Systems and methods for advanced iterative decoding and channel estimation of concatenated coding systems

摘要

Systems and methods for decoding block and concatenated codes are provided. These include advanced iterative decoding techniques based on belief propagation algorithms, with particular advantages when applied to codes having higher density parity check matrices. Improvements are also provided for performing channel state information estimation including the use of optimum filter lengths based on channel selectivity and adaptive decision-directed channel estimation. These improvements enhance the performance of various communication systems and consumer electronics. Particular improvements are also provided for decoding HD Radio signals, including enhanced decoding of reference subcarriers based on soft-diversity combining, joint enhanced channel state information estimation, as well as iterative soft-input soft-output and list decoding of convolutional codes and Reed-Solomon codes. These and other improvements enhance the decoding of different logical channels in HD Radio systems.

主权项

1. A system for generating check-to-variable messages during an iteration in decoding of codes represented by a parity check matrix, the system comprising:
a de-mapper configured to receive a modulation signal comprising symbols, and convert the modulation signal into coded bit log-likelihood ratios; and at least one decoder coupled to the de-mapper, wherein the at least one decoder is configured to receive the coded bit log-likelihood ratios from the de-mapper and iteratively perform message passing decoding for a set of variable nodes identified in the check parity matrix so as to generate a decoded signal comprising bits, and wherein for at least one variable node in the set of variable nodes during the iteration, the at least one decoder is further configured to: a. calculate a check-to-variable message MCV(i,j) from check node i to variable node j, b. identify two smallest absolute values, Min1 and Min2, in a set of variable-to-check messages MVC(i,k), where k≠j, excluding the message from variable j to check node i, MVC (i,j), c. calculate a scaling factorα=1-β⁢Min1Min2,where β is a non-negative number such that 0≦β≦1,
d. scale the check-to-variable message MCV(i,j) as MCV(i,j)=α·MCV(i,j), e. update check node i and variable node j with said scaled check-to-variable message MCV(i,j), and f. output the generated decoded signal.