Enabling Intelligent Handovers in Heterogeneous Wireless Networks

In the future Wireless Internet, mobile nodes will be able to choose between providers offering competing services at a much finer granularity than we find today. Rather than months, service contracts may span hours or minutes. Connectivity, however, is just one of many possible services. Providers will begin to offer network and application-level services targeted at improving the overall wireless experience of the user. Determining the best path through the various networks will require accurate information describing which services are being offered by each provider. In this paper, we model the process of propagating this information as an instance of a distributed, hierarchical cache. Access routers actively discover and collect information about the immediate network neighborhood on behalf of mobile nodes. Mobiles fill their own caches through queries to their local access routers, and then employ the cached information to make informed, intelligent handover decisions. Through simulation, we show that high cache hit rates at the mobile node can be achieved even when the discovery process at the access router is incomplete. In comparison to static and centralized approaches, our dynamic approach requires less configuration and maintenance, avoids single points of failure, and provides a scalable solution that spans administrative domains. Robert C. Chalmers received his B.S. in Computer Science from the California State Polytechnic University, Pomona in 1997, and his M.S. in 2003 from the University of California in Santa Barbara. He is currently a Ph.D. candidate at the University of California in Santa Barbara where his main research interests focus around leveraging intelligence within the network. Particularly, he has studied multicast and its effect on resource utilization, as well as how to provide services for small, mobile devices in edge networks. He was awarded the Ericsson Fellowship in 2001 and is currently a Eugene Cota-Robles Fellow. Govind Krishnamurthi received an M.S. (Electrical Engineering) and Ph.D. degree (Computer Engineering) from the University of Washington and the Iowa State University, in 1997 and 1999 respectively. He spent the summer of 1995 as an intern at Bellcore, Morristown, NJ. He is a recipient of the Research Excellence Award from the Iowa State University for his Ph.D. thesis. Since the summer of 1999 he has been a Senior Research Engineer at the Nokia Research Center, Boston, MA. He has authored several publications and holds 3 patents. His current interests deal with QoS, location based services and security issues in IP based wireless networks. Kevin C. Almeroth earned his Ph.D. in Computer Science from the Georgia Institute of Technology in 1997. He is currently an associate professor at the University of California in Santa Barbara where his main research interests include computer networks and protocols, multicast communication, large-scale multimedia systems, and performance evaluation. At UCSB, Dr. Almeroth is a founding member of the Media Arts and Technology Program (MATP), Associate Director of the Center for Information Technology and Society (CITS), and on the Executive Committee for the University of California Digital Media Innovation (DiMI) program. In the research community, Dr. Almeroth is on the Editorial Board of IEEE Network, has co-chaired NGC 2000, Global Internet 2001, NOSSDAV 2002, and MMNS 2002; has served as tutorial chair for several conferences, and has been on the program committee of numerous conferences. Dr. Almeroth is serving as the chair of the Internet2 Working Group on Multicast, and is a member of the IETF Multicast Directorate (MADDOGS). He is also serving on the advisory boards of several startups including Occam Networks, NCast, Hidden Footprint, and the Santa Barbara Technology Incubator.