Class / Patent application number | Description | Number of patent applications / Date published |
375262000 | Maximum likelihood decoder or viterbi decoder | 62 |
20080219373 | CODEBOOK SELECTION FOR TRANSMIT BEAMFORMING - A method select a codebook for transmit beamforming. The method constructs an estimated channel matrix based on a codebook, selects a channel submatrix from the estimated channel matrix, calculates a selection matrix from the channel submatrix; and assigns a steering matrix based on the selection matrix. There may be multiple codebooks and the method may construct an estimated channel matrix, select a channel submatrix, and calculate a selection matrix for each of the codebooks, then select an optimal codebook. The steering matrix is assigned based on the optimal codebook. The steering matrix may be used in steering a transmitted packet. The method may also calculate a post-MIMO equalizer signal-to-noise ratio for a data stream, based on the estimated channel matrix and the selected codebook. A related system is also disclosed. Other embodiments are provided, and each of the embodiments described herein can be used alone or in combination with one another. | 09-11-2008 |
20080225974 | Max-Log Receiver for Multiple-Input Multiple-Output (MIMO) Systems - A method includes the steps of i) listing out all possibilities for a first symbol of a two stream signal; ii) determining a second symbol of the two stream signal for each of the first symbol listed out, iii) evaluating a metric for each of the first symbol and second symbol pair, iv) listing out all possibilities for second symbol, v) determining a first symbol for each choice of the second symbol listed out, vi) evaluating a metric for each of the second symbol and first symbol pair, vii) determining an exact maximum log likelihood ratio for all bits using the metrics, and viii) decoding codeword(s) in the two stream signal using the determined exact maximum log likelihood ratio for all bits. | 09-18-2008 |
20080232500 | Soft Output Sphere Decoding Method - Provided is a soft output sphere decoding method for a MIMO system. The soft output sphere decoding method includes the steps of: detecting a maximum likelihood symbol nearest to a receiving signal; calculating a lattice point nearest to the receiving signal and having a symbol bit opposite to the detected maximum likelihood symbol for all bits of the receiving signal; and calculating a ratio between a distance from the receiving signal to the detected maximum likelihood symbol and a distance from the receiving signal to the calculated lattice points for each bit. | 09-25-2008 |
20080240276 | Multi-Input Multi-Output System For Enhancing Transmission Performance - The present invention relates to a multi-input multi-output (MIMO) system for enhancing transmission performance. The MIMO system uses space-time encoding and transmit antenna selection methods, and includes a transmitter ( | 10-02-2008 |
20080240277 | Reducing computational complexity in maximum likelihood MIMO OFDM decoder - A method and a system for reducing computational complexity in a maximum-likelihood MIMO decoder, while maintaining its high performance. A factorization operation is applied on the channel Matrix H. The decomposition creates two matrixes: an upper triangular with only real-numbers on the diagonal and a unitary matrix. The decomposition simplifies the representation of the distance calculation needed for constellation points search. An exhaustive search for all the points in the constellation for two spatial streams t(1), t(2) is performed, searching all possible transmit points of (t2), wherein each point generates a SISO slicing problem in terms of transmit points of (t1); Then, decomposing x,y components of t(1), thus turning a two-dimensional problem into two one-dimensional problems. Finally searching the remaining points of t(1) and using Gray coding in the constellation points arrangement and the symmetry deriving from it to further reduce the number of constellation points that have to be searched. | 10-02-2008 |
20080247482 | Ofdm Reception in Multi-Antenna Mode - A signal is received by P antennas. It includes frames having symbols occupying respective positions distributed along an axis of time and of frequency, a frame including M blocks having N reference symbols M groups of P weighting coefficients are determined, each one of the groups relating to one of the blocks emitted, with the coefficients of a group being associated to the blocks which are received on the P antennas and which correspond to the block emitted relating to the group. The coefficients are determined so as to increase via a threshold value, an error value for each block emitted, between the reference symbols of the block emitted, and the symbols obtained using the symbols received on each antenna at the positions of reference symbols corresponding to the block emitted and the associated coefficients. Then, weighting coefficients are obtained for the other symbols of the frame Finally, a composite signal is generated by summing up the symbols received respectively weighted by the associated weighting coefficients. | 10-09-2008 |
20080267306 | Systems and Methods for Low-Complexity Maximum-Likelihood MIMO Detection - Embodiments provide novel systems and methods for low-complexity maximum-likelihood detection, for use in various communication systems, e.g., multiple-input multiple-output (MIMO) systems, etc. These systems and methods enable computation of a detector that is more accurate than the max-log approximation. Embodiments comprise systems and methods for computing, using a maximum-likelihood detector, a set of log-likelihood ratio (LLR) values for a cost function of a channel input by implementing at least one accumulate LLR functional definition. | 10-30-2008 |
