NC State University

Department of Computer Science Colloquia 2000-2001

Date: Tuesday, August 29, 2000
Time: 3: 30 PM (talk)
Place: 402A Withers, NCSU Historical Campus (click for courtesy parking request)

Speaker: Sandeep Gupta, Computer Science, Colorado State University, Ft. Collins, CO

Dynamically Adapting Registration Areas to User Mobility and Call Patterns for Efficient Location Management in PCS Networks

Abstract: Location management is an essential service in mobile networks. It provides mechanisms for recording and querying location of mobile units in the network. This is needed for establishing calls or deliverying messages to mobile units. In personal communication service (PCS) networks, location management protocols such as IS-41 and GSM use statically defined Registration Areas (RAs). Each RA consists of all the  communication cells in its geographical area. Associated with each RA is a database called Location Registrar. Further, each mobile unit has a pre-assigned Home Location Registrar (HLR). A mobile unit informs its location (location update operation) whenever it moves from one communication cell to another. When the move results in move from one registration area to another updates are made to home location registrar. In order to locate a mobile unit the initator of the call or (sender of the message) first contacts the HLR of the destination mobile unit to know its current location (registration area). Location Mangement based on statically defined registration areas is unable to adapt to changing mobility and call patterns of the users.

In this talk, we present an extension to PCS location management protocol which uses dynamically overlapped registration areas. Overlapping of registration areas helps in reducing the number of location updates for a fixed mobility pattern. Further, dynamically changing the registration area is used to adapt to changes in aggregate mobility and call pattern.  This reduces and balances the signaling and database access load on the mobile services stations (MSS).  In order to study the adaptiveness of the proposed scheme, we have simulated our scheme under various mobility and call patterns. Our simulation results show that by dynamically adapting the registration areas to aggregate mobility and call pattern of the mobile units is useful when the mobility pattern exhibit locality. For such mobility and call patterns, the proposed scheme can greatly reduce the average signaling and database access load on MSSs. Further, the cost of adapting the registration areas is shown to be low in terms of memory and communication requirements.

Short Bio: Dr.Sandeep Kumar S. Gupta received the M.S. and Ph.D. degree in computer and information science from The Ohio State University, Columbus, Ohio, in 1991 and 1995, respectively. He is currently an assistant professor in Department of Computer Science at Colorado State University, Ft. Collins, Colorado. Prior to joining Colorado State University he has held research and teaching positions at Duke University and Ohio University. His research interests include parallel and distributed computing, compilers, and mobile computing. He has published over 40 refreed journal and conference technical articles. Dr. Gupta has given tutorials on Mobile IP and Mobile ATM. He was program chair for Int'l workshop on Group Communication and program co-chair for Int'l Workshop on Wireless Networks and Mobile Computing, and Int'l Workshop on Pervasive Computing. He has served as a program committee member for Mobile Data Access (MDA'99) and 1999 Int'l Conference on Parallel Processing (ICPP'99). Dr. Gupta is a member of the ACM and the IEEE Computer and Communication Societies.

Host:  C. Healey, Computer Science, NCSU

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