An Efficient NB-LDPC Decoder Architecture for Space Telecommand Links

Abstract

In the frame of error correction in space telecommand (TC) links, the Consultative Committee for Space Data Systems (CCSDS) currently recommends short block-length BCH and binary LDPC codes. Other alternatives have been discarded due to their high decoding complexity, such as LDPC and eBCH codes with MRB decoding and NB-LDPC codes. NBLDPC codes perform better than their binary counterparts over AWGN and jamming channels, being excellent candidates for space communications. In this brief, we show the feasibility of NB-LDPC coding for space TC applications by proposing a highly efficient decoding architecture. The proposed decoder is implemented for a (128,64) NB-LDPC code over GF(16) and the design is particularized for a space-certified Virtex-5QV FPGA. The results prove that NB-LDPC coding is an alternative outperforming the standardized binary LDPC at a reasonable cost. Given that the maximum rate for TC recommended by the CCSDS is 2 Mbps, the proposed architecture achieves a throughput of 2.4 Mbps using only 8797 LUTs and 5460 FFs (no dedicated memories are used). In addition, this architecture is suitable for any regular (2,4) NB-LDPC (128,64) code over GF(16) independently of the H matrix, allowing great flexibility for the use with the recently proposed short block-length NBLDPC codes in upcoming telecommand uplink standards.