Distributed Mini-Clustering MAC Protocol for Improving Performance in Under Water Acoustic Sensor Networks
The characteristics of the underwater environments create new challenges for networking protocols.The underwater acoustic sensor network (UASN) is characterized by limited bandwidth and long propagation delays because it uses radio waves to transmit data packets. The limitations pose challenges to the MAC (Medium Access Control) protocol design. The handshaking based MAC protocol degrades the performance of the UASN due to the large delay in exchanging control and data packets.Also, as the number of nodes increases, the probability of collision increases and the performance decreases. In this paper, we propose a distributed mini-clustering (DMC) MAC protocol to solve the problem of performance degradation due to long propagation delay and high collision probability.In the proposed protocol, neighboring nodes form a mini-cluster and select a mini cluster header. Only the selected mini cluster headers perform channel contention to transmit packets to the destination node.After the mini-cluster header obtains the channel access right, it determines the schedule for the member nodes with data packets to be transmitted and notifies them. The member nodes transmit their data packets to the destination node at their scheduled times.In the proposed protocol, only the mini-cluster headers participate in the channel contention, not all the nodes, thereby reducing the collision probability and improving the network performance.
Keywords - Channel Contention, Collision, MAC, Mini-Cluster,UASN.