Adaptive packet scheduling for the uplink traffic in IEEE 802.16e networks

摘要

IEEE 802.16e is a telecommunication standard technology designed to support a wide variety of multimedia applications. It defines five service classes, each one with its respective QoS requirements, but does not define the scheduling algorithm for these service classes. In this paper, an adaptive packet scheduling algorithm for the uplink traffic in IEEE 802.16e networks is proposed. This algorithm is designed to be completely dynamic, mainly in networks that use various modulation and coding schemes (MCSs). The algorithm is applied directly to the bandwidth request queues in the base station (BS) and aims at supporting the real-time and non-real-time applications. Using a cross-layer approach and the states of the bandwidth request queues in the BS, a new deadlines based scheme was defined, aiming at limiting the maximum delay to the real-time applications. Moreover, this algorithm interacts with the polling management mechanisms of the BS and controls the periodicity of sending unicast polling to the real-time and non-real-time service connections, in accordance with the QoS requirements of the applications. The proposed algorithm was evaluated by means of modeling and simulation in environments where various MCSs were used and also in environments where only one type of modulation was used. The simulations showed satisfactory results in both environments.