Inventors list

Assignees list

Classification tree browser

Top 100 Inventors

Top 100 Assignees


Fourier transform

Subclass of:

370 - Multiplex communications

370203000 - GENERALIZED ORTHOGONAL OR SPECIAL MATHEMATICAL TECHNIQUES

Patent class list (only not empty are listed)

Deeper subclasses:

Entries
DocumentTitleDate
20090201797RADIO COMMUNICATION SYSTEM, RECEIVER, RECEIVING METHOD, TRANSMITTER, TRANSMITTING METHOD, AND DEVICE FOR AND METHOD OF CALCULATING DELAY TIMES FOR MULTI-CARRIER TRANSMISSION - Multi-carrier transmission is performed without inserting a repetitive signal into guard interval periods. A transmitter provides guard interval periods by using a null signal to save transmission power and prevent the deterioration of the SN ratio. Delayed waves at the head of each received symbol cause high-frequency waves to occur and carriers to interfere with one another. Accordingly, a receiver adds a component following each received symbol to a delayed-wave component at the head of the received symbol. As a result, the delayed-wave component at the head of the received symbol and the added component become continuous in wave form and subcarriers do not interfere with each other.08-13-2009
20090196166RECEIVER AND FREQUENCY INFORMATION ESTIMATING METHOD - A receiver 08-06-2009
20090245091BUFFERED DEMOD AND DEMAP FUNCTIONS - An apparatus operable in a wireless communication system, the apparatus may include an FFT symbol buffer and a demapping device. The FFT symbol buffer can feed FFT symbol data derived from received communication signals to a channel estimation device and a shared buffer. The channel estimation device can also provide intermediate data to the shared buffer. The intermediate data may be in tile form and can be derived from the FFT symbol data. Further, the intermediate data can be stored in the shared buffer. The demapping device can extract the intermediate data from the shared buffer in various forms including sub-packet form.10-01-2009
20090185476DURATION-SHORTENED OFDM SYMBOLS - A communications network comprises a base station (07-23-2009
20100067366Method to Improve the Channel Estimate in Broadband SIMO/MIMO Cellular Radio Networks During Abrupt Interference Variations - A channel response matrix gathering all unknown elements for all K pilot subcarriers on links between transmitting and receiving antennas, is Least Squares (full-rank) estimated. The interference covariance matrix is estimated from the residual. The correlation of the interference covariance matrix is computed at each new symbol and compared with a threshold. If the interference is significantly changed, the interference covariance matrix is re-initialized, otherwise a running average of the interference covariance matrix is updated with the actual value. Both the updated/re-initialized interference covariance matrix and the autocorrelation matrix of the transmitted pilot sequences (stored in the receiver) are used for whitening the estimated channel matrix before submission to modal filtering for rank reduction. The original spatial and/or temporal correlations are reintroduced in the reduced-rank channel matrix by inverse whitening. After estimation in the discrete-time domain, DFT for conversion is applied for estimation in the whole frequency band.03-18-2010
20110194402METHOD AND APPARATUS FOR WAVEFORM INDEPENDENT RANGING - A system and method for calculating a time of arrival (TOA) of an electromagnetic signal is presented. A method receives a fast Fourier transform (FFT) signal that is a FFT of an original electromagnetic signal containing symbol data. The FFT signal is either multiplied or divided with a value to remove the symbol data. Removing the symbol data generates a perturbed data values representing perturbed signal with a perturbed covariance. The method calculates a perturbed covariance of the perturbed data values. After the perturbed covariance is calculated, the method at least partially corrects the perturbed covariance to produce a corrected covariance. The TOA of the original electromagnetic signal is calculated based, at least in part, on the perturbed covariance.08-11-2011
20130077467RECEIVER IN ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM AND SIGNAL PROCESSING METHOD THEREOF - According to an exemplary embodiment of the present invention, a receiver in an orthogonal frequency division multiple access (OFDMA) system includes: an extraction unit that extracts received user signal subvectors for subcarriers assigned to the receiver from received signal vectors received from a transmitter; and a fast Fourier transform (FFT) unit that performs a fast Fourier transform on the received user signal subvectors.03-28-2013
20130077468Preambles in OFDMA System - The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-1 and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.03-28-2013
20130077469Preambles in OFDMA System - The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-I and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.03-28-2013
20130077466RADIO COMMUNICATION DEVICE AND SIGNAL DIVISION METHOD - Provided is a radio communication device which can reduce ISI caused by destruction of an orthogonal DFT matrix even when an SC-FDMA signal is divided into a plurality of clusters and the clusters are respectively mapped to discontinuous frequency bands. The radio communication device includes a DFT unit (03-28-2013
20130039165DISCRETE FOURIER CALCULATION DEVICE, RADIO COMMUNICATION DEVICE, AND DISCRETE FOURIER CALCULATION METHOD - A discrete Fourier calculation device includes a twiddle factor table storage unit that stores therein a twiddle factor table that associates twiddle factors with phases of the corresponding twiddle factors; a correction value specifying unit that specifies first and second correction values for correcting a phase of an input signal in accordance with an amplitude of the input signal; a generating unit that corrects the phase of the input signal by using the specified first and second correction values to generate first and second phases; an addition unit that adds an arbitrary phase corresponding to an arbitrary twiddle factor stored in the twiddle factor table, to each of the generated first and second phases; and a rotation calculation unit that acquires, from the twiddle factor table, first and second twiddle factors corresponding to the first and second phases and sums the acquired first and second twiddle factors.02-14-2013
20100046360WIRELESS COMMUNICATION METHOD, RECEIVING METHOD, AND WIRELESS COMMUNICATION DEVICE - A wireless communication method, comprising: allocating, by a base station device, elements of a sequence having an index indicative of a communication parameter to synchronization channel symbols; generating, by the base station device, a synchronization channel while maintaining symmetry of the sequence; transmitting, by the base station device, signals including the synchronization channel; receiving the signals by a mobile station device, correcting, by the mobile station device, the signals based on the symmetry of the sequence; and extracting, by the mobile station device, the communication parameter.02-25-2010
20100046359Wireless Terminal, Base Station and Channel Characteristic Estimating Method - In a wireless communication system based on an OFDM access system, when forgetting averaging channel estimation is performed, there occurs a phase difference between a present channel estimated value and a past estimated value due to a change of FFT operation timing at a reception side. The error of the channel estimated value caused by the phase difference is corrected. A synchronization catching/tracking unit to determine an operation timing of an FFT from a received signal is provided, and an FFT operation timing difference acquisition section to grasp a change of the operation timing of the FFT generated by the synchronization catching/tracking unit is provided. Based on an FFT operation timing change amount as an output of the FFT operation timing difference acquisition section, a rotation operation is performed on a propagation path estimated result stored in a channel estimation section to estimate a propagation path from a received pilot signal, so that the error of the channel estimated value is corrected.02-25-2010
20100046358TRAINING SEQUENCES FOR VERY HIGH THROUGHPUT WIRELESS COMMUNICATION - Methods and systems for communications that generate a plurality of spatial streams, wherein each of the spatial streams comprises a data packet with a training sequence; and multiply at least a portion of the training sequence in each of the spatial streams with a different spreading sequence. Methods and systems that receive a plurality of spatial streams, wherein each of the spatial streams comprises a data packet with a training sequence; multiply at least a portion of the training sequence in each of the spatial streams with a different spreading sequence; and decode the plurality of spatial streams based on the different spreading sequences.02-25-2010
20100097923Peak-to-Average Reduction of SC-FDMA Signals with Frequency Mask - A wireless transmitter exhibits improved power de-rating reduction, which improves the power efficiency of non-constant envelop communication systems by mapping N first samples of a first discrete Fourier transform (DFT) of a group of coded symbols to M sub-carriers according to a first sub-carrier mapping rule (04-22-2010
20100322066METHOD AND APPARATUS FOR TRANSMITTING MIDAMBLE IN WIRELESS COMMUNICATION SYSTEM - A method and apparatus of transmitting a midamble in a wireless communication system is provided. A base station (BS) generates a midamble sequence for each of a plurality of antennas, and transmits the midamble sequence to a user equipment for each antenna. A location of a subcarrier to which each midamble sequence is mapped is determined based on a frequency reuse factor (FRF).12-23-2010
20100322065APPARATUS AND METHOD FOR TRANSMITTING/RECEIVING SIGNAL IN SINGLE CARRIER FREQUENCY DIVISION MULTIPLEXING ACCESS COMMUNICATION SYSTEM - A method and apparatus for transmitting a signal in a Single Carrier-Frequency Division Multiplexing Access (SC-FDMA) communication system are provided. The method includes determining if a Bandwidth Expansion Factor (BEF) Q is an integer, the BEF being determined as N/M according to a number N of subcarriers of a system band and a number M of subcarriers of an allocated band, expanding an input signal to be transmitted Q times in a time domain when the Q is an integer, generating an SC-FDMA signal, and transmitting the SC-FDMA signal.12-23-2010
20090154336CONTINUOUS PHASE MODULATION PROCESSING FOR WIRELESS NETWORKS - Various example embodiments are disclosed herein. According to an example embodiment, a method may include receiving a plurality of data symbols, generating a continuous phase modulated waveform based on the data symbols, generating a plurality of coefficients which represent the continuous phase modulated waveform, and wirelessly transmitting the plurality of coefficients via a plurality of subcarriers.06-18-2009
20100039928METHOD AND APPARATUS FOR TRANSMITTING UPLINK SIGNALS USING MULTI-ANTENNA - A method and apparatus for allowing a UE to transmit uplink signals using a MIMO scheme are disclosed. In order to maintain good Peak power to Average Power Ratio (PAPR) or Cubic Metric (CM) properties when the UE transmits uplink signals using the MIMO scheme, the UE uses a preceding scheme based on a preceding matrix established in a manner that one layer is transmitted to each antenna in specific rank transmission.02-18-2010
20100027409Method for transmitting control signal - There is provided a method of enabling a user equipment to transmit a control signal to a base station. The method includes allocating a control signal to a control region on a subframe, the subframe comprising the control region for the control signal and a data region for user data, wherein different frequency bands within the control region are allocated to different user equipments, and transmitting the subframe in uplink direction. A control signal can be robustly transmitted under variance of channel condition.02-04-2010
20100067367METHOD OF SELECTING MODULATION AND CODING SCHEME (MCS) INDEX IN A WIRELESS COMMUNICATION SYSTEM AND APPARATUS FOR IMPLEMENTING THE SAME - A method of selecting a modulation and coding scheme (MCS) in a wireless communication system is disclosed. More specifically, the method includes selecting a MCS index having a coding rate that is greater than a specified coding rate threshold if a resource allocation scheme of a transmitting end employs a localized resource allocation scheme, and selecting the MCS index having the coding rate that is less than the specified coding rate threshold if the resource allocation scheme of the transmitting end employs the distributed resource allocation scheme.03-18-2010
20090323512Combined OFDMA Preamble Index Identification, Integer Frequency Offset Estimation, and Preamble CINR Measurement - A wireless signal processor for use in identifying a maximum Carrier to Noise Interference Ratio (CINR) associated with a plurality of received OFDMA subcarriers has a candidate generator for forming a plurality of candidate values from a particular set of received subcarriers by forming candidate values based on the received subcarriers in combination with possible integer preamble offsets and possible preamble values. A candidate evaluator selects which of the possible preamble values and integer frequency offset values have the maximum CINR, and provides the maximum CINR with IFO and preamble index as outputs.12-31-2009
20130088950METHOD AND DEVICE FOR SINR ESTIMATION04-11-2013
20090303869ROBUST NARROWBAND SYMBOL AND FRAME SYNCHRONIZER FOR POWER-LINE COMMUNICATION - An embodiment is a method and apparatus to perform symbol synchronization. A correlation estimator computes a correlation of a sample vector representative of a narrowband signal. A synchronization detector detects symbol synchronization.12-10-2009
20090303867APPARATUS AND METHOD FOR PREVENTING DATA READ ERROR FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYMBOL DEMODULATION - Disclosed are an apparatus and a method for preventing data read error for OFDM symbol demodulation. An average time synchronization offset estimating unit estimates average time synchronization offset between a pilot symbol of a time synchronized data frame and pilot symbols of data frames next to the time synchronized data frame. A data buffer control unit acquires a start location of a data frame to be read using the estimated average time synchronization offset, and controls reading of written data frames using the acquired start location information of the data frame to be read. In the apparatus and the method, a data buffering using a ring buffer construction may compensate time synchronization offset of samples containing real data in an OFDM symbol and prevent an erroneous read error in order to improve a receiving performance of a receiver.12-10-2009
20090040919Transmission Using Nested OFDMA - A transmission of information within a wireless cellular network may include a first and second group of samples. A first group of samples is created comprising at least a first and a last subgroup, wherein the last subgroup is same as the first subgroup. A second group of samples created. A transformed set of samples produced by jointly transforming the created first and second group with a discrete Fourier transform (DFT). The transformed set of samples is expanded to produce an expanded set, and the expanded set is transformed with an inverse discrete Fourier transform (IDFT) to produce an OFDM symbol with a fractional payload. The first group of samples is a reference signal (RS), which is known to the receiver before the transmission occurs, while the second group of samples is information data.02-12-2009
20090040918Random Access Preamble Detection for Long Term Evolution Wireless Networks - This invention is a method for preamble detection with estimation of UE timing advance (TA) and channel quality information (CQI) which uses a sliding window to detect the preamble and estimate user timing advance and channel quality information. The window length is set to the cyclic prefix length of data transmission. A preamble detection threshold is computed semi-analytically according to noise sample statistics.02-12-2009
20090040917Transmitting Apparatus, Receiving Apparatus, Transmitting Method, Receiving Method, Information Recording Medium and Program - In a transmission device 02-12-2009
20090092041Apparatus and Method for Performing a Scan Procedure and Mobile Station Comprising the Same - An apparatus for performing a scan procedure according to an orthogonal frequency division multiple access (OFDMA) signal and a mobile station comprising the same are provided. The characteristic of the apparatus is that it comprises two FIT input buffers. In a first period of a downlink subframe, the first FFT input buffer is used for data transmission. In a second period of the downlink subframe, the second FFT input buffer is used for storing more than one OFDMA sample in advance for further processing. In a third period of an uplink subframe, the stored OFDMA samples can be used to generate a refined frame boundary and calculates a CINR value of each of a plurality of neighboring base stations. Therefore, the apparatus and the MS can perform the scan procedure without downgrading the network efficiency.04-09-2009
20090268604APPARATUS AND METHOD FOR REDUCING PAPR OF PREAMBLE SIGNAL IN DIGITAL BROADCASTING SYSTEM - A method and apparatus for reducing a Peak to Average Power Ratio (PAPR) in a digital broadcasting system are provided. Reserved tones are determined, and the determined reserved tones are used to transmit a signal having an impulse characteristic in locations of sub-carriers that do not collide with a pilot signal of a preamble in a frame. The signal having the impulse characteristic is transmitted through the reserved tones in a symbol interval for which the preamble is transmitted.10-29-2009
20090268603MULTIPLE STAGE FOURIER TRANSFORM APPARATUS, PROCESSES, AND ARTICLES OF MANUFACTURE - In embodiments, a fast Fourier transform (FFT) engine includes a series of stages, each stage containing a butterfly and a data normalization device configured to scale output of the stage's butterfly. The scaling factors are adjusted, for example, periodically or on as-needed basis, so that the dynamic range of the butterflies and the buffers is increased for a given bit-width, or the bit-width of these devices is decreased for the same dynamic range. Additionally, bit-width of other buffer(s) is decreased because of the scaling of the data.10-29-2009
20090231994DEMODULATING CIRCUIT, DEMODULATING METHOD, PROGRAM, AND RECEIVING DEVICE - Disclosed herein is A demodulating circuit including: an FFT processing section; an intercarrier interferential component removing section; an extracting section; a transmission path characteristics estimating section; an interpolating section; a symbol sequence estimating section; and an interference replica generating section.09-17-2009
20090231993Methods of uplink channelization in LTE - Methods of a slot-level remapping physical uplink control channels into two resource blocks respectively located at two slots of a subframe, are generally adapted to a 3GPP LTE physical uplink where ACK/NAK resource blocks may be applied by the extended cyclic prefix, adapted to a complex 3GPP LTE physical uplink where mixed resource blocks (where the ACK/NAK and CQI channels coexist) may be applied by the normal cyclic prefix, and adapted to a complex 3GPP LTE physical uplink where mixed resource blocks (where the ACK/NAK and CQI channels coexist) may be applied by the extended cyclic prefix.09-17-2009
