In Situ Multi-Bit Decision for Successive Cancellation List Decoding of Polar Codes

Abstract

Polar codes are the first capacity-achieving error-correction code which has attracted much research attention. Among many decoding methods, successive cancellation list decoding (SCLD) is considered as a representative decoding method that can achieve a good error-correcting performance. However, the long latency of SCLD is a significant matter that hinders practical applications, which is mainly caused by two features of the SCLD process: tree traversal and path-splitting. To alleviate the main reasons, a new multi-bit SCLD algorithm is proposed in this paper to decode several bits simultaneously without conducting any tree traversal and path-splitting when a node in the decoding tree holds a specific condition. In addition, a path ignoring (PI) technique is proposed to mitigate the condition of the multi-bit SCLD, which results in an additional reduction of latency. The proposed multi-bit decoding method and the PI technique play a significant role in reducing the number of path-splitting cases, by 96% compared to the conventional SCLD method. Simulation results show that compared to the conventional SCLD with list sizes 8 and 16, the proposed multi-bit decoding associated with the PI technique reduces the overall decoding cycles by 77% and 79%, respectively, with almost no degradation of error-correcting performance.