An Efficient Routing Protocol and Void Avoidance Algorithm for Underwater Sensor Networks

More than 70 percent of Earth is covered with water, while human knowledge of the underwater environment is negligible compared to the land. Underwater wireless acoustic sensor network (UWASN) is one of the newest technology to investigate the underwater. UWASNS is a subdivisions of WSNs in which a variable number of autonomous and self-organize sensor nodes and vehicles are deployed manually or randomly in interested area in underwater environment in order to collect special information from deep or shallow water and transmit it to the surface sink(s). These nodes are equipped with acoustic modems to communicate with each other. Communication via acoustic in underwater has some challenges such as Doppler spread, high propagation delay, multi-path, noise, high energy consumption, low bandwidth, and high path loss. In addition, three dimensional nature and dynamic topology of underwater turn it to a complex and new area for research. Although many routing protocols have been proposed in tressteril wireless sensor networks (Tressteril WSN), these protocols cannot be used in the underwater environment due to aforementioned challenges and routing in underwater environments is in its infancy End-to-end routing is inapplicable in UWASNs due to high movement of nodes by water current while greedy hop-byhop routing is most promising approach in this environment. Greedy hop-by-hop routing is divided into location-based and location-free category. Due to inapplicability of GPS in UWASNs, finding a location information of nodes is so expensive. Therefore, the aim of this research is to design efficient greedy locationfree routing protocols which handle the mobility of nodes with water current. Furthermore, an algorithm will be designed to handle the communication voids in three dimensional underwater environment. KEYWORD Underwater sensor networks, routing, void handling