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 decoding codes of length N that include a message of K bits represented by a parity check matrix of dimension (N−K)×N, wherein N−K represents check nodes and N represents variable nodes, comprising:
a de-mapper configured to receive a modulation signal comprising symbols, and convert the modulation signal into 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 and generate a decoded signal comprising bits, and wherein the at least one decoder is further configured to:
a. generate a plurality of P parity check matrices with N−K sparse columns wherein up to N−K sparse columns contain only a single entry equal to 1 per column, wherein sparse columns of each of the plurality of P parity check matrices correspond to different subsets of N−K bit log-likelihood ratios of N−K+R least reliable bit log-likelihood ratios, wherein R≧P is a configurable integer associated with R least reliable bits,b. decode channel log-likelihood ratios using said plurality of P parity check matrices with sparse columns to produce updated log-likelihood ratios by employing soft-input soft-output (SISO) message passing decoding until a desired number of iterations is reached or until said decoding using at least one of said plurality of P matrices produces a valid codeword,c. on the condition that decoding using said plurality of P parity check matrices produces no valid codeword, perform additional decoding that is based at least in part on algebraic decoding of sequences of said updated log-likelihood ratios; andd. output the generated decoded signal.