Zone based seamless vertical handoff technique between WiFi and WiMax

Abstract

Due to small cell size deployment of IEEE 802.11 WLAN is limited to buildings and small campuses. User moving out of the coverage area of AP gets disconnected from WLAN. IEEE 802.16 is a WMAN technology which is gaining popularity because of its good bandwidth and wide coverage area. For seamless mobility, the coverage area of WLANs may be made to fall within the coverage area of a WMAN. User devices having both WLAN and WMAN interfaces can perform vertical handoff to WMAN while moving out of range of WLAN network. Devices needs to perform network entry process while joining a WMAN and requires considerable time to handoff from WLAN to WMAN. For real time applications like VoIP, handoff latency needs to be within 50 ms. In this paper we propose a scheme where vertical handoff latency is reduced to zero. © 2011 Springer-Verlag.