Energy-Efficient Routing Schemes for Underwater Acoustic Networks

TLDR

Underwater acoustic networks are increasingly important for ocean monitoring, but their propagation and energy‑consumption characteristics differ markedly from terrestrial radio, requiring new protocol design criteria. The study analyzes how attenuation, noise, propagation delays, and distance‑dependent bandwidth and power affect underwater acoustic networks, aiming to understand their impact on protocol design. Based on these insights, the authors design energy‑efficient routing protocols and implement a detailed ns2 acoustic channel model to evaluate routing performance with realistic MAC and PHY layers. The protocols outperform existing routing strategies in realistic scenarios and achieve near‑optimal total path energy consumption, offering practical guidance for design and deployment.

Abstract

Interest in underwater acoustic networks has grown rapidly with the desire to monitor the large portion of the world covered by oceans. Fundamental differences between underwater acoustic propagation and terrestrial radio propagation may call for new criteria for the design of networking protocols. In this paper, we focus on some of these fundamental differences, including attenuation and noise, propagation delays, and the dependence of usable bandwidth and transmit power on distance (which has not been extensively considered before in protocol design studies). Furthermore, the relationship between the energy consumptions of acoustic modems in various modes (i.e., transmit, receive, and idle) is different than that of their terrestrial radio counterparts, which also impacts the design of energy-efficient protocols. The main contribution of this work is an in-depth analysis of the impacts of these unique relationships. We present insights that are useful in guiding both protocol design and network deployment. We design a class of energy-efficient routing protocols for underwater sensor networks based on the insights gained in our analysis. These protocols are tested in a number of relevant network scenarios, and shown to significantly outperform other commonly used routing strategies and to provide near optimal total path energy consumption. Finally, we implement in ns2 a detailed model of the underwater acoustic channel, and study the performance of routing choices when used with a simple MAC protocol and a realistic PHY model, with special regard to such issues as interference and medium access.