LDPC Error Floor Improvement

Abstract

The error-correcting performance of low-density parity check (LDPC) codes, when decoded using practical iterative decoding algorithms, is known to be close to Shannon limits. In this paper we study the LDPC codes performance when varying code rate, constellation level and the maximum number of iteration, this paper shows better coding gain can be obtained at the cost of higher complexity or higher bit rate. For some cases, due to their inability to reach very low bit error rates (e.g., 10− 12 ) at low signal-to-noise ratios (SNRs), a consequence the error rate floor phenomenon associated with iterative LDPC decoders is produced. This paper demonstrates that the concatenation system used LDPC as an inner code and the Bose, Chaudhuri, and Hocquenghem codes (BCH) as an outer code can successfully lower the floor. Connecting BCH codes lower the LDPC BER floor by a factor( from 32 to 22) at about SNR (from -1dB to 1.8 dB) with the same overall cod rate(i.e without any reduction in the bandwith efficiency) and restricted few number of iteration ( only 5 iterations).

A Review of Modern and Recent Studies on the Low-Density Parity-Check Technology Approach

“…Focusing on the LDPC error floor, to improve coding gain arrives at the expense of increasing complication or bit rate, and it is demonstrated were [56] demonstrated that a combination system based on LDPC as an internal code and the Bose, Chaudhuri, and Hocquenghem codes (BCH) as an exterior may lower error limit.The effect of LDPC upon system performance across Additive White Gaussian Noise (AWGN) with Binary Phase Shift Keying (BPSK) and some random fading (Raleigh and Rician) channels has been examined by [57]. The results demonstrate that LDPC is capable of enhancing transceiver systems for many channel types.…”