A Bit-Interleaved Coded Modulation Scheme Based on the Polar Code in Underwater Acoustic OFDM Communication System

A Bit-Interleaved Code Modulation (BICM) scheme based on the polar codes (Polar-BICM), suitable for the underwater acoustic (UWA) communication system utilizing orthogonal frequency division multiplexing (OFDM) is proposed in this paper. In the proposed scheme, the design and implementation of the encoder and the modulator are combined to improve the communication rate, while the traditional schemes usually consider independently. The system BER performance affected by variance interleaver types, interleaver lengths and code lengths are carefully discussed in this paper. The LDPC-BICM system and the Trellis Coded Modulation (TCM) scheme are chosen as the control schemes. Simulation and experimental results show that the BER performance of the UWA OFDM communication system based on Polar-BICM is much better than that based on the TCM scheme. Moreover, a higher coding gain than the LDPC-BICM UWA OFDM system is obtained because of the Polar Code. At the same time, the compiled code implementation of Polar Code is relatively simpler than that of the LDPC coding scheme. Therefore, the Polar-BICM system improves the transmission efficiency of the system effectively without losing reliability, which contributes a lot to the practical application of the coding and modulation combination technology in UWA communication.