关键词: IEEE 802.16e, 节能类型I, 休眠模式, 休眠延迟, 休假排队

Abstract: In mobile broadband MAN，how to control energy consumption is one of the most important issues for mobile stations.IEEE 802.16e proposes an energy saving mechanism named as sleep mode for mobile stations.Based on power saving class of type I with sleep-delay，a queuing model with multiple exponential vacations and a sleep-delay is built.By employing an embedded Markov chain method and boundary state variable theory，the queuing model is analyzed，and the expressions for the performance measures in terms of handover ratio，energy saving ratio and average response time for the power saving class of type I are presented.In numerical results，the dependency relationships are investigated between the system performance measures and the length of the sleep-delay timer for different system loads.Furthermore，a cost function is built considering all the performance measures，and an optimal design proposal for setting the system parameters is given.

Key words: IEEE 802.16e, power saving class of type I, sleep mode, sleep delay, vacation queue