Soft decision multi-stage threshold decoding with sum-product algorithm

Sum-Product Algorithm (SPA) is usually used in LDPC codes. This paper presents a method to improve the performance of soft decision multi-stage threshold decoding (SMTD) by using SPA. Parity check coding is used to improve further. This paper also presents a brief comparison among various multi-stage threshold decoding (MTD) techniques. SPA concatenated (ConC) with SMTD and parity check code is also compared with specific types of repeat accumulate (RA) code and LDPC code. The SPA ConC with SMTD outperforms the conventional multi-stage threshold decoding techniques having a performance gain of 0.3 dB to 0.7 dB at bit error rate (BER) of 10
⁻⁵
. Furthermore, the SPA ConC with SMTD and parity check code gives 0.2 dB performance gain over the SPA ConC with only SMTD at BER of 10
⁻⁵
.