20080317153 | ADAPTIVE TECHNIQUE FOR INTER-CARRIER-INTERFERENCE CANCELING IN OFDM SYSTEMS - ICI canceling in an OFDM system includes taking a FFT of a wireless electrical signal to produce an OFDM signal; estimating a DC component of a frequency-selective channel in the OFDM system; obtaining an initial estimate of data symbols associated with data bits of the OFDM signal; correcting the data bits with a Viterbi decoder; encoding the corrected data bits to acquire corrected data symbols; re-estimating the DC component of the frequency-selective channel using the corrected data symbols; filtering the corrected data symbols and sub-carrier of the frequency-selective channel; calculating a first order differential function of the frequency-selective channel based on successive ones of the corrected data symbols; removing an ICI component from the calculated first order differential function; and re-estimating the data symbols as a function of the removed ICI component. The filtering occurs using a low pass filter comprising a bank of eight filters. | 12-25-2008 |
20090003483 | Detector and Method for Estimating Data Probability in a Multi-Channel Receiver - A detector and method for estimating channel data probability in a multi-user or multiple-input multiple-output communication system includes summing conditional bit probabilities conditioned on hypothetical channel data patterns over stochastically selected hypothetical channel data patterns. Various detailed hardware structures and circuits are also described. | 01-01-2009 |
20090016459 | USING CODEWORDS IN A WIRELESS COMMUNICATION SYSTEM - Systems, methodologies, and devices are described that can facilitate bandwidth efficient non-coherent signaling for uplink control channel transmissions. A communication device (e.g., a mobile device, base station) can be configured to utilize or generate a set of complex orthogonal codewords to facilitate transmission of control channel information using non-coherent signaling in a bandwidth efficient manner. A complex orthogonal codeword set can comprise a first subset of codewords where such codewords have a desirable cross-correlation property and another subset(s) of codewords that can include expurgated codewords, where the expurgated codewords can include discarded codewords and/or codeword pairs that produce a worst-case cross-correlation property. The codeword set and subsets are determined based at least in part on a predefined codeword criterion. A portion of the discarded codewords can be used for other purposes, such as erasure decoding, interference-level estimation, and/or multi-mode control channel operation. | 01-15-2009 |
20090060078 | NEAR SOFT-OUTPUT MAXIMUM-LIKELIHOOD DETECTION FOR MULTIPLE-INPUT MULTIPLE-OUTPUT SYSTEMS - Systems and methodologies are described that provide low-complexity soft-output detection for MIMO communication systems. Looping can be performed over a set of constellation points per spatial stream to obtain distance metrics for each of a series of transmitted streams, for which values for the other transmitted streams can be estimated using a MIMO channel matrix and a sub-optimal MIMO algorithm. Examples of MIMO algorithms that can be utilized include Per-Stream List Detection (PSLD), Lattice-Reduced Detection (LRD), and a Guided-M Algorithm. Performance can be further improved by pre-processing the MIMO channel matrix and/or by utilizing techniques for Enhanced Metric Usage (EMU). | 03-05-2009 |
20090080556 | Reducing Peak-to-Average-Power-Ratio in OFDM/OFDMA Signals by Deliberate Error Injection - A method and system reduces a peak to average power ratio of a transmitted OFDM signal. An input signal is encoded using a forward error correcting code to produce a codeword corresponding to the input signal. A peak power corresponding to the codeword is measured. The peak power is compared with a predetermined threshold, and a set of selected bits in the codeword are manipulated if the peak power is greater than the predetermined threshold to deliberately produce an erroneous codeword in which the peak power is less than the predetermined threshold, which is transmitted. | 03-26-2009 |
20090086839 | METHODS AND DEVICES FOR DECODING AND ENCODING DATA - A method for decoding an input data sequence is provided. The method comprises generating a plurality of test sequences, determining an order for the plurality of test sequences, such that each test sequence differs from its adjacent test sequences by a respective predefined number of bits, and carrying out a maximum likelihood process with the ordered test sequences and the input data sequence thereby generating a maximum likelihood sequence. | 04-02-2009 |
20090086840 | Apparatus and method for transmitting feedback information in communication system - Disclosed is a system and method for transmitting feedback information in a communication system. A receiver calculates a minimum distance of each two symbol vectors among all symbol vectors which can be received through a k | 04-02-2009 |
