ENERGY EFFICIENT AND VOID AVOIDING ROUTING PROTOCOLS FOR UNDERWATER WIRELESS SENSOR NETWORKS

Abstract

Abstract Underwater wireless sensor networks (UWSN) are an active area of research and development. The underwater environment is harsh; acoustic channel characteristics such as high attenuation and absorption are an important challenge for the implementation of UWSNs. Void holes in networks, where a node can receive but cannot transmit to any node other than the sender, also present a significant challenge. This dissertation is motivated by these challenges and investigates solutions for energy efficient and void avoiding routing protocols for UWSNs. A proposed greedy routing protocol called Energy Efficient Depth-Based Opportunistic Routing (EEDOR) is designed and simulated. This protocol uses a novel holding time formula that incorporates both the priority of the candidate node and the depth difference between the packet sender and each candidate node of its forwarding set. The protocol uses a simple design that allows sensor nodes to form their forwarding sets by exchanging local information only. Nodes can collect information efficiently by listening and responding to forward request and forward reply messages. Simulation results show that the proposed protocol achieves significant energy savings as compared to popular protocols, thereby also extending network lifetime significantly. A void avoiding protocol called the called Energy Efficient Depth-Based Opportunistic Routing with Void Avoidance (EEDOR-VA) is also proposed. The novelty of this technique lies in employing a hop-count to determine paths between the source node and sink(s). Trapped and void nodes are recognized and eliminated from node forwarding sets. This protocol is shown to have a high packet delivery ratio (PDR). The protocol is evaluated using two different sets of simulation settings. Finally, the impact of the number of sinks and the sink deployment method on energy conservation and PDR is investigated. Simulation results show that using a deterministic multi-sink deployment can reduce the number of request and reply messages. As a result, the network overhead is reduced, decreasing the energy usage and increasing the PDR of the network.