Global versus Local Re-Association Approach to Extend the Lifetime of Large-Scale IEEE 802.15.4/ZigBee Wireless Sensor Networks

Thanks to recent technological improvements, new products using the Wireless Sensor Networks (WSNs) are used to control some real world physical phenomena. A wireless sensor network consists of a large number of nodes with limited energy source. Lifetime of such a network is strongly dependent on the lifetime of its nodes´ batteries. However, to successfully achieve their mission, WSNs should meet a required lifetime. The ZigBee Alliance and the IEEE 802.15.4 standard afford a complete protocol stack providing key features that typically fit the requirements of WSNs. This protocol defines the association procedure that allows the sensors to self-organize into a resulting topology through which data can be routed toward their destination. It defines also a re-association procedure performed only by orphaned devices. In this paper, we propose new association approaches designed to optimize the initial topology formation of IEEE 802.15.4/ZigBee network. We propose global and local re-association approaches in order to balance the energy consumption over time and extend the network lifetime accordingly. Then, we use simulation to highlight the efficiency of our proposals in terms of energy conservation and packet delivery for IEEE 802.15.4/ZigBee sensor networks. Compared to the global re-association approach, the local one can deal with the network scalability which is a major characteristic of WSNs.