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252 results about "Maximum likelihood detection" patented technology
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The Maximum Likelihood (ML) detection of signals transmitted over Multiple Input Mul- tiple Output (MIMO) channels is an important problem in modern communications that is well-known to be NP-complete.
MIMO OFDM system
ActiveUS7068628B2Improve system performanceEnhances channel parameter estimationSpatial transmit diversityTime-division multiplexChannel impulse responsePre whitening
A MIMO OFDM system includes a plurality of space-time encoders for encoding respective data blocks with independent space-time codes. The transformed data block signals are transmitted by a plurality of transmit antennas and received by a plurality of receive antennas. The received data is pre-whitened prior to maximum likelihood detection. In one embodiment, successive interference cancellation can be used to improve system performance. Channel parameter estimation can be enhanced by weighting the channel impulse response estimates based upon a deviation from average.
Owner:AT&T INTPROP I L P
Reduced-complexity multiple-input, multiple-output detection
InactiveUS20090304124A1Data representation error detection/correctionCode conversionMulti inputAlgorithm
Owner:AVAGO TECH INT SALES PTE LTD
Maximum likelihood detection of asynchronous servo data employing interpolation
ActiveUS6912099B2Modification of read/write signalsSynchronisation error detectionSample sequenceMaximum likelihood detection
A repeatable run-out (RRO) detector employs one or more digital interpolators to interpolate asynchronous sample values representing an RRO address mark (AM) and RRO data, an asynchronous maximum-likelihood (AML) detector to detect the RRO AM, and a RRO data decoder to decode the RRO data. The AML detector employs an AML algorithm, such as a Viterbi algorithm, to detect the series of peaks of the RRO AM based on detection of the entire sequence of observed peaks. AML detection selects one of either the asynchronous or interpolated sample sequences that are closest in distance to the ideal RRO AM sample sequence. Once the RRO AM is detected, the AML detector provides a RRO AM found signal as well as the selected one of the sample sequences having the best phase for detecting and decoding the RRO data.
Owner:AVAGO TECH INT SALES PTE LTD
Method and apparatus for maximum likelihood detection of data employing interpolation with compensation of signal asymmetry
ActiveUS7180693B2Modification of read/write signalsDriving/moving recording headsSample sequenceMaximum likelihood detection
Owner:AVAGO TECH INT SALES PTE LTD
Iterative detection in MIMO systems
ActiveUS7254192B2Reduced-state maximum likelihood decisionImprove performanceOther decoding techniquesPolarisation/directional diversityCommunications systemEngineering
Detection for a MIMO (multiple-input, multiple-output) wireless communications system with symbols iteratively detected in subsets with maximum likelihood hard decisions within subsets. Previously detected subsets of symbols are used to regenerate corresronding input signals for interference cancellation. With a 4-transmitter antenna, 4-receiver antenna system, two subsets of two symbols are possible with the first two symbols detected with zero-forcing or MMSE soft estimates which feed maximum likelihood hard decisions; and the hard decision for the first two symbols are used for interference cancellation followed by zero-forcing or MMSE soft estimates for the second two symbols which then feed further maximum likelihood hard decisions.
Owner:TEXAS INSTR INC
Maximum likelihood detection method and system
ActiveUS20080181339A1Data representation error detection/correctionCode conversionParametric searchMaximum likelihood detection
A maximum likelihood detection (MLD) method is disclosed. Received data is processed to obtain preliminary parameters. An initial radius r is determined. r2 is multiplied by a corresponding scaling factor according to a partial Euclidean distance (PED) constraint function to determine the upper limit values of PED for each layer. It is examined whether a sub-lattice exceeds a search scope according to the upper limit values of PED for each layer to search a better solution by utilizing the preliminary parameters.
Owner:IND TECH RES INST
SIM-OFDM communication method
InactiveCN103595685AIncrease the minimum Euclidean distanceImprove BER (BitErrorRatio) performanceMulti-frequency code systemsTelecommunicationsAnti jamming
The invention discloses an SIM-OFDM communication method, and belongs to the communication anti-jamming technical field. The mapping method of subcarrier index modulation is improved at a transmitting end, namely a novel mapping method is introduced, so that subcarriers in each subblock are mutually independent, in this way, the minimum Euclidean distance is increased, and system performance is improved; at a receiving end, with respect to the complexity of maximum likelihood detection, a novel frequency domain detection technology is provided, hence, the maximum likelihood detection performance is achieved, and meanwhile the complexity can be extremely lowered.