20090231992METHOD FOR DESIGNING OPERATION SCHEDULES OF FFT AND MIMO-OFDM MODEM THEREOF - The present invention provides a method for designing operation schedules of a fast Fourier transform (FFT) and a multiple input multiple output orthogonal frequency division multiplexing modem (MIMO-OFDM modem) thereof. According to the present invention, an operation speed of an FFT operator is set up, a receiving symbol is arranged in an OFDM symbol duration in an FFT after receiving the symbol, a transmitting symbol is arranged in an OFDM symbol duration in the FFT schedule before transmitting the symbol, a transmitting/receiving symbol which has the same timing is inserted into an idle symbol duration of the FFT schedule, an FFT schedule which is good to be deleted is deleted, and symbols of the deleted FFT schedule are re-arranged in order to not have an error occur in transmitting/receiving timing. According to the present invention, the FFT operation and the IFFT operation are processed by one FFT/IFFT operator in the MIMO-OFDM modulation/demodulation apparatus, so that symbols to be modulated/demodulated may be properly scheduled, a minimum number of FFT/IFFT operators may be needed, and a delay of data processing may be minimized.09-17-2009
20100271931CHANNEL STATE INFORMATION RECONSTRUCTION FROM SPARSE DATA - Accurate downlink channel estimates are calculated based on infrequently transmitted Channel State Information (CSI) feedback data from a UE 10-28-2010
20090010150Apparatus for Band Limiting in Sc-Fdma Communications Systems and Method Thereof - A method for band limiting in a Single Carrier Frequency Division Multiple Access (SC-FDMA) communications system comprises generating a SC-FDMA data symbol block and band-limiting the SC-FDMA data symbol block using a window (01-08-2009
20100080114LOW COMPLEXITY BANDWIDTH EFFICIENT CARRIER FREQUENCY OFFSET ESTIMATION TECHNIQUE FOR OFDMA UPLINK TRANSMISSIONS - A system and a method for estimating low complexity bandwidth efficient carrier frequency offset for orthogonal frequency division multiple access (OFDMA) and or single carrier frequency division multiple access (SC-FDMA) uplink transmissions in a communication network systems comprising a group of subscriber stations, a base station including carrier frequency offset unit, said method steps comprising:04-01-2010
20080310296Systems and Methods for Transmit-Only Peak-to-Average Ratio Reduction in the Oversampled Regime Using Reserved Tones - Systems and methods for reducing the peak-to-average power ratio (PAR) at the transmitter can reduce the dynamic range required in various analog components. PAR can be reduced by applying a time-domain compensation signal in the oversampled regime, using tones reserved for PAR reduction. A set of vectors corresponding to PAR tones is generated by processing out-of-phase symbols for each PAR tone to form a span matrix. The span matrix is used to find a best fit of a desired target signal to a time-domain compensation signal comprising only PAR tones.12-18-2008
20130163403DATA PROCESSING DEVICE OF MULTI-CARRIER SYSTEM AND DATA PROCESSING METHOD THEREOF - A data processing method of a multi-carrier receiving device, according to an embodiment of the present invention, includes determining a data processing order for user data provided from a plurality of different users according to a unit data length detected from user information, processing in parallel the user data according to the determined data processing order by using a plurality of inverse discrete Fourier transform (IDFT) engines, and recombining the in-parallel-processed data on a per-user basis with reference to the data processing order and timing information.06-27-2013
20090323511Combined OFDMA Preamble Index Identification, Integer Frequency Offset Estimation, and Preamble CINR Measurement - A wireless signal processor for use in identifying a maximum Carrier to Noise Interference Ratio (CINR) associated with a plurality of received OFDMA subcarriers has a candidate generator for forming a plurality of candidate values from a particular set of received subcarriers by forming candidate values based on the received subcarriers in combination with possible integer preamble offsets and possible preamble values. A candidate evaluator selects which of the possible preamble values and integer frequency offset values have the maximum CINR, and provides the maximum CINR with IFO and preamble index as outputs.12-31-2009
20080316913Method and Apparatus for Transmitting by Using Transmit Diversity at Dft Spread Ofdma - The present invention relates to a packet data transmission method in an OFDMA system and an apparatus thereof. The present invention provides a user packet data transmission method including generating a RACH burst for channel information estimation, selecting a first antenna among a plurality of antennas, transmitting the RACH burst through the first antenna to a base station, receiving a data transmission acceptance signal from the base station, in response to the RACH burst, transmitting user packet data through the first antenna when receiving a signal indicating that the data transmission is allowed, and selecting a second antenna that is difference from the first antenna and transmitting a RACH burst through the second antenna when receiving a signal indicating that the data transmission is not allowed, and a transmitting apparatus of a mobile station having the plurality of antennas. According to the present invention, the RACH burst and user packet data are transmitted by using a mobile station having a plurality of antennas in an LTE-applied OFDMA system, and therefore data transmission can be performed with a wide bandwidth and high data rate and a deep fading period that may occur during the data transmission can be reduced, thereby preventing call dropping and improving data transmission performance.12-25-2008
20100246378Method for Signal Mapping and Signal Transmission with Subcarrier Shift Schemes - A signal mapping method and a signal transmission method applying a subcarrier shift method are described. A signal mapping method using shifted subcarriers includes shifting positions of data subcarriers by as much as a frequency band corresponding to half of spacing between data subcarriers on a frequency axis, and shifting positions of random access preamble subcarriers by as much as a frequency band corresponding to half of spacing between the data subcarriers and to a specific ratio of spacing between the random access preamble subcarriers, and mapping data and a random access preamble to the data subcarriers and the random access preamble subcarrier, respectively. Even when the spacing between the data subcarriers is a multiple of the spacing between the random access preamble subcarriers, DC distortion can be minimized.09-30-2010
20090323513WEIGHTED TONE RESERVATION FOR OFDM PAPR REDUCTION - A weighted tone reservation (WTR) method and system are disclosed, for PAPR reduction. The WTR method solves the peak re-growth problem with minimum overhead. By avoiding the drawbacks of conventional tone reservation approaches, systems employing the WTR method may experience a significant PAPR reduction. The WTR method may be applied to next generation OFDMA-based wireless broadband technologies to increase system throughput and cell coverage.12-31-2009
20110299384PILOT SIGNAL IN AN FDMA COMMUNICATION SYSTEM12-08-2011
20110299381MOBILE MULTIMEDIA BROADCAST TRANSMISSION SYSTEM - A mobile multimedia broadcast transmission system is provided, which comprises: a Reed-Solomon (RS) coding and byte interleaving unit, a Low Density Parity Check (LDPC) coder, a bit interleaver, a constellation mapping unit, a frequency domain symbol generator, a scrambler, an Inverse Fast Fourier Transform (IFFT) unit, a time domain framing unit, and a transmitter. According to the technical solutions provided in the present invention, the system can provide high-quality mobile multimedia services for users in a 6 MHz operation bandwidth. Furthermore, an optimized selection is performed on RS coding according to the operation bandwidth of the system, thereby selecting an appropriate coding mode according to different channel conditions. Accordingly, the byte interleaver is optimized, such that suitable interleaving parameters can be used to perform byte interleaving. With the technical solutions provided in the present invention, the continuous pilots, the discrete pilots and the digital sub-carriers of the system can be suitably configured and allocated according to the actual bandwidth of the system, thereby suitably configuring the system overhead of the mobile multimedia broadcast transmission system to efficiently utilize spectral resources for data transmission.12-08-2011
20110299383METHOD FOR TRANSMITTING DATA IN MULTIPLE ANTENNA SYSTEM - An apparatus for data transmission in a multi-antenna system is provided. The apparatus includes: a modulation mapper for modulating codewords into modulation symbols that express a position on a signal constellation; a layer permutator for mapping the modulation symbols to different layers; a transform precoder for generating a discrete Fourier transform (DFT) symbol of a frequency domain by performing DFT on the modulation symbol mapped to the layer; a resource element mapper for mapping the DFT symbol to a physical resource element; and a signal generator for generating a single carrier-frequency division multiple access (SC-FDMA) signal from the DFT symbol mapped to the resource element, wherein a modulation order of the modulation symbols is determined depending on the layer mapped by the layer permutator.12-08-2011
20110299382COMMUNICATION DEVICES FOR GENERATING AND USING A MATRIX-MAPPED SEQUENCE - A communication device for generating a matrix-mapped sequence is described. The communication device includes sequence generation circuitry. The communication device also includes mapping circuitry coupled to the sequence generation circuitry. The mapping circuitry applies a first matrix with at least one column multiplied by −1 to a sequence. The communication device also includes a transmit block coupled to the mapping circuitry.12-08-2011
20090257344ALL OPTICAL OFDM WITH INTEGRATED COUPLER BASED IFFT/FFT AND PULSE INTERLEAVING - A method and apparatus for all optical orthogonal frequency division multiplexing (OFDM) employing Inverse Fast Fourier Transform/Fast Fourier Transform by integrated coupler interferometrically.10-15-2009
20090245093APPARATUS AND METHODS FOR UPDATE OF SYMBOL INFORMATION - Apparatus and methods for updating symbol information in a communication device with hardware such as a microcontroller are disclosed. The disclosed apparatus and methods employ waiting for the beginning of a symbol in a sample stream at a predetermined time. One or more programmed instructions are read at the beginning of the symbol, and then symbol information is updated based on the one or more programmable instructions and setting a time for a beginning of a next symbol. The programmed instructions consist of instruction code words that are executed by a dedicated microcontroller or similar hardware, which affords flexibility for updating symbol information, particularly for multimode communication devices operable across multiple communication technologies.10-01-2009
20090296564METHOD AND APPARATUS FOR PRODUCING/RECOVERING OFDM/OFDMA SIGNALS - The present invention discloses a method of producing a multi-layered OFDM symbol using a plurality of small IFFT blocks. The produced OFDM symbol is able to reduce complexity in performing IFFT or FFT while maintaining orthogonality of a related art OFDM symbol. In particular, by avoiding the related art scheme using the N-sized IFFT, the layered IFFT is executed in a manner of grouping N data symbols into P groups each of which includes Q data symbols (N=P−Q). In order to produce an OFDM signal equal to that of the related art N-sized IFFT, it is preferable that phases are aligned for the data symbols on which Q-sized IFFT has been performed.12-03-2009
20110007627METHOD AND APPARATUS FOR GENERATING RANGING PREAMBLE CODE IN WIRELESS COMMUNICATION SYSTEM - A method and apparatus of generating a ranging preamble code in a wireless communication system is provided. A mobile station (MS) generates one of a plurality of ranging preamble codes, wherein the plurality of ranging preamble codes are based on a padded Zadoff-Chu (ZC) sequence to which a cyclic shift is applied in a unit of N01-13-2011
20100034076BASE STATION, USER APPARATUS, AND METHOD - A base station used in a mobile communications system which uses orthogonal frequency division multiplexing (OFDM) for downlink is disclosed. The base station includes: a unit which provides a reference signal; a unit which multiplexes a control signal and the reference signal, and generates a transmit symbol; and a unit which inverse Fourier transforms the transmit symbol and wirelessly transmits the transformed transmit symbol, wherein a first sequence including a random code sequence and a second sequence belonging to an orthogonal-code sequence group are multiplied with the reference signal, mutually different ones of the orthogonal code sequences are used in the respective multiple sectors belonging to the same cell, and different ones of the random code sequences are used in the respective two or more cells.02-11-2010
20100091642APPARATUS OF CELL ACQUISITION IN WIRELESS COMMUNICATION SYSTEM AND THE METHOD THEREOF - An apparatus and a method for performing a cell search are disclosed. The apparatus includes fast Fourier transform (FFT) units converting signals received by the multiple antennas into frequency domain signals, inverse randomizers inverse-randomizing the frequency domain signals, an alignment unit aligning the inverse-randomized frequency domain signals to form an aligned signal, an inverse fast Fourier transform (IFFT) unit converting the aligned signal into a time-domain signal, a maximum value detector detecting a maximum value of the time-domain signal and a determiner determining whether a preamble is obtained based on the maximum value detected by the maximum value detector. Therefore, communication performance and quality may be improved and complexity may be reduced since one IFFT unit is used with respect to the signals received by a plurality of antennas.04-15-2010
20100128594METHOD OF RESOLVING OVERLAPS IN DATA TRANSMISSION AND USER EQUIPMENT THEREFOR - A user equipment and method of transmitting symbols by the user equipment in a wireless communication system. The method includes: generating a first symbol by adding a cyclic prefix (CP) to a first inverse fourier transformed samples, the CP being copied from the first fourier transformed samples; generating a next consecutive second symbol by adding a CP to a second inverse fourier transformed samples, the CP being copied from the second fourier transformed samples; removing samples overlapped with the first symbol from the next consecutive second symbol when the next consecutive second symbol is to be advanced in transmission timing; and transmitting the first symbol and the next consecutive second symbol to a base station.05-27-2010
20090303868Control Channel Transmission Method And Radio Communication Apparatus - A control channel transmission method in a radio communication apparatus which has a plurality of antennas, including, generating signal which are orthogonal to each other on a frequency axis between each of the antennas; modulating the signal using a control signal corresponding to a control channel respectively; and transmitting the modulated signal from each of the antennas using a single carrier transmission.12-10-2009
20100118693METHOD AND SYSTEM FOR USING THE SYNCHRONIZATION CHANNEL TO OBTAIN MEASUREMENTS IN A CELLULAR COMMUNICATIONS SYSTEM - A method and apparatus that utilizes the synchronization channel (SCH) by the user equipment (UE) to obtain time synchronization information and to perform cell search. In order to perform the SCH detection, only a correlation between the known SCH signal and the received sequence is needed, hence the FFT is not involved in the synchronization step. Typically the SCH and pilot symbols are transmitted with a constant power which is the same for all base stations. Hence, based on the serving cell (SC) SCH and pilot symbols, the power relation between these signals is estimated and the ratio applied when performing time synchronization to other cells (i.e. correlation the received sequence with the SCH from that particular NC) to estimate the pilot signal strength for the NB cell.05-13-2010
20090185475NON-ORTHOGONAL SUBCARRIER MAPPING METHOD AND SYSTEM - A method and system of accommodating multiple users through non-orthogonal subcarrier mapping of a single carrier frequency division multiple access system in which input data to a transmitter is modulated via an N-point discrete Fourier transform (N-point DFT), non-orthogonal subcarrier mapping, M-point inverse discrete Fourier transform (M-point IDFT), and cyclic prefix (CP) insertion; the modulated data is transmitted to and received by a receiver; and the received data is demodulated for cyclic prefix (CP) removal, M-point discrete Fourier transform (M-point DFT), subcarrier demapping and equalization, and N-point inverse discrete Fourier transform (N-point IDFT).07-23-2009
20100118694Wireless Communication Device - The mobile station performs Fourier transform of a signal received from a base station presently in communication in parallel to demodulation processing, by means of a plurality of FFT each having FFT start timing shifted one after another, so as to detect the synchronous timing of another base station by detecting correlation through a pattern comparison with a subcarrier signal including the pilot signal of the other base station.05-13-2010
20100080113TONE RESERVATION TECHNIQUES FOR REDUCING PEAK-TO-AVERAGE POWER RATIOS - Embodiments of the present disclosure describe closed loop scheduled peak-to-average power (PAPR) reduction systems and methods to facilitate desired PAPR reduction. Other embodiments describe weighted tone reservation (WTR) methods and systems for PAPR reduction. Still other embodiments may be described and claimed.04-01-2010
20090141620APPARATUS AND METHOD FOR TIME-VARYING CYCLIC DELAY DIVERSITY IN A WIRELESS COMMUNICATION SYSTEM - An apparatus and method for Time-Varying Cyclic Delay Diversity (TV-CDD) in a wireless communication system are provided. The method includes, if there is a signal of an antenna path to be transmitted, determining if a current time corresponds to a preamble zone within a frame and, if the current time corresponds to the preamble zone within the frame, shifting a partial antenna path signal forward compared to a reference timing and shifting a remaining partial antenna path signal equally or backward compared to the reference timing.06-04-2009
20090046571Method and apparatus for transmitter timing adjustment - A timing adjustment value is received, and from the received timing adjustment value is determined an integer portion and a fractional portion. In the frequency domain, the determined fractional portion is applied by rotating a signal. Optionally, a phase shift may also be imposed with the rotation. In the time domain, the determined integer portion is applied by one of inserting samples in the rotated signal or removing samples from the rotated signal in an amount corresponding to the determined integer portion. After the signal rotation to apply the fractional portion, the active sub-carriers are mapped, and the transition from frequency domain to time domain occurs by means of an inverse Fourier transform. A cyclic prefix CP may be added after the Fourier transform, separately or functionally combined with the integer portion shift by modifying the size of the CP to impose the determined integer portion. After other conventional processing known in the art, the rotated signal as advanced/delayed by the sample removal/addition is then transmitted.02-19-2009
