A carrier interleaved underwater acoustic MC-CDMA communication system using complete complementary sequence

In consideration of the harsh environment of underwater acoustic channel and the high reliability transmission requirement, a carrier interleaved underwater acoustic MC-CDMA communication system using complete complementary sequence (MIC-CDMA/CCS) is proposed in this paper. We use OFDM modulation to reduce the complexity of the system, obtain the diversity gain by frequency domain spread spectrum, and design a carrier interleaving scheme to reduce the channel correlation fading. The complete complementary sequence is used as the spreading code to lay the foundation for multi-user applications in the future, and the channel estimation is carried out by using the DFT-based LS algorithm. The simulation results show that the complete complementary sequence has good crosscorrelation and auto-correlation properties, and can reduce the PAPR of the system to a certain extent. At the same time, singleuser MC-CDMA system has better performance than OFDM system, the carrier mapping scheme based on carrier interleaving has a certain performance improvement compared with the traditional mapping one. For single-user MC-CDMA systems, the greater is the spread gain, the better the system performs, but it is at the expense of the rate. Finally, the system proposed in this paper is compared with MC-CDMA systems mentioned in other papers and the results show that the proposed system has higher rate and better bit error rate performance.