Improving Both Energy and Time Efficiency of Depth-Based Routing for Underwater Sensor Networks

摘要

Underwater Sensor Network (UWSN) is a representativethree-dimensional wireless sensor network. Due to theunique characteristics of underwater acoustic communication,providing energy-efficient and low-latency routing protocols forUWSNs is challenging. Major challenges are water currents,limited resources, and long acoustic propagation delay. Networktopology of UWSNs is dynamic and complex as sensors havealways been moving with currents. Some proposed protocolsadopt geographic routing to address this problem, but three-dimensional localization is hard to obtain in underwater environment. As depth-based routing protocol (DBR) uses depthinformation only which is much more easier to obtain, it ismore practical for UWSNs. However, depth information is notenough to restrict packets to be forwarded within a particulararea. Packets may be forwarded through multiple paths whichmight cause energy waste and increase end-to-end delay. In thispaper, we introduce underwater time of arrival (ToA) rangingtechnique to address the problem above. To maintain all theoriginal advantages of DBR, we make the following contributions:energy-efficient depth-based routing protocol that reducesredundancy energy cost in some blind zones; low-latency depth-basedrouting protocol that is able to deliver a packet throughan optimal path. The proposed protocols are validated throughextensive simulations.