Owner:UNIV OF ELECTRONIC SCI & TECH OF CHINA
Low complexity maximum likelihood detection of concatenated space codes for wireless applications
InactiveUS6853688B2Data representation error detection/correctionSpatial transmit diversityViterbi decoderSpace time diversity
Good transmission characteristics are achieved in the presence of fading with a transmitter that employs a trellis coder followed by a block coder. Correspondingly, the receiver comprises a Viterbi decoder followed by a block decoder. Advantageously, the block coder and decoder employ time-space diversity coding which, illustratively, employs two transmitter antennas and one receiver antenna.
Owner:AT&T WIRELESS SERVICES
Safe transmission method of physical layer in wireless communication
InactiveCN101902265AAvoid accessEnsure secure communicationSpatial transmit diversityError preventionBlind equalizationSecure transmission
Owner:XI AN JIAOTONG UNIV
Maximum likelihood detection for MIMO receivers
InactiveUS20070077969A1Spatial transmit diversitySubstation equipmentMaximum likelihood detectionSystem transformation
Maximum likelihood detection of signals in a MIMO receiver. A system transformation is obtained by selecting a weighting matrix that when linearly transforming a channel utilized for wireless communication, results in a particular transformed triangular matrix. The weighting matrix is then used to provide a transformed vector for a received signal that allows a search in one constellation. In searching the constellation recursion values are used to calculate the Euclidean distances between set points of the constellation and the location on the constellation corresponding to the received signal for both bit values 0 and 1. Minimum Euclidean distances are determined for bit values 0 and 1 and the difference of the minimum Euclidean distances is used to compute the maximum likelihood value for bits contained in the received signal.
Owner:AVAGO TECH WIRELESS IP SINGAPORE PTE
Low-complexity differential spatial modulation detection algorithm
ActiveCN105245477ASolve the problem that cannot be reversedIncrease the number of information bitsSpatial transmit diversityError preventionRound complexityMaximum likelihood detection
The invention provides an LC-DSM algorithm (low-complexity differential detection algorithm). Firstly, a symbolic matrix is constructed at the transmitting end of a differential spatial modulation system by applying a bit filling scheme and a transmission bit calculation formula, and a receiving signal is obtained at the receiving end through differential transformation and transmitting. Then a search mode of detection by column is adopted on a receiving matrix based on the equation structure of a differential maximum likelihood detection algorithm to perform signal decision column by column so that a transmitting symbol and the sequence number of a transmitting antenna are obtained. Finally information bits are obtained through inverse mapping according to the corresponding relation of the bit and the transmitting symbol and the bit and the sequence number of the transmitting antenna. The method is obtained by combination of the low-complexity detection algorithm under spatial modulation and the equation structure formed by the maximum likelihood detection algorithm under the differential spatial modulation system. The research indicates that complexity is greatly reduced relative to the differential maximum likelihood detection algorithm by using the LC-DSM algorithm under the premise of guaranteeing no loss of algorithm performance.
Owner:CHINA JILIANG UNIV
Estimation method of flat fading channel in cdma communication system and apparatus for the same
InactiveUS20060062284A1Accurate channel estimationThe result is accurateData representation error detection/correctionCode conversionTelecommunications3g mobile communications
The invention provides a method and apparatus for estimating flat fading channel in CDMA communication system, said method is implemented by using an adaptive forward prediction technique based on lattice filter and maximum likelihood technique of Viterbi algorithm. The adaptive lattice filter is used to carry out prediction of LS criteria on channel fading, and a maximum likelihood detection technique completes Viterbi algorithm in accordance with a channel fading value obtained by the prediction, thus obtaining final estimation and decision about the transmitting signals. The present invention has the advantages that it can obtain accurate result for channel estimation and sequence decision when it operates in the fast fading channel, and overcome fast fading influence due to motion speed up of mobile station, thereby satisfying mobile station speed and corresponding receiving performance required in 3G mobile communication.
