Maximum Likelihood Decoder Or Viterbi Decoder Patents (Class 375/341)
  • Patent number: 8750433
    Abstract: A demodulation circuit includes a hard decision process unit and a soft decision process unit. The hard decision process unit is configured to perform a hard decision process using a demodulated signal, and the demodulated signal is a demodulated received signal. The soft decision process unit is configured to determine a range of assignment with respect to a transitioning part in the demodulated signal, calculate a likelihood value of a bit, and perform a soft decision process.
    Type: Grant
    Filed: April 9, 2012
    Date of Patent: June 10, 2014
    Assignee: Fujitsu Limited
    Inventors: Naoto Adachi, Masataka Umeda
  • Patent number: 8751895
    Abstract: A semiconductor memory device includes a semiconductor memory unit which stores LDPC encoded data, and a decoding unit which decodes the encoded data, wherein the decoding unit performs serial decoding using the posterior likelihood ratio as it is for a column element likelihood ratio when the absolute value of the posterior likelihood ratio is not smaller than a threshold and using the column element likelihood ratio as it is for the posterior likelihood ratio when the absolute value of the column element likelihood ratio is not smaller than the threshold, and if the decoding does not succeed even after a predetermined first cycle count of iterative processing is performed or if the number of syndrome errors becomes smaller than a predetermined first syndrome error count, the decoding unit shrinks the absolute values of at least some of posterior likelihood ratios and resets all prior likelihood ratios to “0.
    Type: Grant
    Filed: August 8, 2012
    Date of Patent: June 10, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Haruka Obata, Tatsuyuki Ishikawa, Hironori Uchikawa, Kenji Sakurada
  • Publication number: 20140153673
    Abstract: A communication device is configured adaptively to process a receive signal based on noise that may have adversely affected the signal during transition via communication channel. The device may be configured to identify those portions of the signal of the signal that are noise-affected (e.g., noise-affected sub-carriers of an orthogonal frequency division multiplexing (OFDM) signal), or the device may receive information that identifies those portions of the signal that are noise-affected from one or more other devices. The device may be configured to perform the modulation processing of the received signal to generate log-likelihood ratios (LLRs) for use in decoding the signal. Those LLRs associated with noise-affected portions of the signal are handled differently than LLRs associated with portions of the signal that are not noise-affected. The LLRs may be scaled based on signal to noise ratio(s) (SNR(s)) associated with the signal (e.g., based on background noise, burst noise, etc.).
    Type: Application
    Filed: October 31, 2013
    Publication date: June 5, 2014
    Applicant: Broadcom Corporation
    Inventors: Ba-Zhong Shen, Richard S. Prodan, Avi Kliger, Leo Montreuil, Jonathan S. Min, Tak K. Lee, Kelly Brian Cameron, Hau Thien Tran
  • Publication number: 20140153676
    Abstract: A technique includes jointly demodulating a desired signal and an interfering signal of a received signal in response to a carrier-to-interference ratio estimate for the received signal being below a threshold level. The jointly demodulating is based on first channel impulse response coefficients associated with the desired signal and second channel impulse response coefficients associated with the interfering signal. The technique includes determining the first channel impulse response coefficients based on a first cross-correlation function between the received signal and a training sequence of the desired signal and determining the second channel impulse response coefficients based on a second cross-correlation function between the received signal and a training sequence of the interfering signal.
    Type: Application
    Filed: February 10, 2014
    Publication date: June 5, 2014
    Applicant: AT&T Intellectual Property I, L.P.
    Inventors: Richard A. Kobylinski, David Randall Wolter
  • Publication number: 20140153625
    Abstract: Systems and methods for decoding block and concatenated codes are provided. These include advanced iterative decoding techniques based on belief propagation algorithms, with particular advantages when applied to codes having higher density parity check matrices. Improvements are also provided for performing channel state information estimation including the use of optimum filter lengths based on channel selectivity and adaptive decision-directed channel estimation. These improvements enhance the performance of various communication systems and consumer electronics. Particular improvements are also provided for decoding HD Radio signals, including enhanced decoding of reference subcarriers based on soft-diversity combining, joint enhanced channel state information estimation, as well as iterative soft-input soft-output and list decoding of convolutional codes and Reed-Solomon codes. These and other improvements enhance the decoding of different logical channels in HD Radio systems.
    Type: Application
    Filed: December 3, 2012
    Publication date: June 5, 2014
    Applicant: Digital PowerRadio, LLC
    Inventors: Branimir R. Vojcic, Farnaz Shayegh, Hakan Dogan, Wookwon Lee
  • Patent number: 8744017
    Abstract: A method and system for demapping a hierarchical signal is disclosed. The method includes receiving a hierarchical signal comprising first and second encoded, modulated signals. A conditional probability relating to the structure of the second encoded, modulated signal is determined. The hierarchical signal is demodulated using the conditional probability to generate a first encoded data stream. The first encoded data stream is decoded to recover information bits.
