Piecewise Linear Interpolation based LOG-BP algorithm for 5G LDPC codes

BP algorithm is one of the most prominent decoding algorithms based on message passing. However, it is not commonly adopted in hardware implementation for the high computational complexity. The normalized min-sum (NMS) algorithm was then proposed to solve this problem but with performance flaws. To satisfy the comprehensive requirements of complexity and accuracy in 5G systems, we introduce an approximated algorithm based on BP in log-domain and name it piecewise linear interpolation based LOG-BP (PLI-LOG-BP) algorithm. In our novel algorithm, the non-linear mapping function in the horizontal step of BP is replaced by several linear functions for simplification. Meanwhile, we also propose an MMSE-based selection algorithm of segment points that improves the approximation accuracy. To verify the validation of the proposed algorithm, we apply 5G LDPC codes in our simulation and obtain BLER performance results. According to these results, PLI-LOG-BP algorithm decoding performance is significantly better than the NMS algorithm and even almost as good as the BP algorithm.