Hybrid weighted symbol-flipping decoding for nonbinary LDPC codes

Liu ., Jun, Gao Gao +4 more

Bing Liu, Jun Gao, Wei Tao +1 more

박성현

M. K. Dharani, C. Kalamani

A hybrid decoding algorithm which proposed for nonbinary and binary low density parity (LDPC) codes, both the algorithm combines the weighted symbol flipping (WSF) algorithm with the fast Fourier transform q-ary sum product algorithm (FFT-QSPA).The flipped position and value are determined by the symbol flipping metric and the received bit values in the first stage WSF algorithm. If the low complexity WSF algorithm is failed, the second stage FFT-QSPA is activated as a switching strategy. They are particularly effective for decoding LDPC codes constructed based on finite geometries and finite fields. Analyzing both the techniques nonbinary LDPC codes gives the better error performance and greatly reduces the computation complexity compared to binary LDPC codes. The proposed hybrid algorithm is used for some applications in communication systems for high speed and low power consumption. Keywords Nonbinary and binary low density parity-check (LDPC) code, Weighted symbol –flipping (WSF), Hybrid weighted symbol-flipping (HWSF), iterative decoding. 1.

Bing Liu, Gaoqi Dou, Wei Tao +1 more

A two-stage hybrid iterative decoding algorithm with an efficient stopping criterion for nonbinary low-density parity-check (LDPC) codes is proposed, which combines weighted symbol-flipping (WSF) algorithm and fast Fourier transform q-ary sum-product algorithm (FFT-QSPA). The first WSF decoding would be stopped in advance by analyzing the trend of the number of unsatisfied checks. If the first stage decoding is stopped or failed, the second powerful FFT-QSPA is activated. The proposed decoding with the efficient stopping achieves error performance as good as that of FFT-QSPA with a low complexity, and converges faster than hybrid WSF (HWSF) algorithm.

Lailson Ferreira dos Santos, Jaime Portugheis, Celso de Almeida

This paper analyzes a weighted symbol-flipping (SF) algorithm for nonbinary low density parity-check (NB-LDPC) codes over binary input AWGN (BI-AWGN) channels. The weighted SF algorithm has two main parts: the symbol-flipping function and the new candidate symbol rule. First, it is demonstrated that a rule for choosing the new candidate symbol based on absolute values of observed channel outputs is equivalent to a rule based on Euclidean distances. Then, it is verified that the weighting factor of flipping function has negligible impact on algorithm performance. Motivated by this fact, a SF decoding algorithm is proposed whose flipping function requires only syndrome values and flips symbols in parallel. It is observed that SF decoding outperforms WSF for q-ary codes with large q.