Concatenations of systematic polar codes with inner repeat accumulate codes

Abstract

Polar codes, proposed by Erdal Arikan, have attracted a lot of interest in the field of channel coding for their capacity-achieving trait as well as their low encoding and decoding complexity of the order O(NlogN) under successive cancellation (SC) decoder. However, there remains one significant drawback, that is, the error correction performance of small and moderate length polar codes is unsatisfactory, especially when compared with low density parity check (LDPC) codes and turbo codes. To this end, We propose a novel concatenation scheme which employs interleaved repeat accumulate (RA) codes as inner codes and systematic polar codes as outer codes. At the end of this paper, we present the simulation results in binary-input additive white Gaussian noise (BI-AWGN) channel with binary phase shift keying (BPSK) modulation, and we observe that, our proposed concatenation scheme significantly outperforms the conventional non-systematic inner polar codes in the high signal-to-noise (SNR) regime.