Energy-Aware Qos Scheduling at Mac Level in Wimax

Abstract

In a mobile wireless network, energy saving of mobile devices is one of the most important features for the extension of devices' life-time and the network. In mobile networks, the device is expected to have several connections, each with different QoS (Quality of Service) requirements. Meeting the QoS requirements on such devices along with better power saving is a challenging task. Moreover, in realtime scenarios, connections are expected to join and leave the network randomly. Before admitting a connection to the network, its QoS requirements must be checked to make sure that the network has adequate resources to accommodate it. Without a proper call admission control mechanism, the system cannot provide the promised QoS to the real-time applications. This research proposes a scheduling algorithm and a call admission control policy for IEEE 802.16e broadband wireless access standard. The proposed scheduling algorithm is designed towards minimizing power consumption at mobile stations, while maintaining different QoS requirements for real-time traffic. The proposed algorithm considers the dynamic nature of connection joining and termination. Connections will be allowed to join the network only if their QoS parameters can be met without violating those of existing connections. Simulation results show that when QoS delay requirements of the connections are not too restrictive, power savings of approximately 75% and 50% at the mobile station can be achieved for low- and moderate- rate Unsolicited Grant Service traffic types, respectively.