    Type: Grant
    Filed: March 2, 2012
    Date of Patent: June 3, 2014
    Assignee: CMMB Vision USA Inc.
    Inventors: Zixia Hu, Hui Liu
  • Patent number: 8743942
    Abstract: A receiver includes a constellation processing module and a plurality of demodulation stages. The constellation processing module groups points of a constellation associated with a transmitted signal into a plurality of subsets, were at least two adjacent ones of the subsets have one or more common constellation points so that the at least two adjacent subsets overlap. The constellation processing module also determines a centroid-based value for each of the subsets of constellation points and groups the centroid-based values into one or more sets. Each of the demodulation stages except for the last demodulation stage localizes a search for a final symbol decision using the set of centroid-based values input to or selected by the demodulation stage as constellation points. The last demodulation stage determines the final symbol decision using the subset of constellation points input to or selected by the last demodulation stage.
    Type: Grant
    Filed: October 4, 2012
    Date of Patent: June 3, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (Publ)
    Inventor: Ali S. Khayrallah
  • Patent number: 8744018
    Abstract: Certain embodiments provide methods that may allow for improvements in performance and power consumption by terminating the turbo decoding process early when one of at least two test criterion is satisfied in communications systems, including UMTS, WCDMA, and TD-DCMA.
    Type: Grant
    Filed: April 5, 2012
    Date of Patent: June 3, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Jinghu Chen, Wanlun Zhao, Mingxi Fan, Fuyun Ling, Peter John Black
  • Patent number: 8743936
    Abstract: Various embodiments of the present invention provide systems and methods for estimating noise components in a received signal set. For example, one embodiment of the present invention provides a noise estimation circuit that includes a data detector circuit and a noise component calculation circuit. The data detector circuit receives a series of data samples and provides a detected output, and the noise component calculation circuit provides an electronics noise power output and a media noise power output each calculated based at least in part on the detected output and the series of data samples.
    Type: Grant
    Filed: January 5, 2010
    Date of Patent: June 3, 2014
    Assignee: LSI Corporation
    Inventors: George Mathew, Shaohua Yang, Yuan Xing Lee, Hongwei Song
  • Publication number: 20140146925
    Abstract: A communication apparatus with a multiple-input and multiple-output (MIMO) channel, includes a minimum mean square error (MMSE) detector configured to estimate quadrature amplitude modulation (QAM) symbols based on signals received through the MIMO channel. The apparatus further includes a QAM demodulator configured to demodulate the estimated QAM symbols, and estimate a first posterior probability of each of encoded bits of the estimated QAM symbols, and a first module configured to remove a first prior probability of each of the encoded bits from the first posterior probability to generate soft estimates of the encoded bits. The apparatus further includes a channel decoder configured to decode the encoded bits based on the soft estimates, and generate an improved posterior probability of each of the encoded bits, and a second module configured to generate a second prior probability of each of the encoded bits based on the improved posterior probability.
    Type: Application
    Filed: November 26, 2013
    Publication date: May 29, 2014
    Applicant: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Andrey Leonidovich Rog, Alexei Olegovich Melnikov, Michael Vladimirovich Golikov, Vitaliy Borisovich Kreyndelin, Mikhail Germanovich Bakulin
  • Patent number: 8737541
    Abstract: Provided is a decoding apparatus capable of reducing the error rate of the decoding results and also the circuit scale. A computing unit computes a plurality of distances only for a number of code word candidates of code words from demodulated data, the number being smaller than a number of values the code words can express, the code words having a possibility of being transmitted. A decoding unit decodes the code words from the plurality of computed distances. This invention is applicable to a decoding apparatus for Long Term Evolution (LTE).
    Type: Grant
    Filed: October 12, 2010
    Date of Patent: May 27, 2014
    Assignees: NEC Corporation, NTT DoCoMo, Inc.
    Inventors: Nobuyuki Tanaka, Masao Orio
  • Patent number: 8737542
    Abstract: A method and apparatus for receiving data in high-speed applications wherein an analog-to-digital converter (ADC) samples a received signal and a data decoder implemented with a tree search algorithm detects the bits of the sampled data for timing recovery. In some embodiments, a Viterbi detector is implemented to provide accurate bit detection for data output while tree search detected data is used to determine the optimal sampling phase for the ADC. In some embodiments, after the phase acquisition stage of timing recovery has completed, the tree search decoder may decrease the rate of data detection to maintain phase tracking.
    Type: Grant
    Filed: January 7, 2011
    Date of Patent: May 27, 2014
    Assignee: Marvell International Ltd.
