A relay device relaying, to a reception device, a signal stream transmitted by a transmission device through MIMO transmission, the relay device including a lattice base reduction processing unit transforming bases of the signal stream transmitted by the transmission device through MIMO transmission, to increase orthogonality of a lattice of the signal stream, a MIMO equalization unit detecting, by equalization, reception symbols in the signal stream with the bases transformed by the lattice base reduction processing unit, a symbol quantization unit performing quantization by mapping the reception symbols detected by the MIMO equalization unit, to a region on a complex plane delimited by quantization threshold values, and a transmission unit transmitting, to the reception device, at least a signal quantized by the symbol quantization unit.

Methods, systems and devices for lattice reduction in decision feedback equalizers for orthogonal time frequency space (OTFS) modulation are described. An exemplary wireless communication method, implementable by a wireless communication receiver apparatus, includes receiving a signal comprising information bits modulated using OTFS modulation scheme. Each delay-Doppler bin in the signal is modulated using a quadrature amplitude modulation (QAM) mapping. The method also includes estimating the information bits based on an inverse of a single error covariance matrix of the signal, with the single error covariance matrix being representative of an estimation error for all delay-Doppler bins in the signal.

The present disclosure includes an ML (Maximum Likelihood) detector. An embodiment of the ML detector comprises a search value selecting circuit and an ML detecting circuit. The search value selecting circuit is configured to select a search value according to a communication index and a modulation type or determine the search value according to a predetermined value, in which the communication index is related to a reception signal or a derivative thereof, the search value is associated with a search range, and a number of candidate signal value(s) in the search range is not greater than a number of all candidate signal values of the modulation type. The ML detecting circuit is configured to execute an ML calculation according to the search value and one of the reception signal and the derivative thereof, so as to calculate a log likelihood ratio of every candidate signal value in the search range.

An apparatus and method for optimizing the performance of satellite communication system receivers by using the Soft-Input Soft-Output (SISO) BCJR (Bahl, Cocke, Jelinek and Raviv) algorithm to detect a transmitted information sequence is disclosed. A Sliding Window technique is used with a plurality of reduced state sequence estimation (RSSE) equalizers to execute the BCJR algorithm in parallel. A serial data stream is converted into a plurality of data blocks using a serial-to-parallel converter. After processing in parallel by the equalizers, the output blocks are converted back to a serial data stream by a parallel-to-serial converter. A path history is determined using maximum likelihood (ML) path history calculation.

Methods, systems and devices for lattice reduction in decision feedback equalizers for orthogonal time frequency space (OTFS) modulation are described. An exemplary wireless communication method, implementable by a wireless communication receiver apparatus, includes receiving a signal comprising information bits modulated using OTFS modulation scheme. Each delay-Doppler bin in the signal is modulated using a quadrature amplitude modulation (QAM) mapping. The method also includes estimating the information bits based on an inverse of a single error covariance matrix of the signal, with the single error covariance matrix being representative of an estimation error for all delay-Doppler bins in the signal.

A relay device relaying, to a reception device, a signal stream transmitted by a transmission device through MIMO transmission, the relay device including a lattice base reduction processing unit transforming bases of the signal stream transmitted by the transmission device through MIMO transmission, to increase orthogonality of a lattice of the signal stream, a MIMO equalization unit detecting, by equalization, reception symbols in the signal stream with the bases transformed by the lattice base reduction processing unit, a symbol quantization unit performing quantization by mapping the reception symbols detected by the MIMO equalization unit, to a region on a complex plane delimited by quantization threshold values, and a transmission unit transmitting, to the reception device, at least a signal quantized by the symbol quantization unit.

The present invention discloses a receive data equalization apparatus. A delay-compensating calculation circuit retrieves training data groups of a training data signal to retrieve total delay amount, generate signed compensation amounts according to a relation among training data contents of training data in each of the training data groups to generate total compensation amount accordingly, and solve equations that correspond total delay amount of the training data groups to the total compensation amount to obtain each of the compensation amounts. A receive data equalization circuit receives the compensation amounts and retrieves a receive data group in a receive data signal, generate signed receive compensation amounts according to a relation among receive data contents of receive data in the receive data group to generate a total receive compensation amount accordingly to perform equalization on a terminal edge of the receive data group according to the total receive compensation amount.

The present invention discloses a receive data equalization apparatus. A delay-compensating calculation circuit retrieves training data groups of a training data signal to retrieve total delay amount, generate signed compensation amounts according to a relation among training data contents of training data in each of the training data groups to generate total compensation amount accordingly, and solve equations that correspond total delay amount of the training data groups to the total compensation amount to obtain each of the compensation amounts. A receive data equalization circuit receives the compensation amounts and retrieves a receive data group in a receive data signal, generate signed receive compensation amounts according to a relation among receive data contents of receive data in the receive data group to generate a total receive compensation amount accordingly to perform equalization on a terminal edge of the receive data group according to the total receive compensation amount.

Methods, systems and devices for lattice reduction in decision feedback equalizers for orthogonal time frequency space (OTFS) modulation are described. An exemplary wireless communication method, implementable by a wireless communication receiver apparatus, includes receiving a signal comprising information bits modulated using OTFS modulation scheme. Each delay-Doppler bin in the signal is modulated using a quadrature amplitude modulation (QAM) mapping. The method also includes estimating the information bits based on an inverse of a single error covariance matrix of the signal, with the single error covariance matrix being representative of an estimation error for all delay-Doppler bins in the signal.

Systems and methods are disclosed for detecting sequences of symbols in a received signal in the presence of inter-symbol interference. Maximum Likelihood Sequence Detection (MLSD) is a known method for optimum detection of such sequences. To reduce the complexity of the MLSD, a Reduced-State Sequence Detection (RSSD) technique has been considered based on partitioning the states of the MLSD. In this approach, a simplified sequence detector is placed within a global decision feedback loop. The disclosed architecture shortens the feedback loop by moving the sequence detector outside the loop and converting the interaction between the two to a feed-forward manner. This is achieved through slicing the signal and closing a nested loop around the sliced bins. A further variant simplifies the detector even more by reducing the number of bins.