSTEM FOR A SOFT-OUTPUT NORDSTROM-ROBINSON DECODER - Aspects of a method and system for a method and system for a soft output Nordstrom-Robinson (NR) decoder may include one or more processors and/or circuits that are operable to more efficiently compute cross correlation values for a received soft output word based on a NR codebook in comparison to brute force computation approaches. Log likelihood ratios may be computed for each information bit corresponding to the received soft output word by determining corresponding maximum cross correlation values.03-03-2011
20090175390RECEIVER APPARATUS IN MULTI-USER COMMUNICATION SYSTEM AND CONTROL METHOD THEREOF - A receiver apparatus in a multi-user communication system and a control method are provided. The receiver apparatus includes a multi-user detector for creating a soft decision value by using multiple received signals and priori information output from a prior iteration, and a channel decoder for performing local iterative decoding on the soft decision value created by the multi-user detector, and updating the soft decision value. The receiver apparatus also includes a global decoding controller for checking the soft decision value updated by the channel decoder, and controlling whether or not to perform global iterative decoding. Accordingly, it is possible to minimize a processing time delay and to reduce the complexity through an interference cancellation processing for multiple user signals and an iterative decoding processing, and also it is possible to minimize the decoding delays of user signals by processing soft decision values for multiple user signals as many as a predetermined number of decoding iterations before terminating.07-09-2009
20090175389METHODS AND SYSTEMS FOR TURBO DECODING IN A WIRELESS COMMUNICATION SYSTEM - Certain embodiments provide methods and apparatus for decoding a string of data bits, encoded with a turbo encoding scheme, in a wireless communication system. One or more a-priori bit values corresponding to expected bit values at one or more identified bit locations in the string of data bits may be identified. One or more branch metrics used in a turbo decoding scheme may be manipulated to effectively remove decoding paths, from a collection of possible decoding paths, based at least on the identified one or more a-priori bit values, resulting in one or more remaining decoding paths. The string of data bits may be decoded by selecting a decoding path from the one or more remaining decoding paths.07-09-2009
20090175388DECODING SCHEME USING A-PRIORI INFORMATION ABOUT TRANSMITTED MESSAGES - A method and apparatus for decoding encoded data bits of a wireless communication transmission are provided. A set of a-priori bit values corresponding to known bit values of the encoded data bits may be generated. Decoding paths that correspond to decoded data bits that are inconsistent with the a-priori bit values may be removed from the possible decoding paths to consider, and decoding the encoded data bits by selecting a decoding path from remaining decoding paths of the possible decoding paths that were not removed.07-09-2009
20110261909Frequency Offset Estimation - A frequency offset of a received signal comprising a number of subsequently received data symbols is estimated. A first estimate is determined from a calculated change in phase of the received signal between two received symbols having a first time distance between them. At least one further estimate is determined from a calculated change in phase of the received signal between two received symbols having a different time distance. A frequency periodicity is determined for each estimate from the distance between the two received symbols from which the estimate was determined. A set of integer values is determined for each estimate so that frequency values calculated for each estimate as the frequency periodicity multiplied by the integer value added to the estimate are at least approximately equal to each other, and a corrected estimate of the frequency offset is determined from the integer values.10-27-2011
20100027721Method and System for Implementing a Multiple-Input Multiple-Output (MIMO) Decoder Scheme - The teachings of the present disclosure relate to a method for receiving “N” data streams (wherein “N” is a number greater than one) from “N” endpoints. Each of the data streams are received from a different respective endpoint. The method also includes decoding the “N” data streams by generating a decoding signal input comprising the “N” data streams and then iteratively repeating the following steps “N”−1 times: determine a most reliable stream; decode the most reliable stream using linear multiple-input and multiple-output (MIMO) decoding; output the decoded most reliable stream; estimate a signal estimate based on the most reliable stream and modulation information associated with the most reliable stream; and generate a residual signal that comprises the remaining data streams less the signal estimate. Upon the residual signal comprising two data streams, the method includes updating the decoding signal input to be the residual signal. Upon the residual signal comprising a single received stream, the method includes decoding the residual signal using a maximum likelihood decoder.02-04-2010
20100020904EXPLOITING KNOWN PADDING DATA TO IMPROVE BLOCK DECODE SUCCESS RATE - A method and system of decoding a convolutionally encoded data block having known padding bits. A Viterbi decoder is constrained to a state corresponding to k−1 padding bits immediately adjacent to data bits of the data block, where k is a constraint length of a convolution encoder used to encode the data block. Symbols of the encoded data block that have influence only from the padding bits are discarded.01-28-2010
20110216857RECEIVER FOR A WIRELESS TELECOMMUNICATION SYSTEM WITH A CHANNEL DEINTERLEAVER - A receiver for wireless broadband telecommunication transmissions, the receiver including a demodulator for receiving transmitted modulated symbols, a channel deinterleaver memory coupled to the demodulator for receiving interleaved soft symbols and outputting deinterleaved soft symbols, an LLR calculator coupled to the channel deinterleaver memory for receiving the deinterleaved soft symbols and calculating LLRs therefore, a descrambler coupled to the LLR calculator for descrambling the LLRs, and an interleaved scrambling sequence generator coupled to the descrambler for generating an interleaved scrambling sequence and providing it to the descrambler.09-08-2011
20090052593LOG LIKELIHOOD RATIO CALCULATION METHOD, TRANSMIT SIGNAL DETECTION METHOD, AND RECEIVER - The present invention relates to a log-likelihood ratio calculation method, a transmitting signal detection method, and a receiver. The present invention estimates a channel on the basis of the received signal and rearranges a plurality of layers. Further, at the time of rearrangement of the layers, a symbol of a layer having the lowest reliability is considered for every constellation dot, and the successive interference for the remaining layers is removed corresponding to the constellation dots of the layer having the lowest reliability to set the transmitting symbol candidate vector. Furthermore, a log-likelihood ratio for every bit of the plurality of layers is calculated using the transmitting symbol candidate vector to decode the channel.02-26-2009
20120307946METHOD OF ESTIMATING THE SYMBOLS OF A DIGITAL SIGNAL AND RECEIVER FOR IMPLEMENTING SAID METHOD - The invention relates to a method of estimating symbols carried by a digital signal that is received by a receiver over a communication channel (12-06-2012
20110305303INTERFERENCE CANCELLATION UNDER NON-STATIONARY CONDITIONS - A method for timing and frequency synchronization in a wireless system is provided. The method comprises the steps of receiving a burst of symbols, selecting a subset of the burst of symbols, iteratively adjusting the subset of the burst of symbols by a plurality of timing offsets and calculating, for each timing offset, a first performance metric corresponding to the adjusted subset. The method further comprises the steps of determining one of the plurality of timing offsets to be a preferred timing offset based upon the first performance metric thereof, iteratively rotating the subset of the burst of symbols by a plurality of frequency offsets and calculating, for each frequency offset, a second performance metric corresponding to the rotated subset, and determining one of the plurality of frequency offsets to be a preferred frequency offset based upon the second performance metric thereof.12-15-2011
20090141835Apparatus and method for receiver in multiple antenna system - Detection apparatus and method for achieving performance close to a Maximum Likelihood (ML) detection having optimal performance and reducing computational complexity in a Multiple-Input Multiple-Output (MIMO) system including a plurality of transmit antennas and receive antennas are provided. The apparatus includes a hard decision part for confirming an initial hard decision value of a receive symbol vector; a candidate symbol selector for selecting candidate symbols restricted to neighbor values of the initial hard decision value; and an interference canceller for canceling interference in the selected candidate symbols and selecting a final candidate symbol from the received symbols using a result of the interference cancellation.06-04-2009