20090097582 | Methodology and method and apparatus for signaling with capacity optimized constellations - Communication systems are described that use geometrically shaped constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. In several embodiments, the geometrically shaped is optimized based upon a capacity measure such as parallel decoding capacity or joint capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel. In numerous embodiments, the communication uses adaptive rate encoding and the location of points within the geometrically shaped constellation changes as the code rate changes. One embodiment of the invention includes a transmitter configured to transmit signals to a receiver via a communication channel, wherein the transmitter, includes a coder configured to receive user bits and output encoded bits at an expanded output encoded bit rate, a mapper configured to map encoded bits to symbols in a symbol constellation, a modulator configured to generate a signal for transmission via the communication channel using symbols generated by the mapper. In addition, the receiver includes a demodulator configured to demodulate the received signal via the communication channel, a demapper configured to estimate likelihoods from the demodulated signal, a decoder that is configured to estimate decoded bits from the likelihoods generated by the demapper. Furthermore, the symbol constellation is a capacity optimized geometrically spaced symbol constellation that provides a given capacity at a reduced signal-to-noise ratio compared to a signal constellation that maximizes d | 04-16-2009 |
20090116571 | TRANSMITTER, RECEIVER, AND COMMUNICATION METHOD - A transmitter, a receiver and a communication method enabling improvement of the data rate of an MIMO system. One signal x | 05-07-2009 |
20090129496 | FULL-RATE DISTRIBUTED SPACE-TIME CODES FOR COOPERATIVE COMMUNICATIONS - A full-rate distributed space-time (ST) code design is provided for amplify-and-forward cooperative wireless channels. A signal space diversity technique is employed at the source node and a unique signature vector at each relay node. The distributed space-time (ST) codes can achieve full cooperative diversity and full rate. The achievable diversity gain is M+1, where M is the number of relay nodes. Optimal power allocation can be used to maximize the coding gain under a total power constraint. | 05-21-2009 |
20090135934 | METHOD FOR THE TRANSMISSION ON MULTIPLE-CARRIER COMMUNICATIONS SYSTEMS, AND CORRESPONDING TRANSMITTER AND COMPUTER-PROGRAM PRODUCT - A method for loading bits over a set of subcarriers of a multiple-carrier communications system comprises the operation of associating with the subcarriers respective numbers of bits chosen from among a plurality of available constellations. The method envisages definition of a performance target for the system and execution of bit loading, guaranteeing the aforesaid target on a plurality of subcarriers. The performance target can be a target error rate, such as a bit-error rate (BER), or else be transferred into a constraint, such as, for example, a threshold, in a metric of log-likelihood ratios (LLRs). In this case, there is preferably envisaged application to the signals received within the multiple-carrier system a function that estimates a signal to noise ratio on each sub-carrier. The aforesaid metric of log-likelihood ratios (LLRs) is hence defined as a function of said signal to noise ratios. | 05-28-2009 |
20090190682 | SYSTEM AND METHOD FOR MAXIMUM LIKELIHOOD DECODING IN MULTIPLE OUT WIRELESS COMMUNICATION SYSTEMS - A system and method for a simplified Maximum Likelihood (ML) decoding ( | 07-30-2009 |
20090190683 | MIMO RECEIVER USING MAXIMUM LIKELIHOOD DETECTOR IN COMBINATION WITH QR DECOMPOSITION - A MIMO receiver is provided with a preprocessor for performing QR decomposition of a channel matrix H wherein the factored reduced matrix R is used in place of H and Q*y is used in place of the received vector y in a maximum likelihood detector (“MLD”). The maximum likelihood detector might be a hard-decision MLD or a soft-decision MLD. A savings of computational complexity can be used to provide comparable results more quickly, using less circuitry, and/or requiring less consumed energy, or performance can be improved for a fixed amount of time, circuitry and/or energy. Where the MLD uses approximations, such as finite resolution calculations (fixed point or the like) or L | 07-30-2009 |
20090213954 | TREE POSITION ADAPTIVE SOFT OUTPUT M-ALGORITHM RECEIVER STRUCTURES - A method and apparatus for tree position adaptive SOMA receiver structures are disclosed herein. In one embodiment, a device for use in a wireless communication system comprises a receiver to receive information-bearing signals from the transmitter wirelessly transmitted using OFDM and bit interleaved coded modulation, where the receiver includes an inner decoder structure having a soft output M-algorithm (SOMA) based multiple-in multiple-out (MIMO) joint demapper that uses a SOMA-based MIMO detection process to perform joint inner demapping over each tone, and wherein the SOMA-based MIMO joint demapper is operable to search a detection tree for each tone using a tree-search symbol order that is adapted for each tone based on channel state information and extrinsic information from the outer decoder, where only a number of best alternatives from every level of the tree are expanded. | 08-27-2009 |
20090232241 | LOW COMPLEXITY OPTIMAL SOFT MIMO RECEIVER - A low-complexity optimal soft MIMO detector is provided for a general spatial multiplexing (SM) systems with two transmit and NR receive antennas. The computational complexity of the proposed scheme is independent from the operating signal-to-noise ratio (SNR) and grows linearly with the constellation order. It provides the optimal maximum likelihood (ML) solution through the introduction of an efficient Log-likelihood ratio (LLR) calculation method, avoiding the exhaustive search over all possible nodes. The intrinsic parallelism makes it an appropriate option for implementation on DSPs, FPGAs, or ASICs. In specific, this MIMO detection architecture is very suitable to be applied in WiMax receivers based on IEEE 802.16e/m in both downlink (subscriber station) and uplink (base station). | 09-17-2009 |
