Full-Duplex Directional Collision Avoidance Medium Access ControlProtocol for Underwater Acoustic Networks br

A great improvement in Underwater Acoustic Network (UAN) has been witnessed in past few years,but severe challenges still remain, and energy efficiency becomes the primary consideration of UAN. In addition,the reliability and effectiveness of underwater acoustic communication technology are seriously restricted by thelarge propagation delay of the underwater acoustic channel and the limitation of available bandwidth, and theperformance of UAN is limited. Through the ability to focus a beam, the above challenges can be effectivelyaddressed by directional communication technology, resulting in a higher communication range and signal-to-noise ratio than omnidirectional communication, as well as energy consumption efficiency and spatial reuseratio of the whole network are improved. However, a priori knowledge of the location of the destination node isrequired and the problem of deafness occurs. Therefore, the Full-Duplex Directional Collision Avoidance(FDDCA) Medium Access Control (MAC) protocol is proposed in this paper, with which the problem ofdeafness is resolved by using two transducers that work in omnidirectional and directional modes, respectively,as well as the exposed terminal problem. Results supporting the conclusions are shown in the simulations,where 90% and 94% energy savings, 140% and 400% throughput improvements are acquired in differentnetwork topologies by FDDCA, compared with UnderWater Aloha (UW-Aloha) and Slotted FAMA (S-FAMA)protocol