Dynamic transmission power control based on exact sea surface movement modeling in underwater acoustic sensor networks

Prediction of sea surface movement can be an important tool for the estimation of time-variant acoustic channel because signal attenuation caused by reflection occupies a large proportion in path loss. Although a number of researches have proposed resource allocation schemes based on the channel modeling, they did not consider reflection loss and time-variant characteristic. This paper suggests a transmission power control based on the prediction of time-variant channel by using the RMS (Root Mean Square) wave-height for low power consumption and stable throughput. The proposed scheme adopts transfer function including reflection coefficient overlooked in other papers using the Kirchhoff approximation. In addition, it defines the transmission power needed to guarantee a pre-specified SNR (Signal-to-Noise Ratio) threshold using the transfer function. The BELLHOP and WAFO simulators were utilized to build simulation environment similar to actual ocean. The simulation results show that the proposed method is practical by considering the reflection impact on the power control and reduces energy consumption by 32.79% compared with the existing methods which do not use the adaptive power control based on channel condition.