20100061491TRANSMITTING/RECEIVING SYSTEM AND METHOD OF PROCESSING BROADCAST SIGNAL IN TRANSMITTING/RECEIVING SYSTEM - A receiving system and a method of processing broadcast signal. The receiving system includes a signal receiving unit, an equalizer, a turbo decoder, a demultiplexer, first and second error correctors, and a block interleaver. The signal receiving unit receives a broadcast signal, the broadcast signal comprising a data group, which includes mobile service data, a plurality of known data sequences, and signaling data, and demodulating the received broadcast signal. The equalizer channel-equalizes the data group using at least one of the plurality of known data sequences. The turbo decoder turbo-decodes the signaling data contained in the channel-equalized data group. The demultiplexer distinguishes transmission parameter channel (TPC) data and fast information channel (FIC) data from the turbo-decoded signaling data. The first error corrector corrects an error in the TPC data. The block deinterleaver block-deinterleaves the FIC data. The second error corrector corrects an error in the block-deinterleaved FIC data.03-11-2010
20120039423Method and System for Decoding Control Data in GSM-Based Systems Using Inherent Redundancy - A method and system for decoding control data in GSM-based systems using inherent redundancy and physical constraints are presented. At least one estimated GSM-based bit sequence may be selected by performing searches that start from trellis junctions determined by the decoding algorithm. The estimated bit sequences may be selected based on corresponding redundancy verification parameters. At least one physical constraint test may be performed on the selected estimated GSM-based bit sequences to select a decoded output GSM-based bit sequence. A multilayer decoding process may comprise a burst process and a frame process. Results from a first burst process may be utilized to generate a decoded GSM bit sequence in the frame process. The frame process may utilize redundancy information and physical constraints to improve the performance of a decoding algorithm.02-16-2012
20120177152LOW LATENCY SIMD ARCHITECTURE FOR ITERATIVE DECODERS - Systems, methods, and other embodiments associated with iterative decoders are described. According to one embodiment, an apparatus includes a set of decoders that are configured to receive data to be decoded. The apparatus may also include a controller configured to separately control each decoder to initiate a decoding sequence based on an occurrence of a transition point. The transition point is a global transition that occurs iteratively for the set of decoders and is based on iterations in a decoding sequence.07-12-2012
20120099680Combining Soft Decisions In A Weather Band Radio - According to one aspect of the present invention, an apparatus is provided to enable weather band radio signals to be received and processed using a digital signal processor (DSP). The DSP can include functionality to implement both frequency modulation (FM) demodulation and weather band data demodulation, i.e., specific area encoding (SAME) demodulation. In one such embodiment, soft decision samples of a SAME message can be combined, and based on a combined result, a hard decision unit can generate a bit value of weather band data.04-26-2012
20120099679RECEIVING APPARATUS AND RECEIVING METHOD - A receiving apparatus and reception method reduces degradation due to multipath interference without increasing the amount of computation even in a system that has a large number of subcarriers. A signal detector, using the symbol replica generated by symbol replica generator and the channel estimate which a channel estimator estimated based on the received pilot signal, suppresses interference attributed to delayed waves exceeding the GI and outputs a suppressed signal for the received signal. A demodulator decodes the signal of which interference has been alleviated, to determine code bit LLR as bit likelihood information. A decoder performs an error correction decoding process on the input code bit LLR. If no error exists in the result of error correction decoding, the decoder outputs information bits to complete the reception process. If there is an error in the decoded result, the decoder outputs the code bit LLR to symbol replica generator.04-26-2012
20110090994Decoding Method and Associated Apparatus - A decoding method for determining a preferred survivor path in a decoding process is provided. The method includes calculating a first determination value of a first survivor path at a first time point, the first determination value being determined by a first sub determination value and a second determination value at a second time point, and the second time point being prior to the first time point; calculating a third determination value of a second survivor path at the first time point, the third determination value being determined by a second sub determination value and a fourth determination value at the second time point; and when a difference between the first determination value and the third determination value is equal to or less than a predetermined value, determining the preferred survivor path at the first time point according to the second and the fourth determination values, or the first and the second sub determination values.04-21-2011
20100158161POST DECODING SOFT INTERFERENCE CANCELLATION - The present patent application discloses a method and apparatus for decoding, comprising decoding signals iteratively, mutually exchanging extrinsic information, calculating APP LLRs for both systematic and parity bits and making a hard decision after a plurality of iterations is completed based on accumulated soft information. The present patent application also discloses a method and apparatus for post decoding soft interference canceling, comprising generating updated a posteriori probabilities for systematic and parity bits from a turbo decoder, mapping the posteriori probabilities to soft symbols, quantizing the soft symbols, re-encoding a data packet, filtering a chip sequence, reconstructing an interference waveform, and scaling reconstruction filter coefficients using the symbols.06-24-2010
20100246733TRELLIS DECODER FOR DECODING DATA STREAM INCLUDING SYMBOLS CODED WITH MULTIPLE CONVOLUTIONAL CODES - A trellis decoder decodes a stream of encoded symbols, including symbols of a first type (e.g. symbols encoded with a first trellis code) and symbols of a second type (e.g. encoded with a second, more robust, trellis code), without storing path indicators along a trellis for symbols of the first type. In this way, limited memory may be used to store path indicators along the trellis for symbols of the second type. This allows for more accurate decoding of the symbols of the second type. For transitions from symbols of the second type to symbols of the first type, states of the trellis decoder may be stored. In this way, paths may be traced back along the trellis for trellis decoding, without the path indicators for the symbols of the first type.09-30-2010
20120057661MIMO OFDM System - A MIMO OFDM system includes a plurality of space-time encoders for encoding respective data blocks with independent space-time codes. The transformed data block signals are transmitted by a plurality of transmit antennas and received by a plurality of receive antennas. The received data is pre-whitened prior to maximum likelihood detection. In one embodiment, successive interference cancellation can be sued to improve system performance. Channel parameter estimation can be enhanced by weighting the channel impulse response estimates based upon a deviation from average.03-08-2012
20090016469ROBUST JOINT ERASURE MARKING AND LIST VITERBI ALGORITHM DECODER - Joint erasure marking and list Viterbi algorithm (JELVA), decoder schemes, methods, and systems are provided which perform robust trellis decoder techniques and do not require an estimate of the impulsive noise distribution. Joint Erasure marking and Viterbi Algorithm (JEVA) is integrated with the list Viterbi algorithm (LVA) to form two-dimensional joint erasure marking and list Viterbi technique (2D JELVA) and switched JELVA technique. By combining the respective strengths of the JEVA and the LVA, the integrated decoding schemes are able to achieve significant performance gains over JEVA and achieve a wide range of performance-complexity-delay tradeoffs, according to system design considerations. The disclosed details enable various refinements and modifications according to decoder and system design considerations.01-15-2009
20120207251BLIND FREQUENCY-OFFSET ESTIMATION FOR SPATIALLY CORRELATED SIGNAL - An iterative, blind, frequency-offset estimation process that does not require any training signal or demodulated information symbols is disclosed. Receivers embodying the disclosed processes can produce periodic frequency-offset estimates, without running computationally intensive equalization or demodulation algorithms, by exploiting the temporal correlation of the received signal in the time domain, as well as the received signal's correlation across in-phase and quadrature dimensions, in some embodiments, to find a frequency-offset estimate that best fits the received signal in a maximum-likelihood sense. In an exemplary method of estimating receiver frequency offset, a spatially stacked signal block is formed from multi-branch signal samples corresponding to each of two or more time-separated samples of the received signal. The spatially stacked signal block is used in computing a maximum-likelihood joint estimate of the receiver frequency offset and the spatial covariance of the spatially stacked signal block de-rotated by the receiver frequency offset.08-16-2012
