Dynamically anchored conferencing handoff for dual-mode cellular/WLAN handsets |
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Authors: | Mohammed Smadi Terence D Todd Vytas Kezys Vahid Azhari Dongmei Zhao |
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Affiliation: | (1) Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario, Canada;(2) Research In Motion Inc., Waterloo, Ontario, Canada |
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Abstract: | In this paper we consider vertical handoff for enterprise-based dual-mode (DM) cellular/WLAN handsets. When the handset roams
out of WLAN coverage, the DM's cellular interface is used to maintain the call by anchoring it through an enterprise PSTN
gateway/PBX. Soft handoff can be achieved in this case if the gateway supports basic conference bridging, since a new leg
of the call can be established to the conference bridge while the existing media stream path is active. Unfortunately this
requires that all intra-enterprise calls be routed through the gateway when the call is established. In this paper we consider
a SIP based architecture to perform conferenced dual-mode handoff and propose a much more scalable mechanism for short-delay
environments, whereby active calls are handed off into the conference bridge prior to the initiation of the vertical handoff.
Results are presented which are taken from a dual-mode handset testbed, from analytic models, and from simulations which characterize
the scalability of the proposed mechanism.
Mohammed Smadi received the B.Eng and Mgmt and M.A.Sc degrees in Computer Engineering from McMaster University in Hamilton, Ontario, Canada.
Mohammed received an NSERC doctoral award in 2005 and is currently a Ph.D. student at the Wireless Networking Group at McMaster
University.
Terence D. Todd received the B.A.Sc, M.A.Sc and Ph.D. degrees in Electrical Engineering from the University of Waterloo, Waterloo, Ontario,
Canada. While at Waterloo he spent 3 years as a Research Associate with the Computer Communications Networks Group (CCNG).
He is currently a Professor of Electrical and Computer Engineering at McMaster University in Hamilton, Ontario, Canada.
Professor Todd spent 1991 on research leave in the Distributed Systems Research Department at AT&T Bell Laboratories in Murray
Hill, NJ. He also spent 1998 on research leave at The Olivetti and Oracle Research Laboratory in Cambridge, England. While
at ORL he worked on the piconet project which was an early embedded wireless network testbed.
Dr. Todd’s research interests include metropolitan/local area networks, wireless communications and the performance analysis
of computer communication networks and systems. He is a past Editor of the IEEE/ACM Transactions on Networking and currently
holds the NSERC/RIM/CITO Chair on Pico-Cellular Wireless Internet Access Networks.
Dr. Todd is a Professional Engineer in the province of Ontario and a member of the IEEE.
Vytas Kezys was born in Hamilton, Canada in 1957. He received the B.Eng. degree in Electrical Engineering from McMaster University, Canada,
in 1979.
From 1979 to 1998, Mr. Kezys was involved in radar and communications research as Principal Research Engineer at the Communications
Research Laboratory, McMaster University. While at McMaster, his research activities included array signal processing for
low-angle tracking radar, radar signal processing, and smart antennas for wireless communications. Mr. Kezys was founder and
President of TalariCom Inc., a start-up company that developed cost effective smart antenna technologies for broadband wireless
access applications.
Currently, Mr. Kezys is Director of Advanced Products at Research in Motion in Waterloo, Canada.
Vahid S. Azhari received his B.S. and M.S. from the Department of Electrical and Computer Engineering, IUST and University of Tehran, Iran,
in 2000 and 2003 respectively. His M.S. research focused on designing scheduling algorithms for switch fabrics. He also worked
for two years for the Iranian Telecommunication Research Centre on developing software for SDH switches. He is currently pursuing
his Ph.D. degree at the Wireless Networking Laboratory, McMaster University, Canada. His main area of research includes handoff
management in integrated wireless networks, WLAN deployment techniques, and wireless mesh networks.
Dongmei Zhao received the Ph.D. degree in Electrical and Computer Engineering from the University of Waterloo, Waterloo, Ontario, Canada
in June 2002. Since July 2002 she has been with the Department of Electrical and Computer Engineering, McMaster University,
Hamilton, Ontario, Canada where she is an assistant professor. Dr. Zhao’s research interests include modeling and performance
analysis, quality-of-service provisioning, access control and admission control in wireless cellular networks and integrated
cellular and ad hoc networks. Dr. Zhao is a member of the IEEE. |
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Keywords: | Wireless LANs IEEE 802 11 Cellular networks Dual mode handset Soft handoff |
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