A New QoS Architecture for Performance Enhancement of IEEE 802.11e EDCA by Contention Window Adaption

Wireless Local Area Network (WLAN) has become ubiquitous and is being used to access multimedia services. After the success of 802.11 wireless network standards in the industries, quality of service (QoS) issue in wireless channels became one of the main areas of the research. Compared to the wired networks wireless networks have more limitations in terms of QoS. There have been many proposals addressing end-to-end QoS guarantee in 802.11 WLAN. IEEE 802.11e standard addresses these QoS requirements of WLAN [7]. It provides enhancements to the medium access control (MAC) layer protocol for supporting both prioritized and parameterized traffic between a QoS station (QSTA) and QoS access point (QAP). A thorough investigation is made about the issues of QoS in 802.11 WLAN and the techniques to address these QoS requirements such as bandwidth and delay with different approaches like differentiated service and integrated service are adapted [3]. In this paper we have proposed an algorithm using IEEE 802.11e standard by collision avoidance and adaptively adjusting the Contention Window (CW) for enhancing the QoS of IEEE 802.11 WLAN channel.