Title: A simulation study of overflow replacement policies for location management in mobile networks

Authors: Ying Luo, Jie Li, Yang Xiao, Xiaola Lin

Addresses: Department of Computer Science, Georgia State University, Atlanta, GA 30303, USA. ' Institute of Information Sciences and Electronics, University of Tsukuba, Tsukuba Science City, Ibaraki 305-8573, Japan. ' Computer Science Division, The University of Memphis, Memphis, TN 38120, USA. ' Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong

Abstract: Location management is one of the most important issues of mobile networking systems. Most current mobile systems employ a two-tier database structure to store mobile users| information. HLR (Home Location Register) is used to retrieve user|s information, and VLR (Visitor Location Register) is the temporal database for storing visitors| profiles. In the case when the number of users exceeds the capacity of the VLR due to mobility, database overflow occurs. To solve this problem, different replacement policies have been developed: random, most-idle, and inactive. In this paper, we propose a new policy, the least frequent replacement policy, which selects the least frequently accessed users as replacement candidates. Extensive simulation is carried out to predict the performance of the existing replacement policies and the proposed least frequent policy. Our simulation results show that the most idle and least frequent policies outperform the inactive and random replacement policies in most cases and the least frequent policy performs slightly better than the most idle replacement policy.

Keywords: mobile networks; location update; call delivery; database overflow; least-frequent replacement policy; location management; mobile communications.

DOI: 10.1504/IJMC.2004.004662

International Journal of Mobile Communications, 2004 Vol.2 No.2, pp.103 - 127

Published online: 25 May 2004 *

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