A Survey on Medium Access Control in Underwater Acoustic Sensor Networks

A medium access control (MAC) protocol permits the nodes to access the shared medium by providing contention resolution mechanism. The design of MAC protocol in ad hoc networks becomes a more challenging task due to the interruptible energy source or limited battery life of nodes. This brings energy efficiency as the preliminary goal of the MAC protocol. MAC protocol for underwater acoustic sensor networks (UWASN) has to face even more challenges; many of them are due to the harsh underwater channel. Recently, a number of MAC protocols have been proposed for UWASN and selection of a suitable protocol has a great impact on the system efficiency. In this paper, we first highlight the unique aspects of acoustic channel and the problems associated with the MAC layer in UWASN. Existing MAC solutions for UWASN and open research issues are investigated and the summary of the protocols is provided to see the performance against different parameters considered in UWASN applications for selection of protocol.