    Inventor: Jagadish Venkataraman
  • Publication number: 20140140448
    Abstract: A method of performing maximum likelihood detection on spatially-multiplexed streams in a multiple-input multiple-output (MIMO) communication system, the method comprising: receiving plurality of received signals at a plurality of receiver antennas, the plurality of received signals corresponding to a plurality of transmit symbols, each transmit symbol being one of a number M possible symbols, for each of a value k=1 to M: select a first stream candidate symbol, for each receiver antenna, calculate a residual signal, combine said calculated residual signals, select a second stream candidate symbol for said value k based on the result of said combination to form a symbol pair comprising said first stream candidate symbol and said second stream candidate symbol; and calculate a corresponding distance metric for said symbol pair for said value k, selecting one of the symbol pairs based on said calculated distance metrics.
    Type: Application
    Filed: November 19, 2012
    Publication date: May 22, 2014
    Applicant: RESEARCH IN MOTION LIMITED
    Inventors: Martin Geoffrey LEACH, Ernst Slawomir ZIELINSKI
  • Patent number: 8731114
    Abstract: A Log-Likelihood Ratio (LLR) combining method and apparatus for Hybrid Automatic Repeat Request (HARQ) in a wireless communication system for reducing a number of the LLR bits of previous packet stored for LLR combining are provided. The LLR combining apparatus includes an LLR combiner for combining a first LLR of a currently received packet and a second LLR of a previously received packet, an LLR buffer for storing the second LLR and a first packet exponent for recovering the second LLR in the same size as the first LLR, and an HARQ controller for determining whether the currently received packet is a retransmission packet or an initial transmission packet, and for controlling the LLR combiner to generate a third LLR by combining the first and second LLRs for the retransmission packet and to bypass the initial transmission packet.
    Type: Grant
    Filed: February 4, 2010
    Date of Patent: May 20, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Seul Ki Bae, Joo Hyun Lee, Sung Hwan Kim
  • Patent number: 8731115
    Abstract: The present inventions are related to systems and methods for pre-equalizer noise suppression in a data processing system. As an example, a data processing system is discussed that includes: a sample averaging circuit, a selector circuit, an equalizer circuit, and a mark detector circuit. The sample averaging circuit is operable to average corresponding data samples from at least a first read of a codeword and a second read of the codeword to yield an averaged output based at least in part on a framing signal. The selector circuit is operable to select one of the averaged output and the first read of the codeword as a selected output. The equalizer circuit is operable to equalize the selected output to yield an equalized output, and the mark detector circuit is operable to identify a location mark in the equalized output to yield the framing signal.
    Type: Grant
    Filed: March 8, 2012
    Date of Patent: May 20, 2014
    Assignee: LSI Corporation
    Inventors: Shaohua Yang, Jin Lu
  • Publication number: 20140133541
    Abstract: A wireless communication apparatus includes a wireless section configured to receive a plurality of signals via a plurality of antennae from a transmitting device having another plurality of antennae; and a demodulation section configured to apply QR decomposition to a channel matrix generated based on the received signals from the wireless section, to extract a plurality of weight coefficients corresponding to a symbol to be demodulated from a unitary matrix Q, to filter the received signals weighted with the weight coefficients, and to separate the filtered received signals based on a submatrix of an upper triangular matrix R.
    Type: Application
    Filed: August 21, 2013
    Publication date: May 15, 2014
    Applicant: FUJITSU LIMITED
    Inventor: Tsuyoshi HASEGAWA
  • Patent number: 8724685
    Abstract: An apparatus and a method for interference cancellation in a Multiple Input Multiple Output (MIMO) wireless communication system. The method for interference cancellation includes equalizing first reception signals received through two or more reception antennas to estimate transmission signals transmitted through two or more transmission antennas, generating two or more second reception signals in which a mutual interference between the transmission signals is removed from the first reception signals by using the estimated transmission signals, independently equalizing the generated two or more second reception signals, and combining the independently equalized two or more second reception signals to estimate a transmission signal in which an interference is removed.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: May 13, 2014
    Assignees: Samsung Electronics Co., Ltd., Korea University Research and Business Foundation
    Inventors: Young-Min Ki, Byonghyo Shim, Jong-Yoon Hwang, Seung-Hwan Won, Chae-Man Lim
  • Patent number: 8724694
    Abstract: A decoder pipeline may include a decoding (prior to deblocking) stage followed by a deblocking stage. A memory can be coupled to the decoder pipeline. A decoded first macroblock can be output from the decoding stage directly into the deblocking stage, bypassing the memory, if a decoded second macroblock depended on to deblock the first macroblock is already deblocked. Otherwise, the decoded first macroblock is stored in the memory until the second macroblock is deblocked and available to deblock the first macroblock.
