E2RIC: Energy-Efficient Receiver-Initiated Cooperative MAC Protocol for IoUT Networks

In the field of exploration and monitoring the underwater environment, the Internet of Underwater Things (IoUT) shows a significant influence nowadays. Due to the challenging IoUT environment, medium access control (MAC) protocols designed for traditional terrestrial networks cannot perform effectively in IoUT networks. Long propagation delay, high channel fading and limited bandwidth refrain radio waves to underwater usage. To overcome these limitations, acoustic waves are preferred. Moreover, a sensor has limited energy and battery replacement is not easy under water. Hence, retransmission and multiple transmission concept-based MAC protocols designed for IoUT networks are found energy inefficient due to suffering from higher transmission delay, lower bandwidth utilization and longer duty cycle. In this paper, we propose an Energy-Efficient Receiver-Initiated Cooperative (E2RIC) MAC Protocol for IoUT Networks where the data receiver is an autonomous underwater vehicle (AUV). To ensure energy efficiency, communication reliability and higher sensor lifetime, the AUV selects an optimal cooperator/relay for each of the sender nodes to perform cooperative data communication by eliminating retransmission and multiple transmission concepts. In comparison to the state-of-the-art MAC schemes, the proposed E2RIC-MAC protocol exhibits considerable improvements in terms of energy consumption, overall network throughput, and end-to-end latency.