A Quasi-Cyclic LDPC Codes Decoder Based on Min-Sum Approximation Algorithm

Xin Lu

Quasi Cyclic Low Density Parity Check(QC-LDPC) code is an important branch of LDPC code research.It is a kind of constructed LDPC code with check matrix H constructed by quasi cyclic method.IEEE 802.16e proposes a parity check matrix with quasi cyclic character which makes the encoding and hardware easy to be implemented.This article will mainly introduce the encoding process and analyze the decoding performance of various decoding algorithms.Simulations show that Min-Sum(MS) algorithm compares to the Log-BP performance has approximately 0.5dB loss for high-speed rate coding.And the performance of Normalized Min-Sum(NMS) and Row Weight Matched Min-Sum(Rwm-MS) with relatively low complexity is nearly the same as that of Log-BP algorithm.

양경철

Otgontsetseg Sukhbaatar

Xin Lu, Zhan Shaobin, Xu Jiong

Next generation wireless systems, such as IEEE802.11n and 802.16e, need high error-correction capacity to achieve high data rate transmission. Therefore, a low-density parity-check code(LDPC code) is adopted as a FEC code. Quasi-cyclic LDPC code(QC-LDPC) code is an important branch of LDPC code research. IEEE 802.16e proposes a parity-check matrix with quasi-cyclic character which makes the encoding very simply. This paper introduces the encoding process and several decoding algorithms for LDPC including Log-BP algorithm, Min-Sum(MS) algorithm and modified MS algorithm. Simulations results under a next generation wireless LAN system show that MS comparing with the Log-BP performance has approximately 0.5dB loss for high-speed rates codes over AWGN channel, however the performance of normalized MS and row weight matched MS with relatively low complexity is nearly the same as that of Log-BP algorithm.

Keke Liu, Shu Lin, Khaled Abdel-Ghaffar

An effective reduced-complexity min-sum algorithm for decoding algebraic quasi-cyclic LDPC codes is presented. The proposed decoding algorithm significantly reduces the hardware implementation complexity, the size of memory required to store information, and the computational complexity of a decoder with no or a small loss in performance compared to the scaled min-sum algorithm.

Juntan Zhang, M.P.C. Fossorier, Daqing Gu +1 more