Distributed Minimum-Cost Clustering Protocol for UnderWater Sensor Networks (UWSNs)

In this paper, we study the node clustering problem in underwater sensor networks (UWSNs). We formulate the problem into a cluster-centric cost-based optimization problem with an objective to improve the energy efficiency and prolong the lifetime of the network. For this purpose, a cost metric is defined for a potential cluster, which takes into account three important parameters that are relevant to the energy status of the cluster, including (1) the total energy consumption of the cluster members for sending data to the cluster head; (2) the residual energy of the cluster head and its cluster members; and (3) the relative location between the cluster head and the underwater sink (uw-sink). To solve the formulated problem, a novel distributed clustering protocol called minimum-cost clustering protocol (MCCP) is proposed, which selects a set of non-overlapping clusters from all potential clusters based on the cost metric assigned to each potential cluster and attempts to minimize the overall cost of the selected clusters. MCCP can adapt geographical cluster head distribution to the traffic pattern in the network and thus avoid the formation of hot spots around the uw-sink. It can also balance the traffic load between cluster heads and cluster members through periodical re-clustering the sensor nodes in the network. Simulation results show that MCCP significantly improves the energy efficiency and the lifetime of a UWSN as compared with the well-known HEED protocol.