Fast and efficient vertical handoffs in wireless overlay networks

Mobile IP is used to keep track of location information and make the data available to the mobile device anytime, anywhere. It designed to address the macromobility management problem, it does not address microlevel mobility issues such as handoff latency and packet loss. In this paper, we propose a fast and efficient handoff scheme to handle the movements of mobile nodes among a different wireless network technologies. Our scheme combines: (a) A hierarchical mobility management architecture to hide mobility of mobile nodes within the foreign domain from the home agent, (b) The use of multicast as the packet forwarding mechanism from the getaway foreign agent to the base stations, (c) The use of our proposed virtual cells in order to reduce the upward vertical handoff latency and disruption as much as possible. Our design is based on the Internet protocol (IP) and is compatible with the mobile IP standard (MIP). We also present simulation results showing that our handoff scheme is very fast and avoid packet loss.