20110199889SEQUENCE-GENERATING METHOD, AND APPARATUS FOR SAME - The present invention relates to a wireless communication system. More particularly, the present invention relates to a method for enabling a transmitter to transmit a sequence in a wireless communication system, and to an apparatus for the same. A sequence-transmitting method comprises the steps of: performing at least one of a complex conjugate operation and a reverse operation on a first sequence to generate a second sequence; mapping the second sequence to a plurality of subcarriers in an Orthogonal Frequency Division Multiple Access (OFDMA) symbol; and transmitting the OFDMA symbol to a receiver. The invention also relates to an apparatus for the sequence-generating method.08-18-2011
20090201796LOW CONVERSION RATE DIGITAL DISPERSION COMPENSATION - A method of suppressing effects of aliasing in a system for digitally processing a high speed signal having a symbol rate of 1/T. The high speed signal is sampled at a fractional multiple (N) of the symbol rate, wherein 108-13-2009
20090279421APPARATUS AND METHODS FOR ESTIMATING AND COMPENSATING SAMPLING CLOCK OFFSET - An apparatus for sampling clock recovery (SCO) and methods for estimating and compensating SCO are provided. The apparatus comprises a symbol timing adjustment module for shifting forward or backward symbol timing of the transmitted OFDM symbols; a discrete Fourier transform (DFT) processor for performing DFT to an output from the symbol timing adjustment module; a channel estimator for undertaking a channel frequency response estimation based on a channel estimation sequence; a SCO phase rotator for receiving and performing phase shift on the transmitted OFDM symbols of a frame header and a frame payload; an SCO estimation stage for undertaking an SCO estimation based on a pilot-subcarrier-related output of the SCO phase rotator and the CFR estimation; and an SCO compensation distributor for dividing the SCO estimation into integer and fractional portions and then distributing them into the symbol timing adjustment module and the SCO phase rotator, respectively.11-12-2009
20090274039WIRELESS COMMUNICATION DEVICE ADOPTING OFDM MODULATION - A wireless communication device includes a converting circuit, a discrete Fourier transformer, a separating circuit, a correcting unit. The converting circuit converts an analog signal having an in-phase component and a quadrature component into a digital signal having a real part and an imaginary part of complex number respectively. The discrete Fourier transformer converts the real part and the imaginary part of the digital signal obtained in the converting circuit from a time domain to a frequency domain. The separating circuit separates the digital signal into a first sum of a symmetrical component of the real part and an antisymmetrical component of the imaginary part of the digital signal and a second sum of the antisymmetrical component of the real part and the symmetrical component of the imaginary part of the digital signal. The correcting unit corrects a value of the second sum.11-05-2009
20090274038Digital broadcasting receiving apparatus with channel estimation function - A delay profile generating circuit 11-05-2009
20090296563TRANSMISSION APPARATUS, TRANSMISSION METHOD, RECEPTION APPARATUS, AND RECEPTION METHOD - A disclosed transmission apparatus includes a multiplexing portion that multiplexes a common pilot channel, a shared control channel, and a shared data channel; a symbol generation portion that performs an inverse Fourier transformation on the multiplexed signal so as to generate a symbol; and a transmission portion that transmits the generated symbol. The multiplexing portion multiplexes the shared control channel including control information necessary for demodulation of the shared data channel including a payload and the common pilot channel to be used by plural users in a frequency direction, and the shared data channel in a time direction with respect to the common pilot channel and the shared control channel. Even when the number of symbols composing a transmission time interval (TTI) is reduced, transmission efficiency of channels excluding the common pilot channel can be maintained by reducing insertion intervals of the common pilot channel accordingly.12-03-2009
20080304405Signal Generating Unit and Signal Receiving Unit - A signal generating unit (12-11-2008
20090290482METHOD FOR ESTIMATING TRANSMISSION DELAY AND RECEIVER USING THE SAME - There is provided a receiver for processing a ranging channel. The receiver includes a Fourier transformer for transforming a received signal into a frequency domain signal, a ranging channel extraction and ranging code elimination unit for extracting a ranging channel from the frequency domain signal, and eliminating a code of a ranging code from the ranging channel and a ranging channel processor for estimating transmission delay or transmission power from a time domain signal. By estimating transmission delay and/or transmission power in a time domain, it is possible to rapidly and accurately adjust the transmission delay and transmission power intensity in the ranging procedure.11-26-2009
20090103428SYSTEM FOR GENERATING SPACE FREQUENCY BLOCK CODE RELAY SIGNAL AND METHOD THEREOF - A method and system for generating a space frequency block code relay signal includes a signal detection unit which detects a received signal by receiving a first and second source signals transmitted from a first and second source nodes, a relay signal generation unit which generates a relay signal cooperating with the first and second source signals using a space frequency block code (SFBC) scheme based on the received signal, and a signal transmitter which transmits the relay signal to a destination node.04-23-2009
20100110875 MODIFIED SLM SCHEME WITH LOW COMPLEXITY FOR PAPR REDUCTION OF OFDM SYSTEMS - Provided are an apparatus and method for reducing a PAPR with less computation complexity without distortion using a selected mapping scheme (SLM) in an OFDM system. The method includes: generating a plurality of OFDM signal sequences by performing an inverse fast Fourier transform (IFFT) operation on input symbol sequences, which are probabilistically independent and have identical information; linearly combining the plurality of OFDM signal sequences by using complex numbers; and generating different OFDM signal sequences based on the linear combination. Accordingly, the number of phase sequences can be increased without almost increasing a computation amount of SLM.05-06-2010
20080212464METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING CONTROL INFORMATION IN A SINGLE CARRIER FDMA SYSTEM - Provided is a method and an apparatus for transmitting a large quantity of control information in a mobile communication system. When there is no uplink data to be transmitted, a UE spreads second control information, a quantity of which is less than or equal to a pre-defined threshold, by using a ZC sequence cyclic-shifted according to resource blocks, each of which indicates at least one time interval used for a transmission of the second control information. When there is uplink data to be transmitted, the UE performs TDM of the uplink data with third control information. When there is no uplink data to be transmitted and the quantity of control information exceeds a pre-defined threshold, or when the first control information includes various types of information, the UE spreads the first control information in a time domain by the orthogonal codes.09-04-2008
20120294138BASE STATION AND METHOD OF ADJUSTING REFERENCE TIMING ON BASE STATION - An FFT processing unit performs an FFT process on an OFDM signal received by a reception unit. Based on an output signal of the FFT processing unit, an interference wave level acquisition unit obtains a signal level of an interference wave in a unit radio resource not used by the base station with respect to each of a plurality of candidate timings for the reference timing in the base station. A reference timing adjustment unit determines a new timing of the reference timing from the plurality of candidate timings based on the signal level of the interference wave obtained by the interference wave level acquisition unit.11-22-2012
20100142364Method and Arrangement Relating to the Insertion of Pilot Tones in the Frequency Domain in SC-FDMA - The present invention relates to a method and arrangement for enhancing efficiency of transmission using Single Channel-Frequency Division Multiple Access (SC-FDMA). The method comprises the step of: applying a Discrete Fourier Transformation (DFT) of time signal providing No samples in a first resulting signal, inserting N1 pilot tones in said resulting signal providing No+N1 tones, Interpolating said signal provided with No+N1 tones to a required size, N, by insertion of zero bins in a middle section of said DFT providing a modified signal, applying Inversed Fast Fourier Transform (IFFT) on said modified signal, and performing a cyclic prefix insertion before transmitting the modified signal. Thus, similar equalising techniques as for OFDM are possible for efficacy signal reception.06-10-2010
20090034408APPARATUS AND METHOD OF RECONSTRUCTING AMPLITUDE-CLIPPED SIGNAL - A method and apparatus for compensating a distortion due to a clipped amplitude when an amplitude of a signal is clipped to reduce a peak to average power ratio (PAPR) in a wireless communication system using an orthogonal frequency division multiplexing (OFDM) scheme and a transmit diversity method using an orthogonal coding.02-05-2009
20080232241Superimposed Composite Channel Filter - Methods and systems are provided to generate digital coefficients for a filter. The generation of coefficients relies on a Fourier transformation of an impulse response in time domain that is zero padded, e.g., zeros are appended to an array corresponding to a sampled input signal of length M. A unit prototypical filter is generated through a frequency domain response of length N09-25-2008
20090109835TECHNIQUES TO GENERATE CONSTANT ENVELOPE MULTICARRIER TRANSMISSION FOR WIRELESS NETWORKS - Various example embodiments are disclosed herein. According to an example embodiment, an apparatus for use in a wireless transmitter may include a continuous phase modulation (CPM) sample generator configured to generate a group of constant envelope CPM modulated signal samples, a Fourier transform block configured to perform a Fourier transform on the group of constant envelope signal samples to generate an initial group of Fourier coefficients, a zero insertion block configured to generate an expanded group of Fourier coefficients by inserting one or more zeros in the initial group of Fourier coefficients, and an inverse Fourier transform block configured to perform an inverse Fourier transform on the expanded group of Fourier coefficients to generate a group of constant envelope time-domain samples and to map the constant envelope time-domain samples onto a group of orthogonal subcarriers for transmission.04-30-2009
20080205261Multi-Hop Booster - A two-way wireless repeater and booster system and method are disclosed. The system and method improve signal quality and strength for the middle hop of a three-hop repeater, between User and Network Units operating in the unlicensed bands (ISM and/or UNII), and supporting the cellular (or wireless) network communications channels. The system and method enables the support of a wider repeat spectrum or bandwidth for a given communications bandwidth in the unlicensed band.08-28-2008
20080212463AMBLE MODULATION SERIES - An amble modulation series in a downlink relay zone in an IEEE 802.16 network, the amble modulation series being a reverse version of a preamble modulation series of the network. For example, the amble modulation series is related to a preamble modulation series PN09-04-2008
20100142365BEACON CODING IN WIRELESS COMMUNICATIONS SYSTEMS - Systems and methodologies are described that facilitate transmitting beacon symbols of a beacon message such that a sequence of symbols can satisfy a linear constraint over a field where the field elements can be identified with carriers. In this regard, a coding scheme can be applied to a beacon message; the coding scheme can produce a plurality of beacon symbols to transmit on given subcarriers. A receiving device of the beacon symbols can decode a beacon message by receiving less than the total number of symbols in a beacon message and determining the remaining symbol subcarriers based on the linear constraint. Thus, more efficient decoding of beacons is facilitated as well as resolving beacon ambiguity by figuring out which symbols satisfy linear constraints for the symbols, and resolving time and frequency shift by detecting an offset that would result in satisfaction of the linear constraint.06-10-2010
20090190465Downlink Acquisition - The subject matter disclosed herein provides methods and apparatus, including computer program products, for detecting a preamble to enable acquisition of a downlink. In one aspect, there is provided a method. The method may include receiving a plurality of symbols. From an autocorrelation of the received symbols, a guard interval may be detected. The guard interval may represent a receive/transmit transition gap (RTG). A metric may be used to verify whether at least one symbol positioned after the detected guard interval is a preamble. Related systems, apparatus, methods, and/or articles are also described.07-30-2009
20090129259CODING AND MULTIPLEXING OF CONTROL INFORMATION IN A WIRELESS COMMUNICATION SYSTEM - Techniques for sending control information in a wireless communication system are described. In an aspect, a UE spreads control information across frequency with a DFT and across time with an orthogonal sequence to obtain output data for the control information. In one design, the UE receives codewords for N HARQ processes in N downlink subframes, determines an ACK value for each HARQ process, codes N ACK values for the N HARQ processes to obtain ACK information, generates output data for the ACK information, and sends the output data in one of M uplink subframes. In another aspect, first control information is processed based on a first coding and multiplexing scheme utilizing code division multiplexing in time and frequency domains. Second control information is processed based on a second coding and multiplexing scheme utilizing code division multiplexing in time domain and spreading in frequency domain.05-21-2009
20090161529TRANSMITTER AND RECEIVER - A description is given of a transmitter including a baseband chip, a radio frequency chip and an interface unit coupling the baseband chip and the radio frequency chip. The radio frequency chip includes a modulation unit configured to modulate multiple data streams, wherein each of the data streams is assigned to a subcarrier having a frequency differing from the frequencies of the other subcarriers.06-25-2009
20090285086OFDM Receiver and OFDM Receiving Method - An FFT unit generates a frequency domain signal by converting an OFDM signal using Fourier transform. A delay amount calculation unit generates a delay profile of the OFDM signal. The control determination unit detects a main wave and an interference wave using the delay profile. When the time difference between the main wave and a preceding wave is larger than a guard interval of the OFDM signal, an FFT window control unit sets the start position of the FFT window at a position shifted forward from the symbol start position of the main wave by an amount corresponding to the guard interval.11-19-2009
20080316911Simultaneous Cell Group and Cyclic Prefix Detection Method, Apparatus and System - A method, and associated apparatus and system, for simultaneous cell group and cyclic prefix (CP) detection, having the steps of determining primary synchronization signal (P-SyS) timing τ using the P-SyS; based on τ, determine a secondary synchronization signal (S-SyS) timing; placing a single Fast Fourier Transform (FFT) window; FFT processing the signal to obtain the frequency domain S-SyS symbols; equalizing the frequency domain S-SyS signal; phase correcting the S-SyS signal; and detecting the cell group and CP length by the correlation giving maximum energy.12-25-2008
20080316912Combined Ofdm and Wavelet Multi-Carrier Transceiver - A multicarrier transmitter and receiver uses a first inverse fast Fourier transformer for performing an Inverse Fast Fourier Transform (IFFT) on a parallel input data signal, an imaginary component filter for filtering out the imaginary component of an output signal of the first transformer and a real component filter for filtering out the real component of the output signal of the first. The multicarrier transmitter and receiver also uses a first polyphase filter having real coefficients. The first filter accepts output data from the imaginary component filter. The multicarrier transmitter and receiver also uses a second polyphase filter having real coefficients which are selected as the real coefficients of the first filter with the sign of each odd-numbered real coefficient inverted. The second filter accepts output data from said real component filter. A combined OFDM and wavelet multi-carrier transceiver is proposed sharing an IFFT block.12-25-2008
20090252028APPARATUS AND METHOD FOR CONTROLLING RANGING OF MOBILE TERMINALS IN WIRELESS COMMUNICATION SYSTEM - Disclosed are an apparatus and a method for controlling ranging in a wireless communication system. The apparatus according to the present invention comprises a Radio Frequency (RF) module converting RF band signals received via antenna to low-frequency band signal; a Fast Fourier Transform (FFT) module converting the low-frequency band signal of time-domain to frequency-domain signal; a derandomizer performing derandomizing the frequency-domain signals by using a random sequence being transmitted by the terminals; a depermutation module combining the frequency-domain signals output from the derandomizer by unit of burst and outputting the combined signal; and a ranging controller controlling periodic ranging of the terminal corresponding to the respective bursts by estimating phase change in the frequency-domain signals of burst unit.10-08-2009
20090252027WIC AND LIC ESTIMATION IN MEDIAFLO SYSTEMS - An apparatus and method for WIC/LIC estimation without channel mode construction in a MediaFLO™ system comprising a receiver, a transmitter and transmission channel, wherein the method comprises receiving a signal comprising a MediaFLO™ mobile multimedia multicast system superframe comprising WIC/LIC symbols; setting a first sparseness index value of the digital signal to zero; setting a local copy WIC/LIC number of the digital signal to one; generating a local copy of all possible values of the WIC/LIC symbols corresponding to a WID/LID value from zero to fifteen; dividing the received WIC/LIC symbol values by a local copy WIC/LIC value corresponding to WIC/LIC number one; performing an IFFT of all the possible values of the WIC and LIC symbols; calculating a second sparseness index value of the IFFT of sixteen possible values of the WIC/LIC symbols; and extracting a WIC/LIC symbol from the digital signal corresponding to the second sparseness index.10-08-2009