20090252246 | Receiving apparatus and method for maximum likelihood in a single carrier system - A receiving apparatus and method of a Maximum Likelihood (ML) scheme in a Single-Carrier (SC) system are provided. The apparatus includes at least two antennas, at least two Orthogonal Frequency Division Multiplexing (OFDM) demodulators, at least two subcarrier mappers, at least two OFDM modulators, and a detector. The antennas receive signals. The OFDM demodulators convert the signals into frequency domain signals. The subcarrier mappers confirm signals mapped to frequency domain subcarriers. The OFDM modulators convert the signals into time domain signals. The detector constructs at least one set for candidate transmission symbols and detects receive signals through ML detection using the set. | 10-08-2009 |
20090268833 | METHOD AND SYSTEM FOR PREDICTING CHANNEL QUALITY INDEX (CQI) VALUES FOR MAXIMUM LIKELIHOOD (ML) DETECTION IN A 2X2 MULTIPLE INPUT MULTIPLE OUTPUT (MIMO) WIRELESS SYSTEM - Aspects of a method and system for predicting CQI values for ML detection in a 2×2 MIMO system are presented. In one aspect of the system, a CQI value for a MIMO communication system may be computed based on a computed channel realization by reverse mapping the computed channel realization to a corresponding CQI value. Based on the computed CQI value, a coding rate may be selected. The coding rate may be selected from a lookup table, wherein the computed CQI value is utilized as an index to the lookup table. The reverse mapping may utilize a function, which is computed using radial basis function networks. In another aspect of the system, a joint mutual information value may be computed for the MIMO communication system. The joint mutual information value may be computed based on a Shannon mutual information value and a matched filter mutual information value. | 10-29-2009 |
20090268834 | METHOD AND SYSTEM FOR PREDICTING CHANNEL QUALITY INDEX (CQI) VALUES FOR MAXIMUM LIKELIHOOD (ML) DETECTION IN A KXK MULTIPLE INPUT MULTIPLE OUTPUT (MIMO) WIRELESS SYSTEM - Aspects of a method and system for predicting CQI values for ML detection in a K×K MIMO system are presented. In one aspect of the system, a CQI value for a K×K MIMO communication system may be computed by decomposing the K×K MIMO system into a series of 2×2 MIMO systems. For each 2×2 MIMO system a CQI value may be computed by reverse mapping a PER computed for the 2×2 MIMO system and an SNR value for a SISO communication system. By summing CQI values among the series of 2×2 MIMO systems a CQI value for the K×K MIMO system may be computed. Based on the computed CQI value for the K×K MIMO system, a coding rate may be selected. The selected coding rate may be selected to maximize a computed information throughput rate at a MIMO receiver that utilizes ML detection. | 10-29-2009 |
20090296843 | SEGMENTED-FRAME SYNCHRONIZATION FOR ISDB-T AND ISDB-TSB RECEIVER - A technique for segmented frame synchronization for Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) and Integrated Services Digital Broadcasting-Terrestrial Sound Broadcasting (ISDB-TSB) systems, wherein the method comprises receiving a wireless digital signal comprising an Orthogonal Frequency Division Multiplexing (OFDM) frame, further comprising ODFM symbols, in a receiver and wherein the receiver comprises a time de-interleaver, a bit de-interleaver, and a descrambler; filling memory of time de-interleaver and bit de-interleaver by the received wireless digital signal; determining an OFDM segmented frame boundary when memory of the time de-interleaver and bit de-interleaver are full; decoding bits from time de-interleaver and bit de-interleaver using a Viterbi decoder; outputting the Viterbi decoding bits from time de-interleaver and bit de-interleaver when the OFDM segmented frame boundary is detected; obtaining a segmented multiplexing frame boundary upon receipt of the first bit from the Viterbi decoder; and synchronizing the OFDM frame based on the segmented multiplexing frame boundary. | 12-03-2009 |
20090310695 | COMMUNICATION APPARATUS, COMMUNICATION METHOD AND COMPUTER PROGRAM - There is provided a communication apparatus, including a transmission pattern generation unit that generates a transmission pattern according to a modulation method, a metric calculation unit that calculates an inter-signal distance between a received signal vector of received signals and an estimation vector, which is a product of channel information and the transmission pattern, a maximum likelihood pattern determination unit that determines a maximum likelihood signal pattern from the inter-signal distance calculated by the metric calculation unit, and an error estimation unit that estimates a phase error component and an amplitude error component contained in the received signal vector, wherein the metric calculation unit calculates the inter-signal distance between the received signal vector and the estimation vector by reflecting the phase error component and/or the amplitude error component estimated by the error estimation unit. | 12-17-2009 |
20090323846 | METHOD AND APPARATUS FOR COMPUTING SOFT DECISION INPUT METRICS TO A TURBO DECODER - A method and apparatus for computing soft decision input metrics to a turbo decoder includes circuits associated with eight-ary phase shift keyed (8PSK) modulation and sixteen-ary quadrature amplitude modulation (16QAM). In both implementations log-likelihood ratio (LLR) metrics on code symbols are estimated as products of various constant values and various combinations of the in-phase and quadrature components of a demodulated soft decision. In the implementation associated with the 16QAM modulation scheme, an estimate of the carrier-signal-to-interference (C/I) ratio is also used to estimate some of the LLR metrics. Estimates of the LLR metrics may also be obtained in association with generalized square QAM and M-ary PSK modulation schemes including, e.g., 64QAM, 256QAM, and 16PSK. | 12-31-2009 |
