A Stage-Combined Belief Propagation Decoder for Polar Codes

Abstract

Message-passing decoding algorithm based on belief propagation is a widely used decoding algorithm for error correction codes. For moderate length polar codes, it achieves the error correction performance similar to the successive cancellation algorithm at the cost of high storage and computation requirements. In this paper, a novel modification is introduced for the belief propagation decoder of polar codes, wherein adjacent two processing stages are efficiently combined together to speed up the decoding. Corresponding path based belief estimation method is presented in detail. The proposed decoder halves the number of stages of the conventional decoder and thus can significantly reduce the message memory requirement. The architecture of the proposed decoder is presented. In general, the proposed decoder achieves 50 % memory reduction, more than 77 % throughput gain and significant area reduction without decoding performance degradation.