Research Journal of Applied Sciences, Engineering and Technology 3(9): 1022-1025, 2011 ISSN: 2040-7467 © Maxwell Scientific Organization, 2011 Submitted: July 26, 2011 Accepted: September 07, 2011 Published: September 20, 2011 Corresponding Author: Syed ZainRaza Mehdi, Department of Computer Science COMSATS Institute of Information Technology, Wah Cantt, Pakistan 1022 Minimizing Latency During Handover Between UMTS, WiFi and WiMAX Networks 1 Syed Zain Raza Mehdi, 1 Ehsan Ullah Munir, 2 Waqas Anwar and 1 Wasif Nasir 1 Department of Computer Science, COMSATS Institute of Information Technology, Wah Cantt, Pakistan 2 Department of Computer Science, COMSATS Institute of Information Technology, Abbottabad, Pakistan Abstract: Applications running on mobile networks have different requirements. Thus it is very difficult to provide best services even during vertical handoff. IEEE 802.21 provides a very good framework using Media Independent Handoff (MIHF). In this paper we have proposed a system for Vertical Handoff by enhancing the capability of Link Going Down event to take decision fast and selecting best interface. The system takes into account the user preferences, application requirements, lower layer network information and make decisions depending on that information. This system will allow the mobile terminals to be always best connected and provide seamless mobility in vertical handoff. Key words: Correspondent node, mobile node INTRODUCTION Emerging technologies have introduced new mobile devices with multiple-interfaces. New technologies will work together to allow mobile users to seamlessly roam between heterogeneous networks. These mobile devices will be able to provide applications with high usability. We need to provide high bandwidth and good resources for these applications to run in a good manner. In wireless communication it is very challenging task to provide multimedia services such as, VoIP, Video Streaming, High data rate connectivity during handover between multiple technology networks. When a mobile user changes its location from one place to another then it is called handoff. Handoff within a network is called Horizontal Handoff. Handoff between two networks is called Vertical Handoff as shown in Fig. 1. To achieve seamless vertical handoff, decision making plays an important role. It describes how and when to make a handoff decision. The received signal strength is the main handoff metric in traditional handoff. However, it is not enough to make a handoff decision in case of vertical handoff. These metrics may include available bandwidth, cost of service, and user preferences. An efficient vertical handoff decision algorithm becomes a challenge to develop for optimal resource utilization with diverse QoS support. The vertical handoff can occur any time and may not take place only at the cell edge. It can execute even when the Mobile Node (MN) does not move, depending on the network conditions and user preferences or in case of network congestion. The main part of this kind of vertical handoff is to make a decision to trigger a handoff according to the application requirements and user preference. Therefore, an effective and efficient vertical handoff decision algorithm in the interworking between 802.11, 802.16 and UMTS is needed to maximize the resource utilization. In order to allow users to take advantages of multiple interfaces and allow them seamless mobility, IEEE has introduced a standard 802.21 Media Independent Handoff; it allows mobile interfaces to connect to multiple interfaces and providing vertical handoff independently. LITERATURE REVIEW The integration of UMTS, WLAN, WiMAX to provide seamless mobility with minimum delay and merging these technologies to provide continuous communication as all are diverse technologies is very Fig. 1: MN seamless movement between networks.