Performance Analysis for Power Saving Class Type II in IEEE 802.16e for Wireless MAN

Effective power saving mechanism is the most significant issue for extending the lifetime of mobile stations in wireless metropolitan area network (MAN). In this paper, we propose an effective method to analyze the system performance of the power saving class type II in IEEE 802.16e. We present a queueing model with two kinds of vacation mechanisms to capture the working principle of the networks with the power saving class type II. We also propose measure methods in terms of the energy saving ratio, the handover ratio and the average response time, and give the expressions for these performance measures. Moreover, considering both the energy saving ratio and the average response time, we develop a cost function to determine the optimal length of the sleep window for minimizing the total system cost. Numerical illustrations are provided to demonstrate the relationship between the system performance and the configuration parameters. The research in this paper provides a theoretical basis for improvement of the power saving class type II, and has potential application when solving other energy conserving related problems in wireless mobile networks.