20130121131SYSTEMS AND METHOD FOR ORTHOGONAL FREQUENCY DIVISIONAL MULTIPLEXING - Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to de-modulate symbols from at least one of a plurality of spectrally overlapping carrier signals to produce a receiver output; a transmitter configured to modulate symbols onto at least one of a plurality of the spectrally overlapping carrier signals; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform to the data transmitted by the transmitter; the processor coupled to the receiver, wherein the processor applies a Fourier transform to the receiver output; and a controller programmed to instruct the transmitter to transmit at least one symbol representing a request for bandwidth allocation on a first carrier; wherein the controller is further programmed to determine when a collision has occurred on the first carrier.05-16-2013
20120127849SIGNAL RECEIVING APPARATUS AND COMMUNICATION SYSTEM - There is provided a signal receiving apparatus including first to pth stage computers configured to apply, in a step-by-step manner, butterfly operations to 205-24-2012
20090310479RECEIVING APPARATUS, INTEGRATED CIRCUIT AND RECEIVING METHOD - For a data group composed of pieces of data each indicating channel characteristics of a scattered pilot signal position whose phase is adjusted by dividing scattered pilot signals included in an OFDM signal by a scattered pilot signal at the time of transmission, a carrier extension circuit 12-17-2009
20120182857Sounding Reference Signal Processing for LTE - A wireless communication receiver including a serial to parallel converter receiving an radio frequency signal, a fast Fourier transform device connected to said serial to parallel converter converting N07-19-2012
20080279091Fourier-transform based linear equalization for MIMO CDMA downlink - In the reception of a downlink MIMO CDMA signal, the receiving unit performs a simplified process of linear equalization that eliminates the need for inverting the correlation matrix. The correlation matrix is approximated to a good degree by a circulation matrix that is diagonalized by FFT operations, thus substituting two FFTs and one IFFT having a complexity of11-13-2008
20090245092APPARATUS, PROCESSES, AND ARTICLES OF MANUFACTURE FOR FAST FOURIER TRANSFORMATION AND BEACON SEARCHING - In embodiments, a wireless receiver employs a hardware-based Fast Fourier Transform (FFT) engine controlled by firmware. The FFT engine executes tasks stored in a task list. Each task is associated with a different portion of a signal, for example, one or more Orthogonal Frequency Division Modulated (OFDM) symbols. Each task may include configuration information for the FFT engine for configuring the engine to process the associated portion of the signal, a pointer to the portion to be processed, and another pointer to the memory for storing the output. The task list may be firmware controlled. Division of the FFT into a configurable hardware part driven by firmware to read and execute the tasks in the task list may speed up the FFT process and make it more flexible. A hardware beacon sorter may be coupled to the FFT engine to sort the sub-carriers according to their energies.10-01-2009
20090245090Broadband Pilot Channel Estimation Using A Reduced Order FFT and a Hardware Interpolator - Within a receiver, a channel estimation mechanism involves a hardware interpolator. In a first mode, narrowband pilot values are analyzed to generate channel parameters that are supplied to the interpolator such that the interpolator generates channel estimate values. The channel estimate values are used to demodulate a tile of a frame. In a second mode, broadband pilot values are supplied to an IFFT, thereby generating time domain values. After time domain processing, an FFT is employed to generate intermediate channel estimate values. These intermediate values are analyzed to determine channel parameters, which in turn are supplied to the hardware interpolator so that the interpolator generates a larger number of channel estimate values. After phase adjustment, the channel estimate values are used in demodulation. Use of the interpolator in the broadband mode allows the FFT employed to be of a smaller order, and to consume less power and/or processing resources.10-01-2009
20090219803ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING WIRELESS COMMUNICATION OPERABLE ON FREQUENCY SELECTIVE CHANNEL, AND CHANNEL COMPENSATION METHOD - Disclosed is an OFDM (orthogonal frequency division multiplexing) wireless communication system operable on a frequency selective channel, and a channel compensation method. An IDFT (inverse discrete Fourier transform) unit of a transmitter includes first through third N-point IDFT units, and performs IDFT on a binary information signal twice. A DFT (discrete Fourier transform) unit of a receiver includes first through third N-point DFT units, a channel predictor and interpolator, and a channel compensator, and performs DFT on the signal received from the transmitter twice.09-03-2009
20090219802APPARATUS AND METHOD FOR TRANSMITTING DATA USING A PLURALITY OF CARRIERS - The present invention relates to a data transceiving method in a communication system based on a plurality of carriers, and more particularly, to a method of designing a sequence in a communication system using orthogonal subcarriers. The present invention includes the steps of generating a time-domain sequence with a specific length in a time domain, generating a frequency-domain sequence by performing a DFT or FFT operation on the time-domain sequence according to a length of the generated sequence, including a DC subcarrier and a guard subcarrier in the frequency-domain sequence, and performing an IDFT or IFFT operation on the frequency-domain sequence including the DC subcarrier and the guard subcarrier.09-03-2009
20090219801TRANSMITTER IN FDMA COMMUNICATION SYSTEM AND METHOD FOR CONFIGURING PILOT CHANNEL - The present invention relates to a transmitter in a frequency division multiple access communication system. The transmitter generates a plurality of pilot symbols, and groups the plurality of pilot symbols into a plurality of groups according to a location of a subcarrier. In addition, the transmitter inverse fast Fourier transforms the pilot symbol in each group, and sequentially outputs a first pilot symbol sequence corresponding to each group. The transmitter generates a plurality of pilot blocks respectively corresponding to the plurality of groups, and converts the first pilot symbol sequence of each group into a second pilot symbol sequence of a corresponding pilot block among the plurality of pilot blocks.09-03-2009
20090245089BIT-WIDTH MINIMIZATION SCHEME FOR WIRELESS COMMUNICATION - A technique for generating a reduced bit-width in a signal generated by a first-type modulator in a communication apparatus that includes two distinct modulators. In particular, the communication apparatus includes a first modulator adapted to generate a first modulated signal quantified to a first bit-width, a second modulator adapted to generate a second modulated signal quantified to a second bit-width that is less than the first bit-width, and a device to generate a third modulated signal comprising a combination of the first and second modulated signals. In an exemplary implementation, the first modulator includes an OFDMA modulator, the second modulator includes a CDMA, and the combining device includes an IFFT. Additionally, an apparatus for processing a communication signal includes a tasklist cache memory having a tasklist, a processor adapted to provide a task to the tasklist, and a communication module adapted to fetch the task from the tasklist, and process the communication signal based on the retrieved task.10-01-2009
20120195184SYSTEMS AND METHODS FOR ORTHOGONAL FREQUENCY DIVISIONAL MULTIPLEXING - Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a transmitter configured to modulate symbols onto at least one of a plurality of the spectrally overlapping carrier signals; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform to the data transmitted by the transmitter; the processor modulating a first carrier of the plurality of spectrally overlapping carrier signals based on a first modulation scheme while modulating a second carrier of the plurality of spectrally overlapping carrier signals based on a second modulation scheme.08-02-2012
20100157787METHOD FOR TRASMITTING SIGNALS FOR INCREASING THE AMOUNT OF DATA TRANSMISSION - A signal transmission method for increasing the amount of data transmission is described. When a specific transmitting side transmits signals in a signal transmission mode applied to a low-speed transmitting side, the specific transmitting side reduces the number of times of pilot transmission, thereby efficiently increasing a data transmission rate. The amount of data transmitted through one subchannel is set to be the same. To this end, improved subchannel structure, and improved system parameters in which a guard interval is adjusted are provided.06-24-2010
20100002574APPARATUS AND METHOD FOR CHANNEL ESTIMATION IN A MOBILE COMMUNICATION SYSTEM - An apparatus and a method for estimating a Channel Impulse Response (CIR) with respect to a location where a power of a channel exists are provided to enhance a channel estimator in a mobile communication system. The apparatus includes a CIR searcher for selecting a CIR group that is a region where a channel power exists, a CIR estimation part for estimating a CIR of the selected CIR group, and a Discrete Fourier Transform (DFT) for performing a DFT on the estimated CIR.01-07-2010
20100157786BASE STATION, RADIO TERMINAL AND RADIO COMMUNICATION METHOD - According to an aspect of the present invention, there is provided with a radio communication method using an OFDMA scheme for uplink communication from a plurality of radio terminals to a base station, including: detecting communication states of the radio terminals; and arranging null subcarriers between subcarriers used by the radio terminals to which frequency bands neighboring on the frequency domain are assigned, depending on the communication states of the radio terminals.06-24-2010
20100002572Dynamic precision for datapath modules - A system and method for dynamically reducing the precision of datapath modules within an FFT unit without adversely affecting the demodulation of an orthogonal frequency division multiplexing (OFDM) signal. An FFT unit is typically implemented in an OFDM receiver to separate sub-carriers within a received OFDM signal. In general, an FFT unit implemented within an OFDM receiver must be designed to operate with a precision high enough such that quantization noise, introduced within the FFT unit, does not dominate the overall maximum SNR requirement of the system. However, the SNR requirement for many OFDM receivers is dynamic and, as a result, OFDM receivers often have an instantaneous SNR requirement far below the required maximum. In these situations, it would be advantageous to reduce the precision of datapath modules within the FFT to conserve power, which is often limited in wireless devices.01-07-2010
20100002573Detection of Access Bursts in a Random Access Channel - A technique for detecting one or more access bursts (01-07-2010
20100177628OFDM SIGNAL TRANSMISSION APPARATUS AND METHOD - An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus and a method thereof are disclosed. The OFDM signal transmission apparatus includes an inverse Fourier transform (IFT) unit for transforming a frequency domain OFDM signal to a time domain OFDM signal according to one of transmission modes of 4K, 16K, and 32K; a guard interval inserting unit for inserting a guard interval into the transformed time domain OFDM signal according to a predetermined guard interval inserting rate; and a transmitting unit for transmitting the OFDM signal having the guard interval. Therefore, the data transmission rate is enhanced.07-15-2010
20100226242METHOD AND SYSTEM FOR SUPPORTING SCALABLE BANDWIDTH - Methods and systems for supporting scalable bandwidth in radio telecommunications networks are provided. When signals are transmitted to user equipments using a transmitter of a radio telecommunication network, the signals are frequency multiplexed, each signal lying within a frequency band having an equal or narrower bandwidth than a reception bandwidth of each user equipment that is to receive a signal. Then the multiplexed signal is converted to a time domain signal.09-09-2010
20100232284RADIO TRANSMITTING APPARATUS AND RADIO TRANSMITTING METHOD - A radio transmitting apparatus and a radio transmitting method wherein the throughput is improved and a fast initial access processing including an RA burst is accomplished. According to these apparatus and method, a signature table storing part (09-16-2010
20100118692WIRELESS COMMUNICATION APPARATUS - A wireless transmission apparatus is a wireless communication apparatus constituting a base station capable of communicating with one or more terminals, via a wireless LAN, the wireless communication apparatus including: an inverse fast Fourier transform processing section configured to obtain an output signal sequence in a time region from an input signal sequence in a frequency region; and a control section configured to use an output of the inverse fast Fourier transform processing section in the case of giving a signal sequence in which a same pattern is repeated for subcarrier indexes of the inverse fast Fourier transform processing section, to the inverse fast Fourier transform processing section as the input signal sequence, as a wakeup signal, in order to cause the terminal in a sleep mode to transition to an active mode.05-13-2010
20090279420BASE STATION APPARATUS, RADIO TRANSMISSION SYSTEM, RADIO BASE STATION PROGRAM, AND TIMING ESTIMATION METHOD - A base station apparatus (11-12-2009
20090245088COMMUNICATION EQUIPMENT WHICH RECEIVES OFDM SIGNAL, OFDM-BASED WIRELESS COMMUNICATION SYSTEM AND METHOD FOR RECEIVING OFDM SIGNAL - When a receiving apparatus which employs a OFDM-based cellular wireless communication scheme detects as an excessive signal for each frame, the signal having signal intensity exceeding a reference value after a Fourier transform, a gain variable according to an excessive quantity relative to the reference value is used for each frame to control signal intensity such that the amplitude thereof is at most the reference value.10-01-2009
20090323514APPARATUS AND METHOD FOR TRANSMITTING/RECEIVING AND RELAYING SIGNAL IN A COMMUNICATION SYSTEM USING DOFDM/DOFDMA - A signal transmission apparatus in a Double Orthogonal Frequency Division Multiplexing (DOFDM)/Double Orthogonal Frequency Division Multiple Access (DOFMA) communication system generates a first signal by performing row-wised Orthogonal Frequency Division Multiplexing (OFDM) on M sub-samples for each of N sub-carriers, generates a second signal by performing column-wised OFDM on the first signal generated for each of the N sub-carriers, and transmits the second signal to a signal reception apparatus. Here, N denotes a number of sub-carriers used in the DOFDM/DOFDMA communication system, and M denotes an integer greater than or equal to 1.12-31-2009
20090135714METHODS AND APPARATUS FOR GENERATING AND PROCESSING TRANSMITTER SIGNALS - Transmitter signals are modulated with one or more codes which may represent a pulse even though the code(s) are not shaped as pulses. The code(s) may be generated by defining a pulse by its Fourier components, and then adding random phases to the Fourier components. A time-domain signal may then be created, which may serve as the code to be modulated on a carrier wave. Upon reflection of the transmitter signal, the received signal may be processed by a receiver to recover the pulse. The time-of-flight of the transmitter signal can then be determined, enabling distance measurements to be made.05-28-2009
20080291821ORTHOGONAL SPREAD-SPECTRUM WAVEFORM GENERATION WITH NON-CONTIGUOUS SPECTRAL OCCUPANCY FOR USE IN CDMA COMMUNICATIONS - The technology in this application solves these problems (and others) and meets the desirable goals identified above (and others). The technology spreads a signal over an available discontinuous spectrum, such as a radio frequency band, so that the spread signal only occupies the non-contiguous spectrum. In this way, CDMA transmission and reception can be used in a fragmented or non-contiguous spectum that otherwise would not be useable for direct sequence spreading. Spreading over non-contiguous portions of spectrum is preferably performed without producing unacceptable interference in portions of unavailable spectrum located between the allowed spectrum. By avoiding unacceptable interference in portions of unavailable spectrum located between the allowed spectrum, the unavailable spectrum may be used by other users or services.11-27-2008
20080267059Methods and arrangements to determine a reception of a signal - Methods and arrangements for wireless communications are described. Embodiments include transformations, code, state machines or other logic to receive from a transmitter a signal representing a known sequence of symbols. The signal may be transmitted over a plurality of sub channels. The embodiments may also include determining channel responses at the sub channels and determining a reception of the known sequence. The determining may include treating the channel responses at the sub channels in a differential manner to cancel out channel phase responses and obtain channel amplitudes. In some embodiments, the cancelling may be performed by multiplying frequency domain values representing reception of a sub channel by the complex conjugate of frequency domain values of a neighboring sub channel. Many embodiments may also include calculating a carrier to interference and noise ratio (CINR) of the signal. In several embodiments, the signal may represent the preamble of a wireless frame.10-30-2008
20100296386METHOD AND APPARATUS FOR WIDEBAND WIRELESS TRANSMISSION AND TRANSMISSION SYSTEM - A method of wideband radio transmission is disclosed, the method includes the following steps: obtaining the parallel data symbols; encoding the obtaining parallel data symbols respectively; superposing the encoded data symbols; performing the fast Fourier inverse transform for the superposed data symbols and transmitting them. Applying the solution, the transmission efficiency and the transmission dependability of the OFDM system is raised. An apparatus for wideband radio transmission and a transmission system are also disclosed.11-25-2010
20100302931OFDM SIGNAL RECEIVING SYSTEM - A signal receiving unit receives the OFDM signal and to convert the OFDM signal into a baseband OFDM signal. A time wave operation unit performs a predetermined calculation on a time wave signal that is an output of the signal receiving unit. A Fourier transform unit performs a Fourier transform on an output of the time wave operation unit. A frequency component extraction unit extracts a specific frequency component from an output of the Fourier transform unit. An inverse Fourier transform unit performs an inverse Fourier transform on the frequency component extracted by the frequency component extraction unit. A reception quality measurement unit measures quality of an output signal of the inverse Fourier transform unit and generate reception quality data. A time wave control unit controls the time wave operation unit based on the reception quality data.12-02-2010
