Combined Normalized and Offset Min-Sum Decoding Algorithm for Irregular LDPC Codes

In this paper, a combined normalized and offset min-sum algorithm (NOMSA) is proposed for decoding irregular Low-Density Parity Check (LDPC) codes. The proposed algorithm focuses on improving the decoding performance by avoiding the loss of sign bit information associated with an output reliability value. Also, the proposed algorithm is made suitable for low complexity hardware implementation by selectively applying the proposed min-sum approximation for check node update with normalized and offset min-sum approximation. The simulation results for irregular LDPC codes show that the proposed algorithm achieves better decoding performance at high signal to noise ratio (SNR) without causing performance degradation and error floors when compared to Conventional Min-Sum algorithm (CMSA), Normalized Min-Sum algorithm (NMSA) and Offset Min-Sum algorithm (OMSA).