An energy efficient medium access control protocol for target tracking based on dynamic convey tree collaboration in wireless sensor networks

Collisions and interferences among nodes pose a challenge for data aggregation in many applications, such as target tracking by adopting dynamic convey tree-based collaboration (DCTC). Because coordination with a time division multiple access (TDMA) medium access control (MAC) might provide an opportunity for better interference control, in this paper, we refine slot allocation to nodes in a dynamic convey tree and design an energy efficient MAC protocol called dynamic-time division multiple access (D-TDMA). The D-TDMA protocol avoids collisions and interferences and allocates contiguous active slots to nodes as far as possible during data aggregation from leaf nodes to a root node. As a result, energy consumption in switching from sleep to active state is saved. In comparison with Always-On scheme, theoretical analysis results show that the proposed protocol D-TDMA improves energy efficiency by up to 28.3% during one data aggregation. Furthermore, simulation results show that D-TDMA does not suffer from collisions and interferences among nodes in a dynamic convey tree and performs similar throughput to that of Always-On scheme. Because of its advantage of parallel and continuous scheduling among node pairs in the convey tree, D-TDMA outperforms efficient slot reservation in both energy efficiency and low delay because of to slot saving. Copyright (c) 2012 John Wiley & Sons, Ltd.