A sequence detector is provided for detecting symbol values corresponding to a sequence of input samples obtained from a transmission channel. The sequence detector comprises a branch metric unit (BMU), a path metric unit (PMU) and a survivor memory unit. The branch metric unit calculates branch metrics for respective possible transitions between states of a trellis. The path metric unit accumulates branch metrics provided by the branch metric unit in order to establish path metrics. The survivor memory unit selects a survivor path based on the path metrics and outputs a survivor sequence of the detected symbols corresponding to the survivor path. The sequence detector is configured such that the synchronization length is different than the survivor path memory length.

A electronic system includes: a support chip configured to receive an input code stream; a circular Viterbi mechanism, coupled to the support chip, configured to: generate a final path metric for the input code stream, store intermediate path metrics at the repetition depth, generate a repetition path metric for the input code stream, and calculate a soft correlation metric based on the final path metric, the repetition path metric, and the intermediate path metrics.

Certain aspects of the present disclosure relate to techniques and apparatus for enhanced decoding, for example, by providing a multi-phase tail biting convolutional code (TBCC) decoding algorithm. An exemplary method generally includes obtaining, via a wireless medium, a codeword encoded with a TBCC encoding scheme, generating metrics for candidate paths through trellis stages of a decoder, propagating information from at least one of the trellis stages to a later trellis stage, while generating the metrics, selecting a set of the candidate paths based on the propagated information, and decoding the encoded codeword by evaluating the selected set of candidate paths based, at least in part, on the generated metrics. Other aspects, embodiments, and features are claimed and described.

A sequence detector is provided for detecting symbol values corresponding to a sequence of input samples obtained from a transmission channel. The sequence detector comprises a branch metric unit (BMU), a path metric unit (PMU) and a survivor memory unit. The branch metric unit calculates branch metrics for respective possible transitions between states of a trellis. The path metric unit accumulates branch metrics provided by the branch metric unit in order to establish path metrics. The survivor memory unit selects a survivor path based on the path metrics and outputs a survivor sequence of the detected symbols corresponding to the survivor path. The sequence detector is configured such that the synchronization length is different than the survivor path memory length.

Embodiments of the present invention disclose a channel decoding method, apparatus, and system. The channel decoding apparatus includes a memory storing instructions; and a processor coupled to the memory to execute the instructions to: obtain decoding information of first channel decoding of a data block; determine whether the first channel decoding fails; in response to determining that the first channel decoding fails, obtain a reference sequence number of the data block; obtain at least one matching historical demodulated soft value; combine the demodulated soft value of the data block and the at least one matching historical demodulated soft value to obtain a combined demodulated soft value of the data block; and perform second channel decoding on the combined demodulated soft value of the data block.

A sequence detector is provided for detecting symbol values corresponding to a sequence of input samples obtained from a transmission channel. The sequence detector comprises a branch metric unit (BMU), a path metric unit (PMU) and a survivor memory unit. The branch metric unit calculates branch metrics for respective possible transitions between states of a trellis. The path metric unit accumulates branch metrics provided by the branch metric unit in order to establish path metrics. The survivor memory unit selects a survivor path based on the path metrics and outputs a survivor sequence of the detected symbols corresponding to the survivor path. The sequence detector is configured such that the synchronization length is different than the survivor path memory length.

A sequence detector is provided for detecting symbol values corresponding to a sequence of input samples obtained from a transmission channel. The sequence detector comprises a branch metric unit (BMU), a path metric unit (PMU) and a survivor memory unit. The branch metric unit calculates branch metrics for respective possible transitions between states of a trellis. The path metric unit accumulates branch metrics provided by the branch metric unit in order to establish path metrics. The survivor memory unit selects a survivor path based on the path metrics and outputs a survivor sequence of the detected symbols corresponding to the survivor path. The sequence detector is configured such that the synchronization length is different than the survivor path memory length.

Certain aspects of the present disclosure relate to techniques and apparatus for increasing decoding performance and/or reducing decoding complexity. A transmitter may divide data of a codeword into two or more sections and then calculate redundancy check information (e.g., a cyclic redundancy check or a parity check) for each section and attach the redundancy check information to the codeword. A decoder of a receiver may decode each section of the codeword and check the decoding against the corresponding redundancy check information. If decoding of a section fails, the decoder may use information regarding section(s) that the decoder successfully decoded in re-attempting to decode the section(s) that failed decoding. In addition, the decoder may use a different technique to decode the section(s) that failed decoding. If the decoder is still unsuccessful in decoding the section(s), then the receiver may request retransmission of the failed section(s) or of the entire codeword.

Certain aspects of the present disclosure provide techniques for Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for determining a minimal list size to use in list decoding operations for reducing resource consumption (e.g., compute, memory, and power) at a decoder. A method includes receiving a codeword comprising a plurality of channel bits encoded with an error-correcting code, the plurality of channel bits comprising, at least, a plurality of information bits, determining a payload size of the codeword, determining a channel capacity metric for the plurality of channel bits, determining a minimal list size for a list decoding operation based on at least the payload size and the channel capacity metric; and performing the list decoding operation on the codeword based on the minimal list size to obtain the plurality of information bits.

Methods and apparatuses are provided for operating a list Viterbi decoder. A path metric difference (PMD) threshold is set based on an input signal level and a PMD limit value. Decoding is performed by using the PMD threshold. Performing the decoding includes determining a PMD of a best path, comparing the determined PMD and the PMD threshold, and declaring a decoding failure and ending performing of the decoding, if the PMD is greater than or equal to the PMD threshold.