On optimizing the transmission power of multi-hop underwater acoustic networks

This paper analyses how to optimize the transmission power for multi-hop underwater acoustic networks in a rigorous and theoretical way. In practical design, the transmission power is the function of two variables: internode distance d and signal frequency f, and for a prespecified d, there exists an optimal frequency which minimizes the transmission power. A close-form approximation for the optimal frequency as a function of d is obtained using curve-fitting, and the optimal transmission power as a function of only one variable d is deduced. A power-based cost function is proposed for a linear multi-hop network model to identify the minimum number of hops that optimizes the transmission power of the whole link. Besides, two communication strategies, namely direct-access strategy and relay strategy, are investigated in the linear multi-hop scenario to set forth how communication strategy affects the total power consumption. Simulation results show that the strategy which saves more power consumption is relaying, whose savings become more significant at longer distances.