20100014606 | SYMBOL DETECTOR AND SPHERE DECODING METHOD - A symbol detector with a sphere decoding method implemented therein. A baseband signal is received to determine a maximum likelihood solution using the sphere decoding algorithm. A QR decomposer performs a QR decomposition process on a channel response matrix to generate a Q matrix and an R matrix. A matrix transformer generates an inner product matrix of the Q matrix and the received signal. A scheduler reorganizes a search tree, and takes a search mission apart into a plurality of independent branch missions, wherein the search tree defines a full search depth N | 01-21-2010 |
20100046655 | APPARATUS AND METHOD FOR TRANSMITTING AND RECEIVING IN A MULTI-ANTENNA SYSTEM - Apparatuses and methods for transmitting and receiving in a multi-antenna system are provided. A receiver for reducing a quantization error of channel information feedback in a multi-antenna system includes a restore vector generator for selecting a codeword c | 02-25-2010 |
20100054355 | Wireless communication system - In a wireless communication system including a radio-signal receiver and a radio-signal transmitter, the radio-signal receiver includes a unit for making a generalized inverse matrix for carrying out maximum likelihood estimation, based on a matrix indicating a training series used for carrying out channel estimation, a unit for carrying out singular value decomposition to the generalized inverse matrix, a unit for truncating singular values in the generalized inverse matrix in accordance with a threshold by which a singular value is turned to zero in a greater order, a unit for estimating an impulse-response vector, based on the generalized inverse matrix, a unit for interpolating zero to the impulse-response vector, and a unit for acquiring channel estimation by carrying out Fourier transform, and the radio-signal transmitter includes a unit for quantifying spread of the singular values, and optimizing the training series in accordance with the quantified spread of the singular values, to thereby make a new training series. | 03-04-2010 |
20100067596 | METHODS AND SYSTEMS FOR HYBRID MIMO DECODING - Certain embodiments of the present disclosure allow a receiver to utilize both a minimum mean square error (MMSE) detection algorithm and a maximum likelihood (ML) detection algorithm. The receiver may control, based on various conditions, a mode selection signal to select between output generated with the MMSE detection algorithm and the ML detection algorithm. By sharing logical components, certain embodiments may allow a receiver to implement both ML and MMSE detection algorithms with minimal computational overhead when compared to implementing a single one of the decoding algorithms. | 03-18-2010 |
20100067597 | METHODS AND SYSTEMS FOR MAXIMUM-LIKELIHOOD DETECTION USING POST-SQUARING COMPENSATION - A “post-squaring” detection algorithm, and related devices, that may reduce the complexity of maximum likelihood detection (MLD) schemes while preserving their performance is provided. Rather than search for optimum metrics (such as minimum distance metrics) based on squared norm values, a search may be based on un-squared norm metrics, and the squaring may be postponed, for example, until subsequent log-likelihood ratio (LLR) computation. For certain embodiments, approximations of un-squared norm values may significantly reduce computation complexity. | 03-18-2010 |
20100067598 | Method and System for LLR Buffer Reduction in a Wireless Communication Modem - A system involves a transmitting device (for example, a first wireless communication device) and a receiving device (for example, a second wireless communication device). In the receiving device, LLR (Log-Likelihood Ratio) values are stored into an LLR buffer. LLR bit width is adjusted as a function of packet size of an incoming transmission to reduce the LLR buffer size required and/or to prevent LLR buffer capacity from being exceeded. The receiver may use a higher performance demodulator in order to maintain performance despite smaller LLR bit width. In the transmitting device, encoder code rate is adjusted as a function of receiver LLR buffer capacity and packet size of the outgoing transmission such that receiver LLR buffer capacity is not exceeded. Any combination of receiver LLR bit width adjustment, demodulator selection, and encoder code rate adjustment can be practiced to reduce LLR buffer size required while maintaining performance. | 03-18-2010 |
20100091899 | COMMUNICATION SYSTEM - A communication system that performs encoding and decoding for communication includes a transmitting apparatus and a receiving apparatus. The transmitting apparatus includes a turbo encoding unit including a first encoding unit that encodes an input signal and generates a first parity bit by bit-based encoding and n (n=1, 2, 3, . . . ) second encoding units that encode the input signal and generate second parity bits by bit-based encoding, and a symbol mapping unit that maps an output from the turbo encoding unit to a symbol by bit-based mapping operation and modulates the output. And the receiving apparatus includes a demodulating unit that demodulates a transmission signal, and a turbo decoding unit that performs turbo decoding on the demodulated signal by bit-based decoding. | 04-15-2010 |
