Abstract
Underwater Wireless Sensor Networks (UWSNs) are the most crucial method for exploring the hidden resources under the water. It enables many underwater applications, such as military, commercial, disaster prevention, ocean sampling, and other emergencies. Data transmission through a single relay node creates a hotspot, which will minimize the network lifetime and reduce the network reliability. Therefore, the cooperative technique is essential for transferring data between the source and the destination. This research proposes an improved version of Reliability and Adaptive Cooperation for Efficient (RACE), a well-known cooperative routing protocol for UWSNs known as RACE-SM. RACE-SM solved the single relay node issues by using the sink mobility scheme. All sensor nodes transfer data directly to the sink node if the sink node is in the communication range. Otherwise, sensor nodes use the cooperative combining strategies scheme to send the data from the source to the destination or sink node. The performance of the proposed method is then compared with the current protocols. The simulation results show that the RACE-SM outperforms in average up to 40.60%, 59%, 278%, and 77% than current protocols in terms of alive nodes, energy consumption, packet delivery ratio (PDR), and end-to-end delay respectively.