20120045024METHODS AND APPARATUS FOR ITERATIVE DECODING IN MULTIPLE-INPUT-MULTIPLE-OUTPUT (MIMO) COMMUNICATION SYSTEMS - Methods and apparatus for receiving, processing, and decoding MIMO transmissions in communications systems are described. A non-Gaussian approximation method for simplifying processing complexity where summations are used is described. Use of a priori information to facilitate determination of log likelihood ratios (LLRs) in receivers using iterative decoders is further described. A Gaussian or non-Gaussian approximation method using a priori information may be used to determine a K-best list of values for summation to generate an LLR is also described.02-23-2012
20090154607Method and Apparatus for Blind Decoding - According to the teachings presented herein, a method and apparatus provide a reduced search space for blindly decoding a message included in a signal received at a communication receiver, where the message has an unknown format. Improving blind detection efficiency in this manner offers numerous advantages, including but not limited to lower power consumption through reduced processing overhead, and lower power consumption through expanded sleep opportunities. As a non-limiting example, the communication receiver comprises a mobile station configured for operation according to Long Term Evolution (LTE) standards, as promulgated by the 3GPP for E-UTRA systems, where the mobile station is configured to reduce a search space of DCI message decoding by determining message format likelihoods and blindly decoding a received DCI message based on the message format likelihoods.06-18-2009
20120014482DATA COMMUNICATION DEVICES, METHODS, & SYSTEMS - Data communication devices, methods, and systems are discussed in this application. In one embodiment, a receiving apparatus generally comprises a detector, an indicator, and a decision device. The detector can detect a number of data streams contained in a signal received on a single physical channel. Detection can be made by comparing a received signal with one or more predetermined sequences and identifying one or more of the plural predetermined sequences as being likely contained within the received signal. Each data stream can be associated with at least one predetermined sequences. The indicator can provide an indication of the data streams likely contained in the signal based on the identified sequences. A decision device can provide data defining a receiver configuration based on the indication, the receiver configuration being suitable for configuring a decoder to decode only the one or more data streams indicated as being likely contained in the signal. Other aspects, embodiments, and features are also claimed and discussed.01-19-2012
20120014483LOW COMPLEXITY OPTIMAL SOFT MIMO RECEIVER - A low-complexity optimal soft MIMO detector is provided for a general spatial multiplexing (SM) systems with two transmit and N01-19-2012
20120057660MIMO WIRELESS SYSTEM WITH DIVERSITY PROCESSING - A MIMO wireless system with Diversity processing is provided having Turbo Codes Decoders for computing orthogonal multipath signals from multiple separate antennas. The invention decodes multipath signals that have arrived at the terminal via different routes after being reflected from buildings, trees or hills. The Turbo Codes Decoder with Diversity processing increases the signal to noise ratio (SNR) more than 6 dB which enables the Wireless system to deliver data rates from up to 600 Mbit/s. A Turbo Codes Decoder block is provided to compute baseband signals from multiple different receiver paths. Several pipelined max-Log-MAP decoders are used for iterative decoding of received data. A Sliding Window of Block N data is used for pipeline operations.03-08-2012
20120014481Data Receiver with Improved Response to Long and Short Term Fading - The invention relates to apparatus for the receipt of digital data which is transmitted as a data signal from a remote location and a method by which the receiving apparatus can be designed with a configuration to improve the ability to receive the data signal. The design of the configuration is generated with reference to at least one decision metric which is adapted to suit the known characteristics of the data signal which is being received.01-19-2012
20090238311Reverse serial list Viterbi decoding to improve frame error rate performance - A convolutionally encoded frame to be decoded includes a first portion of bits having additional error protection and another portion without additional error protection. The decoding of the frame involves reverse Viterbi decoding or Viterbi decoding on a reversed bit sequence followed by applying a serial list Viterbi algorithm to the first portion. The result is that the list of probable sequences have unique sets of bits in the first portion.09-24-2009
20080273631TURBO DECODER AND METHOD FOR TURBO DECODING A DOUBLE-BINARY CIRCULAR RECURSIVE SYSTEMATIC CONVOLUTIONAL ENCODED SIGNAL - A Turbo decoder and method for decoding a double-binary circular recursive systematic convolutional (DBCRSC) encoded signal with unknown initial and final states executes iterations of forward and backward recursion on a payload block of the DBCRSC encoded signal and a padded block using an estimated forward state metric (FSM) and an estimated backward state metric (BSM), which are updated at one or more iterations.11-06-2008
20090135964METHOD OF CALCULATING LOG-LIKELIHOOD RATIO AND METHOD OF DETECTING TRANSMISSION SIGNAL - The present invention relates to a method of calculating a log-likelihood ratio and a method of detecting a transmission signal. According to the present invention, when a transmission symbol candidate vector is detected on the basis of a received signal, a threshold value and an ML metric of each transmission symbol candidate vector are calculated and the ML metric that is larger than the threshold value is updated by the threshold value. Further, a log-likelihood ratio of the transmission signal bit is calculated using the updated ML metric and the threshold value, and a transmission signal is detected using the log-likelihood ratio.05-28-2009
20090135967METHOD AND CIRCUIT SYSTEM FOR DECIDING A SYMBOL UPON RECEPTION OF RECEIVED SYMBOLS COUPLED WITH A QUADRATURE SIGNAL PAIR - The invention relates to a method and a circuit system for deciding a symbol (S) upon reception of received symbols coupled with a quadrature signal pair (I, Q). For deciding a symbol upon reception of an input signal using received symbols (S) coupled with a quadrature signal pair, wherein phase noise (PN) and Gaussian noise (GN) are superimposed on at least one such received symbol, the phase noise (PN) as well as the Gaussian noise (GN) are determined or estimated for at least one such received symbol (S). This is advantageously achieved by the fact that when the phase noise (PN) and the Gaussian noise (GN) are determined or estimated, a differentiation is made between the phase noise (PN) and the Gaussian noise, and a result of the differentiating determination or estimation is used for controlling reception parameters for decisions concerning subsequently received symbols (S). In particular, the measured values of the phase noise (PN) are orthogonalized to the Gaussian noise (GN).05-28-2009
20090135966METHOD FOR RECOVERING A BIT STREAM FROM A RADIO SIGNAL - The invention relates to a method for recovering a bit stream from a radio signal (05-28-2009
20120250805METHOD OF DEMODULATING A QUADRATURE AMPLITUDE MODULATION SIGNAL AND METHOD OF DATA COMMUNICATION - To demodulate a quadrature amplitude modulation (QAM) signal, a reception point is determined corresponding to a symbol in the QAM signal that is received where the symbol is mapped to one reference point of a plurality of reference points in a rotated constellation and the plurality of reference points are represented by an in-phase (I) coordinate and a quadrature-phase (Q) coordinate. A plurality of candidate points corresponding to a portion of the plurality of reference points are selected based on distances between the reception point and the respective reference points. The reception point is demapped by calculating a plurality of log-likelihood ratios based on the plurality of candidate points, the plurality of log-likelihood ratios corresponding to bits of data represented by the reception point.10-04-2012
20120250804Efficient Square-Root Free 2 Symbol Max-Log Receiver - The present invention employs a look up table based implementation for the metric computations which eliminate redundancy and substantially reduce the number of multiplications. Moreover, inventive method exploits the fact that the un-normalized constellation symbols are complex integers so that the product of a real-number and an un-normalized constellation symbol can be implemented by only additions. The inventive method also enables a greater efficiency for whitening colored noise prior to demodulation, one of which involves no square-root operation. The invention results in less complexity, faster operation, lower power consumption, without sacrificing performance10-04-2012
