A Fast MAC Mechanism for Handoff Process in Heterogeneous Wireless Networks

Next generation wireless communications will likely rely on integrated networks consisting of multiple wireless technologies. Hybrid networks based, for instance, on systems such as WMAN and WLAN can combine their respective advantages on coverage and data rates. WLAN is provided in hotspots, places like coffee bars, airports, shopping centers etc. where the hotspots are covered by access points. As the mobile node moves, it may leave the current wireless network and enter another wireless network; vertical handoff should be taken to the new network so as to maintain the current connection. Existing methods require more time for the vertical handoff process, which causes serious problems for multimedia applications. Vertical handoff delay should be minimum to have seamless vertical handoff communication. To achieve seamless handoff communication a Layer2 handoff method is proposed. In this method, a mobile with two radios of dualmode capability, and WLAN having the extended region capability is used. The second interface is switched between 802.16 and 802.11 to know ahead to which network it is about to enter. Mobile node comes to know about its nearby network before actually entering the network, thereby reducing vertical handoff delay, making it suitable to seamless vertical handoff Communication. Keywords-Horizontal handoff, Vertical handoff, IEEE 802.11, WiMax.