Asynchronous Reservation MAC Protocol for Underwater Acoustic Sensor Network

Reservation is an efficient technique to avoid data packet collision and has been introduced to the underwater acoustic sensor network (UASN) MAC protocols recently. Usually synchronization among the sensor notes are required to schedule the transmitting and receiving time in the reservation. However, due to the high and variable propagation delay in the underwater acoustic channels, accurate synchronization is difficult to implement in the UASNs. In this paper, a new reservation based MAC protocol for the UASN is proposed, in which the synchronization requirement are loosed by employing an asynchronous reservation scheme. A sleep/wait-up mechanism is also incorporated into the reservation process to further reduce the energy consumption. Simulations show that the proposed protocol outperforms the CSMA-ALOHA and DACAP protocols in throughput, successful rate and energy consumption.