20120300886METHODS FOR EARLY TERMINATION OF RECEPTION OF A BIT STREAM - A method of receiving a bitstream. The method includes receiving a sequence of bits of a bitstream, assigning a confidence level to each bit in the sequence of bits, maintaining a running confidence level of the sequence of bits as the bits are received, comparing the running confidence level to a threshold, terminating reception of the bitstream when the running confidence level is below the threshold, and requesting retransmission of the bitstream. Wherein the reception of the bitstream and the requesting of retransmission of the bitstream occurs prior to the entire bitstream being received.11-29-2012
20120300885System and/or method for reducing ambiguities in received SPS signals - The subject matter disclosed herein relates to a system and method for resolving ambiguities associated with signals received from space vehicles (SVs) in a satellite navigation system.11-29-2012
20120106684METHOD AND ARRANGEMENT FOR SOFT-DECISION SPHERE DECODING - A method is provided for soft-decision sphere decoding for softbit computation which can be applied to all sphere decoding algorithms, in particular sphere decoding algorithms in any MIMO OFDM receiver implementations. Complexity reduction is achieved by using an approximate of linear Euclidean distances during the sphere decoding search. The method can be used in conjunction with MIMO OFDM communication systems like LTE, WiMax and WLAN.05-03-2012
20120106683METHOD AND APPARATUS FOR PARALLEL TURBO DECODING IN LONG TERM EVOLUTION SYSTEM (LTE) - Provided are a method and an apparatus for parallel Turbo decoding in LTE, comprising: storing input check soft bits and a frame to be decoded, when storing said frame, dividing the frame into blocks, storing each block respectively as system soft bits; simultaneously performing component decoding once for several blocks of one said frame, and in the process of component decoding, dividing each block into several sliding windows according to a sliding window algorithm, calculating the following parameters according to system soft bits, check soft bits and priori information: branch metric value γ, forward state vector α, backward state vector β, LLR, and priori information, storing the priori information for use in a next component decoding; completing a decoding process after several component decoding; performing a hard decision on LLR, and if judged that a result of the hard decision meets an iteration ending condition, outputting a decoding result, otherwise, performing next iteration decoding.05-03-2012
20120155579Efficient Implementation of M-Algorithm Based on QR Decomposition for Higher-Order Constellations - A method of detecting received data in a communication system includes the steps of: performing a QR decomposition on a received input vector as a function of one or more characteristics of a communication channel over which the input vector was transmitted; generating a subset of best symbol candidates from a symbol constellation by comparing an input sample (corresponding to an element of the input vector) with one or more prescribed thresholds; identifying at least one symbol satisfying prescribed minimum Euclidian distance criteria among multiple ambiguity symbols in the subset of best symbol candidates; and generating a subset of best symbols including a prescribed number of symbols from the symbol constellation determined to be closest to the input sample. The subset of best symbols is used in a subsequent iteration of the steps of generating the subset of best symbol candidates and identifying at least one symbol satisfying the prescribed minimum Euclidian distance criteria.06-21-2012
20110080981Method and System for Minimum Mean Squared Error Soft Interference Cancellation (MMSE-SIC) Based Suboptimal Maximum Likelihood (ML) Detection for Multiple Input Multiple Output (MIMO) Wireless System - Various aspects of a method for minimum mean square error soft interference cancellation (MMSE-SIC) based sub-optimal maximum likelihood (ML) detection for a multiple input multiple output (MIMO) wireless system may comprise selecting at least one constellation point in a constellation map based on at least one of a plurality of received symbols. A number of the at least one constellation point may be less than or equal to a number of previously selected constellation points in a previous constellation map. At least one of the plurality of received symbols may be decoded based on the selected at least one constellation point.04-07-2011
20100172447DIGITAL BROADCASTING TRANSMISSION/RECEPTION DEVICES CAPABLE OF IMPROVING A RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - Disclosed is a digital broadcasting transmission/reception system having an improved reception performance and a signal-processing method thereof. A digital broadcasting transmitter comprises a randomizer for inputting dual TS stream consists of robust and normal packets having stuff bytes inserted in predetermined positions and randomizing the dual TS stream; a stuff byte exchanger for replacing the stuff byte of a randomized data stream from the randomizer to a predetermined known data; and an encoder for encoding a data streams to which the known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization, so that the digital broadcasting reception performance can be improved at poor multipath channels.07-08-2010
20110103527Phase Detector For Timing Recovery Loop - In one embodiment, a (hard-drive) read channel has a phase detector used in a timing recovery loop. The phase detector utilizes the sign bit and confidence value from a received log-likelihood ratio (LLR) signal to generate a mean value. The mean value is convolved with a partial response target to generate an estimated timing error signal. When implemented in a hard-drive read channel, the phase detector allows for timing recovery with lower loss-of-lock rates.05-05-2011
20110103528METHOD AND APPARATUS FOR MERGING BIT PROBABILITY INFORMATION IN SERIAL LOCALIZATION WITH INDECISION - Probability information generated by a decoder as part of the symbol decoding process is fed back for use by a multi-stage demodulator that employs serial localization with indecision so that the accuracy of the final symbol decision generated by the multi-stage demodulator is improved. The multi-stage demodulator has one or more non-final stages operable to localize a search for the final symbol decision of a received signal using centroid-based values as constellation points instead of modulation symbols associated with the received signal. A final stage of the multi-stage demodulator is operable to determine the final symbol decision using a subset of the modulation symbols as constellation points. The decoder is operable to decode the final symbol decision, including generating probability information related to the modulation symbols. The multi-stage demodulator is operable to revise the final symbol decision based on the probability information related to the modulation symbols.05-05-2011
20120121046Repetition Coding For A Wireless System - A system and method are disclosed for transmitting data over a wireless channel. In some embodiments, transmitting data includes receiving convolutionally encoded data and enhancing the transmission of the data by further repetition encoding the data.05-17-2012
20120121047COMMUNICATION SIGNAL DECODING AND SOFT DEMAPPING METHODS AND SYSTEMS - Symbol detection and soft dempapping methods and systems are provided. Individual subset symbol detection according to an embodiment of the invention involves identifying a search subset of a transmission symbol set for a transmission symbol. For each other transmission symbol in communication signals, multiple search subsets of the transmission symbol set are identified. The multiple search subsets include respective search subsets based on each transmission symbol in either the search subset for the first identified one of the transmission symbols or each of the multiple search subsets identified for a different one of the other transmission symbols. Symbol detection errors may be detected by identifying competing symbols and computing competing distances. Soft demapping may be provided by calculating soft decision results based on detected symbols and weighting the soft decision result.05-17-2012
20120121045MIMO RECEIVING METHOD - To provide a space multiplex signal detection circuit capable of obtaining an excellent error rate characteristic by suppressing an increase in the circuit scale if when a modulation multivalued number is particularly increased in the case of receiving a signal subjected to space multiplexing to detect the signal. SOLUTION: A transmission signal candidate narrow-down circuit 05-17-2012
20100290568DECODING FREQUENCY CHANNELISED SIGNALS - There is disclosed a method and receiver for decoding a data signal from analogue signals received at one or more receiving antennas (11-18-2010
20110110468DECODING CIRCUIT OPERATING IN RESPONSE TO DECODED RESULT AND/OR A PLURALITY OF VITERBI TARGET LEVELS WITH PATTERN DEPENDENCY - A decoding circuit includes: a level adjuster with pattern dependency arranged to generate a plurality of Viterbi target levels with pattern dependency; and a Viterbi decoder arranged to perform Viterbi decoding according to the Viterbi target levels with pattern dependency. A decoding circuit includes a Viterbi decoder arranged to perform Viterbi decoding, and the Viterbi decoder includes a branch metric generator arranged to generate a plurality of branch metrics with pattern dependency according to an input of the Viterbi decoder and a plurality of Viterbi target levels with pattern dependency. In particular, the branch metric generator includes: a plurality of branch metric generation paths arranged to generate a plurality of intermediate values according to the input of the Viterbi decoder and the Viterbi target levels with pattern dependency, respectively; and a selection unit for selecting a portion of the intermediate values as the branch metrics with pattern dependency.05-12-2011
