Forming priority based and energy balanced ZigBee networks—a pricing approach

Abstract

ZigBee networks utilize a mixed routing method combining hierarchical/tree routing and Ad hoc On-demand Distance Vector (AODV) routing. Tree routing is a proactive routing scheme that routes packets from sensors to sink based on the parent-child relationships formed during network setup, while AODV is a pure on-demand route acquisition algorithm that broadcasts discovery packets when a route needs to be established. Studies in the open literature have shown that tree routing has many advantages over mesh routing in avoiding additional routing messages and the associated overhead, thus reducing latency and energy consumption. Nevertheless, currently the ZigBee network tree hierarchy is formed simply based on detecting signal strength and finding the available parent. There is no consideration taken into account of end devices' priorities and routers' energy levels. In this paper, we propose to utilize a pricing approach for forming a priority-based and energy-balanced ZigBee network. The approach is achieved through a distributed decision making process in which the requesting node tries to maximize its utility by requesting to join the parent with the least depth, and potential parents tried to maximize their revenues by rejecting nodes with payments lower than their charging rates and adjusting charging rate with each over-payment. We show that through this decision process, end devices of higher priority and routers with higher energy level are more likely to be assigned to parents with a less depth. Furthermore, we verify the improvement of network performance achieved by our pricing approach by showing that end devices of higher priorities achieve a shorter end-to-end delay compared to the case in which our pricing approach is not utilized.