Owner:HUAWEI TECH CO LTD
Maximum likelihood detection method and system
InactiveUS8042031B2Data representation error detection/correctionOther decoding techniquesParametric searchMaximum likelihood detection
Owner:IND TECH RES INST
Non-data aided maximum likelihood based feedforward timing synchronization method
InactiveUS6768780B1Network topologiesRadio/inductive link selection arrangementsCommunications systemFrequency spectrum
A system and method of timing estimation for use in a digital receiver within a communication system. An algorithm calculates the timing offset by evaluating the spectral component at the symbol clock frequency. The spectral component is generated using a nonlinearity operation. However, the maximum likelihood non-data-aided timing estimation equation reveals an alternative approximation for the logarithm of the hyperbolic cosine function present in the maximum likelihood equation, which offers a compromise between implementation complexity and variance performance. The estimated timing offset is then fed to a timing correction unit, which calculates the data samples corresponding to the sampling clock phase and removes the redundant samples. The ideal sampled signal is then forwarded to additional synchronization and functional units for further processing.
Owner:MINERAL LASSEN +2
Wireless communication system and method using grouping maximum likelihood detection
ActiveUS7366222B2Regard to overcoming effectsReduce complexitySignal channelsLocal circuitsCommunications systemGroup method
Disclosed is a method for increasing a data transfer rate without an increase in the whole bandwidth using intrinsic spreading codes and orthogonal codes. The method uses interleaving, OFDM modulation / demodulation, and maximum likelihood detection (MLD) to overcome the effects of multipath fading or signal interference, determines grouped optimal values by a grouping method of dividing the intrinsic spreading codes in series, and calculates an integrated optimal value for all the intrinsic spreading codes using the grouped optimal values, thereby reducing the complexity of MLD according to the length of the intrinsic spreading code and acquiring an improved performance.
Owner:PANTECH CORP
Apparatus and method for canceling interference in multi-antenna system
InactiveUS20090147890A1Cancel any interferencePolarisation/directional diversityAmplitude-modulated carrier systemsSystem capacityMaximum likelihood detection
An apparatus and a method for canceling interference based on Maximum Likelihood (ML) at a receiver of a multi-antenna system are provided. The method includes estimating a channel using a signal received over one or more receiver antennas; generating one or more weights using the estimated channel to cancel interference; detecting a candidate symbol having the shortest Euclidean distance through Maximum Likelihood using a first weight; and soft-decoding the candidate symbol using a second weight. Therefore, by receiving the signal based on the ML under the interference, the system capacity can be increased and the reception performance can be enhanced.
Owner:SAMSUNG ELECTRONICS CO LTD
Anti-eavesdropping index modulation OFDM (Orthogonal Frequency Division Multiplexing) transmission method in multi-antenna system
ActiveCN108736936AAdd dimensionIncrease speedCommunication jammingRadio transmissionOriginal dataCarrier signal
Owner:XI AN JIAOTONG UNIV
Environment backscattering system and signal transmission method thereof
ActiveCN106685538AEasy to implementImprove performanceTransmission monitoringSensing by electromagnetic radiationCommunications systemRadio frequency signal
The invention provides a signal transmission and detection method of an environment backscattering system; the system comprises an environment radio source for emitting a source radio frequency signal, a label for receiving the source radial signal and reflecting the radio frequency signal and a reader for receiving the source radio frequency signal and the radio signal, wherein the label continuously emits an equiprobable binary character loaded on the source radio frequency signal; the binary character is corresponding to if the label reflects the radio frequency signal; the reader judges if the received signal is the binary character emitted by the label on the basis of a maximum likelihood detection method or a joint energy detection method. The method is simple in practice, good in performance, and very strong in practicability.
