Prevent-scan: A novel MAC layer scheme for the IEEE 802.11 handoff

Wireless networks, specifically those based on the IEEE 802.11 standard (Wi-Fi), are experiencing rapid growth due to their low cost and high-speed connectivity. To cover larger areas, many AP´s are required which need the use of handoff between different AP´s. Therefore, handoff latency has become essential issue in wireless LANs. This delay affects the quality of real-time applications like VoIP. In this paper we evaluate the performances of the prevent-scan solution. This technique is an improved fast handoff mechanism developed to minimize the overall handoff latency and enhance the quality of service (QoS) for multimedia streams. The prevent-scan evaluation is performed by using our new WHand-Sim simulator. We prove that this technique decreases handoff latency significantly and achieves both fast and smooth handoff that multimedia applications entail.