An energy-efficient MAC protocol for underwater wireless acoustic networks

We propose a distributed, scalable, energy-efficient MAC protocol that works despite long, unknown propagation delays of the underwater acoustic medium. This protocol can be used for delay-tolerant applications such as underwater ecological sensor networks between energy-limited nodes. Our protocol differs significantly from ALOHA, MACA, and MACAW protocols in that energy is the main performance metric in our case rather than bandwidth utilization. It is shown that under a realistic underwater sensor network scenario, our proposed MAC protocol wastes only 3 percent of the transmit energy due to collisions, when an average number of 1-hop neighbors is 5, and the duty cycle is 0.004. This distributed, scalable MAC protocol has the potential to serve as a primer for the development of energy-efficient MAC protocols for future underwater sensor networks.