20100309775Transmission Using Nested OFDMA - A transmission of information within a wireless cellular network may include a first and second group of samples. A first group of samples is created comprising at least a first and a last subgroup, wherein the last subgroup is same as the first subgroup. A second group of samples created. A transformed set of samples produced by jointly transforming the created first and second group with a discrete Fourier transform (DFT). The transformed set of samples is expanded to produce an expanded set, and the expanded set is transformed with an inverse discrete Fourier transform (IDFT) to produce an OFDM symbol with a fractional payload. The first group of samples is a reference signal (RS), which is known to the receiver before the transmission occurs, while the second group of samples is information data.12-09-2010
20100182899OFDM Time Basis Matching With Pre-FFT Cyclic Shift - In OFDM communication, a pre-FFT cyclic shift is used to achieve time basis matching among symbols, and/or between symbols and their corresponding channel estimates.07-22-2010
20090067319SYSTEMS AND METHOD FOR ORTHOGONAL FREQUENCY DIVISIONAL MULTIPLEXING - Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a method for ranging comprises: receiving at a host a plurality of upstream symbols transmitted from a plurality of remote units, the upstream symbols transmitted on a plurality of orthogonal carriers modulated using an inverse Fourier transform; comparing a phase of at least one ranging symbol received from at least one of the plurality of remote units with a phase of a symbol transmitted by the host; and transmitting an adjustment instruction instructing the at least one of the plurality of remote units to vary a phase of transmissions transmitted from the at least one of the plurality of remote units based on a difference in phase between the at least one ranging symbol and the symbol transmitted by the host unit.03-12-2009
20100046361DEVICE AND METHOD FOR TRANSMITTING AND RECEIVING PILOT SIGNAL IN WIRELESS COMMUNICATION SYSTEM - Disclosed is a pilot signal transmitting/receiving device and method in a wireless communication system. When generating a pilot signal block that is shorter than the length of a data signal, a frequency for each predetermined pilot signal block is transitioned so as to guarantee frequency domain channel estimation performance. A cyclic prefix according to the length of the transitioned pilot signal is added to the pilot signal, a data signal is time division multiplexed together with the pilot signal, and a resultant signal is transmitted through an antenna. In advance to this, a position of a subcarrier for transmitting the pilot signal and the data signal is determined, a data signal is mapped on the determined subcarrier, and in this instance, diversity on the channel for a symbol is used to map the data signal on the transmission method using one of the localized FDMA (L-FDMA) channel and the distributed FDMA (D-FDMA) channel. Therefore, the frequency resolution in the frequency domain is maintained to thus provide high-quality channel estimation performance.02-25-2010
20110044160FFT NUMEROLOGY FOR AN OFDM TRANSMISSION SYSTEM - An exemplary fast Fourier transform (FFT) numerology for an orthogonal frequency division multiple access (OFDMA) downlink transmission system is described. The exemplary FFT numerology reduces the FFT sampling rate for a given transmission bandwidth, thereby increasing the battery life of a UE. The FFT numerology increases robustness against Doppler spread, phase noise, and frequency offset, enabling operation in channels with high delay spread, such as occurs in mountainous regions. The described numerology might provide the following without altering standard sub-frame duration: increased intercarrier spacing; reduced FFT sampling frequency across the transmission bandwidths; reduced FFT size across all transmission bandwidths; increased number of OFDM symbols per sub-frame; and/or increased cyclic prefix length choices.02-24-2011
20110044161RADIO COMMUNICATION SYSTEM, RADIO COMMUNICATION DEVICE, RADIO COMMUNICATION METHOD, AND PROGRAM - A radio communication system according to the present invention has a plurality of radio communication devices that transmit and receive subframes one by one. Each of the plurality of radio communication devices includes a subframe generation unit that generates the subframe with a plurality of symbols and causes an effective symbol length of a last symbol of the subframe to be 1/X (where X is an integer equal to or greater than 2) and a transmission unit that transmits the subframe to another radio communication device.02-24-2011
20110116361DIGITAL SIGNAL DEMULTIPLEXING APPARATUS AND DIGITAL SIGNAL MULTIPLEXING APPARATUS - A digital signal demultiplexing apparatus that can demultiplex and a digital signal multiplexing apparatus that can multiplex signals of channels having arbitrary frequency intervals and bandwidths are provided. The digital signal demultiplexing apparatus performs discrete Fourier transform on an input signal, output samples existing within frequency bands of each channel from samples of the frequency domain, add samples such that the number of samples of each channel become a power of two, and performs, on the samples of each channel, discrete inverse Fourier transform of a length the same as the number of the samples. The digital signal multiplexing apparatus performs discrete Fourier transform of a length the same as the number of samples of an input signal for a predetermined period, outputs samples existing within frequency bands of each channel from samples of the frequency domain of each channel, and arrange the samples according to frequency assignment of each channel to perform discrete inverse Fourier transform.05-19-2011
20110116360OFDM SYSTEM AND METHOD EMPLOYING OFDM SYMBOLS WITH KNOWN OR INFORMATION-CONTAINING PREFIXES - Systems and methods for transmitting and receiving OFDM symbols are provided which enable the otherwise wasted transmission time normally used as a prefix for each OFDM symbol to contain useful information. At the receiver, the received signal is processed to convert received OFDM symbols from a linear convolution with the channel to a cyclic convolution.05-19-2011
20110242963SYSTEMS AND METHODS FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING - Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising spectrally overlapping carrier signals from at least two of a plurality of remotes, wherein the spectrally overlapping carrier signals are modulated using an inverse Fourier transform algorithm; a transmitter; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; a controller programmed to calculate an elapsed time for each of the two remotes, the elapsed time representing a time between transmitting a ranging signal to a remote and receiving a signal from the remote in response to the ranging signal; the controller further programmed to reducing any difference between at least two elapsed times by instructing at least one of the plurality of remotes to adjust a delay.10-06-2011
20100149962APPARATUS AND METHOD FOR TRANSMITTING/RECEIVING UPLINK PILOT IN FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM - Method and apparatus for transmitting/receiving an uplink pilot used for channel estimation and measurement of an uplink in an FDMA system. Pilot symbols are transmitted with different frequency mapping patterns in first and second pilot symbol intervals of one time slot interval including data symbol intervals and the inconsecutive first and second pilot symbol intervals which have a shorter length than the data symbol intervals. As a result, interpolation of a frequency domain during channel estimation is not necessary, and can correctly obtain channel-estimated values of a frequency at which data is transmitted, in a fast time-varying channel environment.06-17-2010
20100149963APPARATUS AND METHOD FOR FAST FOURIER TRANSFORM/INVERSE FAST FOURIER TRANSFORM - An FFT/IFFT apparatus and method are provided. The FFT/IFFT apparatus includes a storage unit, a first FFT/IFFT unit, a second FFT/IFFT unit, and a third FFT/IFFT unit. The storage unit has as many addresses as the number of bits of input data. The first FFT/IFFT unit sequentially stores half of the input data in the storage unit, performs a first-point FFT/IFFT operation while sequentially receiving the other half of the input data, and stores the first-point FFT/IFFT operation result in the storage unit. The second FFT/IFFT unit performs a second-point FFT/IFFT operation on the first-point FFT/IFFTed data, and stores the second-point FFT/IFFT operation result in the storage unit. The third FFT/IFFT unit performs a third-point FFT/IFFT operation on the second-point FFT/IFFTed data, and stores the third-point FFT/IFFT operation result in the storage unit.06-17-2010
20100124162TRANSMITTER AND SSB SIGNAL GENERATION METHOD - A transmitter which is capable of producing an SSB signal having a sharp spectrum cut. The transmitter generates the SSB signal using an FFT circuit (05-20-2010
20100254253METHOD, SYSTEM AND APPARATUS FOR SIGNAL GENERATION AND MESSAGE TRANSMISSION IN BROADBAND WIRELESS COMMUNICATIONS - Method for signal generation in broadband wireless communications, comprises: A. modulating, segmenting and serial-parallel converting the signal data to be transmitted, then computing DFT of the serial-parallel converted data so as to transfer them to frequency domain; B. performing block unit modulating processing and block repeat modulating processing on the frequency domain data, then mapping the block units to assigned time-frequency positions; C. computing IFFT of the mapped block units, then adding them to the cycle prefix, thus the random sequences in time domain are generated. Apparatus for signal generation, Method and system for message transmission in broadband wireless communications are also disclosed. The problem of resource allocation and scheduling, and problem of interference coordination and control are solved, the throughput and performance of communication system are greatly improved.10-07-2010
20110242964DOWNLINK ACQUISITION - The subject matter disclosed herein provides methods and apparatus, including computer program products, for detecting a preamble to enable acquisition of a downlink. In one aspect, there is provided a method. The method may include receiving a plurality of symbols. From an autocorrelation of the received symbols, a guard interval may be detected. The guard interval may represent a receive/transmit transition gap (RTG). A metric may be used to verify whether at least one symbol positioned after the detected guard interval is a preamble. Related systems, apparatus, methods, and/or articles are also described.10-06-2011
20100061224TRANSMITTER FOR EXTENDING GUARD INTERVAL FOR INDIVIDUAL USER EQUIPMENT IN OFDMA SYSTEMS - Provided is a technology for extending a guard interval for individual user equipment in an OFDMA system. The transmitting apparatus includes: a guard interval extension processor for generating symbols with a guard interval extended by copying a part of a current symbol and pasting the copied part to a last part of a previous symbol; a Fourier Transform (FT) processor for receiving the processed symbols from the guard interval extension processor and performing an FT process on the received processed symbols; an Inverse Fast Fourier Transform (IFFT) processor for performing an IFFT process on the FT processed symbols from the FT processor; a mapping processor for mapping outputs of the FT processor to input points of the IFFT processor to load the FT processed frequency-domain data on corresponding sub-carriers; and a cyclic prefix inserter for inserting a cyclic prefix code to output of the IFFT processor.03-11-2010
20090034407Receiver-site restoration of clipped signal peaks - A method, a computer program, a computer program product, a device and a system are shown for modulation symbol estimation, wherein a block of transmit modulation symbols is processed to obtain a transmit signal, wherein the transmit signal is transmitted over a transmission channel to obtain a receive signal, wherein the receive signal is processed to obtain a block of receive modulation symbols, wherein signal peaks of at least one of the transmit signal and said receive signal are clipped if the signal peaks exceed a clipping level, wherein a noise portion contained in the block of receive modulation symbols is estimated, wherein clipping-affected modulation symbol components are determined based on the estimated noise portion, wherein the determined clipping-affected modulation symbol components are added to the block of receive modulation symbols to obtain a block of refined receive modulation symbols, and wherein the transmit modulation symbols of the block of transmit modulation symbols are estimated from the block of refined receive modulation symbols.02-05-2009
20100054116Radio Base Station and Radio Mobile Station - The base station transmits a synchronization signal that contains a pattern of repeated SYNC's generated by dividing FFT size by N wherein the pattern of repeated SYNC's is inverted in polarity for each of the SYNC's according to a code outputted from a code generating circuit. CP length is M/N of FFT size, and the number of divisions (M+N) of a symbol of the synchronization signal is brought into agreement with the code length L of Barker code. The mobile station detects the synchronization signal by using a first matched filter that has as many taps as (FFT size/N) stages, and uses a pattern of SYNC's generated by dividing FFT size by N as a tap coefficient, and a second matched filter that has as many taps as (M+N) stages and uses Barker code as a tap coefficient.03-04-2010
20120275291WIRELESS COMMUNICATION APPARATUS AND WIRELESS COMMUNICATION METHOD - By using a discrete Fourier transform equation that is used to transform N data values (N is an integer equal to or greater than one) to N transformation values, a wireless communication apparatus calculates three continuous transformation values from the N data values. Then, the wireless communication apparatus obtains a fixed change in the phase difference from the three calculated transformation values; multiplies the calculated transformation value by a twiddle factor that is obtained from the change in the phase difference; and calculates not-yet calculated transformation values.11-01-2012
20100135150METHOD OF GENERATING AND DETECTING SYNCHRONIZATION SIGNALS - A method of generation and detection of a synchronization signal for use in a telecommunication system is disclosed by the present disclosure. According to the present disclosure, the synchronization signal is generated by performing a circular time shift on a centrally symmetric signal, and the circular time shift is performed so that the synchronization signal is centrally asymmetric. The detection of the synchronization signal is then performed by utilizing the symmetries of the synchronization signal to reduce computation complexity of the detection.06-03-2010
20100135149SYSTEM AND METHOD FOR IN-PHASE/QUADRATURE MULTIPLEXING - Systems and methods for multiplexing signals are disclosed. In one embodiment, the method comprises receiving a first signal having at least a real component, receiving a second signal having at least a real component, generating an in-phase signal based, at least in part, on the first signal, the in-phase signal being real in a first domain, generating a quadrature signal based, at least in part, on the second signal, the quadrature signal being imaginary in the first domain, adding the in-phase signal and the quadrature signal to generate a multiplexed signal, and transmitting the multiplexed signal.06-03-2010
20090213724METHOD AND SYSTEM FOR I/Q BRANCH EQUALIZATION IN OFDM SYSTEMS - Aspects of a method and system for I/Q branch equalization in OFDM systems may include determining a transfer function mismatch between an in-phase processing branch, and/or a quadrature processing branch in an OFDM receiver. The determined transfer function mismatch may be compensated for, by applying equalization after a fast Fourier transform (FFT) in an in-phase processing branch and/or a quadrature processing branch. The OFDM system may be compliant with, for example, UMTS LTE (EUTRA), WiMAX (IEEE 802.16), DVB-H, and WLAN (IEEE 802.11). A transfer function may be measured for an in-phase branch filter and/or quadrature branch filter to determine the transfer function mismatch. The transfer function mismatch may be compensated for, in frequency domain by the equalizer. The transfer function mismatch may comprise magnitude and/or phase response mismatch, wherein the magnitude and/or phase response mismatch may be a function of frequency.08-27-2009
20110058471OFDEM SYSTEM AND NYQUIST PULSE SHAPING METHOD WITH HIGH SPECTRUM EFFICIENCY - A receiver system to receive an orthogonal frequency division multiplexing (OFDM) symbol of a certain spectrum efficiency. The receiver system includes a guard interval remover, a memory device, and a pulse shaper. The guard interval remover removes a guard interval from the OFDM symbol received by the receiver. The memory device stores a pulse shaping algorithm. The pulse shaper performs the pulse shaping algorithm to substantially maintain the certain spectrum efficiency in conjunction with the utilization of a Nyquist pulse shape with an excess bandwidth ≦1.0.03-10-2011
20110149719METHOD FOR SEPARATING BLIND SIGNAL AND APPARATUS FOR PERFORMING THE SAME - A method for separating a blind signal includes: converting mixed signals of a time domain collected by using a plurality of sensors into mixed signals of a frequency domain; calculating a separation filter from the mixed signals which have been converted into those of the frequency domain; calculating an inverse filter of the separation filter; calculating the difference in phase between the respective sensors from the calculated inverse filter; permutation-sorting the separation filter by using the calculated phase difference; and separating the mixed signals of the frequency domain by using the permutation-sorted separation filter.06-23-2011
20100296385USER SIGNAL TRANSMITTING AND RECEIVING METHOD, APPARATUS AND SYSTEM IN OFDMA SYSTEM - This invention provides a user signal transmitting method in an OFDMA system, where all the time-frequency grids of each timeslot are divided into sub-channels, each sub-channel comprises N11-25-2010
20100302930Low Power Quality-Energy Scalable OFDMA Baseband Design - In an energy scalable OFDMA energy metric baseband design for an OFDM transmission process operable using a QoS-guaranteed adaptive resource allocation algorithm, the improvement of effecting power savings and memory access reductions comprising:12-02-2010
20100246377MIMO BEAMFORMING-BASED SINGLE CARRIER FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM - A multiple-input multiple-output (MIMO) beamforming-based single carrier frequency division multiple access (SC-FDMA) system is disclosed. At the transmitter, a fast Fourier transform (FFT) is performed on transmission data to generate frequency domain data. The frequency domain transmit data is mapped to assigned subcarriers. An inverse fast Fourier transform (IFFT) is performed on the transmit data mapped to the assigned subcarriers to generate time domain transmit data. The time domain transmit data is transmitted via antennas. At a receiver, an FFT is performed on the received data to generate frequency domain received data. Subcarrier demapping is performed to extract data mapped on the assigned subcarriers. A channel estimator generates a channel matrix which is decomposed into U, D and V09-30-2010