Owner:TSINGHUA UNIV
Multi-symbol detecting and symbol synchronizing method based on CPM (critical path method) modulation
ActiveCN102185688AReduce the minimum signal-to-noise ratioAdapt to Modulation Index ErrorPhase-modulated carrier systemsSynchronising arrangementLoop filterStart time
The invention discloses a multi-symbol detecting and symbol synchronizing method based on CPM (critical path method) modulation. The arithmetic comprises the following steps: determining the starting time of receiving the baseband signal symbol so as to carry out multi-symbol detection treatment; generating local likelihood detecting codes; adopting a single-symbol cycle lead-lag likelihood detection arithmetic to extract phase discrimination information; carrying out clock regeneration by a loop filter circuit; controlling the lead-lag likelihood detection circuit by the regeneration clock, thus achieving the aim of completing high-quality symbol synchronization. The method has the following effective technical effects: the method is based on the maximum likelihood detection so as to ensure the synchronous performance under the low signal-to-noise ratio condition; the time window of the likelihood detection of symbol synchronization is a symbol cycle, and the likelihood detection matching baseband has simple waveform, so that the engineering is convenient to realize.
Owner:CHONGQING JINMEI COMM
Maximum likelihood detection apparatus and method in a wireless communication system
InactiveUS20090022251A1Reduce complexityError preventionLine-faulsts/interference reductionError ratioMaximum likelihood detection
A Maximum Likelihood (ML) detection apparatus and method in a wireless communication system are provided, in which a Euclidean distance are calculated using at least one of channel matrix information, noise power information and modulation order information of each stream, Pairwise Error Rate (PER) are calculated using the Euclidean distance, an error probability of the each stream is calculated using the PER, the error probability of the each stream is ordered and sorted, and ML detection is performed using a result of the ordering and sorting.
Owner:SAMSUNG ELECTRONICS CO LTD
Interference suppression method for multi-user MIMO collaborative relay system
InactiveCN102694628ASuppression of interfering signalsImprove resource utilizationSpatial transmit diversityError prevention/detection by diversity receptionResource utilizationWireless ad hoc network
The invention discloses an interference suppression method for a multi-user MIMO collaborative relay system, mainly solving the problem that each user has multiple antennas in a common-channel multi-user relay system. The interference suppression method comprises the steps that: a user determines a beamforming vector by adopting a signal space alignment method, and sends out a signal after weighting the signal with the beamforming vector in a multiple-access time slot; a relay constructs a precoding matrix based on an orthogonal projection principle, and amplifies and sends the received signal after precoding; the user receives the signal and suppresses interference signals between user pairs by adopting a decoding vector, and conducts a maximum likelihood detection to obtain the needed signal. According to the invention, a network transmission rate and a resource utilization rate are improved, diversity gains of multiple antennas are achieved, channel fading resisting capability of the system is enhanced, and a bit error ratio is decreased. Further, the interference suppression method of the invention can be applied in a transmission mode under centralized management and control of a wireless ad hoc network and base station, wherein data can be exchanged directly through user-relay-user mode.
Owner:XIDIAN UNIV
Method and Receiver For Jointly Decoding Received Communication Signals Using Maximum Likelihood Detection
ActiveUS20120033683A1Balance performanceReduce complexityModulated-carrier systemsFrequency-division multiplexTelecommunicationsInverse discrete fourier transform
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.
Owner:TELEFON AB LM ERICSSON (PUBL)
Method and system for signal detection using a reduced transmitter constellation
Owner:AVAGO TECH WIRELESS IP SINGAPORE PTE
Physical layer network coding-based joint antenna selection space multiplexing method
InactiveCN102142874AImprove spectrum utilizationImprove energy efficiencySpatial transmit diversityHigh level techniquesPrecodingMultiplexing
Owner:TSINGHUA UNIV
Wavelet domani value denoising method for maximum likelihood estimator based on wavelet denoising algorithm
InactiveCN101360079AReduce decoding error rateReduce estimation errorMulti-frequency code systemsTransmitter/receiver shaping networksWavelet denoisingAlgorithm
Owner:TIANJIN UNIV
Reduced-complexity multiple-input, multiple-output detection
InactiveUS20060104390A1Reduce settingsAmplitude-modulated carrier systemsRadio transmissionRound complexityWaveform shaping
A wireless receiver detects signals generated with a multiple-input, multiple-output (MIMO) transmitter. The receiver applies maximum-likelihood detection (MLD) for soft-output signal detection, where an MLD exhaustive search across all candidate vectors is performed recursively by computing and accumulating the differences between, for example, the Euclidean metrics of consecutive candidate tests. Difference terms used for the accumulation are also calculated recursively. An ordering of candidates, such as by a triangular-waveform shaped ordering, is employed such that only one candidate variable is changed between any two consecutive candidate evaluations, leading to a reduced set of computations.
