Overlapped Message Passing Technique with Resource Sharing for High Speed CMMB LDPC Decoder

Abstract

Today, demands for high speed digital communication are getting bigger due to wide deployment of 4G mobile communications and mobile TV services. Requirement for high speed data processing makes forward error correction crucial. LDPC is one of the most popular error correcting codes. In this paper, we propose a novel LDPC decoder for the China Multimedia Mobile Broadcasting (CMMB) standard. The LDPC decoding is carried out iteratively, which leads to relatively long decoding latency. Also, due to long code words, the amount of required memory is huge. To resolve these issues, we propose a novel Overlapped Message Passing (OMP) algorithm with an efficient resource sharing technique. Using the proposed method, we find the best permuted parity check matrix of the CMMB to improve the throughput while minimizing the memory requirement. Using the OMP algorithm only, we could improve the performance by 10%. To avoid potential memory access conflicts, a memory grouping technique to improve pipelining performance is also proposed. By applying all the techniques that we propose in this paper, we could improve the performance up to by 45.