Mobility management techniques for heterogeneous wireless networks

This research investigates internetworking challenges that need to be addressed to enable seamless mobility in next-generation heterogeneous access environments. The primary objective of this dissertation is to explore the issues related to mobility management in diverse wired/wireless networks. Handoff management is one of the most important issues for mobility across heterogeneous wireless networks. In this work, we investigate and propose various handoff management solutions for achieving smooth mobility across different access technologies such as cellular (UMTS, GPRS), Wireless LANs, etc.;It is imperative to design architectures that efficiently and cost-effectively integrate various wide area and local area wireless networks. In this research, we develop a handoff management approach based on soft handoff techniques that achieves a low-latency network transition between cellular and Wireless Local Area Networks.;Discovering available wireless networks is an initial and essential requirement of a handoff procedure. Many wireless devices provide hardware and software support for many network access interfaces. However, switching the right interface on at a particular time, is one of the key factors that contributes to the power efficiency of the wireless device. To address this issue, we developed and investigated a cell-id based location-management technique that has a low wireless discovery time, and increases the battery time of wireless devices by eliminating the need to keep all interfaces on at all times for discovering available wireless networks.;With the increasing deployment of a variety of wireless access networks, wireless devices face the challenge of selecting the most suitable network from a set of available access networks. There exist a wide set of criteria that affect the selection of an appropriate access network. In this research, we investigated various factors that can influence a handoff decision for mobile users. We also developed and demonstrated how a wireless device can implement network selection using a numerous parameters such as the Quality of Service (QoS) offered by each network, the cost of services, the minimum QoS requirements of applications actively running on the mobile device, the preferences specified by the end-user, and other dynamic factors such as the wireless signal perception of the mobile device, and the power requirement of each network interface.;The proper execution of a handoff for switching access networks plays a significant role in the success of mobile services for end-users. To provide efficient support for mobile multimedia applications as well as for seamless network connectivity, it is important that handoff delays are minimized. In this dissertation, we explored the use of Mobile Agent technology for implementing fast handoffs. We investigated and developed a handoff implementation technique that makes Mobile Agents migrate over the wired network from one network access point to another and carry with them the required service parameters necessary to enable a wireless device to quickly reestablish network connectivity and services through the new network. We conducted experimental tests in a real wireless networking testbed which revealed that by deploying Mobile Agents, it is possible to achieve much lower handoff delays as compared to conventional messaging techniques.