Sub Cluster Aided Data Collection in Multihop Wireless Sensor Networks

Clustering is an effective approach to achieve prolonged network lifetime, high energy efficiency and scalability in wireless sensor networks (WSNs). In many real world scenarios, due to the limited communication range of sensor nodes, the cluster heads have to forward their collected data back to the sink via multihop routes. In such cases, data from some nodes are first collected by a cluster head farther away from the sink, and then relayed back towards the sink. Such back and forth data transmission wastes precious energy in WSNs. In this paper, we present the novel concept of sub cluster for energy efficient data collection and relay. The utilization of sub clusters is proved beneficial whenever a clustering scheme is implemented in the context of whatever multihop routing protocols. We propose a protocol, SAIC (sub cluster aided interest-driven clustering) to realize this concept. SAIC is then extended to support a sink moving in discrete pattern. We analyze the benefit of introducing sub clusters, and demonstrate its gain in terms of energy efficiency in simulation. Attractively, a mobile sink boosts the benefit of sub clusters.