20100246732DETECTING APPARATUS AND METHOD IN MIMO SYSTEM - Provided are a detecting apparatus in a Multiple Input Multiple Output (MIMO) system and a method thereof. The apparatus includes a first detector for decoding a received signal, to thereby generate a decoded vector; a candidate elements decision unit for calculating an instantaneous signal-to-interference plus noise ratio (SINR) value for each element of the decoded vector, and deciding candidate elements for estimating a transmission data based on the decoded vector by comparing the calculated instantaneous SINR value and a threshold value; a signal eliminator for generating a signal with respect to the candidate elements determined in the candidate elements decision unit and outputting a modified signal by subtracting the signal from the received signal; and a second detector for decoding the modified signal received from the signal eliminator based on a more precise detection method than the first detector.09-30-2010
20100246730Cyclic prefix-based enhanced data recovery method - The cyclic prefix-based enhanced data recovery method retains the cyclic prefix (CP) upon reception and routes the CP to a data detection module to enhance the operation of the orthogonal frequency division multiplexed (OFDM) receiver whether operating in the blind, semi-blind, training, or perfectly known channel modes. Processing of the OFDM symbol and the CP is performed in the data detector and obtains data recovery by computing a maximum likelihood estimation based on the CP and the OFDM symbols.09-30-2010
20100246731Method, Apparatus, and Computer Program Product for Decoding Signals in a Wireless Communication Environment - An apparatus for decoding a received plurality of multi-path signals to recover the data content of transmitted signals may include an integrated circuit. The integrated circuit may be configured to generate a logarithm likelihood ratio based on a received plurality of multi-path signals, where the received plurality of multi-path signals is representative of transmitted data content. The integrated circuit may be further configured to arrange coefficients of an expression generated based on the received plurality of multi-path signals and integrate the expression. The integrated circuit may be further configured to divide the integrated expression by prior information. As a result, the integrated circuit may be configured to receive the plurality of multi-path signals and decode the signals via integration. Associated methods and computer program products may also be provided.09-30-2010
20120128105MULTIANTENNA RECEIVING DEVICE - A multiantenna receiving device is provided to make it possible to cope with both improvement in error rate characteristic and simplification in structure. The multiantenna receiving device is comprised of soft judgement output units for carrying out a soft judgement of a modulation signal in accordance with signal point distances between a plurality of candidate signal points with respect to a plurality of multiplexed modulation signals and a receiving signal, decoding units for obtaining digital data of the modulation signals by using the judged results obtained by the soft judgement output units, and signal point decreasing units for decreasing the number of the candidate signal points used in the soft judgement output units by recursively using a part of the digital data except self-modulation signals obtained by the decoding units.05-24-2012
20120128104SPACE-TIME DECODER AND METHODS FOR DECODING ALAMOUTI-ENCODED SIGNALS IN HIGH-DOPPLER ENVIRONMENTS - Embodiments of a space-time decoder and methods for decoding Alamouti-encoded signals in high-Doppler environments are generally described herein. Other embodiments may be described and claimed. In some embodiments, soft-symbol outputs are generated from received symbols, a channel rate-of-change, and channel coefficients. Maximum-likelihood decoding may be performed to generate hard-symbol outputs from the soft-symbol outputs.05-24-2012
20120134452SOFT-DEMAPPING OF QAM SIGNALS - This invention concerns soft-decision demapping of Quadrature Amplitude Modulation (QAM) signals to enable soft-decision channel decoding in a communications system. In a first aspect the invention is a method for performing the soft-decision demapping of Quadrature Amplitude Modulation (QAM) signals to enable soft-decision channel decoding in a communications system. The method comprises the steps of: Extracting baseband signals from both I-and-Q channels. Sampling the baseband signals to extract a stream of complex numbers. Converting the stream of complex numbers to frequency domain vectors with components for each subcarrier frequency. Approximating bit log-likelihood ratios for each symbol directly from the real and imaginary parts of the corresponding frequency vector, without equalisation by the estimated channel. And, soft-decoding of the channel codes using the approximated log-likelihood ratios. In other aspects the invention concerns a device for performing the method and software for performing the method.05-31-2012
20120134453METHOD FOR DEMODULATING RECEIVED SIGNALS AND APPARATUS THEREFORE - Disclosed are a method for demodulating received signals and an apparatus therefore which can maintain quality of signals and can reduce computational complexity. A demodulation method of a receiving device for receiving a plurality of signals modulated through a M-ary (M is a natural number of 1 or more) modulation method includes: comparing channel frequency response power of a first channel with channel frequency response power of a second channel, selecting M reference signals on the basis of the compared result, selecting corresponding signals paired with respective selected M reference signals, and estimating transmitting signals from the M signal pairs including pairs of the reference signal and the corresponding signal. Accordingly, the computational complexity is reduced from O (M05-31-2012
20120134451Method and System for a Low-Complexity Soft-Output MIMO Detection - An approach for Soft-output K-Best MIMO detection comprises computing an estimated symbol vector and Log-Likelihood Ratio (LLR) values for transmitted bits. The approach includes a relevant discarded paths selection process, a last-stage on-demand expansion process, and a relaxed LLR computation process. The relevant discarded paths selection process includes analyzing the K-Best paths and discarded paths at each intermediate tree level and selecting only those discarded paths for further processing that will help in LLR computation for at least one of the transmitted bits. The last-stage on-demand expansion process includes expanding K paths at the tree level 2N05-31-2012
20090060098Algorithm for multiple-symbol differential detection - A method for differential phase evaluation of M-ary communication data is employed in which the data consists of N sequential symbols r03-05-2009
20090060097DIGITAL BROADCASTING TRANSMISSION AND RECEPTION DEVICES AND METHODS THEREOF - Digital broadcasting transmission and reception devices and methods thereof are provided. The digital broadcasting transmission device includes a randomizer which randomizes a dual transport stream including a normal stream and a robust stream, a supplementary reference signal inserter which inserts a certain supplementary reference signal into a stuffing region included in the randomized dual transport stream, a Reed-Solomon (RS) encoder which adds a parity into a parity region included in the dual transport stream, a robust processor which configures a new dual transport stream by convolution-encoding the robust stream among the dual transport stream, an interleaver which interleaves the configured dual transport stream, a trellis encoder which trellis-encode the interleaved dual transport stream, and a modulator which transmits the trellis-encoded dual transport stream. Accordingly, a sub-channel can be provided in which the robust data and the supplementary reference signal will be transmitted.03-05-2009
20090060096MULTI-TRANSPORT STREAM (TS) GENERATING APPARATUS AND METHOD, AND DIGITAL BROADCASTING TRANSMISSION AND RECEPTION APPARATUSES AND METHODS - A multi-transport stream (TS) generating apparatus and method, and digital broadcasting transmission and reception apparatuses and method are provided. The multi-TS generating apparatus includes an adaptor to generate an adaptation field in some packets of a normal stream; an interleaver to interleave the normal stream; a turbo processor to turbo-code a plurality of turbo streams; a stuffer to generate a multi-TS by stuffing the plurality of the turbo streams into the adaptation field; and a deinterleaver to deinterleave the multi-TS. Accordingly, the plurality of the turbo streams can be transmitted far more easily.03-05-2009
20090060095METHODS, APPARATUSES, AND COMPUTER PROGRAM PRODUCTS FOR CLASSIFYING UNCERTAIN DATA - Uncertain data is classified by constructing an error adjusted probability density estimate for the data, and applying a subspace exploration process to the probability density estimate to classify the data.03-05-2009
