An Iterative LLR Derivation Algorithm Based on Extended Min-sum Decoding of Non-binary LDPC Codes

To overcome the drawback of the high complexity of Log Likelihood Ratio (LLR) generation and its accompanying sorting in Extended Min-Sum (EMS) decoding of non-binary Low-Density Parity-Check (LDPC) codes, for non-binary LDPC-coded BPSK modulation systems, a high-speed and low-complexity LLR derivation algorithm is proposed in this paper. The proposed algorithm employs an iterative computation method to generate and sort the LLRs. The front-end of a decoder implementing the proposed algorithm can work in pipeline mode, which accelerates the decoding process and increases the throughput of the decoder. Simulation results show that, the proposed algorithm incurs negligible performance loss, which makes it a good candidate for the hardware implementation of the front-end in non-binary LDPC decoders.