Optimal Cluster Head Rotation for Heterogeneous WSNs

Heterogeneous Wireless Sensor Networks (WSNs) are an essential part of the Internet of Things (IoT). WSNs are composed of battery powered devices with limited processing capabilities in terms of CPU, memory and transmission range. As opposed to homogeneous WSNs where nodes are all equal, heterogeneous ones are composed of nodes that can have different initial energy, different transmission rate and different transmission range. Since devices are battery powered gathering data in an energy efficient way is essential. Clustering is one of the approaches that has been proposed by the research community in order to collect data in an energy efficient way. That requires to organise the WSN into various sets that are clusters. Each cluster has a representative node that is the cluster head (CH). This gathers data from the cluster members and forwards them to the BS. Beside clustering, the rotation of the CH role is a standard means to better distribute energy consumption. In this paper we propose an Optimum Rotation Scheduling (ORS) that is based on Integer Programming. We assume the WSN has been already clustered by using some clustering scheme. We then apply to each cluster a novel Integer Linear Programming formulation in order to define a cluster rotation that produces the optimum cluster lifetime.