ViFi: Virtualizing WLAN using Commodity Hardware

We consider an architecture in which the same WiFi infrastructure can be dynamically shared among multiple operators. Our system, ViFi, virtualizes WLAN resources, allowing for controlled sharing of both the uplink and downlink bandwidth. ViFi operates with stock 802.11 clients, and can be implemented entirely as a software add-on for commodity 802.11 APs. ViFi puts users (customers) of different operators in separate groups, each creating a virtual WLAN. ViFi guarantees proportional fair share of channel access time at group level, and isolates traffic between groups. The key technical contribution of ViFi is a useful form of virtualization without requiring changes to the underlying WiFi protocol.