20100098183 | Decoding System And Method For Digital Communications - A Viterbi decoding system interprets bits in received QAM constellations as many-valued parameters rather than binary valued parameters. It performs the Viterbi algorithm using these many-valued parameters to provide results superior to hard decision decoding. Rather than applying a hard 0-1 function to the QAM data, the system uses a non-stepped linear or curved transfer function to assign values to the bits. In another aspect, a system differentiates between data bits based on their estimated reliability, giving more emphasis to decoding reliable bits than unreliable bits using any of a variety of techniques. By differentiating between god and bad bits and de-emphasizing or ignoring unreliable bits, the system can provide a significant reduction in uncorrectable errors and packet loss. | 04-22-2010 |
20100128809 | COMMUNICATION SYSTEM - A communication system is provided for communicating over a network. A plurality of transmission devices are disposed within a network and connected by transmission channels. A control device calculates initial data required during an initial operation of the transmission devices and sets the initial data to the transmission devices. The transmission devices perform reception processing using maximum likelihood sequence estimation, and the control device obtains, as the initial data, with respect to paths that are signal communication pathways between the transmission devices and in accordance with transmission states of individual paths, initial likelihood information that is initial-stage likelihood information for performing the maximum likelihood sequence estimation. | 05-27-2010 |
20100158150 | MAX-LOG STACK DECODER - A method for demodulating signals in a multi-input multi-output (MIMO) receiver includes obtaining a transformed vector by a coordinate transformation of a received observation vector using a unitary matrix determined through QR decomposition of an estimated channel matrix; maintaining a list containing nodes along with a cost metric for each node; using the list to generate soft-outputs in the form of log-likelihood ratios (LLRs) for selected symbols of interest, based on the transformed vector and a lower triangular matrix determined through QR decomposition of the estimated channel matrix and the constellations to which the input symbols belong. | 06-24-2010 |
20100172428 | FAST CONTROL CHANNEL FEEDBACK FOR MULTIPLE DOWNLINK CARRIER OPERATIONS - A method and apparatus for fast control channel feedback for multiple downlink carrier operations are disclosed. A wireless transmit/receive unit (WTRU) receives signals over a plurality of downlink carriers, generates feedback for each of the plurality of downlink carriers based on the received signals, and transmits via a plurality of antennas, the feedback for at least one of the plurality of downlink carriers over a first physical channel and feedback for another of the plurality of downlink carriers over a second physical channel. | 07-08-2010 |
20100183087 | RECEPTION DEVICE, TRANSMISSION DEVICE, AND ADAPTIVE TRANSMISSION RATE CONTROL METHOD - In a receiver | 07-22-2010 |
20100272203 | SINGLE-CARRIER BLOCK TRANSMISSION WITH TRELLIS CODED MODULATION (TCM), MULTI-LEVEL CODED MODULATION (MLCM) AND BIT-INTERLEAVED MLCM (BIMLCM) - The system ( | 10-28-2010 |
20110002409 | METHOD AND SYSTEM FOR RECONFIGURABLE CHANNEL CODING - Aspects of a reconfigurable system for providing channel coding in a wireless communication device are described. The aspects include a plurality of computation elements for performing channel coding operations and memory for storing programs to direct each of the plurality of computation elements. A controller controls the plurality of computation elements and stored programs to achieve channel coding operations in accordance with a plurality of wireless communication standards. The plurality of computation elements include a data reordering element, a linear feedback shift register (LFSR) element, a convolutional encoder element, and a Viterbi decoder clement. | 01-06-2011 |
20110051831 | UNIFIED ITERATIVE DECODING ARCHITECTURE USING JOINT LLR EXTRACTION AND A PRIORI PROBABILITY - Certain aspects of the present disclosure relate to a method and an apparatus for unified iterative demodulation-decoding that can be employed in both multiple-input multiple-output (MIMO) and non-MIMO wireless systems. | 03-03-2011 |
20110129028 | APPARATUS AND METHOD FOR DETERMINING MODULATION AND CODING SCHEME FOR ADAPTIVE MODULATION AND CODING SCHEME IN MULTIPLE INPUT MULTIPLE OUTPUT SYSTEM - A method and apparatus is provided for determining a modulation and coding scheme in a Multiple Input Multiple Output system with a Maximum Likelihood Detector (MIMO-MLD), in which an upper bound and a lower bound of a Signal to Noise Ratio (SNR) for the MIMO-MLD are determined, an effective Signal to Noise Ratio (eSNR) is computed using a relation between the upper bound and the lower bound, a channel quality is estimated using the eSNR, and a modulation and coding scheme is determined using the estimated channel quality. | 06-02-2011 |
