Patent application number | Description | Published |
20080260056 | Methods for Selecting a Coarse Frequency Offset Estimation for an Orthogonal Frequency Division Multiplexing Modulated Signal - The present invention provides methods for selecting the coarse frequency offset estimation in an orthogonal frequency division multiplexing system that may include: searching within a predefined subset for a set of frequency offset candidates; selectively searching outside the predefined subset for additional frequency offset candidates; and combining one or more ICDC method and CIR based method to select the coarse frequency offset. | 10-23-2008 |
20090097578 | Methods for Decoding TPS Carriers in OFDM Systems - The present invention relates to methods for TPS demodulation, frame boundary detection, and TPS decoding. In particular, the present invention relates to a method for finding a frame boundary in demodulating an OFDM signal, comprising the steps of: differentially demodulating each symbol to generate differentially demodulated symbol bits; and finding a sync word position when the scatter pilot position equals zero, wherein the sync word position is set as the frame boundary. | 04-16-2009 |
20090097596 | Methods and Systems for Impulse Noise Compensation for OFDM Systems - Methods and systems are provided to reduce the effects of impulse noise in decoding a received OFDM signal by reducing the bit error number in burst error positions and by reducing the impulse noise contribution to channel estimation. In order to reduce the performance degradation due to impulse noise, it is important to find the position or the OFDM symbol where impulse noise occurs. The high noise variance gain can then be used for a Viterbi decoder to reduce the bit error number in burst error position, and also to reduce the contribution of the channel estimation by impulse noise in future channel estimations. Accordingly, the performance of the system can be greatly improved. | 04-16-2009 |
20090097597 | Methods For Coarse Frequency Offset Estimation For Orthogonal Frequency Division Multiplexing Schemes - The present invention provides methods for coarse frequency offset estimation, where those methods may comprise the steps of: removing fading channel impact by calculating accumulated correlation values; removing CCI and phase rotation due to large sampling offset by calculating an accumulation metric as a function of the accumulated correlation values, CCI peak, and initial sampling offset, ΞΎ; and finding the coarse frequency offset as a function of the accumulation metric. | 04-16-2009 |
20090103667 | Methods for Modified Signal Acquisition for OFDM Schemes - This invention relates to methods for determining coarse symbol timing and mode detection by using CP correlation-based techniques. In particular, this invention relates to methods for determining symbol timing, frame timing, and system mode for signal acquisition, comprising the steps of: detecting symbol timing and system mode based on cyclic prefix correlation; and determining a null symbol as a function of a pre-defined number of consecutive symbols and using said null symbol to determine frame timing. | 04-23-2009 |
20090110135 | Methods for PRS-Based Symbol Timing Adjustment for OFDM Systems - This invention relates to methods for determining symbol timing shift for a received signal, comprising the steps of: demodulating a received signal; removing a phase reference sequence from the demodulated signal to generate a channel frequency response; converting said channel frequency response to the time domain to generate a channel impulse response; determining a detection threshold; determining a first path and a last path as a function of the detection threshold; and calculating a timing shift as a function of the first path and the last path. | 04-30-2009 |
20090122918 | Methods for Compensating for I/Q Imbalance in OFDM Systems - The present invention relates to methods for demodulating orthogonal frequency division multiplexing (OFDM) modulated signals. In particular, this invention relates to methods for in-phase (I) and quadrature phase (Q) imbalance compensation in OFDM systems. For example, the present invention relates to methods for calculating an IQ imbalance compensated signal from a received signal, comprising the steps of: removing DC from the received signal; calculating an autocorrelation matrix of IQ signal vector of the received signal; estimating IQ imbalance compensation values, K | 05-14-2009 |
20090168930 | Methods and Systems for Doppler Estimation and Adaptive Channel Filtering in a Communication System - A method for Doppler shift estimation for channel estimation of a received signal, comprising the steps of: calculating time domain correlations; providing a Hamming window over the calculated time domain correlations; calculating a power spectrum by using FFT; calculating an adaptive threshold based on a noise floor and an average power density calculated from the power spectrum; and estimating a Doppler shift based on the adaptive threshold. | 07-02-2009 |