    Type: Grant
    Filed: October 14, 2008
    Date of Patent: May 13, 2014
    Assignee: Nvidia Corporation
    Inventor: Wei Jia
  • Publication number: 20140126621
    Abstract: A communications receiver includes an antenna, and a burst signal acquisition circuit coupled to the antenna to detect a burst signal received over a wireless communications channel. The burst signal has a burst structure that includes channel-corrupted known preamble bits, channel-corrupted known probe bits and channel-corrupted unknown data bits. A channel estimator is coupled to the burst signal acquisition circuit to generate a-priori a gain vector based on uncorrupted known probe bits, and to perform a recursive least squares (RLS) operation to determine an impulse response of the wireless communications channel based on the channel-corrupted known probe bits and the gain vector. A maximum likelihood sequence estimator (MLSE) or equalizer is coupled to the channel estimator and the burst signal acquisition circuit.
    Type: Application
    Filed: November 2, 2012
    Publication date: May 8, 2014
    Applicant: Harris Corporation
    Inventors: Joseph B. Shaver, John Wesley Nieto, Michael Patrick Snook
  • Patent number: 8719658
    Abstract: A method for accessing extrinsic information in a turbo decoder is disclosed. Operation phases for Forward State Metric Calculators (FSMCs) and Reverse State Metric Calculators (RSMCs) in multiple maximum a posteriori probability (MAP) decoders are misaligned differently based on whether a current half iteration is even or odd. First extrinsic information is read from a memory into the FSMCs and RSMCs using the misaligned operation phases. Second extrinsic information is determined using the MAP decoders. Each row of the second extrinsic information is stored to a different bank in the memory using the misaligned operation phases.
    Type: Grant
    Filed: September 9, 2010
    Date of Patent: May 6, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Zhiqiang Cui, Iwen Yao, Qiang Huang
  • Patent number: 8718166
    Abstract: Systems and methods are provided for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors based on the same transmitted vector. The receiver linearizes each received signal vector using one or more zero-forcing, MMSE, or other suitable linear equalizers. The components of the equalized signal vectors may be combined using maximum-ratio combining to form the components of a combined equalized signal vector. The components of the combined equalized signal vector may then be decoded individually using a linear decoder.
    Type: Grant
    Filed: August 6, 2007
    Date of Patent: May 6, 2014
    Assignee: Marvell World Trade Ltd.
    Inventors: Jungwon Lee, Woong Jun Jang, Hui-Ling Lou
  • Patent number: 8718188
    Abstract: Apparatus and methods for envelope tracking are disclosed. In one embodiment, a power amplifier system including a power amplifier and an envelope tracker is provided. The power amplifier is configured to amplify a radio frequency (RF) signal, and the envelope tracker is configured to control a supply voltage of the power amplifier using an envelope of the RF signal. The envelope tracker includes a buck converter for generating a buck voltage from a battery voltage and a digital-to-analog conversion (DAC) module for adjusting the buck voltage based on the envelope of the RF signal to generate the supply voltage for the power amplifier.
    Type: Grant
    Filed: April 20, 2012
    Date of Patent: May 6, 2014
    Assignee: Skyworks Solutions, Inc.
    Inventors: Florinel G. Balteanu, Sabah Khesbak, Yevgeniy A. Tkachenko, David Steven Ripley, Robert John Thompson
  • Patent number: 8718205
    Abstract: Low complexity methods for hard and soft bit level demapping in a receiver of QAM signals with non-square, Gray coded constellations created as per U.S. Pat. No. 8,422,579 B1. In these methods the received signal is equalized to remove channel distortion, demodulated into in-phase and quadrature phase related symbols, and these symbols converted into hard-bits or preliminary soft-bits bits via the application of bit decision rules. Further, if converted into preliminary soft-bits, they may be multiplied by a factor to account for the impact of the received signal's signal-to-noise ratio on bit reliability, thereby creating final-soft-bits.
    Type: Grant
    Filed: July 3, 2013
    Date of Patent: May 6, 2014
    Inventor: Douglas Howard Morais
  • Patent number: 8718203
    Abstract: Briefly, in accordance with one or more embodiments, in response to receiving a single carrier signal that is not phase locked, channel equalization may be applied to the signal via a channel equalizer. The equalized signal may be phase averaged to provide a signal that is at least partially phase stabilized. The channel equalizer may then be trained by feeding back the at least partially phase stabilized phase reference to the channel equalizer. The resulting signal may then be decoded via coherent or quasi-coherent detection.
    Type: Grant
    Filed: April 12, 2010
    Date of Patent: May 6, 2014
    Assignee: Anchor Hill Communications, LLC
    Inventor: Eric Jacobsen
  • Patent number: 8718156
    Abstract: Methods and systems for indexing signal option selections are disclosed. The signal options can be any of a variety of options that permit the establishment of a communication link, including modulation format, coding rate, precoding index and assigned subbands. The selected options can be represented as a vector and the index can be determined by employing a worth function for a particular selected vector element that is dependent on a selection occurrence count of the element and on an element position count of the element. In particular, the index can be the summation of worth function values for each selected element.