20120134433 | METHOD AND SYSTEM OF ENHANCED PERFORMANCE IN COMMUNICATION SYSTEMS - A method of spatial modulation to identify a transmitter within a transmission array, wherein the transmitter has a unique bit sequence and defines a spatial component indicative of relative location is disclosed, comprising the following steps: receiving transmitted bits from the transmission array and identifying the unique bit sequence, the spatial component and a signal components; encoding the unique bit sequence and the spatial component by grouping the transmitters into transmitter groups such that the transmitters in each group have a maximum spatial separation relative to one another to thereby form an encoded signal; decoding the encoded signal to identify the transmitter from which the transmitted bits were transmitted by determining the transmitter location from the or each group. The method preferably comprises trellis coded spatial modulation. Also, a corresponding system is disclosed, the system comprising an encoder for encoding the unique bit sequence and the spatial component identified and received from the transmission array, the encoding including grouping the transmitters into transmitter groups such that the transmitters in each group have a maximum spatial separation relative to one another to thereby form an encoded signal. The system preferably uses trellis coded spatial modulation. | 05-31-2012 |
20130170571 | Methods and Apparatuses for Signaling with Geometric Constellations - Communication systems are described that use signal constellations, which have unequally spaced (i.e. ‘geometrically’ shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes d | 07-04-2013 |
20140003546 | ADAPTIVE SLICER AND CONSTELLATIONS FOR QAM COMMUNICATIONS | 01-02-2014 |
20140153660 | USE OF ORTHONORMAL TRANSFORMATION FOR IMPROVING PERFORMANCE OF DIGITAL TRANSMISSION UNDER HEAVILY FADED CHANNELS WITH DOPPLER EFFECTS - The proposed invention teaches basic principles of “orthonormal transform” to be used to convert a set of discrete samples into a set of coefficient real samples that is contained in a finite field. The number of real values in each coefficient samples is finite and coded for transmission using digital modulation. It also teaches that handling of multi-path fading of Doppler effects implies that the Bit Error Rate (BER) performance as a function of Bit Energy/Noise (E | 06-05-2014 |
20150055722 | ADAPTIVE NON-LINEAR MODEL FOR HIGHLY-SPECTRALLY-EFFICIENT COMMUNICATIONS - A receiver may be operable to generate estimates of transmitted symbols using a sequence estimation process that may incorporate a non-linear model. The non-linear model may be adapted by the receiver based on particular communication information that may be indicative of non-linearity experienced by the transmitted symbols. The receiver may generate a reconstructed signal from the estimates of the transmitted symbols. The receiver may adapt the non-linear model based on values of an error signal generated from the reconstructed signal, and the values of the error signal may be generated from a portion of the generated estimates that may correspond to known symbols and/or information symbols. The values of the error signal corresponding to the known symbols may be given more weight in an adaptation algorithm, and the values of the error signal corresponding to the information symbols may be given less weight in the adaptation algorithm. | 02-26-2015 |
20150117559 | LOW COMPLEXITY NEAR OPTIMAL TWO SPATIAL STREAM MAXIMAL LIKELIHOOD DETECTOR - Methods, apparatuses, and systems are provided for generating a candidate search set for ML detection of 2 | 04-30-2015 |
20150146810 | METHOD AND APPARATUS FOR PERFORMING SOFT DEMAPPING IN ROTATED QUADRATURE AMPLITUDE MODULATION (QAM) BASED COMMUNICATION SYSTEM - A method of performing a soft demapping, includes obtaining a signal from a symbol representing bits that is transmitted from a transmitter, and calculating a gradient of a reference line in a constellation for a bit based on a rotation angle and a channel state of the constellation. The method further includes selecting a candidate for each of lines that corresponds to a logic value of the bit from constellation points included in the constellation based on the signal and the gradient of the reference line, and calculating a log-likelihood ratio (LLR) of the bit based on the signal and the selected candidate for each of the lines. | 05-28-2015 |
20150326411 | SYSTEM FOR DETECTING SIGNAL BASED ON PARTIAL MAXIMUM LIKELIHOOD AND METHOD THEREOF - Disclosed is a receiver including: a partial filter generating unit selecting a signal as large as a predetermined magnitude among sampled signals and extracting a filter coefficient for the selected signal magnitude to perform QR resolution for the filter coefficient; a partial ML setting unit determining the lengths and the number of candidate symbol combinations of a signal to be detected and generating a candidate ML symbol combination based on the determined lengths and number of candidate symbol combinations; a signal detecting unit detecting residual symbols in a predetermined part of the sampled signal based on the generated candidate ML symbol combination; and a final signal selecting unit choosing a candidate symbol closest to the sampled signal among the detected candidate symbols as a finally detected signal. | 11-12-2015 |
20150349997 | BROADCAST SIGNAL TRANSMISSION APPARATUS, BROADCAST SIGNAL RECEPTION APPARATUS, BROADCAST SIGNAL TRANSMISSION METHOD, AND BROADCAST SIGNAL RECEPTION METHOD - The present invention provides a method for transmitting a broadcast signal. The method for transmitting the broadcast signal according to the present invention may comprise the steps of: formatting input streams into multiple data pipes (DPs); encoding data of the multiple DPs according to a code rate for each DP; generating at least one signal frame by mapping the encoded data of the multiple DPs; and modulating data of the generated signal frame in an orthogonal frequency division multiplexing (OFDM) scheme, and transmitting the broadcast signal including data of the modulated signal frame. | 12-03-2015 |
