Energy saving with multi-connections over IEEE 802.16e networks

This paper considers the energy saving problem of IEEE 802.16e networks which consist of a base station and multiple mobile stations. The mobile station may establish one or multiple connections that have specific QoS requirements, including a bandwidth requirement and delay bounds. Since the mobile station turns off the transceiver to save energy when all connections of the mobile station enter sleep mode. Hence, for minimizing the energy consumption of the mobile station has to schedule each connection efficiently according to the QoS requirements and its sleep cycle. The proposed problem is formulated as an ILP problem that minimize the total number of active frames to save energy. A heuristic algorithms, bandwidth reservation scheme (BRS), is also proposed to improve the computing efficiency. Our approaches not only guarantee the QoS for real-time connections, but also minimize power consumption of mobile stations. Simulation results demonstrate that BRS outperform the previous approaches in terms of energy saving and bandwidth utilization.