Remaining Energy-Aware Power Management Mechanism in the 802.16e MAC

The sleep-mode operation in power management helps to increase the life of a mobile station by saving energy consumption while it increases the MAC service data unit (SDU) response delay. Due to the trade-off relationship between these two performance metrics, it is important to determine the suitable values for two operating parameters, the initial sleep interval (T_min) and the final sleep interval (T_max), which manipulate the sleep-mode operation in the IEEE 802.16e MAC. To reach a fuller understanding of this problem, this paper first presents the sleep-mode operation. A new power management mechanism based on the knowledge on remaining energy in a mobile subscriber station (MSS) is then proposed. Benefits of this mechanism are to reduce the MAC SDU response delay under sufficient energy and to increase the life of a station under insufficient remaining energy. An analytical model for sleep-mode operation is developed, and the proposed mechanism is validated by computer simulation.