20150350001 | BLIND PHASE-SHIFT KEYING (PSK) AND QUADRATURE AMPLITUDE MODULATION (QAM) IDENTIFICATION - Technology for blind phase-shift keying (PSK) and quadrature amplitude modulation (QAM) identification of a received radio frequency (RF) signal is disclosed. One method can include: uniform sub-sampling the received RF signal to eliminate a phase contribution from a carrier frequency of the received RF signal; and computing a likelihood function of observed phase differences of the sub-sampled received RF signal of a phase sequence for each PSK modulation type. Another method can include: non-uniformly sub-sampling the received RF signal for a distribution of signal amplitudes of the received RF signal; and computing a likelihood function of the signal amplitudes of the sub-samples of the received RF signal for each modulation type. | 12-03-2015 |
20160094933 | RECEIVER FOR BACKSCATTER COMMUNICATION - A backscatter receiving module and a method of backscatter communication is described. A front-end module receives the backscatter signal from an antenna and generates high-speed and low-speed data. A high-speed decoding module outputs first data in response to the high-speed data having high-speed symbols that were encoded at a first frequency. The high-speed symbols include a first subset of symbols and a second subset of symbols. A low-speed decoding module outputs second data in response to receiving the low-speed data that was encoded into the backscatter signal at a second frequency. The low-speed decoding module generates a first state of the second data when the high-speed symbols of the high-speed data are in the first subset for a length of time. The low-speed module generates a second state of the second data when the high-speed symbols of the high-speed data are in the second subset for the length of time. | 03-31-2016 |
20190149197 | METHOD AND DEVICE FOR RECEIVING SIGNAL IN WIRELESS COMMUNICATION SYSTEM TO WHICH MULTIPLE-TRANSMISSION TECHNIQUE IS APPLIED | 05-16-2019 |
20190149215 | SHAPING OF TRANSMISSION BEAMS | 05-16-2019 |
20190149251 | RADIO COMMUNICATION SYSTEM, RECEIVING APPARATUS, CORRECTION APPARATUS, ANTENNA CORRECTION METHOD AND PROGRAM | 05-16-2019 |
20220140869 | MULTI-INPUT AND MULTI-OUTPUT ANTENNA APPARATUS - The present invention relates to a multi-input and multi-output antenna apparatus, and in particular, the antenna apparatus provides an advantage of easy heat dissipation and calibration control by comprising: an antenna unit in which a transmission and reception substrate and an antenna substrate having a plurality of electric elements provided on one surface or the other surface thereof are stacked and arranged in the front-rear direction; a control unit in which a BB substrate and a PSU substrate having a plurality of electric elements provided on one surface or the other surface thereof are stacked and arranged in the front-rear direction, and which is provided so as to enable calibration control by using a connection between the antenna unit and a power supply or a control signal; and at least one connecting card which is provided so as to enable connection of the power supply or the control signal between the antenna unit and the control unit. | 05-05-2022 |
20220140920 | CALIBRATION METHOD FOR COOPERATIVE TRANSMISSION OF CELL-FREE WIRELESS NETWORK, AND APPARATUS THEREFOR - A method for calibration, in a serial fronthaul in which a calibration device and L (L is a natural number equal to or greater than 1) access node(s) (AN(s)) are serially connected, may include: transmitting, by the calibration device, to at least part of the L AN(s), a calibration command message indicating calibration of transmission paths; determining, by the calibration device and the at least part of the L AN(s), time delay values and phase characteristic values of the transmission paths of the at least part of the L AN(s); and transmitting, by the calibration device, to the at least part of the L AN(s), a calibration adjustment message indicating calibration of the transmission paths based on the time delay values and the phase characteristic values of the transmission paths of the at least part of the L AN(s). | 05-05-2022 |
20220141060 | METHOD AND DEVICE FOR DETECTING THE POSSIBLE PRESENCE OF AT LEAST ONE DIGITAL PATTERN WITHIN A SIGNAL - In accordance with an embodiment, a device configured to detect a presence of at least one digital pattern within a signal includes J memory circuits having respectively Nj memory locations; and processing circuitry comprising an accumulator configured to successively address the memory locations of the J memory circuits in a circular manner at frequency F and during an acquisition time, and successively accumulate and store values indicative of a signal intensity in parallel in the J addressed memory locations of the J memory circuits, and a detector configured to detect the possible presence of the at least one pattern. | 05-05-2022 |
20220141076 | SEQUENCES FOR ULTRA-WIDEBAND RANGING - Techniques are provided for utilizing a hybrid of ultra-wideband (UWB) and narrowband (NB) signaling to provide more efficient operating range and operating efficiency. For example, a first device may transmit a packet via an NB signal to a second device, whereby the packet comprises information indicating a time period for reception of a plurality of fragments, respectively, via a UWB signal. The first device may then transmit a first fragment of the plurality of fragments to the second device via the UWB signal, whereby the first fragment comprises an intermediary base sequence, the intermediary base sequence being aperiodic and comprising a first set of first sequences and a second set of second sequences. In some embodiments, the intermediary base sequence may contain at least one gap interval that may be used to identify a signature of the link between the first device and the second device. | 05-05-2022 |