Low-density Parity-check Codes with Reduced Decoding Complexity

Download or read book Low-density Parity-check Codes with Reduced Decoding Complexity written by Benjamin Smith and published by . This book was released on 2007 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents new methods to design low-density parity-check (LDPC) codes with reduced decoding complexity. An accurate measure of iterative decoding complexity is introduced. In conjunction with extrinsic information transfer (EXIT) chart analysis, an efficient optimization program is developed, for which the complexity measure is the objective function, and its utility is demonstrated by designing LDPC codes with reduced decoding complexity. For long block lengths, codes designed by these methods match the performance of threshold-optimized codes, but reduce the decoding complexity by approximately one-third. The performance of LDPC codes is investigated when the decoder is constrained to perform a sub-optimal decoding algorithm. Due to their practical relevance, the focus is on the design of LDPC codes for quantized min-sum decoders. For such a decoder, codes designed for the sum-product algorithm are sub-optimal, and an alternative design strategy is proposed, resulting in gains of more than 0.5 dB.