Simplified soft output demapper for non-binary LDPC codes

Combining non-binary LDPC codes and high order constellation, namely Bit-Interleaved Coded Modulation (BICM), is a simple but effective way to improve the bandwidth efficiency. Since the non-binary LDPC codes require soft decisions as the input information, the constellation has to provide soft information (log-likelihood ratio) to it. In this paper, a simplified algorithm to calculate LLR for binary code is applied for non-binary code, which will remarkably reduce the computational complexity, and has nearly no performance loss.