Parallel low-density parity check decoding on a network-on-chip-based multiprocessor platform

Abstract

Low-density parity check (LDPC) codes can achieve performances close to the Shannon limit and they have been widely adopted for various communication standards. However, the irregular message exchange pattern of LDPC codes is a major challenge for decoder design. Additionally, there is a great demand for integrating diverse applications onto a single system where a flexible, scalable and efficient implementation of LDPC decoding is highly preferable. With the enormous computing power provided by integrating many processors on a single chip in advanced process technology, a multiprocessor platform is regarded as a promising solution to tackle these design challenges. In this work, we devised a parallelisation scheme to implement LDPC decoding on a multiprocessor platform. By using a distributed and cooperative way for LDPC decoding, the memory bottleneck, commonly seen in LDPC decoder design, is eliminated. Moreover, we used a graph spectra-based mapping algorithm to reduce heavy message exchanges among processors during the decoding process. Compared to the sequential mapping strategy, our approach has successfully decreased the amount of inter-processor communication by up to 48%/45%/40% for 16/32/64-processor platforms, respectively. Cycle-accurate simulation results from various LDPC codes demonstrate that desirable scalability and speedups are obtained by our approach.