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.

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.

A decoding circuit and a decoding method based on the Viterbi algorithm are provided. The decoding method includes the following steps: decoding an encoded data based on the Viterbi algorithm to generate a decoded data; performing error correction on the decoded data to obtain a data content of the encoded data; comparing the decoded data and the data content to generate bit correction information; using the encoded data to calculate multiple first branch metrics based on the Viterbi algorithm, the first branch metrics corresponding to a target bit of the data content; adjusting at least one of the first branch metrics based on the data content and the bit correction information to generate multiple second branch metrics; and selecting the first branch metrics or the second branch metrics based on the bit correction information.

Techniques are presented for mapping a digital data sequence into a signal point sequence for transmission. The signal point sequence belongs to a set of possible signal point sequences. In one example, a digital data sequence is received. Forbidden branch flags that forbid certain signal points in the possible signal points sequences are applied. The signal point sequence is selected from a subset of all the possible signal point sequences based on the digital data sequence. The subset is defined by the forbidden branch flags.

Techniques are presented for mapping a digital data sequence into a signal point sequence for transmission. The signal point sequence belongs to a set of possible signal point sequences. In one example, a digital data sequence is received. Forbidden branch flags that forbid certain signal points in the possible signal points sequences are applied. The signal point sequence is selected from a subset of all the possible signal point sequences based on the digital data sequence. The subset is defined by the forbidden branch flags.

Devices, systems and methods for convolutional precoding and decoding of polar codes are disclosed. An example method for error correction in a data processing system includes receiving a noisy codeword, the codeword having been generated based on an outer stream decodable code and an inner polar code and provided to a communication channel or a storage channel prior to reception by the decoder, the stream decodable code characterized by a trellis, and performing, based on the trellis, a list-decoding operation on the noisy codeword vector to generate a plurality of information symbols, the list-decoding operation being configured to traverse through a plurality of states at one or more stages of a plurality of decoding stages.

It provides a method (300) for polar decoding a received signal into a number, N, of bits with Successive Cancellation List, SCL. The method (300) includes: at the i-th level of a binary tree for decoding the i-th bit of the N bits, where 1≤i≤N: when the 1-th bit is an information bit, calculating (310) a path metric for each of 2*L.sub.i-1 candidate paths at the i-th level, where L.sub.i-1 is an SCL size at the (i−1)-th level and L.sub.0=1; setting (320) an SCL size at the i-th level, L.sub.i, based on L.sub.i-1 and a statistical distribution of the path metrics calculated for the 2*L.sub.i-1 candidate paths; and selecting (330) L.sub.i surviving paths from the 2*L.sub.i-1 candidate paths based on their respective path metrics.

Methods and apparatus are provided for calculating branch metrics, associated with possible transitions between states of a trellis, in a sequence detector for detecting symbol values corresponding to samples of an analog signal transmitted over a channel. For each sample and each transition, the method calculates a plurality of distance values indicative of distance between that sample and respective hypothesized sample values for that transition. In parallel with calculation of the distance values, the sample is compared with a set of thresholds, each defined between a pair of successive hypothesized symbol values arranged in value order, to produce a comparison result. An optimum distance value is selected as a branch metric for the transition in dependence on the comparison result.

Methods, devices, non-transitory computer-readable medium, and systems are described for compressing audio data. The techniques involve obtaining a sequence of digitized samples of an audio signal, performing a transform using the sequence of digitized samples, to generate a plurality of spectral lines, obtaining a group of spectral lines from the plurality of spectral lines, and quantizing the group of spectral lines to generate a group of quantized values. Quantizing the group of spectral lines to generate the group of quantized values may comprise performing a specialized rounding operation on a spectral line selected from the group of spectral lines and using the specialized rounding operation to force a group parity value, computed for the group of quantized values, to a predetermined parity value. One or more data frames based on the group of quantized values may be outputted.

A decoding circuit and a decoding method based on the Viterbi algorithm are provided. The decoding method includes the following steps: decoding an encoded data based on the Viterbi algorithm to generate a decoded data; performing error correction on the decoded data to obtain a data content of the encoded data; comparing the decoded data and the data content to generate bit correction information; using the encoded data to calculate multiple first branch metrics based on the Viterbi algorithm, the first branch metrics corresponding to a target bit of the data content; adjusting at least one of the first branch metrics based on the data content and the bit correction information to generate multiple second branch metrics; and selecting the first branch metrics or the second branch metrics based on the bit correction information.