20100246379METHOD AND APPARATUS FOR TRANSMITTING SIGNALS FOR MULTIPLE INPUT MULTIPLE OUTPUT WIRELESS COMMUNICATION SYSTEM - A storage unit stores a preamble signal defined in a legacy system and a preamble signal defined in a MIMO system. A monitoring unit in a transmitting apparatus monitors the existence of any communication apparatus which is not compatible with the MIMO system but accepts the legacy system. A channel characteristics acquiring unit derives the characteristics of a radio channel between the transmitting apparatus and a receiving apparatus. A selector selects a packet format based on a monitoring result obtained by the monitoring unit. The selector also selects where to place LTS, based on the characteristics of wireless channel derived by the channel characteristics acquiring unit.09-30-2010
20110164492METHOD AND SYSTEM FOR COMBINING OFDM AND TRANSFORMED OFDM - Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM.07-07-2011
20110164490FAST FOURIER TRANSFORM AND INVERSE FAST FOURIER TRANSFORM (FFT/IFFT) OPERATING CORE - An FFT/IFFT operating core capable of minimizing a required memory depth during operation is disclosed. The FFT/IFFT operating core includes an inputting buffer, a first multiplexer, an operating module, and a controlling module. The inputting buffer stores and outputs a first FFT input sequence. The first multiplexer is utilized to multiplex the first FFT input sequence and a third input sequence. The controlling module generates a process indicating signal and a bypass indicating signal. The operating module has a plurality of operating stages in series. The operating module transforms the first and third FFT input sequences into a first and third FFT output sequences, respectively, and it transforms a second IFFT input sequence into a second IFFT output sequence.07-07-2011
20110164491METHOD AND SYSTEM FOR COMBINING OFDM AND TRANSFORMED OFDM - Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM.07-07-2011
20110069605COAXIAL NETWORK COMMUNICATION NODE AND METHODS FOR COMMUNICATING MULTIMEDIA OVER A COAXIAL NETWORK WITH REDUCED-LENGTH CYCLIC PREFIXES - A coaxial network communication node receives multimedia content with one or more other nodes in a coaxial network. The node determines a delay-spread of a coaxial channel based on receipt of a probe from a transmitting node and configures a channel-shortening time-domain equalizer (TEQ) filter to effectively shorten the channel based on the delay spread. The node instructs the transmitting node to shorten a length of a cyclic prefix for subsequent packet-based transmissions to be received from the transmitting node. The probe is stored and reused until the channel-shortening TEQ filter converges. The nodes may be configured to communicate in accordance with the Multimedia over Coax Alliance (MoCA®) specifications.03-24-2011
20080219148SYSTEM AND METHOD FOR TRANSMITTING DATAIN A MULTIPLE-BRANCH TRANSMITTER-DIVERSITY ORTHOGONAL FREQUENCY-DIVISION MULTIPLEXING (OFDM) SYSTEM - A system and method for transmitting data in multiple-branch transmitter-diversity OFDM systems is presented. In one embodiment, an approach is taken where an inverse Fourier transform (IFT) is performed on data prior to encoding the data for transmission in the multiple-branch transmitter-diversity system. In another embodiment an IFT is performed on data prior to encoding the data using a space-time block code (STBC) algorithm.09-11-2008
20080219147Transmitter and Receiver - The transmitter of one embodiment of the present invention includes: a S/P section for converting original serial data to parallel data which will correspond to a plurality of subcarriers; and a second IFFT section for converting the parallel data from the frequency domain to the time domain. The transmitter includes, between the S/P section and the second IFFT section, a first IFFT section for modulating the plurality of subcarriers using elements of a matrix derived from an expression for Inverse Discrete Fourier Transform involving time domain signal levels and frequency domain signal levels. The configuration enables CI and PO-CI to be implemented on transmitters and receivers with a simple configuration.09-11-2008
20080219146Spectrum interpolation method, spectrum interpolation apparatus, and spectrum interpolation program storage medium - A spectrum interpolation method obtains a spectrum value at an arbitrary frequency by interpolating discrete spectra obtained through sampling one period of a periodic function at N sampling points to perform a Fourier transform. The spectrum value F09-11-2008
20110096658PRECODING METHOD FOR REDUCING UPLINK PAPR AND APPARATUS THEREOF - A radio communication system is provided. An uplink transmission method of a user equipment in a radio communication system includes performing Fourier transform on one or more data sequences to generate one or more first frequency-domain sequences, applying precoding for multi-antenna transmission to the one or more first frequency-domain sequences to generate one or more second frequency-domain sequences; performing inverse Fourier transform on the one or more second frequency-domain sequences to generate one or more transmission symbols, and transmitting the one or more transmission symbols via multiple antennas.04-28-2011
20100165829METHODS AND SYSTEMS FOR PAPR REDUCTION IN SC-FDMA SYSTEMS - Certain embodiments of the present disclosure relate to methods for peak-to-average power ratio (PAPR) reduction of a transmission signal in a single carrier frequency division multiple access (SC-FDMA) system. The proposed methods and systems are based on manipulations of an SC-FDMA transmission signal in a time- and/or a frequency-domain.07-01-2010
20100067368METHOD FOR IMPLEMENTING TRANSMIT DIVERSITY AT A WIRELESS MOBILE COMMUNICATION SYSTEM ADOPTING SC-FDMA SCHEME - A method for implementing transmit diversity in a wireless mobile communication system adopting an SC-FDMA scheme is provided. A sequence of modulation symbols output from a DFT block are precoded prior to IFFT. The precoding is performed independently on an antenna basis. Modulation symbols mapped to each subcarrier of an SC-FDMA symbol, to be transmitted through each antenna may be additionally phase-shifted.03-18-2010
20100195485CHANNEL ESTIMATION FEEDBACK IN AN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM OR THE LIKE - Briefly, in accordance with one embodiment of the invention, a channel state information packet is encoded by a receiver side device and is fed back to the transmitter side device. The transmitter side device decodes the channel state information packet to extract an estimate of the channel response function.08-05-2010
20100034077BASE STATION APPARATUS, USER APPARATUS AND METHOD USED IN MOBILE COMMUNICATION SYSTEM - A base station apparatus is used in a mobile communication system that uses an OFDM scheme in a downlink. The base station apparatus includes: a unit configured to perform inverse Fourier transform on a signal in which a first signal and a second signal is mapped to subcarriers with different transmission power density, and to generate a transmission signal; and a transmission unit configured to transmit the transmission signal to a user apparatus. A subcarrier (prohibited subcarrier) in which mapping of the second signal is prohibited is determined such that transmission power density of the second signal is kept constant among a plurality of OFDM symbols regardless of whether the first signal is included in an OFDM symbol including the second signal. The prohibited subcarrier is determined based on a subcarrier to which the first signal is mapped.02-11-2010
20110261677Apparatus and method for supporting various system bandwidths in a broadband wireless communication system - An apparatus and method support various system bandwidths in a broadband wireless communication system. A Mobile Station (MS) operation includes determining a system bandwidth through a primary preamble for frame synchronization, which a Base Station (BS) transmits. A Fast Fourier Transform (FFT) size, the number of guard subcarriers, and the number of used subcarriers corresponding to the system bandwidth are determined using a first table. An operation parameter of a modem is set according to the FFT size, the number of guard subcarriers, and the number of used subcarriers.10-27-2011
20110261676CM/PAPR REDUCTION FOR LTE-A DOWNLINK WITH CARRIER AGGREGATION - The present invention relates to the reduction of the CM and PAPR of an LTE-A downlink signal after carrier aggregation. The CM and PAPR of the aggregated signal are reduced by introducing cyclic time shifts to the OFDM symbols in each of the component carriers (CC). Out of all the aggregated CCs, one of them is chosen to have zero cyclic time shift, meanwhile an optimal amount of cyclic time shifts is introduced into each of the other aggregated CCs. The optimal cyclic time shift for each CC is calculated by applying every possible shift value to all of the OFDM symbols in that CC and working out for each case the CM value when the OFDM signal of that CC is combined with those in other shifted CCs. For each CC, the optimal cyclic time shift is the amount of cyclic shifts applied to that CC which would give the lowest peak “combined CM value”.10-27-2011
20110149718FAST FOURIER TRANSFORM APPARATUS AND METHOD - A fast Fourier transform (FFT) apparatus and method. The FFT method may include finding a number of subcarriers carrying valid data in reception data, determining a Fourier transform order on the basis of the number of subcarriers, performing complex multiplication on the reception data, and then performing a Fourier transform of the determined Fourier transform order. Using the FFT method, it is possible to reduce the amount of computation and the complexity of an FFT in a frequency division multiplexing (FDM) system and simplify a hardware structure.06-23-2011
20090175162Method of OFDM communication using superposition coding - Improvements are provided in an OFDM network that uses superposition coding. A broadcast signal and e.g. a unicast signal are each subjected to OFDM modulation including processing by an IDFT, combined, and transmitted using non-orthogonal transmission resources. In one approach, the respective signals are combined after instead of before the IDFT processing. In specific examples, a respective cyclic prefix is appended to each signal after the IDFT processing but before the respective signals are combined. In another approach, a broadcast pilot signal and e.g. a unicast pilot signal are transmitted concurrently with the broadcast and unicast information signals. The pilot signals are transmitted using the same time and subcarrier resources, but are mad e more distinguishable by combining each with a respective scrambling or spreading code. In specific examples, embodiments, the unicast pilot signal is used for estimating the data rate for transmission of further unicast information signals.07-09-2009
20090175161Transmission Method Of Mobile Station For Random Access Channel Diversity - A transmission method performed by a mobile station for random access channel (RACH) burst transmission diversity gain is provided. According to the method, by combining and using switching diversity by beam forming, frequency hopping, and power ramping, the probability that when the speed of a mobile station is low, the mobile station falls into a deep fading environment is lowered, thereby increasing the probability of detecting an RACH signature of the base station. Also, by using the transmission parameters (subbands, precoding matrixes, power, etc.) which are used for successful transmission of an RACH burst, for transmission of a successive user packet data, reliable transmission of the successive user packet data can be performed.07-09-2009
20100027410Apparatus and associated methods to perform space-frequency interleaving in a multicarrier wireless communication channel - An apparatus and associated methods for performing space-frequency interleaving in a multicarrier wireless communication system is generally described.02-04-2010
20100020675METHOD AND APPARATUS FOR OFDM BASED ON 3D SIGNAL CONSTELLATION - Provided is an orthogonal frequency division multiplexing (OFDM) apparatus using a 3-dimensional (3D) signal constellation. The apparatus performs 2D inverse fast Fourier transform on a set of 3D subchannel signals that is mapped by a signal constellation including signal points distributed on the surface of a 3D sphere.01-28-2010
20080279090DRM receiver with analog and digital separation filter and demodulation method - A Digital Radio Mondiale (DRM) receiver and demodulation method includes an analog and digital separation filter for filtering and separating a DRM-encoded signal and a non DRM-encoded signal from a composite RF signal received at the receiver. The DRM receiver includes a programmable downsampler and a programmable N-point Fast Fourier Transform (FFT) to recover and demodulate the OFDM symbols in a received DRM-encoded RF signal. The received signal is digitally sampled at a rate operably integer downsampled to achieve a number N samples in the useful portion of the OFDM symbol for input to an N-point FFT, where N equal to a power of two. The downsampling rate and size (N-points) of the FFT depend on the DRM encoding and transmission parameters, notably the robustness mode and spectrum occupancy. The structure and operation of the receiver in this manner simplifies the design and reduces the required filter order of the analog and digital separation filter.11-13-2008
20100039927PILOT TRANSMITTING APPARATUS AND METHOD FOR SC-FDMA SYSTEM - Provided are a pilot transmitting apparatus and method capable of selectively using an OFDMA scheme and an SC-FDMA scheme. The pilot transmitting apparatus includes a pilot inserter for inserting a pilot signal in a modulated symbol and inserting a cyclic prefix code for the inserted pilot signal, an FFT processor for receiving symbols with a pilot inserted thereto from the pilot inserter and performing an FFT process on the received symbols, an IFFT processor for receiving the transformed data from the FFT processor and performing an IFFT process on the transformed data, a mapping processor for mapping the output of the FFT processor to input positions of the IFFT processor to load the frequency domain transformed data on predetermined sub-carriers, and a cyclic prefix inserter for inserting a cyclic prefix code for the output of the IFFT processor.02-18-2010
20100182900APPARATUS AND METHOD FOR REUSING BASE STATION IDENTIFIER IN A BROADBAND WIRELESS COMMUNICATION SYSTEM - Use of Base Station IDentifier (BSID) in a wireless communication system is provided. Operations of a control station which controls a Base Station (BS) includes, when receiving a handover request message that includes a special BSID allocated for reuse as a target BSID, from other control station, sending a handover response message to the other control station; when receiving a handover complete message from a lower BS, determining whether the lower BS uses the special BSID; and sending a handover complete message comprising the special BSID to the other control station.07-22-2010
20100002575ADAPTIVE MODULATION AND CODING IN A SC-FDMA SYSTEM - A method and a system for transmitting data by a transmitter over a channel having a predetermined channel quality estimate, comprises the steps of splitting (S01-07-2010
20080304404ARCHITECTURE FOR OWA BASED TDD-OFDM SYSTEM - As no single wireless standard can provide both broadband high-speed and seamless mobility for commercial wireless communications in terms of technology, cost, spectrum and performance, a new wireless convergence platform based on Open Wireless Architecture (OWA) has been disclosed, wherein the OWA-based TDD-OFDM is utilized as the principal air interface to provide cost-effective and spectrum-efficient broadband high-speed wireless transmissions, and converges with the second air interface, such as TDD-SCDMA or TDD-WCDMA based on OWA convergence platform to provide seamless mobile communications in order to support the future service-oriented wireless multimedia mobility infrastructure.12-11-2008
20110317542Method and Apparatus for Diversity Transmission Scheme in Single-Carrier FDMA Systems - The disclosure relates to transmission of user data over multiple transmission layers in a wireless communication system with single-carrier orthogonal frequency division multiple access. A wireless terminal performs transform precoding on a vector of digital modulation symbols and the resulting complex-valued symbols are mapped to frequency/time/space resources. The digital modulation symbols are reordered, modified by a setting of complex-valued functions, and transform precoded. The resulting second set of complex-valued symbols are transform precoded and mapped to frequency/time/space resources.12-29-2011
20100008217METHOD AND SYSTEM FOR DETECTING ADJACENT CHANNEL INTERFERENCE FROM OFDM/OFDMA BASED BROADBAND WIRELESS ACCESS - Disclosed are a method and system for detecting adjacent channel interference between two systems having neighboring frequencies. The method and system calculates a Fast Fourier Transform (FFT) output for one or more upper and lower frequency side null subcarriers and center data subcarriers of a frequency channel. Power values are calculated for the upper and lower frequency side null subcarriers and the center data subcarriers for use in determining a presence of adjacent channel interference (ACI).01-14-2010
20120057449WIRELESS COMMUNICATION APPARATUS AND FREQUENCY HOPPING METHOD - Disclosed are a wireless communication apparatus and frequency hopping method which minimize the change in the instantaneous power distribution characteristics of the time waveform of transmission signals when a plurality of channels are multiplexed by frequency division. At a terminal (03-08-2012
20100110876BACKWARD-COMPATIBLE LONG TRAINING SEQUENCES FOR WIRELESS COMMUNICATION NETWORKS - A network device for generating an expanded long training sequence with a minimal peak-to-average ratio. The network device includes a signal generating circuit for generating the expanded long training sequence. The network device also includes an Inverse Fourier Transform for processing the expanded long training sequence from the signal generating circuit and producing an optimal expanded long training sequence with a minimal peak-to-average ratio. The expanded long training sequence and the optimal expanded long training sequence are stored on more than 52 sub-carriers.05-06-2010
20120026862VARIABLE BANDWIDTH OFDM RECEIVER AND METHODS FOR RECEIVING OFDM SIGNALS OF DIFFERENT BANDWIDTHS - A variable bandwidth OFDM receiver and methods for receiving OFDM signals of different bandwidths are generally disclosed herein. The variable bandwidth OFDM receiver may be configured to receive signals over wider bandwidths by processing a resource block of subcarriers comprising a greater number of subcarriers, and receive signals over narrower bandwidths by processing a resource block of subcarriers comprising a lesser number of subcarriers. The resource blocks have a number of OFDM symbols in a time dimension to define a time slot, and each wherein the resource block comprises a minimum number of subcarriers for a narrowest bandwidth for a predetermined minimum bandwidth reception and a predetermined maximum number of subcarriers for a maximum bandwidth reception. In some embodiments, the variable bandwidth receiver may operate in accordance with an 3GPP LTE E-UTRAN standard.02-02-2012
