Modeling and Simulation of Underwater Acoustic Communication Systems

This work describes a simple model for underwater acoustic (UWA) channels, taking into account Doppler effects. The performance of orthogonal frequency-division multiplexing (OFDM) systems in UWA channels is also studied. The impact of Doppler effects on OFDM transmissions is thoroughly investi- gated, and a simple two-step compensation strategy is described. In order to evaluate UWA models, a versatile UWA channel simulator is developed and some simulations are performed to measure the OFDM performance for time-variant channels. Those simulations evaluate the bit-error-rate and sensitivity of OFDM systems to Doppler effects. The results are satisfactory and show that only one compensation step is necessary to maintain a reasonable system performance for relative estimation errors of Doppler scaling factor in the order of 10−5, corroborating that OFDM systems are suitable in some specific scenarios.