An analysis of MIMO-OFDM for underwater communications

Underwater wireless channel is characterized by the limitation of bandwidth, inter-symbol inference (ISI) and the influence of the Doppler effect, which cause challenges to high-rate efficiency transmission over long channel. In this paper, we investigate multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) system using advantages of MIMO and OFDM techniques to analyze BER performances of underwater communications. The influences of modulation schemes such as M-PSK, M-QAM, carrier frequency and the Doppler effect to quality of the received signal are taken into account. Computer simulations show the system performance with M-QAM modulation, MMSE equalization and frequency of several ten kHz has the best results compared with that of M-PSK modulation and ZF equalization.