Determination Of Vertical Handoff Time In Heterogeneous System

The innovative research and fast progressing of wireless networking and communication technologies has formed different types of wireless systems (e.g., Bluetooth, IEEE 802.11, UMTS, and satellite networks). These are overlapping networks and are composed of a hierarchical structure ranging from in room to in-building, campus, city, metropolitan, and wide-areas. The motivation to coordinate with each other is provide ubiquitous high-data rate services at anywhere anytime anyway the best network to mobile users. Recently, the combination of different wireless technology is hot issue in wireless world. Not only is that, the service continuity and seamless mobility another key issue for handover in Next Generation Wireless System. For these networks to work as a seamless interworking, optimal mobility management has to be implemented. The traditional horizontal handoff between cells of the same network is not enough for that, as result vertical handoffs between different networks have more impact on system performances. One of the important challenges for seamless vertical mobility is to maintain a user active connectivity while the user is changing its point of attachment. For this the user must have to detect the exact time for handover so that the Mobile Node can connect to the new Base Station without loosing the data packet. In this paper, I developed a Vertical handover time detection mechanism to perform handover seamlessly.Here I use a Vertical Handover Decision Function to select the best network. Then policy based handoff is discussed. The first and main parameter to design a policy is Received Signal Strength (RSS). But the RSS is fluctuated by various fading and path loss. So, to determine the correct RSS I use the Least Square Approach and figure out it on a graph. The value is then used to determine the adaptive threshold also using the MN's speed. This graph not only shows the RSS value but also shows the"Expected Time to be Lost of RSS"value. As a result, the Mobile Node can take right decision to perform the Vertical Handover.