    Type: Grant
    Filed: November 5, 2010
    Date of Patent: May 6, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Mohammad A. Khojastepour, Sampath Rangarajan
  • Patent number: 8718177
    Abstract: Systems and methods are provided for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors based on the same transmitted vector. The symbols of the received signal vectors are combined, forming a combined received signal vector that may be treated as a single received signal vector. The combined received signal vector may be equalized by, for example, a zero-forcing or minimum-mean-squared error equalizer or another suitable linear equalizer. Following equalization, the equalized signal vector may be decoded using a simple, linear decoder.
    Type: Grant
    Filed: February 25, 2013
    Date of Patent: May 6, 2014
    Assignee: Marvell World Trade Ltd.
    Inventors: Jungwon Lee, Hui-Ling Lou, Woong Jun Jang
  • Patent number: 8718204
    Abstract: One of a plurality of candidate data symbols is selected. All possible values of the selected one candidate data symbol are grouped into two or more bit groups. A bit group is selected from the two or more bit groups. A local optimum candidate value from values in the selected bit group is determined for the selected one candidate data symbol for a given set of values corresponding to all of the plurality of candidate data symbols but the selected one candidate data symbol, the local optimum candidate value minimizing a distance value corresponding to a distance between the received data symbol vector and a channel matrix multiplied with the candidate vector, without calculating the distance value. A likelihood value is calculated for a bit in the selected one candidate data symbol based at least in part on the determined local optimum candidate value.
    Type: Grant
    Filed: May 6, 2013
    Date of Patent: May 6, 2014
    Assignee: Marvell International Ltd.
    Inventors: Jungwon Lee, Jiwoong P. Choi, Hui-Ling Lou
  • Patent number: 8718202
    Abstract: A system includes a Viterbi decoder. The Viterbi decoder includes add compare select logic. The add compare select logic determines path metrics for an encoded signal. The add compare select logic also is shared to determine a best state by which trace-back procedure gets started, resulting in hardware saving.
    Type: Grant
    Filed: August 10, 2009
    Date of Patent: May 6, 2014
    Assignee: Texas Instruments Incorporated
    Inventors: Rami Abdallah, Seok-Jun Lee, Manish Goel
  • Publication number: 20140119478
    Abstract: A method of updating the state of a decoder that decodes a wide-band signal including a plurality of sub-band signals, including: receiving the plurality of sub-band signals; for each sub-band signal, storing portions of that sub-band signal in a respective buffer; responsive to determining that a portion of the wide-band signal is degraded, performing a packet loss concealment algorithm to determine wide-band replacement data for the degraded portion; selecting a portion of the sub-band signal stored in each buffer in dependence on the determined wide-band replacement data; and updating the state of the decoder using the selected portions.
    Type: Application
    Filed: October 31, 2012
    Publication date: May 1, 2014
    Applicant: CSR Technology Inc.
    Inventors: Amin Fazeldehkordi, Rogerio G. Alves
  • Patent number: 8711959
    Abstract: The present invention provides an apparatus and method for estimating a frequency offset which are robust against non-Gaussian noise. In a frequency offset estimation method of an Orthogonal Frequency Division Multiplexing (OFDM) system using a training symbol, the method includes receiving a reception signal, setting a specific initial frequency offset corresponding to the reception signal, and calculating a log-likelihood function based on a Complex Isotropic Symmetric ? Stable (CIS?S) probability density function obtained by modeling non-Gaussian noise included in the reception signal and estimating an optimum frequency offset based on the log-likelihood function and the initial frequency offset through a Maximum Likelihood Estimator (MLE). Accordingly, in a non-Gaussian noise environment, frequency offset estimated performance can be improved as compared with a conventional method in which noise is assumed to be a normal distribution.
    Type: Grant
    Filed: September 10, 2012
    Date of Patent: April 29, 2014
    Assignee: Research & Business Foundation Sungkyunkwan University
    Inventors: Youngpo Lee, Seokho Yoon
  • Patent number: 8711988
    Abstract: A demodulator is provided that functions as a reduced-state equalizer and produces reliable soft bit values. According to an embodiment, soft bit values are generated for a sequence of transmitted symbols using a demodulator by updating an M-state trellis managed by the demodulator responsive to a transition from symbol time n?1 to symbol time n, where M is a function of the number of bits per symbol in the sequence of transmitted symbols. Survivor metrics associated with the M states of the trellis are saved each symbol time so that the demodulator can calculate soft bit values with regard to transitions from symbol time n+D?1 to symbol time n+D. The trellis is traced back through to calculate soft bit values for a symbol detected at symbol time n?D based on survivor metrics saved for the M states at symbol time n?D.
    Type: Grant
    Filed: September 11, 2012
    Date of Patent: April 29, 2014
    Assignee: Telefonaktiebolaget LM Ericsson (Publ)
    Inventor: Dayong Chen
  • Patent number: 8711989
    Abstract: In a method for decoding plurality of information streams corresponding to a plurality of layers, where the plurality of information streams have been transmitted via a multiple input multiple output (MIMO) communication channel, a plurality of received signals are processed to decode information corresponding to a first layer. A plurality of modified received signals are generated using the decoded information corresponding to the first layer and the plurality of received signals. Bit metric values are generated for a second layer using MIMO maximum likelihood (ML) demodulation and using the plurality of modified received signals and channel and modulation information for interfering signals. Information corresponding to the second layer is decoded using the generated bit metric values.
