Improvement Of Qos Over Wlans Using Packet Scheduler

The demand for end-to-end Quality of Service (QoS) in Wireless Local Area Networks (WLANs) is becoming ever more important due to the trend towards converged communication networks. However satisfying QoS in WLANs is more challenging than wired networks due to the interference, the mobility of Stations, and channel fading. There are limitations in the recent version WLAN IEEE802.11e providing fairness to different types of traffic. In the shared channel, fair bandwidth assignment is important to insure an acceptable level of QoS and prevent starvation of traffic.This thesis proposes a dynamic packet scheduler in order to insure fairness in WLANs so to provide Quality of Service to applications, by combining three packets schedulers, Weighted Fair Queueing (WFQ), Weighted Round Robin (WRR), and First In-First Out (FIFO). The different traffics classes are mapped into priority levels and weights at the call admission, Real-time traffic uses a Weighted Fair Queueing algorithm specially adapted to the wireless medium. The non-real time uses a Weighted Round Robin scheduler with an adaptation for wireless compensation. The remaining traffic uses a First In- First Out scheduler that is the best effort service.A evaluation of the proposed scheduler through simulation environment using two types of traffics, CBR traffic and a ftp traffic and then followed by a comparison with the Weighted Fair Queue (WFQ) are done. The simulation results show that proposed scheduler provide a minimum delay guarantees to real-time applications better than the Weighted Fair Queue, so maintaining a acceptable end-to-end delay level.