Applying Retirement-Planning Strategy to Sensor Networks: An Integrated Approach to Energy-Aware Medium Access

This report addresses the design of distributed medium access control (MAC) protocols for wireless sensor networks under the performance measure of network lifetime. Integrated in the design of MAC schemes are two key physical layer parameters: the channel state and the residual energy of each sensor. The impact of incorporating these parameters in MAC design on network lifetime is studied. Furthermore, we show that a lifetime-maximizing protocol should dynamically trade off the channel state information (CSI) and the residual energy information (REI) according to the age of the network. Specifically, lifetime-maximizing protocols should be more opportunistic by prioritizing sensors with better channels for transmission when the network is young and more conservative by favoring sensors with more residual energies when the network is old. Following this general design principle, we propose a dynamic protocol for lifetime maximization (DPLM) that exploits both CSI and REI. Analytical results are provided to demonstrate the dynamic property and the asymptotic optimality of DPLM.