Early stopping criterion for LDPC

Abstract

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. The average number of iterations required at low SNRs is significantly reduced without sacrificing the BER performance. At high SNRs, unlike typical stopping criteria which suffer a penalty in the BER performance because the decoder inadvertently stops the decoder too early, the proposed algorithm adaptively switches off at high SNRs. Simulation results are presented for the rate 1 (288, 576) WiMAX 802.16e LDPC code digits using binary phase shift keying (BPSK) over an AWGN channel.