    Type: Grant
    Filed: April 1, 2013
    Date of Patent: April 29, 2014
    Assignee: Marvell International Ltd.
    Inventors: Jungwon Lee, Hui-Ling Lou
  • Patent number: 8711987
    Abstract: The present invention relates to a method in a receiver for decoding at least two received communication signals, wherein the communication signals are modulated, pre-coded by a discrete Fourier transform and transmitted by means of single-carrier frequency division multiple access scheme (SC-FDMA). The method comprises the steps of: performing an antenna combining and equalization on a signal observed at the receiver; performing inverse discrete Fourier transform on a model of the observed signal; whitening a time domain model of the observed signal; and jointly detecting the received at least two communication signals by performing soft value calculations based on maximum likelihood detection of a whitened time domain model using a whitened time domain channel estimate.
    Type: Grant
    Filed: April 16, 2009
    Date of Patent: April 29, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (Publ)
    Inventors: Henrik Sahlin, Ulf Lindgren, Peter Naucler, Chester Park
  • Patent number: 8712336
    Abstract: A method is described for controlling a data unit receiver or a data unit sender. The data unit receiver or sender comprise a gap response procedure for responding to gaps in the sequence of data units received at the receiver. A reordering detection procedure S12 is provided for detecting a reordering indication indicative of a potential re-ordering of data units in the course of a transmission from sender to receiver, and the gap response procedure is adapted in response to detecting a re-ordering indication.
    Type: Grant
    Filed: June 9, 2004
    Date of Patent: April 29, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (Publ)
    Inventors: Henning Wiemann, Joachim Sachs, Michael Meyer
  • Patent number: 8705666
    Abstract: In one aspect there is provided a method. The method may include receiving a signal transmitted through a channel; receiving an estimate of the channel; determining from the estimate of the channel at least one statistic representative of a variability of the estimate of the channel; decoding the received signal by at least searching for an output using a plurality of cost metrics determined based on at least the estimate of the channel and the at least one statistic; and providing, based on at least one of the plurality of cost metrics, the output. Related apparatus, systems, methods, and articles are also described.
    Type: Grant
    Filed: April 4, 2011
    Date of Patent: April 22, 2014
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Boon Sim Thian, Andrea Goldsmith
  • Patent number: 8705411
    Abstract: The present patent application improves DARP by allowing multiple users on one time slot (MUROS). It comprises means, instructions and steps for combining two signals. In one example, it comprises at least one baseband modulator, a plurality of amplifiers where the signals are multiplied by a gain; at least one combiner operably connected to the amplifiers where the signals are combined; and a phase shifter where one of the signals is phase shifted with respect to the other signal. In another example; the apparatus further comprises a phase shifter operably connected to the at least one baseband modulator to provide a ?/2 phase shift between the two signals. In another example, the at least one baseband modulator comprises a BPSK baseband modulator on an I axis and a BPSK baseband modulator on a Q axis.
    Type: Grant
    Filed: October 21, 2008
    Date of Patent: April 22, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Zhi-Zhong Yu, Hassan Rafique
  • Patent number: 8705669
    Abstract: In various aspects, the disclosure describes systems and methods for decoding of convolutionally encoded signals representing, for example, telecommunications signals such as command or content signals used in digital telecommunications. In various embodiments such aspects of the disclosure provide systems and methods for improving the efficiency, speed, and power consumption of such processes by providing architectures and methods for processing various parts of the encoded data records in parallel, using multiple and optionally specially-designed, dedicated memory registers and multiplexers.
    Type: Grant
    Filed: March 19, 2013
    Date of Patent: April 22, 2014
    Assignee: BlackBerry Limited
    Inventor: Martin Kosakowski
  • Patent number: 8705634
    Abstract: A signal compression method and apparatus for a base transceiver system (BTS) in a wireless communication network provides efficient transfer of compressed signal samples over serial data links in the system. For the uplink, an RF unit of the BTS compresses baseband signal samples resulting from analog to digital conversion of a received analog signal followed by digital downconversion. The compressed signal samples are transferred over the serial data link to the baseband processor then decompressed prior to normal signal processing. For the downlink, the baseband processor compresses baseband signal samples and transfers the compressed signal samples to the RF unit. The RF unit decompresses the compressed samples prior to digital upconversion and digital to analog conversion to form an analog signal for transmission over an antenna. Compression and decompression can be incorporated into operations of conventional base stations and distributed antenna systems, including OBSAI or CPRI compliant systems.
    Type: Grant
    Filed: July 26, 2011
    Date of Patent: April 22, 2014
    Assignee: Integrated Device Technology, Inc.
