Experimental testbed for investigating IEEE 802.11 handoff in vehicular environment

Wireless networks based on the IEEE 802.11 standard have become very prevalent recently. Most of these networks support only nomadic mobility of wireless devices. However, in case of vehicle-to-infrastructure communications the mobile devices in the vehicles need to have the ability to quickly switch their association to a new access point (AP) when they move out of range of their initial access point to ensure seamless connectivity. The handoff latency in vehicular environments can be improved if the mobile device has prior knowledge about the channels that access points in its vicinity are using. This paper describes a testbed for testing vehicle-to-infrastructure communications and gives experimental results showing improvement in handoff latency with prior knowledge of channels to scan.