A Reduced-Complexity Successive-Cancellation Decoder of Polar Codes

Polar codes are the first provably capacity-achieving family of codes which have recently attracted more and more attention, especially in 5G network. The complexity of successive cancellation (SC) based decoders is O(N log N), where N is the blocklength of the code. Because the frozen bit is known to the transmitter and the receiver, many redundant computation done in the conventional SC algorithm. In this paper, we prune the computation of frozen bits, and as to nonfrozen bit, we further utilize the property of butterfly architecture to update the likelihood ratio (LR) messages. Compared with the conventional SC decoder, the proposed method reduces the complexity without any loss of performance and the complexity of memory.