An Energy-Saving MAC Protocol for Underwater Acoustic Sensor Networks Based on TDMA

To construct an efficient and reliable marine Internet of Things, there must be effective and dependable communication between underwater nodes. However, the underwater acoustic channel has significant peculiarities, mainly characterized by slow sound propagation speed, spatiotemporal uncertainty, narrow channel bandwidth, time-varying multipath, severe channel fading, exposed and hidden terminals, and limited energy. To address these issues, this paper proposes an energy-saving MAC protocol for three-dimensional environments, aimed at ensuring successful reception of data frames while minimizing collisions to save energy, and at the same time, ensuring a larger throughput and lower latency. This MAC protocol is implemented based on TDMA, divided into three stages.