Efficient Architectures for Multigigabit CCSDS LDPC Encoders

Abstract

Quasi-cyclic low-density parity-check (QC-LDPC) codes have been adopted by the Consultative Committee for Space Data Systems (CCSDS) as the recommended standard for onboard channel coding in Near-Earth and Deep-Space communications. Encoder architectures proposed so far are not efficient for high-throughput hardware implementations targeting the specific CCSDS codes. In this article, we introduce a novel architecture for the multiplication of a dense quasi-cyclic (QC) matrix with a bit vector, which is the fundamental operation of QC-LDPC encoding. The architecture leverages the inherent parallelism of the QC structure by concurrently processing multiple bits, according to an optimized scheduling. Based on this architecture, we propose efficient encoders for CCSDS codes, according to all the applicable low-density parity-check (LDPC) code encoding methods. Moreover, in the special case of the code for Near-Earth communications, we also introduce a preprocessing algorithm to efficiently handle the challenges arising from the generator's matrix circulant size (511 bits). The proposed architectures have been implemented in various field-programmable gate array (FPGA) technologies and validated in Zynq UltraScale+ multiprocessor system-on-chip (MPSoC), achieving a significant speedup compared with previous approaches, while at the same time keeping resource utilization low.