A Void-Avoidable and Reliability-Based Opportunistic Energy Efficiency Routing for Mobile Sparse Underwater Acoustic Sensor Network

Mobile and sparse underwater acoustic sensor networks (MS-UASNs) have attracted much attention due to their wide applications in various fields. However, MS-UASNs comes with intrinsic constraints because it is deployed in the aquatic environment and uses the acoustic signals to communicate. The sparse deployment and topology changes of the network leads to void areas that reduce packet delivery ratio. And the network efficiency is reduced and the lifetime of networks is shortened due to limited energy. Besides, the low speed of the acoustic waves produces high latency. Thereby, our proposed a void-avoidable and reliability-based opportunistic energy efficiency routing (VBOER) protocol is designed to achieve voids avoidance, energy fairness and improve reliability. First, the valid transmission areas (VTA) of the node are divided to avoid unnecessary transmission. Second, the novelty of VBOER is that the qualified forwarding nodes (QFNs) are determined by considering the continual degree (CD) and the life-time of nodes. Then, the VBOER shapes the node energy state prediction model and the node location state prediction model based on Markov chain. Finally, to achieve a balance between the energy efficiency and the network benefits, forward fitness value (FFV) of nodes is proposed, and an opportunistic routing protocol based on FFV is developed to coordinate packet forwarding. The verification of simulation results shows the effectiveness of our proposed VBOER in terms of packet delivery ratio, network lifetime and end-to-end delay in comparison to existing routing protocols.