Topology optimisation-based distributed estimation in relay assisted wireless sensor networks

This study studies a distributed estimation problem in relay assisted wireless sensor networks (WSNs). Different from most existing works, the network consists of two kinds of nodes, that is, sensor nodes (SNs) which is capable of sensing and computing and relay nodes (RNs), which is only capable of simple data aggregation. The problem of how to coordinate two kinds of nodes to facilitate distributed estimation is challenging because of their heterogeneous capability. The authors first develop a min-weighted rigid graph-based topology optimisation scheme to reduce the redundancy of communication links such that the energy consumption in the relay assisted WSN can be reduced. With the optimised topology, a consensus-based estimation algorithm is proposed for SNs and RNs, respectively. The asymptotic unbiasedness and consistency of the estimation algorithm are analysed in the presence of measurement and communication noises. The proposed method is applied to estimate the distribution of slab temperature in the hot rolling process. It is demonstrated that the topology optimisation reduces communication energy consumption, while the deployment of RNs improves temperature estimation accuracy as compared to a homogeneous WSN with SNs only.