Analysis of algorithms for multi-modal communications in underwater sensor networks

Acoustic communication typically dominates the power usage in underwater sensor networks. To balance the conflicting needs of communication and power usage, we utilize a sensor network platform with underwater acoustic communication, surface level radio communication, and a depth adjustment system to switch between them. We focus on determining which nodes should surface to create a radio communication route for situations where, for the message size, it is more energy efficient to transmit via radio yet acoustic messaging and the depth adjustment system still dominate the overall energy usage. For a given path in 2D or 3D, we develop and examine a set of eight algorithms to select these nodes while taking energy usage and packet loss into account. We perform an analysis of the algorithms and show that a decentralized approach where nodes know their two-hop neighbors provides the most energy efficient method.