Performance of SCHT Sequences in Multicarrier Underwater Acoustic Communications System

Abstract

In this paper, we apply complex spreading sequences to the underwater acoustic communications system. We derive the bit error rate (BER) expression of the multicarrier underwater acoustic communications system over Rayleigh fading channels. We compare the BER performance of the communications system with different spreading sequences including sequency-ordered complex Hadamard transform (SCHT) sequences, unified complex Hadamard transform (UCHT) sequences, and Walsh-Hadamard transform (WHT) sequences. The numerical BER simulation results show that the SCHT sequences surpass UCHT and WHT sequences in the asynchronous multicarrier underwater acoustic communications system over Rayleigh fading channels.