20090129515DIGITAL BROADCASTING TRANSMISSION/RECEPTION SYSTEM UTILIZING MULL PACKET AND TRS CODE TO IMPROVE RECEIVING PERFORMANCE AND SIGNAL PROCESSING METHOD THEREOF - A digital broadcasting transmission and/or reception system having an improved reception performance and a signal-processing method thereof. A digital broadcasting transmitter comprises a TRS encoder for to TRS-encode a MPEG-2 transmission stream having null data for inserting a Known data and a TRS parity at predetermined positions, randomizer to input and randomize data stream from the TRS encoder, a null packet exchanger to replace the null data for inserting the Known data to the known data, and an encoder for encoding a data streams to which the Known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization and further uses the TRS parity for correcting error of the received signal, so that the digital broadcasting reception performance can be improved at poor multipath channels.05-21-2009
20120076247SISO decoder for a block code - A soft-in-soft-out (SISO) decoder for a general block code includes a source bit generator which generates k guessed source bits; a channel encoder which maps the k guessed source bits to an n-bit channel codeword; a QAM symbol mapper which generates a locally generated symbol sequence comprising m consecutive QAM symbols based on the n-bit channel codeword; a correlator which receives a symbol sequence, a channel state information sequence, and the locally generated symbol sequence to calculate a correlation associated with the received symbol sequence based on the received symbol sequence, the channel state information sequence, and the locally generated symbol sequence; and a log-likelihood ratio calculator which is connected to the source bit generator and the correlator to thereby calculate the required log-likelihood ratios associated with all coded bits corresponding to the received symbol sequence.03-29-2012
20090110126REDUCED COMPLEXITY VITERBI DECODER - A Viterbi decoder includes a branch metric unit, an add-compare select unit coupled to the branch metric unit, and a trace-back unit coupled to the add-compare select unit. The branch metric unit includes a branch metric computation unit coupled to a thresholder unit. The branch metric computation unit is configured to compute a branch metric. The thresholder unit is configured to compare the branch metric with a threshold value. If the branch metric is greater than the threshold value, the thresholder unit is configured to forward the threshold value to the add-compare select and not forward the branch metric to the add-compare select unit. Implementing such a branch metric ceiling allows for a predictable reduction in the significant bits of calculations in the Viterbi decoder, which allows for reduction of complexity via elimination of gates and storage elements.04-30-2009
20120177154CALCULATION OF SOFT VALUES FOR UPLINK COMMUNICATION - The present invention relates to a node (07-12-2012
20120177153METHODS AND SYSTEMS FOR IMPROVING RETRANSMISSION PERFORMANCE OF DATA CHANNELS IN A WIRELSS COMMUNICATION SYSTEM - Certain aspects of the present disclosure provide a system and method for improving performance of HARQ operation in a wireless communication system. The proposed method enables a receiver to update a receive buffer only if newly received values corresponding to a data packet are more reliable than previous values corresponding to the same data packet (that are stored in the receive buffer). The receiver may use the more reliable information (e.g., the newly received values or the previously stored values) for decoding.07-12-2012
20110002421RECEPTION DEVICE - It is possible to demodulate a plurality of modulated signals transmitted from a plurality of antennas by using a comparatively small-size circuit with a preferable error ratio characteristic. Partial bit judgment units (01-06-2011
20120263261INCREMENTAL LATTICE REDUCTION SYSTEMS AND METHODS - An exemplary embodiment of the present invention provides an incremental lattice reduction method comprising: receiving an input signal at a plurality of input terminals; evaluating a reliability assessment condition using a primary symbol vector estimate of at least a portion of the input signal; terminating the incremental lattice reduction method if the reliability assessment condition is satisfied; and if the reliability assessment condition is not satisfied, performing at least one iteration of a lattice reduction detection sub-method to obtain a secondary symbol vector estimate.10-18-2012
20110235757DECODING METHOD AND DECODING DEVICE - The decoding method comprises storing, successively performing, determining, first performing, second performing, and outputting. The storing stores the N received branchwords in memory. The successively performing performs Viterbi updates on a sequence of branchwords. The determining determines a first encoder state at the end of the third block most likely to have generated the final branchword in the sequence from the best path metric. The first performing performs a Viterbi traceback procedure from the first encoder state at the end of the third block to determine a second encoder state at the start of the third block of branchwords. The second performing performs a Viterbi traceback procedure from that second encoder state at the start of the third block to determine a third encoder state at the start of the second block of branchwords. The outputting outputs a derived tail-biting path, if the second and third encoder states are identical.09-29-2011
20090202023METHOD AND APPARATUS OF BINARIZING INPUT SIGNAL, DISC DRIVER AND RECORDING MEDIUM - A method and an apparatus are provided for binarizing an input signal, which is capable of reliably correcting an offset of the input signal even when the input signal does not reach a reference level or has a single frequency, a disc driver and a recording medium. The binarizing method includes viterbi-decoding the input signal to obtain a viterbi-decoded signal; slicing the input signal based on a predetermined reference level to obtain a sliced signal; obtaining an offset of the input signal by low-pass filtering the viterbi-decoded signal or the sliced signal; and correcting the offset of the input signal based on the obtained offset. The viterbi-decoded signal is a binary signal of the input signal.08-13-2009
20090086855LINK ADAPTATION BASED ON GENERIC CINR MEASUREMENT ACCORDING TO LOG-LIKELIHOOD RATIO DISTRIBUTION - Techniques are provided to compute the carrier to interference-plus-noise ratio (CINR) in a wireless communication system using log-likelihood ratio (LLR) data generated from a received transmission. The LLR data are collected as they are sent from a detector to a forward error correction (FEC) decoder in a wireless communications device. In one embodiment, decision-aided LLR based CINR is computed using the decoded bits output from the FEC decoder as feedback. In another embodiment, blind LLR based CINR is computed without feedback. The CINR may be used to adjust a modulation and/or coding parameters associated with wireless communication between wireless communication devices.04-02-2009
20100232551EFFICIENT OPTIMAL ML DETECTOR - An efficient optimal maximum-likelihood output detector reducing the complexity of demodulation/decoding computations in multiple-input multiple-output communication systems. A plurality of received signals may be combined into a plurality of combined received signals by multiplication of a matrix representing the plurality of received signals with another matrix that meets certain conditions. The plurality of combined received signals may then allow for slicing operations as well as calculation of distance metrics with significantly reduced complexity.09-16-2010
20100232550TRANSMITTING/RECEIVING SYSTEM AND METHOD OF PROCESSING BROADCASTING SIGNAL IN TRANSMITTING/RECEIVING SYSTEM - A transmitting system, a receiving system, and a method of processing a broadcast signal are disclosed herein. The receiving system include a tuner, a demodulator, a block decoder, an RS frame decoder, and a service manager. The tuner receives a broadcast signal. Herein the broadcast signal includes mobile service data, a service map table signaling access information of the mobile service data, and a plurality of known data sequences. The mobile service data and the service map table are packetized to an RS frame. The demodulator demodulates the received broadcast signal. The block decoder turbo-decodes the mobile service data and the service map table included in the demodulated broadcast signal in block units. The RS frame decoder forming an RS frame including the turbo-decoded mobile service data and service map table, performs primary first cyclic redundancy check (CRC)-decoding and RS-decoding, and performs secondary CRC-decoding on the primarily CRC-decoded and RS-decoded RS frame. The service manager acquires source IP address information of IP datagrams of the RS frame-decoded mobile service data from the service map table.09-16-2010
20100232549SIGNAL SEPARATING DEVICE AND SIGNAL SEPARATING METHOD - Provided is a signal separating device capable of reducing the calculation amount and improving the communication quality. The signal separating device performs signal separation by the MLD method using the QR decomposition. The signal separating device includes: a nearest-neighbor signal point candidate detecting unit (09-16-2010
