Scheduled power-saving mechanism to minimize energy consumption in IEEE 802.16e systems

A mobile station in IEEE 802.16e operates power management using sleep-mode operation with one or more connections supporting several applications. After all of the connections of an MS transit into the sleep state, the MS powers down and then goes into an unavailable state without communicating with the serving base station. To improve energy conservation, this letter proposes a new scheduled power-saving mechanism, which schedules sleep-mode operations for connections, which newly initiate sleep-mode, by controlling operating parameters, such as the minimum sleep interval (T_min) and the maximum sleep interval (T_max), and the initiation time of sleepmode operations of low quality of service (QoS) connections. Performance results show that the proposed mechanism can reduce the available state of an MS through this scheduling, and thus achieve better energy conservation of the MS than the standard mechanism.