CER-CH: Combining Election and Routing Amongst Cluster Heads in Heterogeneous WSNs

Heterogeneous Wireless Sensor Networks (WSNs) are essential to the IoT vision. WSNs implement a virtual layer that can gather data about the real world. WSNs are composed of wireless battery powered devices that can have heterogeneous features related to computational power, memory, and communication capabilities. Because devices are battery powered, gathering data in an energy efficient way is crucial for the lifespan of the network. Clustering is a reasonable solution. This organises the devices into sets (clusters). Each cluster has a cluster head (CH) that gathers data from the nodes belonging to its cluster and communicates with other CHs in order to report data to a centralised base station (BS). This is usually achieved via a CH routing tree that is rooted at the BS. Beside clustering, the rotation in the role of CHs amongst the nodes of the network is a standard means to better distribute energy consumption. In this paper we propose a novel approach (CER-CH) where the CH routing tree definition and the CH rotation are combined together. More precisely, starting from any clustering criteria, we propose a novel rotation heuristic combined with a novel top-down CH routing tree definition in order to balance the node energy consumption and generate more energy efficient CH routing trees. Our experiments show that our rotation strategy enhances on average the network lifespan of 20% when compared to the state of art protocols.