20120321023MIMO OFDM System - A MIMO OFDM system includes a plurality of space-time encoders for encoding respective data blocks with independent space-time codes. The transformed data block signals are transmitted by a plurality of transmit antennas and received by a plurality of receive antennas. The received data is pre-whitened prior to maximum likelihood detection. In one embodiment, successive interference cancellation can be sued to improve system performance. Channel parameter estimation can be enhanced by weighting the channel impulse response estimates based upon a deviation from average.12-20-2012
20100202573METHOD AND SYSTEM FOR AN ADAPTIVE VBLAST RECEIVER FOR WIRELESS MULTIPLE INPUT MULTIPLE OUTOUT (MIMO) DETECTION - Various aspects of a system for an adaptive VBLAST receiver for wireless MIMO detection may comprise utilizing log likelihood ratios (LLR) to selectively cancel interference in a received signal when information contained in one or more layers is encoded. Following the selective cancellation of interference, further computations may be performed on the residual received signal. Various aspects of the invention may comprise a linear detector with improved performance in comparison to some conventional VBLAST receivers. Performance may be measured by, for example, a packet error rate (PER) for a given signal to noise ratio (SNR) associated with the received signal.08-12-2010
20100202571METHODS AND SYSTEMS FOR FREQUENCY DOMAIN GAIN CONTROL IN OFDM MIMO SYSTEMS - Certain embodiments of the present disclosure provide a method for frequency-domain gain control in system utilizing orthogonal frequency division multiplexing (OFDM) multiple input multiple output (MIMO). The proposed method reduces the complexity of the system while maximizing the internal accuracy of the OFDM MIMO decoder and preserving the performance of the system.08-12-2010
20130010905RADIO TERMINAL AND DEMODULATION METHOD - A receiving unit receives information on a modulation scheme applied to signals to a radio terminal from a transmission apparatus. An MLD unit performs maximum likelihood detection of a received signal by using a modulation scheme based on the information received by the receiving unit and a plurality of modulation schemes applicable to signals to the other radio terminals. An estimation unit estimates a modulation scheme applied to signals to the other radio terminals based on predetermined information obtained in a maximum likelihood detection process in each of the plurality of modulation schemes of the MLD unit. A controller controls the MLD unit to perform maximum likelihood detection by using the modulation scheme estimated by the estimation unit and the modulation scheme received by the receiving unit.01-10-2013
20130016799Detection of Radio Signals in a ReceiverAANM Lopez; MiguelAACI SolnaAACO SEAAGP Lopez; Miguel Solna SEAANM Sandberg; KennethAACI EkeroAACO SEAAGP Sandberg; Kenneth Ekero SE - Non-linear distortions, called glitches, occur in radio receivers when automatic gain control (AGC) is employed for regulating the dynamic range of the received signal. It is proposed to determine (S01-17-2013
20130022156VITERBI DEVICE AND METHOD USING A POSTERIORI INFORMATION - New and useful methods and systems for providing improved performance of a Viterbi device are disclosed. For example, in an embodiment a Viterbi device includes metric circuitry configured to determine branch metrics using at least one of a variance signal based on both received data and detected data of the Viterbi device and a priori probabilities of available state transitions within a trellis of the Viterbi device.01-24-2013
20080225994DATA REPRODUCTION APPARATUS AND METHOD CAPABLE OF DETERMINING LEVEL VALUE OF VITERBI DECODER, AND COMPUTER-READABLE RECORDING MEDIUM HAVING RECORDED THEREON PROGRAM FOR IMPLEMENTING THE DATA REPRODUCTION METHOD - A data reproduction apparatus and method to accurately determine an initial level value of a viterbi decoder regardless of whether an operating frequency is in a stable state, and a recording medium having recorded thereon a program for implementing the data reproduction method, the data reproduction apparatus including: a storage unit to store a first input signal; a frequency detection unit to generate a frequency detection signal indicating that a frequency of the first input signal is detected and frequency information of the first input signal based on a second input signal; and a level value determination unit to detect at least one level value for the first input signal by converting a sampling rate for the first input signal based on a ratio between the frequency information and preset frequency information, and to determine the detected level value as an initial level value of the viterbi decoder.09-18-2008
20110261908SOFT DEMAPPING METHOD AND APPARATUS AND COMMUNICATION SYSTEM THEREOF - An exemplary embodiment of the present disclosure provides a soft demapping method. In the soft demapping method, each shortest Euclidean distance of the Euclidean distances from all possible signal vectors corresponding to the bits which are not obtained during a signal detection to a received signal vector is calculated by using channel state information (CSI) and modulation coefficients, so as to establish a complete bit vector-shortest distance mapping table, and a log likelihood ratio (LLR) of each bit is obtained according to the bit vector-shortest distance mapping table. The soft demapping method can be applied along with different signal detection techniques to decode a received signal vector into a bit vector, wherein the signal detection techniques include a maximum likelihood detection (MLD) technique and a sphere decoding (SD) technique.10-27-2011
20130177108TRANSPORT STREAM GENERATING DEVICE, TRANSMITTING DEVICE, RECEIVING DEVICE, AND A DIGITAL BROADCAST SYSTEM HAVING THE SAME, AND METHOD THEREOF - A transport stream (TS) generating apparatus, a transmitting apparatus, a receiving apparatus, a digital broadcast system having the above, and a method thereof are provided. The digital broadcast system includes a transport stream (TS) generating apparatus which generates a multi transport stream (TS) by multiplexing a normal stream and a turbo stream having a variable coding rate, a transmitting apparatus which re-constructs the multi TS by processing the turbo stream, and transmits the re-constructed multi TS, and a receiving apparatus which receives the re-constructed multi TS, and decodes the normal stream and the turbo stream respectively, to recover normal data and turbo data. Accordingly, a multi TS, which includes normal stream and a turbo stream of various coding rates, can be transmitted and received efficiently.07-11-2013
20110274219Apparatus for Estimating Frequency Offset in OFDM System - Provided is an apparatus for estimating a frequency offset by one training symbol including two symbols having the same structure and value in an OFDM system. The apparatus includes a first likelihood function calculator for modeling non-Gaussian impulsive noise included in the training symbol to a Cauchy probability density function in which a characteristic exponent of a BISαS probability density function is 1, and calculating a likelihood function of a Cauchy distribution using the Cauchy probability density function, and a first frequency offset estimator for estimating an effective frequency offset value in which the likelihood function of the Cauchy distribution of the first likelihood function calculator becomes highest as a frequency offset estimation value. Thereby, it is possible to improve the performance of frequency offset estimation in non-Gaussian impulsive noise environments.11-10-2011
20080212722Method and apparatus providing an advanced mimo receiver that includes a signal-plus-residual interference (SPRI) detector - A method is disclosed to obtain M final symbol decisions for signals received through N receive antennas that were transmitted in M parallel data layers, using a same spreading code from M transmit antennas. The method includes space-time equalizing the N received signals to generate M output signals from which at least inter-symbol interference is substantially removed and inter-layer interference is suppressed; despreading each of the M output signals for generating M soft symbol estimates; and processing the M soft symbol estimates to derive M final symbol decisions that are made in consideration of modeled residual inter-layer interference present in the space-time equalized M output signals. Processing includes operating a signal-plus-residual-interference (SPRI) detector that operates in accordance with a maximum likelihood (ML) technique, while space-time equalizing employs a linear minimum mean-square error (LMMSE) criterion. Transmitting may occur at a base station having the M transmit antennas, and receiving may occur at a mobile station having the N receive antennas.09-04-2008
20130114765Method for Reducing Interference in OFDM Wireless Networks - Interference in a received orthogonal frequency division multiplexing (OFDM) symbol, modulated according to selected constellation points S05-09-2013
