Adaptive Transmission Technique in Underwater Acoustic Wireless Communication

Abstract

Underwater acoustic channel (UACh) requires robust techniques to get high speed data transmission for reliable communication. If the channel can be estimated and this estimate sent back to the transmitter, the transmission scheme can be adapted to the channel variation. In this paper, we assume a fixed source and receiver configuration over a slowly-varying UACh, where the instantaneous signal to noise ratio (SNR) is constant over a large number of transmissions and then changes to a new value based on the Rayleigh fading distribution. Theoretical derivation of channel capacity (ChC) shows that we can optimize the data rate allowing the transmit power to vary with SNR, subject to an average power constraint. Simulation study also shows that using adaptive technique, we can adapt the channel variation in UACh communication. We also find that variability of the UACh capacity seems not to be negligible by the sloping condition.