Check node LDPC decoder stopping criterion

摘要

A log-likelihood ratio (LLR) test on the single Mth check node of an LDPC decoder is utilised to develop an improved low complexity stopping criterion that overall outperforms well-known stopping criteria. The average number of iterations required at low SNRs is significantly reduced without sacrificing the BER performance. At high SNRs, the proposed algorithm can be modified to adaptively switch off to minimise its impact on the BER. Simulation results are presented for the rate 1/2 (288, 576) and rate 1/2 (1152, 2304) WiMAX 802.16e LDPC codes with binary phase shift keying (BPSK) over an AWGN channel for well-known criteria and the proposed algorithms in this paper. The performance of a Genie algorithm that would with hindsight stop the decoder to minimise the BER is used to compare all algorithms.