20130114766Decoding Technique for Tail-Biting Codes - A technique for decoding a signal in a communication network is provided. A method implementation of the technique comprises the steps of receiving a signal; identifying a position in the signal; initializing a Viterbi state metric; and decoding the encoded signal by means of a wrap-around Viterbi algorithm. The received signal comprises information, wherein the signal is encoded by a tail-biting convolutional code. The identified position relates to a known portion of the information. The initialized Viterbi state metric is consistent with the known portion of the information. The decoding uses the initial Viterbi state metric, wherein the decoding starts at a decoding step following the identified position.05-09-2013
20130142289PARALLEL IMPLEMENTATION OF MAXIMUM A POSTERIORI PROBABILITY DECODER - A MAP decoder may be implemented in parallel. In one implementation, a device may receive an input array that represents received encoded data and calculate, in parallel, a series of transition matrices from the input array. The device may further calculate, in parallel, products of the cumulative products of the series of transition matrices and an initialization vector. The device may further calculate, in parallel and based on the products of the cumulative products of the series of transition matrices and the initialization vector, an output array that corresponds to a decoded version of the received encoded data in the input array.06-06-2013
20110211659Low-latency Viterbi survivor memory architecture and method using register exchange, trace-back, and trace-forward - In various aspects, the disclosure describes systems and methods for decoding of convolutionally encoded signals representing, for example, telecommunications signals such as command or content signals used in digital telecommunications. In various embodiments such aspects of the disclosure provide systems and methods for improving the efficiency, speed, and power consumption of such processes by providing architectures and methods for processing various parts of the encoded data records in parallel, using multiple and optionally specially-designed, dedicated memory registers and multiplexers.09-01-2011
20080198953Decoding Method and Decoding Apparatus - Disclosed herein is a decoding method of performing maximum a posteriori probability (MAP) decoding of selecting one decoded word from one or more decoded word candidates obtained by subjecting a linear code to iterative decoding by comparison of distances between a reception word and each decoded word candidate. A decoded word candidate in which a known value in a part of a transmission word has been changed to another value is excluded from the one or more decoded word candidates.08-21-2008
20120275548METHOD AND APPARATUS FOR DATA QUANTIZATION AND PACKING WITH VARIABLE BIT WIDTH AND PERIOD - The various embodiments provide circuitry and methods for packing Log Likelihood Ratio (“LLR”) values into a buffer memory in a compressed format which reduces the amount of buffer memory required. Various embodiments use a type of quantization which reduces the bit width of the LLR values that are stored, with the particular level of quantization depending upon the code rate of the data. The degree, pattern, and periodicity of bit width compression employed may depend upon the code rate of the received transmission. Bit width patterns use for LLR value quantization may be generated by a shift register circuit which provides an efficient mechanism for controlling an LLR packer circuit based upon the code rate of the received signal.11-01-2012
20120281790PARALLEL DECODER FOR MULTIPLE WIRELESS STANDARDS - A method of parallel decoding for a plurality of communications standards generally including steps (A) to (C) is disclosed. Step (A) may receive a plurality of first words, at least two of the first words generally have a different length than each other. Step (B) may parse the first words into a plurality of memories. Step (C) may generate a plurality of second words by decoding the first words using a plurality of decoders. The decoders generally operate in parallel. The decoding of at least one of the first words may be performed by at least two of the decoders. The decoding is generally based on a signal that identifies a current one of the communications standards used to transfer the first words.11-08-2012
20110311003SOURCE-CHANNEL APPROACH TO CHANNEL CODING WITH SIDE INFORMATION - Code designs for channel coding with side information (CCSI) based on combined source-channel coding are disclosed. These code designs combine trellis-coded quantization (TCQ) with irregular repeat accumulate (IRA) codes. The EXIT chart technique is used for IRA channel code design (and especially for capacity-approaching IRA channel code design). We emphasize the role of strong source coding and endeavor to achieve as much granular gain as possible by using TCQ. These code designs synergistically combine TCQ with IRA codes. By bringing together TCQ and EXIT chart-based IRA code designs, we are able to approach the theoretical limit of dirty-paper coding.12-22-2011
20110311002Turbo-Equalization Methods For Iterative Decoders - Certain embodiments of the present invention are improved turbo-equalization methods for decoding encoded codewords. In one embodiment, in global decoding iteration i, the magnitude values of all decoder-input LLR values (L12-22-2011
20090262872RECEIVER WITH PREFILTERING FOR DISCRETE FOURIER TRANSFORM-SPREAD-ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (DFT-S-OFDM) BASED SYSTEMS - A receiver for discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) based systems, including a prefilter for received signal codeword(s); and a log-likelihood ratio LLR module responsive to the prefilter; wherein the prefilter includes a pairing and whitening module that based on channel estimates and data rate enables the LLR module to perform either a Serial-In-Serial-Out (SISO) based log likelihood ratio processing of an output from the paring and whitening module or a two-symbol max-log soft output demodulator (MLSD) based log likelihood ratio processing of an output from the pairing and whitening module.10-22-2009
20120093266Apparatus and Method for Trellis-Based Detection in a Communication System - An apparatus for trellis-based detection in a communication system including a processor and memory having computer program code configured to construct a trellis representing a transmitted signal formed from a plurality of symbols, each having a constellation size, transmitted by a number of transmit antennas, and form a log likelihood ratio at nodes of the trellis as a log-sum of a number of exponential terms corresponding to a hypothesized transmitted bit value of the plurality of symbols. The number of exponential terms is limited by a number of most likely paths of the trellis extending from each node of the trellis and the constellation size. The processor and memory including computer program code are further configured to form a list at each node of the trellis of a size limited to the number of the most likely paths of the trellis extending from each node of the trellis.04-19-2012
20130208836RECEIVER AND RECEIVED SIGNAL DECODING METHOD - In a receiver with a demodulator and a decoder performing iterative processing, a solution is provided for reducing the implementation cost of and improving the throughput of an interleaver and a deinterleaver. A receiver includes a symbol demapper outputting first extrinsic information by using one received symbol and a priori information, a check node decoder outputting second extrinsic information by using first extrinsic information and a priori information, a deinterleaver deinterleaving second extrinsic information, a variable node decoder outputting third extrinsic information by using deinterleaved second extrinsic information as a priori information, and an interleaver interleaving third extrinsic information output from the variable node decoder. The check node decoder outputs fourth extrinsic information by using interleaved third extrinsic information as a priori information and the fourth extrinsic information is used as a priori information by the symbol demapper. A plurality of deinterleave/interleaver modules are provided for parallel processing.08-15-2013
20090097596Methods and Systems for Impulse Noise Compensation for OFDM Systems - Methods and systems are provided to reduce the effects of impulse noise in decoding a received OFDM signal by reducing the bit error number in burst error positions and by reducing the impulse noise contribution to channel estimation. In order to reduce the performance degradation due to impulse noise, it is important to find the position or the OFDM symbol where impulse noise occurs. The high noise variance gain can then be used for a Viterbi decoder to reduce the bit error number in burst error position, and also to reduce the contribution of the channel estimation by impulse noise in future channel estimations. Accordingly, the performance of the system can be greatly improved.04-16-2009
20130208835Receiver Circuit and Method for Detecting Data - A method includes a first step of receiving a signal on the basis of a mobile communications standard supporting multiple predefined modulation alphabets and a second step of detecting data of the received signal on the basis of a modulation alphabet which includes modulation symbols of at least two of the multiple predefined modulation alphabets.08-15-2013
20130208837Method of Estimating the Symbols of a Digital Signal and Receiver for Implementing Said Method - The invention relates to a method of estimating symbols carried by a digital signal that is received by a receiver over a communication channel (08-15-2013

Patent applications in class Maximum likelihood decoder or viterbi decoder