An Energy Efficient Scheduling Mechanism for Real-time Services in 802.16e

In the 802.16e system, when multiple mobile stations (MSs) with real-time services are in sleep mode, the QoS of data scheduling and the energy efficiency of sleep mode impact each other. Sleep mode will aggravate the competition of data transport of different MSs and decrease system’s QoS, while improper data scheduling policy will interrupt the sleep mode of MS and decrease the energy efficiency. To address this problem, an energy efficient scheduling mechanism is proposed. The proposed mechanism first focuses on the sleep mode’s impact on data scheduling. In order to smooth the input of BS scheduler, which is the data needed to transmit to the MSs, it tries to make the listening windows of different MSs lie dispersedly and do its best to balance the system load among OFDM frames. Then it considers the data scheduling’s impact on sleep mode. In order to increase the energy efficiency, it improves the widely used EDF mechanism to avoid scheduling MS’ data on its sleeping window by promoting the packets’ priority of the sleeping MS. The simulation result shows that the proposed mechanism can not only improve the energy efficiency but also decrease the signaling overhead while guaranteeing the QoS of the network.