Energy-Efficient Collision Avoidance MAC Protocols for Underwater Sensor Networks: Survey and Challenges

The Medium Access Control (MAC) layer protocol is the most important part of any network, and considered to be a fundamental that aids in enhancing performance networks communications. However, MAC protocol’s design for underwater sensor (UWSNs) has introduced various challenges. This due long acoustic propagation delay, high mobility, low available bandwidth, error probability. These unique channel characteristics make contention-based protocols significantly more expensive than other contentions. Therefore, re-transmission collisions should effectively managed at decrease energy cost enhance network’s throughput. Consequently, handshake-based random access-based do not perform as efficiently their achieved terrestrial networks. To tackle this complicated problem, paper surveys current collision-free proposed literature UWSNs. We first review characteristic its negative impact on layer. It then followed by discussion about problem definition, challenges, features associated with UWANs. Afterwards, currently strategies UWSNs are classified investigated. advantages disadvantages each strategy along recent advances presented. Finally, we present qualitative comparison these also discuss some possible future directions.