Abstract: The IEEE802.16e provides a technique called "sleep mode" to save the energy consumption of the MSS and a standard sleep mode control algorithm is given.This paper proposes an improved sleep mode control algorithm，which adjusts adaptively the sleep mode interval according to the traffic rate.Then this paper compares the 802.16e standard algorithm and the improved algorithm under four actual models.It has been observed that the proposed algorithm for sleep mode saves substantial amount of energy at lower traffic and almost same at higher traffic as compared to 802.16e.