Enhanced power efficient sleep mode operation for IEEE 802.16e based WiMAX

To support battery powered mobile broadband wireless access devices efficiently, IEEE 802.16e defines a sleep mode operation for conserving the power of mobile terminals. In this paper we analyze the power consumption and the mean delay of IEEE 802.16e sleep mode operation with a theoretical Markov chain model. The analytical results show that there is a tradeoff between the power consumption and the mean delay, and the key of the tradeoff is the initial sleep window. Then, we present a heuristic algorithm to tune the initial sleep window dynamically according to the traffic load. Extensive simulation results show that the proposed algorithm can improve the power consumption up to 30% compared to the IEEE 802.16e standard. The price is just little increase of the mean delay. Therefore, the proposed algorithm provides a proper tradeoff between the power consumption and the mean delay