Analysis of Energy Efficiency and Power Saving in IEEE 802.15.4

The limited bandwidth and the finite battery power of mobile devices represent one of the greatest limitations of current WPANs. In this paper, an analytical model for the energy efficiency of the IEEE 802.15.4 slotted CSMA/CA which can be studied as slotted non-persistent CSMA was proposed and validated. Key to the accuracy of the model is a careful study of the idle period after last collision, which has been studied by Zhang et al. (2006). Specifically, a distributed mechanism to improve the energy efficiency for contention control in IEEE 802.15.4 was also present and evaluated and show that power saving and throughput maximization can be jointly achieved. Simulation results indicate that our mechanism is very effective and robust. This mechanism can be used to extend the standard 802.15.4 access mechanism without requiring any additional hardware.