20090207899 | Equalizer training method using re-encoded bits and known training sequences - The present invention provides a multi-branch equalizer processing module operable to cancel interference associated with received radio frequency (RF) burst(s). This multi-branch equalizer processing module includes both a first equalizer processing branch and a second equalizer processing branch. The first equalizer processing branch is operable to be trained based upon known training sequences and equalize the received RF burst. This results in soft samples or decisions which in turn may be converted to data bits. The soft samples are processed with a de-interleaver and channel decoder, where the combination is operable to produce a decoded frame of data bits from the soft samples. A re-encoder may re-encode the decoded frame to produce re-encoded or at least partially re-encoded data bits. An interleaver then processes the at least partially re-encoded data bits to produce and at least partially re-encoded burst. The second equalizer processing branch uses the at least partially re-encoded data bits to train linear equalizer(s) within the second equalizer processing branch. A buffer may initially store the received RF burst(s), which are retrieved and equalized by the second equalizer processing branch once the linear equalizer(s) are trained. This results in alternate soft samples or decisions which in turn may be converted to alternate data bits. The alternate soft samples are processed with the de-interleaver and channel decoder, where the combination is operable to produce an alternate decoded frame of data bits from the alternate soft samples. This allows interfering signals to be cancelled and more accurate processing of the received RF bursts to occur. | 08-20-2009 |
20090219982 | Selectively Disabling Interference Cancellation Based on Channel Dispersion Estimation - A channel dispersion estimation algorithm(s) may be implemented within a channel length estimation module of a multi-branch equalizer processing module that disables a branch of the multi-branch equalizer processing module when the channel length or channel delay spread associated with received radio frequency (RF) bursts exceeds a predetermined threshold. The channel dispersion estimation algorithm identifies when the radio frequency (RF) bursts have a channel length or channel delay spread that can affect receiver performance. The channel length estimation module may disable interference cancellation by a branch of the multi-branch equalizer processing module in response to such a channel length or channel delay spread. | 09-03-2009 |
20100054311 | WCDMA terminal baseband processing module having multi-path scanner module - A baseband processing module according to the present invention includes a multi-path scanner module. The multi-path scanner module is operable to receive timing and scrambling code information regarding an expected multi-path signal component of a WCDMA signal. Then, the multi-path scanner module is operable to identify a plurality of multi-path signal components of the WCDMA signal by descrambling, despreading and correlating a known symbol pattern of/with a baseband RX signal within a search window. The multi-path scanner module is operable to determine timing information for the plurality of multi-path signal components of the WCDMA signal found within the search window and to pass this information to a coupled rake receiver combiner module. | 03-04-2010 |
20100216506 | System and Methods for Supporting Multiple Communications Protocols on a Mobile Phone Device - A mobile phone device utilizing a first communications protocol and a second communications protocol, comprises: a first system having a general processor, a memory, a first communications system providing for the first communications protocol and utilizing a first communications protocol stack, and a first link; a second system having a dedicated communications accelerator providing for the second communications protocol and utilizing a second communications protocol stack, and a second link; wherein the first link and the second link are connected; and wherein the memory in the first system holds the first communications protocol stack and the second communications protocol stack. | 08-26-2010 |
20110182338 | CO-CHANNEL INTERFERENCE AND ADJACENT CHANNEL INTERFERENCE DETECTION AND SUPPRESSION - Methods having corresponding apparatus and computer-readable media comprise: receiving an input signal, wherein the input signal includes a DVB-H signal; detecting co-channel interference (CCI) in the signal; suppressing the CCI in the input signal; and demodulating the DVB-H signal after suppressing the CCI. | 07-28-2011 |
20110228886 | FAST LINK RE-SYNCHRONIZATION FOR TIME-SLICED OFDM SIGNALS - Methods having corresponding apparatus and computer-readable media comprise: receiving an estimated frame index, and an estimated symbol index, for a time-sliced OFDM signal; identifying a plurality of possible frame indexes, and a plurality of possible symbol indexes, based on the estimated frame index and the estimated symbol index; selecting a plurality of possible forward error correction code offsets based on the possible frame indexes and the possible symbol indexes; and selecting one of the possible frame indexes, and one of the possible symbol indexes, based on the possible forward error correction code offsets and a SYNC byte of the time-sliced OFDM signal. | 09-22-2011 |
20110258513 | SNR-Based Variable-Threshold Majority-Logic Decoder - Apparatus having corresponding methods and tangible computer-readable medium embodying instructions executable by a computer to perform the methods comprise: a receiver adapted to receive a signal representing an input code block, wherein the input code block represents information encoded with a (N, K) difference-set cyclic code, wherein the input code block includes N symbols, and wherein the N symbols represent K bits of the information; an estimator adapted to estimate a signal-to-noise ratio of the signal; a raised-threshold majority-logic decoder adapted to decode the input code block according to a raised-threshold majority-logic decoding algorithm when the signal-to-noise ratio does not exceed a first predetermined threshold; and a variable-threshold majority-logic decoder adapted to decode the input code block according to a variable-threshold majority-logic decoding algorithm when the signal-to-noise ratio exceeds the first predetermined threshold. | 10-20-2011 |