A New Low-Complexity Polar Code Construction for BICM Over AWGN Channels

We investigate a polar code construction for bit-interleaved coded modulation (BICM) transmission over an additive white Gaussian noise (AWGN) channel, assuming successive cancellation (SC) decoding. We consider the BICM systems with and without bit interleaving. Several bit interleaving patterns are investigated, where the polar codes are designed based on low-complexity Gaussian approximation (GA) or reciprocal channel approximation (RCA), both originally developed for a binary-input AWGN channel. The adaptation of design SNR based on the bit-wise mutual information (BMI) is introduced for the cases with bit interleaving. On the other hand, in the case without bit interleaving, we propose a hybrid construction based on Monte-Carlo (MC) method and either GA or RCA. It will be shown that the performance without bit interleaving outperforms those with bit interleaving, and in either case, the proposed low-complexity design approaches can achieve performance comparable to high-complexity full MC methods.