Single carrier FDMA over underwater acoustic channels

Underwater acoustic sensor networks (UWASN) have been attracting growing research interests in recent decades. However, underwater acoustic (UWA) communications suffer from the long propagation delay, the limited bandwidth, multipath, and the Doppler effect. Orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA) are attractive to UWA communications because of their robustness against frequency selective distortion. Nevertheless, OFDM and OFDMA have several drawbacks: high sensitivity to the frequency offset, large peak-to-average power ratio (PAPR), and subcarrier nulls. Single carrier frequency division multiple access (SC-FDMA) which is a DFT-precoded version of OFDMA has stimulated wide interests in cellular wireless communication systems because of the inherent merits. However, SC-FDMA over UWA channels has not been investigated in the existing literature. In this paper, we apply SC-FDMA to UWA channels and mainly focus on the receiver design of the localized FDMA (LFDMA) scheme. Furthermore, our proposed receiver algorithm is tested using the experimental data recorded from the ACOMM10 experiment. The experimental results show that with multiple hydrophones combined, an average uncoded bit error rate (BER) of 10^-3 can be achieved.