A Survey of FPGA-Based LDPC Decoders

Low-density parity check (LDPC) error correction decoders have become popular in communications systems, as a benefit of their strong error correction performance and their suitability to parallel hardware implementation. A great deal of research effort has been invested into LDPC decoder designs that exploit the flexibility, the high processing speed, and the parallelism of field-programmable gate array (FPGA) devices. FPGAs are ideal for design prototyping and for the manufacturing of small-production-run devices, where their in-system programmability makes them far more cost-effective than application-specific integrated circuits (ASICs). However, the FPGA-based LDPC decoder designs published in the open literature vary greatly in terms of design choices and performance criteria, making them a challenge to compare. This paper explores the key factors involved in FPGA-based LDPC decoder design and presents an extensive review of the current literature. In-depth comparisons are drawn amongst 140 published designs (both academic and industrial) and the associated performance tradeoffs are characterized, discussed, and illustrated. Seven key performance characteristics are described, namely, their processing throughput, processing latency, hardware resource requirements, error correction capability, processing energy efficiency, bandwidth efficiency, and flexibility. We offer recommendations that will facilitate fairer comparisons of future designs, as well as opportunities for improving the design of FPGA-based LDPC decoders.