    Inventor: Albert W Wegener
  • Patent number: 8705668
    Abstract: A node comprising a receiver for i) receiving at least two signals streams comprising bit sequences and ii) evaluating which bit sequence that is most likely to have been received for a certain sent symbol for each signal stream. The receiver for calculating metrics indicative of which bit sequence that initially is most likely to correspond to a certain sent symbol, the metrics being used a soft value calculation where the receiver is arranged for addition of metric data for a certain signal stream corresponding to an added bit sequence for each case where the available metrics are incomplete for performing the estimation. The missing bit is inserted in the added bit sequence and chosen such that it corresponds to a symbol with the shortest Euclidian distance to the symbol with the said corresponding bit sequence initially being indicated as most likely to correspond to a certain sent symbol.
    Type: Grant
    Filed: September 25, 2009
    Date of Patent: April 22, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventor: Henrik Sahlin
  • Patent number: 8705665
    Abstract: A process for computing Log-Likelihood-ratios (LLRs) in a detector of a wireless communication receiver is disclosed, with the, LLRs being used by a channel decoder. A signal is received from a telecom front end, the signal corresponding to data belonging to a finite set of constellation symbols, each constellation symbol being arranged in a lattice constellation impaired by additive noise and a multiplicative channel. A limited set of distances representative of Euclidian distances between the received signal and a finite set of predetermined constellation symbols are computed, possibly multiplied by the channel. A set of soft decision LLRs are derived from the computed set of distances under the constraint of a limited length of the list of distances. The derived LLRs are completed by clipping values read from a look-up table which is simultaneously addressed by the values of the SNR and a bit index.
    Type: Grant
    Filed: February 14, 2011
    Date of Patent: April 22, 2014
    Assignee: ST-Ericsson SA
    Inventors: Andrea Ancora, Sebastien Aubert
  • Publication number: 20140105333
    Abstract: An apparatus for iteratively estimating a channel in a receiver of a wireless communication system is provided. The apparatus includes a channel estimator configured to estimate a first channel value by using a pilot symbol included in a received signal, a demodulator configured to demodulate the received signal by using the first channel value, a decoding unit configured to decode the received signal demodulated by the demodulator, a feedback determining unit configured to determine whether to iteratively estimate the channel, and a feedback device configured to feed back an input value of the decoding unit when the feedback determining unit determines to iteratively estimate the channel, wherein when the feedback determining unit determines to iteratively estimate the channel, the channel estimator estimates a second channel value by using at least one of the pilot symbol included in the received signal and a data symbol received from the feedback device.
    Type: Application
    Filed: October 1, 2013
    Publication date: April 17, 2014
    Applicant: SAMSUNG ELECTRONICS CO. LTD.
    Inventors: Joo-Han KIM, Tae-Yoon KIM, Chai-Man LIM
  • Patent number: 8699601
    Abstract: Systems and methods are provided for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors from the same transmitted vector. For each received signal vector, the receiver evaluates a decoding metric using each possible value of the transmitted signal vector to produce a set of distances. The receiver then combines distances from across the received signal vectors to produce a combined distance associated with each possible value of the transmitted signal vector. Using the combined distances, the receiver may choose among the possible values of the transmit signal vector to determine the actual transmit signal vector.
    Type: Grant
    Filed: August 3, 2007
    Date of Patent: April 15, 2014
    Assignee: Marvell World Trade Ltd.
    Inventors: Jungwon Lee, Woong Jun Jang
  • Patent number: 8699634
    Abstract: A wireless communications device includes a receiver, and a decoder coupled downstream from the receiver and using a modulation having memory for a received signal and to decode the received signal. The decoder decodes the received signal by at least determining a channel estimate for the received signal, generating partial sum tables based upon the channel estimate and possible values of a transmitted signal, correlating actual values of the received signal to the possible values from the partial sum tables to generate branch metrics associated with the modulation, and demodulating the received signal based upon the branch metrics using an iterative process based upon exchanging extrinsic information with an outer forward error correction (FEC) code.
    Type: Grant
    Filed: June 30, 2011
    Date of Patent: April 15, 2014
    Assignee: Harris Corporation
    Inventors: Joseph B. Shaver, John Wesley Nieto
  • Patent number: 8693587
    Abstract: A method for demodulating time-multiplexed signals able to mutually collide, in particular in the case of an AIS (Automatic Identification System), being a communications system between ships allows collisions between these ships to be limited and allows the maritime traffic in view from the coasts to be monitored thanks to coastal stations that listen to the communications. When these colliding signals are sufficiently “distinct” (in frequency, in power or in time), algorithms exist for discriminating between them. The demodulator offers the possibility of demodulating two colliding signals, whose collision parameters (difference in frequency, in power or their non-synchronization) are sufficiently small to make them virtually inaccessible otherwise. The method and equipment allow the satellite AIS system to utilize cases of signal collisions that were hitherto detrimental in order to improve the overall performance.
