Sequence detectors and detection methods are provided for detecting symbol values corresponding to a sequence of input samples obtained from an ISI channel. The sequence detector comprises a branch metric unit (BMU) and a path metric unit (PMU). The BMU, which comprises an initial set of pipeline stages, is adapted to calculate, for each input sample, branch metrics for respective possible transitions between states of a trellis. To calculate these branch metrics, the BMU selects hypothesized input values, each dependent on a possible symbol value for the input sample and L>0 previous symbol values corresponding to possible transitions between states of the trellis. The BMU then calculates differences between the input sample and each hypothesized input value. The BMU compares these differences and selects, as the branch metric for each possible transition, an optimum difference in dependence on a predetermined state in a survivor path through the trellis.

A signal receiving circuit may include a receiving equalizer and a sequence estimator. The receiving equalizer may be configured to compensate an inter-symbol interference in a signal from an external to output an equalization data, based on a receiving signal from an outside. The sequence estimator may be configured to determine a termination symbol, based on the equalization data, to perform a decoding on the receiving signal, based on the determined termination symbol, and to output the decoded receiving signal as a sequence data.

There is provided a decoder (310) for sequentially decoding a data signal received through a transmission channel in a communication system, the received data signal carrying transmitted symbols, the decoder comprising a symbol estimation unit (311) configured to determine estimated symbols representative of the transmitted symbols carried by the received signal from information stored in a stack, the stack being filled by iteratively expanding child nodes of a selected node of a decoding tree comprising a plurality of nodes, each node of the decoding tree corresponding to a candidate component of a symbol of the received data signal and each node being associated with a predetermined metric, the stack being filled at each iteration with at least some of the expanded child nodes and being ordered by increasing values of the metrics associated with the nodes, the selected node for each iteration corresponding to the node having the lowest metric in the stack. The decoder further comprises a stack reordering activation monitoring unit (313) configured to monitor at least one stack reordering activation condition and, in response to a stack reordering activation condition being verified, to cause the symbol estimation unit to: reduce the metric associated with each node stored in the stack by a quantity, reorder the stack by increasing value of the reduced metric, and remove a set of nodes from the reordered stack so as to maintain a number N of nodes in the reordered stack, the maintained nodes corresponding to the N nodes having the lowest metrics in the reordered stack.

An apparatus including at least one processor configured to execute instructions and cause the apparatus to perform, obtaining for a first possible state (s) of a received sample at the current time step (k), log-likelihood ratio, Ilr, values Ilr.sub.old,min, Ilr.sub.old,max of a first transmitted bit (b.sub.j), wherein, the Ilr values Ilr.sub.old,min, Ilr.sub.old,max are respectively associated with a most likely state and a less likely state related to a received sample at the previous time step (k?1); determining based on path metrics and branch metrics corresponding to the received sample at the current time step (k); a first parameter (Q) related to a difference between likelihoods of the most likely state and the less likely state; updating magnitude of the Ilr value Ilr.sub.old,min at least based on the Ilr value Ilr.sub.old,min, the Ilr value Ilr.sub.old,max, and the first parameter, to obtain an updated Ilr value Ilr.sub.old,updated.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication of a configuration for balanced code communication, the configuration indicating parameters of signals of balanced code communications having sequences, within codewords, that balance. The UE may receive, from a network node, a balanced code communication, the receiving comprising decoding a codeword of the balanced code communication and estimating one or more parameters of communicating with the network node based at least in part on the configuration and based at least in part on using a balancing property of the balanced code communication. Numerous other aspects are described.

Methods are disclosed for improving communications on feedback transmission channels, in which there is a possibility of bit errors. The basic solutions to counter those errors are: proper design of the CSI vector quantizer indexing (i.e., the bit representation of centroid indices) in order to minimize impact of index errors, use of error detection techniques to expurgate the erroneous indices and use of other methods to recover correct indices.

Methods are disclosed for improving communications on feedback transmission channels, in which there is a possibility of bit errors. The basic solutions to counter those errors are: proper design of the CSI vector quantizer indexing (i.e., the bit representation of centroid indices) in order to minimize impact of index errors, use of error detection techniques to expurgate the erroneous indices and use of other methods to recover correct indices.

A decoder or a decoding method for decoding a data signal is provided by iteratively constructing a decoding tree comprising nodes, each representing a component of a symbol of a data signal, each iteration comprising, for a current node of the tree stored in the top of the stack; generating a reference child node of the current node from the data signal; from the reference child node, generating a first and second neighbor child nodes by subtracting/adding a positive integer parameter from/to the value of the reference node; storing in the stack three child nodes derived from the reference, first and second neighbor child nodes, the nodes stored in the stack being ordered by increasing values of a node metric; removing the current node stack; selecting the top node of the stack as the new current node. The data signal is estimated from the stack node information.

Introduced here is at least one technique to better estimate interference at a receiver. The technique includes receiving a plurality of reference signals, which each have information indicative of noise. Thus, the technique further includes, for each reference signal, determining a noise estimation and determining a distance metric and log-likelihood ratio (LLR) of the noise estimation. Once the distance metric and LLR of each reference signal is determined, the receiver can determine a final LLR based on the distance metric and LLR of each reference signal. In this manner, a final LLR is determined. This technique can be applied by any device operating on MIMO technology.

A method includes: receiving a to-be-decoded symbol sequence, where the to-be-decoded symbol sequence includes N symbols; dividing the received to-be-decoded symbol sequence into a first symbol sequence and a second symbol sequence; calculating first distances between the first symbol sequence and each of corresponding 2.sup.K ideal superimposed symbol sequences, and obtaining paths corresponding to relatively small distances based on the first distances; sequentially performing sequence detection on each symbol in the second symbol sequence based on the paths corresponding to the 2.sup.k-1 relatively small distances, calculating second distances between each symbol in the second symbol sequence and each ideal symbol sequence, and after the sequence detection is performed on a last symbol, obtaining an ideal symbol sequence corresponding to a minimum distance based on the second distances; and using the ideal symbol sequence corresponding to the minimum distance as an output symbol sequence.