Noncooperative admission control for differentiated services in IEEE 802.11 WLANs

Recent developments in wireless LAN (WLAN) standardizations have been successful to offer high-speed data services. Hence, a variety of types of traffic must be accommodated in future WLAN environments. IEEE 802.11 working group has been developing a new distributed MAC, called enhanced distributed function (EDCF), to support service differentiation in the IEEE 802.11 MAC protocol. Besides, high-speed WLAN environments are also expected to provide wireless Internet services in hot spots such as airports, parks, and etc. Since there are usually multiple service providers competing for providing wireless network access in hot spots, mobile users are free to choose their own service providers. For a specific service provider, more flows are admitted to transmit in its coverage range, more revenue (e.g., utility or profit) is gained. However, admitting many flows may make the wireless medium overloaded and degrade the QoS satisfactions of ongoing flows since the wireless medium in IEEE 802.11 is share and collision-based. Hence some mobile users may leave the current service provider and subscribe to wireless network access with another service provider. In this paper, we analyze the resource management problem in the competitive environment, in which EDCF protocol is implemented in all access points (APs) and mobile stations. We formulate admission control as a game and prove the game owns a Nash equilibrium solution. Based on the game, a service provider not only fulfills most part QoS satisfactions of ongoing flows but also increases its own revenue. We evaluate the performance by means of throughput, packet delay and bandwidth violation ratio.