Performance evaluation of a hybrid location management scheme for mobile systems

Hierarchical location management schemes have been proposed to cope with the large number of users in future personal communication systems. We have previously proposed a Hybrid scheme that combines the hierarchical architecture and the two-tier architecture into one scheme. The Hybrid scheme benefits from the scalability offered by the Hierarchical scheme while reducing the number of databases updated and queried. In this paper we quantify the costs and benefits of the Hybrid scheme and one of its variations. Unlike our previous work where we considered the user'S calling and mobility behavior in terms of the aggregated Regional Call-to-Mobility Ratio (RCMR), in this paper the performance evaluation is done in terms of the Call-to-Mobility Ratio (CMR) of the user while modeling real life scenarios using an event-driven simulator. It is shown that the Hybrid scheme can result in improvements over the Hierarchical scheme for high values of CMR reaching 20% for the communication cost and 60% for the database cost.