Virtual Contention Window Based Scheme for Service Differentiation Over IEEE 802.11 Wireless LAN

This paper proposes a simple but effective scheme for supporting quality of service (QoS) in IEEE 802.11 WLAN. A station will initiate a virtual contention process before every data packet from network layer being delivered to the 802.11 MAC layer. Service differentiation can be achieved by using different virtual contention windows. An analytical model is then presented for performance evaluation. Simulation results validate the analytical model. Our scheme requires no modifications at 802.11 MAC layer