Energy considerations for MAC protocols in wireless sensor networks

We begin with a survey of energy-saving techniques proposed in the medium access control (MAC) layer, and then develop a framework to minimize energy consumption in wireless sensor networks. While satisfying a range of quality of service requirements, such as the packet transmission success rate and maximum delay constraint, we optimally choose the lengths of periods in which sensors are active and inactive, such that the energy consumption per unit time in the entire network is minimized. We first use our framework to optimize the values of the MAC attributes macBeaconOrder and macSuperframeOrder in an IEEE 802.15.4 beacon-enabled star network. Then we consider a much simpler protocol, which we call “select-and-transmit” (S&T), and the same framework is applied to find the optimal lengths of the active and inactive portions.