20120063294Method for a Radio Base Station and a Radio Base Station in a Communication Network System for Assisting in or Obtaining Assistance in the UL Reception of Signals - In cellular radio systems it is a problem to provide service to UE (user equipment) on the cell border. In systems that apply a frequency re-use of one, and OFDM access technology, the uplink direction need be improved. One embodiment of this application relates to a radio base station that is equipped with one or more FFT processor/s in addition to the FFT-processor that is adapted for being adjusted to the timed aligned arrival of signals from UE served by the radio base station. The additional FFT processor/s is adapted for being adjusted to the arrival of one or more signals from UE that are served by other radio base station/s. The radio base station is further adapted to send Fourier processed signal information relating to the UE of the other radio base station/s and thereby assist the other radio base station in signal reception. The application also relates to a method for assisting another radio base station in signal reception, and to a method for receiving assistance from another radio base station in signal reception.03-15-2012
20090135713METHOD FOR USING FLEXIBLE BANDWIDTH IN OFDMA-BASED COGNITIVE RADIO SYSTEM, BASE STATION AND SUBSCRIBER STATION USING THE SAME - Provided are a method for using a flexible bandwidth in an orthogonal frequency division multiple access (OFDMA)-based cognitive radio system, and a base station (BS) and a subscriber station using the method. The method includes: allocating a channel band from among unused channel bands having a bandwidth that is a natural number times a bandwidth resolution to customer premises equipment (CPE), wherein the bandwidth resolution is a predetermined bandwidth smaller than a bandwidth of a broadcast channel band, and transmitting an OFDMA-based signal comprising band allocation information indicating information regarding the allocated channel band.05-28-2009
20100290334Spectrum Characterization for Communication Equipment - The invention concerns the processing of digital signals, in particular spectral scanning upon reception of a signal. Said processing includes multicarrier shape filtering (11-18-2010
20100208578UPLINK PRECODING METHOD IN 2-Tx SYSTEM - A method for a user equipment to precode and transmit an uplink signal efficiently in a 2-antenna system and a method for a base station to receive the transmitted signal efficiently are disclosed. A 2-antenna codebook includes 4 DFT matrixes and 2 antenna selection matrixes for a rank 1 and one identity matrix for a rank 2 as precoding matrixes. For efficient uplink signal transmission/reception, the present invention provides signal transceiving technology between user equipment and base station using the 2-antenna codebook.08-19-2010
20120213054RADIO COMMUNICATION METHOD, RADIO COMMUNICATION SYSTEM, AND RADIO TRANSMISSION APPARATUS - A transmission apparatus according to the present invention includes: an encoding section; a modulation section; a variable-SF spreading section that performs spreading with variable SF according to control information A from a control section; an IDFT section that performs IDFT on output from the spreading section; a GI inserting section; a parallel/serial conversion section that converts output from the GI inserting section into a serial data sequence; a digital/analog conversion section; and an RF section that transmits a signal from an antenna after converting the signal to a frequency band for analog signal transmission and controlling it to an appropriate transmission power. The control section is configured to generate control information A for determining the variable SF and input the information A to the variable-SF spreading section and the RF section. In control information A, SF is varied depending on transmission power required.08-23-2012
20120314561Method and apparatus for implementing preamble generation - The disclosure involves a method and an apparatus for implementing preamble generation. The method comprises: obtaining a first parameter value according to a root sequence number of a Zadoff-Chu (ZC) sequence; obtaining an initial value of a first sequence, according to a length and a cyclic shift value of the ZC sequence and the obtained first parameter value; performing iterative calculatings on the first sequence according to the initial value of the first sequence and the first parameter value; performing iterative calculatings on a second sequence according to the iteratively calculated values of the first sequence and a preset initial value of the second sequence; performing Discrete Fourier Transform (DFT) on the iteratively calculated values of the second sequence. The method and apparatus in the disclosure can achieve low complexity and high calculation precision in the calculation process and greatly reduce the amount of calculation and storage.12-13-2012
20090323515OFDM TRANSMITTTER AND OFDM RECEIVER - In an environment with large transmission delays, use of an OFDM transmitter which includes: a pilot/data allocator for allocating pilot/data symbols on OFDM symbols and an OFDM receiver which includes: an antenna for receiving the OFDM signals sent out from the antenna of this OFDM transmitter; a ratio unit for frequency transforming the OFDM signals received as RF signals to baseband signals; a frequency offset estimate for estimating an offset value; and a frequency offset corrector for performing frequency compensation by the amount of the frequency offset, improves data transmission efficiency while reducing interference of data between sub-carriers to prevent degradation of reception characteristics by performing appropriate frequency offset correction.12-31-2009
20100195486SIGNALING METHOD IN AN OFDM MULTIPLE ACCESS SYSTEM - A method for reducing the peak-to-average ratio in an OFDM communication signal is provided. The method includes defining a constellation having a plurality of symbols, defining a symbol duration for the OFDM communication signal, and defining a plurality of time instants in the symbol duration. A plurality of tones are allocated to a particular communication device, and a discrete signal is constructed in the time domain by mapping symbols from the constellation to the time instants. A continuous signal is generated by applying an interpolation function to the discrete signal such that the continuous signal only includes sinusoids having frequencies which are equal to the allocated tones.08-05-2010
20100195487SIGNALING METHOD IN AN OFDM MULTIPLE ACCESS SYSTEM - A method for reducing the peak-to-average ratio in an OFDM communication signal is provided. The method includes defining a constellation having a plurality of symbols, defining a symbol duration for the OFDM communication signal, and defining a plurality of time instants in the symbol duration. A plurality of tones are allocated to a particular communication device, and a discrete signal is constructed in the time domain by mapping symbols from the constellation to the time instants. A continuous signal is generated by applying an interpolation function to the discrete signal such that the continuous signal only includes sinusoids having frequencies which are equal to the allocated tones.08-05-2010
20120163159INTERFERENCE RANDOMIZATION FOR UPLINK SIGNALING - A method for transmitting an acknowledgement/negative acknowledgement is described. Cell-specific symbol-level cyclic shift hopping is applied to data single-carrier frequency division multiplexing symbols of the acknowledgement/negative acknowledgement. A discrete Fourier transform is applied to the data single-carrier frequency division multiplexing symbols. Cell-specific symbol-level phase hopping is applied to the data single-carrier frequency division multiplexing symbols. The data single-carrier frequency division multiplexing symbols are transmitted in a slot.06-28-2012
20090116376METHOD FOR COMMON TRANSMISSION OVER MULTIPLE LINE PAIRS, AND TRANSMITTING END AND RECEIVING END THEREFOR - The present disclosure discloses a method for common transmission over multiple line pairs, and a transmitting device and a receiving device therefor. The method for common transmission over multiple line pairs includes: modulating information to be sent; and sending a modulated signal to a receiving device over the multiple line pairs; wherein, a transmission spectrum of each transmitter in the multiple line pairs comprises two parts: a first part is a frequency segment that meets a bearer condition of a modulation method, and a second part is a frequency segment that does not meet the bearer condition of the modulation method.05-07-2009
20120314560INTERFERENCE REJECTION METHOD BASED ON MULTIPLE SUB-BAND PROJECTIONS - This invention describes a cognitive radio signal processing where interference is mitigated using multiple frequency spatial projection to orthogonalize interference. The method is based on the well-known LMS solution of W=(A12-13-2012
20120176886METHOD AND SYSTEM FOR OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING WITH HADAMARD TRANSFORM COMBINED WITH COMPANDING TRANSFORM - A combined Hadamard and companding transform technique is incorporated into orthogonal frequency division multiplexed signals to reduce the peak-to-average ratio of signals. A Hadamard transform is applied to the signals to generate a first transformed signal of subsymbols. An Inverse Fast Fourier Transform is performed on the subsymbols to generate a second transformed signal of the subsymbols. The second transformed signal is then companded, making them ready for transmission as optical signals.07-12-2012
20110103219METHOD AND APPARATUS FOR GENERATING RANGING PREAMBLE CODE IN WIRELESS COMMUNICATION SYSTEM - A method and apparatus of generating a ranging preamble code in a wireless communication system comprises generating a Zadoff-Chu (ZC) sequence in which a cyclic shift is applied to each of a plurality of orthogonal frequency division multiple access (OFDMA) symbols as a ranging preamble code, wherein the cyclic shift is applied for each OFDMA symbol.05-05-2011
20100034078WIRELESS COMMUNICATIONS EQUIPMENTS WITH FUNCTION OF DETECTING RANDOM ACCESS SIGNAL, WIRELESS COMMUNICATIONS SYSTEMS WITH FUNCTION OF DETECTING RANDOM ACCESS SIGNAL AND METHOD OF RANDOM ACCESS SIGNAL DETECTION - In a method by which a base station detects a random access signal transmitted by a user equipment to send a transmission request to the base station in uplinks, the base station omits a MF used only to detect the random access signal, or Fourier transform and inverse Fourier transform meeting the random access signal, and uses a Fourier transform unit for data reception to detect the random access signal. Using output of the Fourier transform unit for data reception, which transmits all received signals to frequency region signals, it is judged whether a random access signal is received by a power pattern of bands allocated to the random access signals in one transmission time interval.02-11-2010
20100284266ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM AND METHOD FOR INTER-CELL INTERFERENCE CANCELLATION OF THE ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM - An orthogonal frequency division multiplexing (OFDM) system and an inter-cell interference cancelling method performed in the OFDM system are provided. The OFDM system includes a Fourier transformer which transforms a received base band signal into a pilot subcarrier signal and a data subcarrier signal, a Doppler/delay spread estimator which estimates a coherent time and a coherent bandwidth from the pilot subcarrier signal, a pilot block size selector which selects a pilot block including at least one pilot signal, based on the coherent time and the coherent bandwidth, a simultaneous channel estimator which estimates a channel response signal based on the at least one pilot signal located in the pilot block, and a simultaneous symbol extractor which extracts a data symbol from the data subcarrier signal on the basis of the channel response signal.11-11-2010
20090022050OFDM MODULATION DEVICE, OFDM DEMODULATION DEVICE, OFDM MODULATION METHOD, AND OFDM DEMODULATION METHOD - It is possible to form an OFDM signal improving frequency use efficiency. An OFDM modulation apparatus includes Nyquist filters (01-22-2009
20090016211HARDWARE IMPLEMENTATION OF A PROGRAMMABLE FFT BASED ON A HALF LENGTH FFT CORE - A method of designing a IEEE 802.11n modem starting from a IEEE 802.11a/g modem using a programmable FFT (Fast Fourier Transform) based on a half length FFT core, modifies data in a reception chain implemented in a IEEE 802.11n standard application. The method uses a N/2 FFT which is validated, along with a wrapper; and, extends and applies the validated N/2 FFT, (e.g., 64 FFT) to a N FFT (e.g., 128 FFT) by splitting the N FFT into two smaller first and second FFTs. The first FFT is applied to selected data samples (e.g., even samples) from the N FFT and the second FFT is applied to remaining data samples (e.g., odd samples) from the N FFT to complete data-handling, wherein the extending step is based on Danielson-Lanzos formula using a reduced number of Cordics. The method is also suitable for IFFT computations in IEEE 802.11n MIMO OFDM modem designs.01-15-2009
20110122760INTERFERENCE CANCELLATION WITH MU-MIMO SCHEME IN SC-FDMA SYSTEM - An apparatus and a method for interference cancellation using a multi-user multiple input multiple output (MU-MIMO) scheme in a single carrier frequency division multiple access (SC-FDMA) system are disclosed. Received data of every terminal are classified into first received data and second received data. The first received data has lower reliability and the second received data has higher reliability than the first received data. The second received data is transmitted to an upper layer. Interference signals are formed with the second received data based on a channel estimation value. The interference signals are removed from the first received data, and the interference signal free first received data is transmitted to the upper layer.05-26-2011
20080298227Method for Interference Estimation for Orthogonal Pilot Patterns - In an OFDM communications system receiver, channel estimates are processed to remove or reduce noise, exploiting the orthogonality of pilot patterns. The de-noised channel estimates are then used to compute inter-cell interference. The noise effects of orthogonal pilot patterns are selectively removed from channel samples in estimating inter-cell interference, depending on whether data subcarriers are subject to the same interference as pilot subcarriers, and whether data subcarriers are subject to interference from sectors with pilot patterns orthogonal to those in the transmitting sector. A further calculation removes noise from cells not identified by an orthogonal pilot sequence, which may be particularly applicable when large variations exist in the frequency domain of the propagation channel across a pilot pattern.12-04-2008
20080298228Transmitting/Receiving Apparatus of Wideband Wireless Channel Apparatus Using Multiple Carriers - The present invention relates to transmitting/receiving apparatuses of a wideband radio channel measuring device using a multi-carrier. The wideband radio channel measuring device using the multi-carrier may measure radio channel characteristics at a frequency domain. Since the radio channel is measured at the frequency domain by the wideband radio channel measuring device using the multi-carrier, the channel characteristics may be simultaneously measured while maintaining a maximum Doppler measurement frequency at a predetermined level regardless of increase of the number of transmitting and receiving antennas, in an MIMO configuration.12-04-2008
20110038250ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING TRANSMITTING AND RECEIVING DEVICE - An orthogonal frequency division multiplexing (OFDM) receiving apparatus, including a receiving unit, a subcarrier demodulation unit and a signal output processing unit, is provided. The receiving unit is for receiving an RF signal to generate a set of discrete signals. The subcarrier demodulation unit is coupled to the receiving unit, and used for demodulating a set of discrete signals to obtain a complex signal. The signal output processing unit is coupled to the subcarrier demodulation unit, and used for capturing and outputting real parts of the complex signal.02-17-2011
20110038249TIMING ADJUSTMENT METHOD, RECEIVING STATION, AND TRANSMITTING STATION IN WIRELESS COMMUNICATION SYSTEM, AND WIRELESS COMMUNICATION SYSTEM - A discontinuous change in a transmission timing in a time domain, which is caused by a transmission timing adjustment processing of an OFDMA uplink or the like, brings about a discontinuous rotation of a signal phase in a frequency domain, resulting in reduced communication quality. A wireless communication system of the present invention allows the signal phase of the frequency domain in a receiving station to be continuous before and after the timing adjustment processings by controlling a signal sequence in a transmission signal after conversion in the time domain in synchronization with the timing adjustment processing.02-17-2011
20120320730System and Method for Initial Ranging in Wireless Communication Systems - A system and method for initial ranging in wireless communication systems is provided. A plurality of orthogonal frequency division multiplexing (OFDM) blocks are received by an OFDMA base station transceiver from a plurality of remote user devices in wireless communication with the base station. A ranging subchannel is extracted from the OFDM blocks. The number of active codes in the ranging subchannel is determined, active codes are identified, and carrier frequency offsets (CFOs) are estimated for each active code. Timing delays and power levels for each active code are then estimated. The estimated CFOs, timing delays, and power levels are broadcasted by the base station to the remote user devices, so that the user devices can utilize same to adjust transmission parameters to optimize power levels and synchronize communication with the base station.12-20-2012
20110216644RECEIVING APPARATUS AND METHOD - A receiving apparatus includes a first transform unit configured to perform orthogonal transform on a time-domain input signal and perform saturation when an overflow occurs to transform the input signal into a plurality of frequency-domain signals, a second transform unit configured to perform orthogonal transform on the time-domain input signal while restricting the number of bits during orthogonal transform and continue operations while not performing saturation when at least one of the operations overflows and leaving the operation overflowing to transform the input signal into a plurality of frequency-domain signals, and a bit restricting control unit configured to control the number of bits during orthogonal transform by the second transform unit based on output signals of the first transform unit.09-08-2011
