SWER: small world-based efficient routing for wireless sensor networks with mobile sinks

The interest in small-world network has highlighted the applicability of both the graph theory and the scaling theory to the analysis of network systems. In this paper, we introduce a new routing protocol, small world-based efficient routing (SWER), dedicated to supporting sink mobility and small transfers. The method is based on the concept of the small worlds where the addition of a small number of long-range links in highly clustered networks results in significant reduction in the average path length. Based on the characteristic of sensor networks, a cluster-based small world network is presented, and an analytical model is developed to analyze the expected path length. SWER adopts a simple and effective routing strategy to forward data to the mobile sink in a small transfer scene and avoid expensive mechanisms to construct a high quality route. We also study the routing scheme and analyze the expected path length in the case where every node is aware of the existence of p long-range links. In addition, we develop a hierarchical mechanism in which the mobile sink only transmits its location information to the cluster heads when it enters a new cluster. Thus we also avoid expensive cost to flood the location of the mobile sink to the whole network.