    Type: Grant
    Filed: May 11, 2011
    Date of Patent: April 8, 2014
    Assignee: Thales
    Inventors: Jérémie Giraud, Thibaud Calmettes
  • Patent number: 8694877
    Abstract: A modified soft output Viterbi algorithm (SOVA) detector receives a sequence of soft information values and determines a best path and an alternate path for each soft information value and further determines, when the best and alternate paths lead to the same value for a given soft information value, whether there is a third path departing from the alternate path that leads to an opposite decision with respect to the best path for a given soft information value. The SOVA detector then considers this third path when updating the reliability of the best path. The modified SOVA detector achieves max-log-map equivalence effectively through the Fossorier approach and includes modified reliability metric units for the first N stages of the SOVA detector, where N is the memory depth of a given path, and includes conventional reliability metric units for the remaining stages of the detector.
    Type: Grant
    Filed: October 1, 2010
    Date of Patent: April 8, 2014
    Assignee: STMicroelectronics, Inc.
    Inventors: Sivagnanam Parthasarathy, Lun Bin Huang, Alessandro Risso
  • Patent number: 8693588
    Abstract: Certain aspects of the present disclosure relate to a technique for two-step joint demapping based on sphere decoding for log-likelihood ratio (LLR) computation related to a received multiple-input multiple-output (MIMO) signal. The first step of the proposed algorithm comprises a linear minimum mean square error (LMMSE) based detection to form soft symbol estimates of symbols being transmitted. Then, the LMMSE-based soft symbol estimates can be utilized to form a set of constellation points of a stream interfering to a stream of interest. These candidate constellation points can be then subtracted (canceled) from the received signal to improve the LLR computations of the stream of interest. After the cancellation, the maximum ratio combining (MRC) can be applied to each individual stream to form more refined soft symbol estimates as well as an effective signal-to-noise ratio (SNR) estimate.
    Type: Grant
    Filed: June 29, 2011
    Date of Patent: April 8, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Michael L. McCloud, Dung Ngoc Doan, Alexei Yurievitch Gorokhov
  • Publication number: 20140093017
    Abstract: A first radio frequency, RF, signal is directly received from a first source radio node in a radio destination node. The first RF signal includes a coded first source information signal. A second RF signal is directly received from a second source radio node that includes a coded second source information signal. A third RF signal is received from an intermediate network node that includes a network coded signal which is a combined coded information signal generated at the intermediate node after demodulating the coded first source information signal and the coded second source information signal received from the first and second source radio nodes.
    Type: Application
    Filed: May 18, 2011
    Publication date: April 3, 2014
    Applicant: TELEFONAKTIEBOLAGET L M ERICSSON (PUBL)
    Inventors: Afif Osseiran, Slimane Ben Slimane
  • Patent number: 8687746
    Abstract: Systems, methods, devices, and computer program products are described for Turbo decoding in a wireless communication system. Turbo encoded wireless signals may be received and demodulated, and forwarded to a branch metric calculator. The branch metric calculator may calculate a set of branch metrics for the demodulated signal. A state metric unit may receive the set of branch metrics and a previously calculated set of state metrics. The state metric unit may perform various comparisons of the set of state metrics before the received set of branch metrics is added to a portion of the state metrics identified through the comparisons.
    Type: Grant
    Filed: May 27, 2010
    Date of Patent: April 1, 2014
    Assignee: QUALCOMM Incorporated
    Inventors: Zhiqiang Cui, Iwen Yao, Qiang Huang
  • Patent number: 8687750
    Abstract: Systems, methods, and other embodiments associated with signal detection with an adjustable number of interfering signals. According to one embodiment an apparatus includes an interferer counter, a detection method selector, and a signal detector. The interferer counter is configured to identify a number of active interfering signals in a received signal. The detection method selector is configured to select a signal detection method based, at least in part, on the number of active interfering signals identified by the interferer counter. The signal detector is configured to process the received signal according to the signal detection method selected by the detection method selector to detect an intended signal in the received signal.
    Type: Grant
    Filed: June 14, 2011
    Date of Patent: April 1, 2014
    Assignee: Marvell International Ltd.
    Inventors: Jungwon Lee, Jiwoong Choi, Yakun Sun
  • Patent number: 8687744
    Abstract: Aspects of a method and system for an improved cellular diversity receiver are described. Aspects of the system may include circuitry that enables generation of an initially decoded output bit sequence by a first frame process for a received bit sequence for a plurality of received multipath signals. The first frame process may utilize redundancy based decoding, which imposes at least one physical constraint during the decoding, which may be performed by a decoding algorithm.
    Type: Grant
    Filed: September 11, 2006
    Date of Patent: April 1, 2014
    Assignee: Broadcom Corporation
    Inventors: Arie Heiman, Nelson Sollenberger