A low-latency algorithm for stochastic decoding of LDPC codes

Abstract

We introduce a low-latency stochastic decoding algorithm, called conditional stochastic decoding, to implement iterative Low-Density Parity-Check (LDPC) decoders. The conditional stochastic decoder, which utilizes reliable messages in the decoding process and the channel receiving probability to generate stochastic streams, improves error rate performance and decreases decoding latency. Compared to conventional stochastic decoders, the proposed algorithm achieves more than 20-percent reduction in the decoding latency for the (1056,528) LDPC code from the WiMAX standard. We also show that the proposed algorithm, due to its lower frame error rate, is a suitable choice to be used in the Hybrid Automatic Repeat reQuest (HARQ) systems.