Owner:AVAGO TECH WIRELESS IP SINGAPORE PTE
Detection method for multi-user signal in large-scale multi-antenna system
ActiveCN104618061AImprove performanceReduce performanceError prevention/detection by diversity receptionComputation complexityMaximum likelihood detection
The invention relates to a detection method for multi-user signal in a large-scale multi-antenna system and belongs to the technical field of wireless communication. The method adopts the obtained CSI to detect the multi-user information at the base station side. The method has low complexity and good error bit rate performance, which is close to the error bit rate performance of the optimal MMSE detection within a few iterations. The method adopts the Lanczo iterative algorithm for obtaining the system of linear equations for avoiding the mode of obtaining MMSE orthogonal matrix by directly using large-scale matrix inversion mode, the detection calculating complexity is greatly reduced; in addition, the method can calculate LLR value of each information bit in lower complexity as the input of the decoder and the joint detection decoding performance is obviously improved. The complexity is obviously reduced while the ratio of the user number K and the base station antenna number N is certain and the number tends to infinity, and the error bit rate performance can gradually reach to the maximum likelihood detection (optimal) performance.
Owner:TSINGHUA UNIV
Apparatus and method for detecting signal by maximum likelihood
InactiveUS20090028265A1Reduce the amount of calculationAmplitude-modulated carrier systemsDiversity/multi-antenna systemsQR decompositionLogit
An apparatus and method for detecting a signal in a receiver by maximum likelihood (ML) are provided, in which symbols are detected according to the number of transmit antennas of a transmitter and a modulation scheme, channels are estimated, an equivalent channel matrix corresponding to the estimated channels is determined, a permuted equivalent channel matrix is determined by multiplying the equivalent channel matrix by a predetermined permutation matrix, the permuted equivalent channel matrix is QR decomposed, a hard decision is performed on predetermined symbols among the detected symbols using a received signal resulting from the QR decomposition, and the log likelihood ratios (LLRs) of the hard-decided symbols are determined.
Owner:SAMSUNG ELECTRONICS CO LTD +1
Spatial modulation and detection method with low complexity
InactiveCN104333434AReduce Detection ComplexityError preventionAnti jammingMaximum likelihood detection
The invention relates to the field of communication anti-jamming technologies, in particular to spatial modulation (Spatial Modulation, SM) technologies, signal vector detection algorithms (Signal Vector Detection, SVD), hard-limiter maximum-likelihood detection algorithms (Hard-Limiter Maximum-Likelihood Detection, HL-ML Detection) and related multiple input multiple output (Multiple Input Multiple Output, MIMO) technologies. By adopting a spatial modulation and detection method with low complexity, through arranging a reasonable threshold, the signal vector detection algorithm and the hard-limiter maximum-likelihood detection algorithm are combined, and the complexity for detection is greatly reduced under the condition that the BER (Basic Error Rate) performance obtained through detection is extremely close to optimal algorithm ML detection.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
Method and system for minimum mean squared error soft interference cancellation (MMSE-SIC) Based suboptimal maximum likelihood (ML) detection for multiple input multiple output (MIMO) wireless system
InactiveUS20070198719A1Minimum errorData representation error detection/correctionDigital computer detailsMaximum likelihood detectionMinimum mean square error
Various aspects of a method for minimum mean square error soft interference cancellation (MMSE-SIC) based sub-optimal maximum likelihood (ML) detection for a multiple input multiple output (MIMO) wireless system may comprise selecting at least one constellation point in a constellation map based on at least one of a plurality of received symbols. A number of the at least one constellation point may be less than or equal to a number of previously selected constellation points in a previous constellation map. At least one of the plurality of received symbols may be decoded based on the selected at least one constellation point.
Owner:AVAGO TECH INT SALES PTE LTD
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