Reducing the Overhead of OFDM Communications Over Underwater Acoustic Channels

ABSTRACT In this paper, we propose a receiver design for single-input multiple-output (SIMO) orthogonal frequency division multiplexing (OFDM) communications over underwater acoustic (UWA) channels. The proposed design consists of two key components: i) time reversal based symbol detection that enables the use of short guard time intervals for interblock interference avoidance; and ii) decision-directed channel tracking with error propagation control that eliminates the need of periodic training for channel tracking. The goal of our design is to improve bandwidth efficiency by reducing the amount of overhead typically associated with SIMO-OFDM UWA communications. The proposed design is tested at a sea-going experiment. The experimental results confirm the merits of our design and demonstrate considerable improvements over a competing alternative