Interleaved local sorting for successive cancellation list decoding of polar codes

Abstract

In the successive cancellation list decoding of polar codes, the metric sorting dominates the overall decoding latency. To reduce the latency of metric sorting, this paper proposes a new sorting method, called interleaved local sorting, that divides the metrics to be sorted into several groups and sorts each group independently. In addition, an interleaving scheme is adopted to recover the performance degradation caused by the local sorting. A hardware architecture that is effective in reducing the overall latency as well as the hardware complexity is also proposed based on the proposed metric sorting. Evaluation results show that the proposed sorting architecture outperforms the state-of-the-art metric sorting architectures in terms of the numbers of comparisons and comparison stages. The proposed architecture reduces the number of comparison stages to less than 43 percent of the previous metric sorting architectures in the literature.