20100232285METHOD AND APPARATUS FOR ALLOCATING BACKHAUL TRANSMISSION RESOURCE IN WIRELESS COMMUNICATION SYSTEM BASED ON RELAY - In a relay based wireless communication system, a method for transmitting an uplink backhaul of a relay node includes obtaining scheduling information for an uplink backhaul sub-frame through a downlink backhaul control channel from a base station, and performing a rate matching and mapping of data by regarding at least one predefined symbol as a blank symbol. The predefined symbol is located at a front part or a rear part of the scheduled uplink backhaul sub-frame. The transmitting method further includes performing a multiplexing of the uplink backhaul sub-frame, and transmitting the multiplexed uplink backhaul sub-frame. This method can eliminate an overlap of transmission and reception timing in a relay node due to an RF transmission/reception switching time delay. Also, the method can make better use of wireless backhaul resources and minimize an influence on conventional systems by offering the compatibility with conventional uplink and downlink sub-frame structures.09-16-2010
20120287771OFDM GENERATION APPARATUS IN A MULTI-CARRIER DATA TRANSMISSION SYSTEM - OFDM generation apparatus and methods generating OFDM transmission signals from OFDM symbols, each including a plural OFDM subcarriers, for transmission in a multi-carrier data transmission system. In OFDM systems using the concept of Absolute OFDM and/or using Segmented OFDM common phase rotations of the OFDM subcarriers of the OFDM symbol with respect to adjacent OFDM symbols of the OFDM transmission signal generally appear. To avoid or compensate those common phase rotations, in the apparatus and method a selected mixing frequency is used for mixing the complex time-domain samples of the OFDM symbol from a baseband frequency up to a passband frequency by use of a mixing frequency to obtain the OFDM transmission signal, wherein the mixing frequency is selected such that common phase rotations of the OFDM subcarriers of the OFDM symbol with respect to adjacent OFDM symbols of the OFDM transmission signal are avoided or compensated after the mixing.11-15-2012
20080239941System and method for FFT window timing synchronization for an orthogonal frequency-division multiplexed data stream - A system and method for determining an FFT window location for reception of an OFDM signal received over a transmission channel. The OFDM signal includes a plurality of symbols each having a guard interval. The system includes a correlation module that determines a location of maximum correlation in a first symbol, an FFT module to perform an FFT on the OFDM signal based upon an initial FFT window location, and an adjustment module. The adjustment module determines a plurality of permissible echo location options based upon the initial FFT window location, selects a permissible echo location option that corresponds most closely to the location of maximum correlation, and adjusts the initial FFT window location based upon the selected permissible echo location option so that the adjusted FFT window location includes substantially all of a useful symbol length of the first symbol while a maximum number of echoes are included within the guard interval of the first symbol.10-02-2008
20080232240METHOD AND APPARATUS FOR RESOURCE ALLOCATION WITHIN A MULTI-CARRIER COMMUNICATION SYSTEM - A method and apparatus for performing resource allocation with lower required overhead is provided herein. Resource allocations for data transmissions are chosen in such a way as to provide channel quality information for various parts of the channel bandwidth (frequency selective channel quality information), such as allocating two different resource blocks (on different sets of subcarriers) to a mobile unit for two different transmissions. These data transmissions are used to estimate frequency selective channel quality information, thereby eliminating or greatly reducing the need for channel sounding with a broadband pilot. As a result, the overhead on the uplink of the communication system may be significantly reduced.09-25-2008
20080225694METHOD AND APPARATUS FOR ID IDENTIFICATION USING PN FOR TDS-OFDM IN TRANSMISSION - In an OFDM system having PN sequences as guard intervals, a method is used for synchronization. The method comprises the steps of: providing a plurality of base stations; providing a plurality of mobile stations; both the base stations and the mobile stations are adapted to transmit and receive signals associated with a parameter using the PN sequences for synchronization.09-18-2008
20080225693METHOD AND APPARATUS FOR UPLINK SCHEDULING SIGNALING IN A WIRELESS COMMUNICATION - A method and apparatus for efficient uplink scheduling grant and scheduling request signaling for evolved universal terrestrial radio access (E-UTRA) are disclosed. A wireless transmit/receive unit sends an uplink scheduling request to a Node-B, whereby the Node-B sends the uplink scheduling grant in response to the uplink scheduling request. The uplink scheduling request includes a data buffer occupancy value that indicates the amount of data that needs to be transmitted in the uplink. The amount of data is quantized to integer factors of the number of bits that may be supported by one RB, and mapped to an index value with N-bit mapping having less than full resolution. The uplink scheduling grant assigns a number of resource blocks to the WTRU for uplink transmission. The number of RBs allocated is mapped to an index value using N-bit mapping having less than full resolution.09-18-2008
20080225692SYSTEMS AND METHOD FOR ORTHOGONAL FREQUENCY DIVISIONAL MULTIPLEXING - Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises:a receiver configured to de-modulate symbols from at least one of a plurality of spectrally overlapping carrier signals; a transmitter configured to modulate symbols onto at least one of a plurality of the spectrally overlapping carrier signals; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform to the data transmitted by the transmitter; the processor programmed to encode upstream information using a forward error correction algorithm based on forward error correction parameters received by the receiver.09-18-2008
20080225691SYSTEMS AND METHOD FOR ORTHOGONAL FREQUENCY DIVISIONAL MULTIPLEXING - Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising a plurality of spectrally overlapping carrier signals from at least two of a plurality of remotes, the carrier signals are modulated using an inverse Fourier transform; a transmitter; a processor coupled to the transmitter, the processor outputs data for transmission to the transmitter, the processor applies an inverse Fourier transform to the data provided to the transmitter; a controller programmed to instruct the transmitter to transmit timing adjustments to the at least two of the plurality of remotes, the timing adjustments instruct the at least two of the plurality of remotes to adjust transmission timing so that transmitted symbols associated with frames of a predetermined multiframe structure are received in sequence from the at least two of the plurality of remotes based on the structure.09-18-2008
20080225690SYSTEMS AND METHOD FOR ORTHOGONAL FREQUENCY DIVISIONAL MULTIPLEXING - Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising spectrally overlapping carrier signals from at least two of a plurality of remotes, wherein the spectrally overlapping carrier signals are modulated using an inverse Fourier transform algorithm; a transmitter; a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; a controller programmed to calculate an elapsed time for each of the two remotes, the elapsed time representing a time between transmitting a ranging signal to a remote and receiving a signal from the remote in response to the ranging signal; the controller further programmed to reducing any difference between at least two elapsed times by instructing at least one of the plurality of remotes to adjust a delay.09-18-2008
20130176841Method and Apparatus for Receiving Physical Uplink Control Channel in LTE System - The present document discloses an apparatus for receiving Physical Uplink Control Channel (PUCCH) in Long Term Evolution (LTE) system, comprising: blocks of system FFT performing system FFT on data from a plurality of antennas, blocks of PUCCH RB processing units receiving the allocated logic resource index table and the local base sequence and output of the blocks of system FFT, and generating DMRS despread outputs and data values; a block of SR detection for receiving the data values and the DMRS despread outputs, and for generating SR detection results; blocks of user data extraction receiving data values and DMRS despread outputs, and performing user data extraction; blocks of PUCCH user processing units receiving an orthogonal sequence index, the data values and an output from blocks of user data extraction, and generating a ACK/NAK/CQI signal for a concerned UE.07-11-2013
20090252026TIMING AND FREQUENCY ACQUISITION FOR MEDIAFLO SYSTEMS - An apparatus, logic, and method of performing timing and frequency estimation in a MediaFLO™ mobile multimedia multicast system comprising a receiver and a transmitter, wherein the method comprises receiving a wireless data stream comprising a MediaFLO™ mobile multimedia multicast system superframe comprising Orthogonal Frequency Division Multiplexing (OFDM) symbols; estimating a Fast Fourier Transform (FFT) trigger point for each of the received OFDM symbols; estimating a fine carrier frequency offset of each OFDM symbol; determining the start of the MediaFLO™ mobile multimedia multicast system superframe by locating a Time Division Multiplexed (TDM) pilot symbol in the superframe; estimating a coarse carrier frequency offset of each of the received OFDM symbols; and synchronizing the receiver to the start of the MediaFLO™ mobile multimedia multicast system superframe and the transmitted OFDM symbols based on the fine carrier frequency offset, the TDM pilot symbol, and the coarse carrier frequency offset.10-08-2009
20120250493Apparatuses and Methods for Detecting a Group Delay in a Communication System - The exemplary embodiments of the present invention relate to a transmission part (10-04-2012
20130114393Method of Handling Shortened Resource Block for MTC Device and Related Communication Device - A method of arranging a shortened resource block (RB) without a direct current (DC) subcarrier for a wireless communication system comprising a communication device and a network is disclosed. The method comprises selecting a RB from a plurality of RBs comprising a plurality of available subcarriers, according to a configuration, wherein the RB comprises a plurality of subcarriers; and removing the DC subcarrier from the plurality of subcarriers of the RB according to the configuration, to construct the shortened RB without the DC subcarrier.05-09-2013
20130094345DYNAMICALLY SELECTING METHODS TO REDUCE DISTORTION IN MULTI-CARRIER MODULATED SIGNALS RESULTING FROM HIGH PEAK-TO-AVERAGE POWER RATIOS - In one embodiment, an algorithm dynamically selects a method for reducing distortion in a multi-carrier modulated signal, such as an orthogonal frequency division multiplexing (OFDM) signal. The algorithm directs a transmitter to transmit peak-to-average power ratio (PAPR)-reduction signals over reserved tones (i.e., frequencies) if reserved tones are available. If reserved tones are not available, then the algorithm directs the transmitter to transmit PAPR-reduction symbols over free tones if free tones are available. If the free tones for this transmitter are used by adjacent transmitters, then interference-reduction techniques may be used to reduce interference with the adjacent transmitters. If reserved tones and free tones are not available, then the transmitter may use an alternative method to reduce distortion, such as successive clipping and filtering. In another embodiment, the transmitter may transmit PAPR-reduction symbols over both free and reserved tones, if available.04-18-2013
20130128717TRANSMITTING DEVICE, RECEIVING DEVICE, AND SIGNAL PROCESSING METHOD IN RADIO COMMUNICATION SYSTEM - A radio communication system using an orthogonal frequency division multiplexing system, including: a baseband unit; and one or plural remote radio units coupled with the baseband unit through an interface; wherein the baseband unit includes a first sample frequency conversion part that performs a first sample frequency conversion processing that down-samples a transmitting signal transmitted through the interface, wherein the remote radio unit includes a second sample frequency conversion part that performs a second sample frequency conversion processing that up-samples a signal received through the interface, and wherein the baseband unit further includes an inverse fast fourier transform part that generates the transmitting signal by an inverse fast fourier transform, and a transmitter characteristic compensation part that conducts frequency characteristic compensation of the first sample frequency conversion processing and the second sample frequency conversion processing for a signal that has not been subjected to the inverse fast fourier transform.05-23-2013
20130148488OFFSET MODULATION ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) AND MULTI-ACCESS TRANSMISSION METHOD WITH CYCLIC PREFIX (CP) - The present invention provides an Offset Modulation Orthogonal Frequency Division Multiplexing (OFDM) and multi-access transmission method with a Cyclic Prefix (CP), including a generating method of the sent signal in the sending terminal and a processing method of the received signal in the receiving terminal, the method includes: in the sending terminal, performing generalized discrete Fourier Transform on real-value digital baseband modulated symbols and obtaining the frequency-domain signal; performing conjugate symmetric extension, frequency-domain filtering, sub-carrier mapping on the frequency-domain signal; performing Inverse Fast Fourier Transform on the frequency-domain signal after sub-carrier mapping; inserting a CP and obtaining the time-domain sent signal; in the receiving terminal, including: removing the CP, performing Fast Fourier Transform on CP removed symbols and obtaining the frequency-domain received signal; and based on multiple user joint frequency-domain equalization performing iterative detection decoding on the frequency-domain received signal. The present invention can obtain the low-signal envelope volatility in the condition of remaining spectrum efficiency, and adopting iterative received signal processing method based on multiple user joint frequency-domain equalization ensures the transmission reliability with low-complexity.06-13-2013
20090122694Method for signaling information by modifying modulation constellations - Methods and systems for communicating in a wireless network may distinguish different types of packet structures by modifying the phase of a modulation constellation, such as a binary phase shift keying (BPSK) constellation, in a signal field. Receiving devices may identify the type of packet structure associated with a transmission or whether the signal field is present by the phase of the modulation constellation used for mapping for the signal field. In one embodiment, the phase of the modulation constellation may be determined by examining the energy of the I and Q components after Fast Fourier Transform. Various specific embodiments and variations are also disclosed.05-14-2009
20100315940SIGNAL TRANSMITTING METHOD, SIGNAL RECEIVING METHOD AND SIGNAL RECEIVING DEVICE IN OFDM SYSTEM - A signal transmitting method, a signal receiving method, and a signal receiving device are adapted to an OFDM system. In the signal transmitting method and signal receiving method, double asymmetric training symbols are used for performing time-varying channel response estimation. In the transmitting method, asymmetric pilot sub-carriers are added in data sub-carriers to form a plurality of first and second training symbols. The pilot symbols in the first and second training symbols are asymmetrically configured. In the receiving method, a channel response corresponding to each pilot sub-carrier is estimated by using two adjacent asymmetric pilot symbols. The received data sub-carrier is then restored through the channel response. Through the signal transmitting method and signal receiving method, even in a transmitter or a receiver moving at a high speed, more bandwidths can be used to transfer data, and contents of the transferred data can be correctly estimated.12-16-2010
20130155833APPARATUS AND METHOD FOR I/Q OFFSET CANCELLATION IN SC-FDMA SYSTEM - The present invention relates to an apparatus and a method for eliminating I/Q offset in a receiver of a SC-FDMA system which improves performance of the system by accurate measurement and cancellation of I/Q offset in a receiver of a SC-FDMA system operating in a 06-20-2013
20110280117BACKWARD-COMPATIBLE LONG TRAINING SEQUENCES FOR WIRELESS COMMUNICATION NETWORKS - A network device for generating an expanded long training sequence with a minimal peak-to-average ratio. The network device includes a signal generating circuit for generating the expanded long training sequence. The network device also includes an Inverse Fourier Transform for processing the expanded long training sequence from the signal generating circuit and producing an optimal expanded long training sequence with a minimal peak-to-average ratio. The expanded long training sequence and the optimal expanded long training sequence are stored on more than 52 sub-carriers.11-17-2011
20110310725SOFT HANDOFF IN OFDMA SYSTEM - Soft handoff in an OFDMA system is disclosed. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone has subcarriers with a subchannel definition, for example, an identical permutation.12-22-2011
20120020201DEVICE AND METHOD FOR FAST FOURIER TRANSFORM - A device and a method for Fast Fourier Transform (FFT) are disclosed. The device includes a data receiving module, an address translation module, a data storage module, a FFT module, a data extraction module and a data output module. The data receiving module is configured to receive the input data. The address translation module is configured to duplicate M/N copies of the received data and then send them to the data storage module. The data storage module is configured to store the received data sent by the address translation module to M/N different addresses. The FFT module is configured to perform M-point FFT on the stored data. The data extraction module is configured to extract one point in every several points of the transformed data, and send the extracted data to the data output module. The data output module is configured to output the received data.01-26-2012
20130201814Methods and Apparatus for Signal Conditioning in OFDMA Systems - Methods and systems for conditioning an orthogonal frequency division multiplex (OFDM) signal are disclosed. The OFDM signal may be conditioned prior to transmission by a transmitter in an orthogonal frequency division multiple access (OFDMA) system operating on a channel with a plurality of subcarriers grouped into subchannels. The OFDM signal may be clipped based on a desired peak-to-average-power ratio (PAPR) to produce a clipped-off portion of the OFDM signal. The clipped-off portion of the OFDM signal may be transformed into the frequency domain to produce a frequency-domain signal. An in-band spectral shaping mask may be applied to subcarriers or subchannels of the frequency-domain signal within the channel to control the levels of distortion on the individual subcarriers or subchannels. The shaped frequency-domain signal is transformed into the time domain to produce a time-domain signal. A conditioned signal is produced for transmission by subtracting the time-domain signal from the OFDM signal.08-08-2013
20090323510Modulation and demodulation of OFDM signals - The invention relates to a method for modulating sub-carrier symbols to an intermediate-frequency OFDM signal having even and odd samples, including following steps: 12-31-2009

Patent applications in class Fourier transform