Topology upgrading method for energy balance in scale-free wireless sensor networks

Scale-free can be seemed as one of the most impacting discoveries in complex networks theory and has already been successfully proved to be highly effective in constructing error-tolerant topology structures of wireless sensor networks (WSNs). As in scale-free WSNs, a few key nodes possess most connections, requiring them to take excessive message-relay tasks. Due to this reason, the energy of these nodes would be depleted much earlier than other sensor nodes, threatening the lifetime of the entire network. In this paper, we propose a topology upgrading method by referencing the concept of small-world. In our method, we present a novel node centrality metric-Directed Betweeness Centrality (DBC) to locate the key nodes and a network centrality metric- Directed Betweeness Network Entropy (DBNE) to measure the energy balance level of the network. Based on DBNE, we propose a shortcut deploying scheme to promote the energy distribution of the network more uniform. The simulations have shown that our scheme is able to improve the energy balance level of the network significantly.