A New Location Caching Scheme Employing Forwarding Pointers in PCS Networks

Abstract

This paper proposes a new location caching scheme that can reduce the signaling cost for location management in PCS networks. In the existing cache scheme, the use of cache information can effectively reduce the signaling traffic for locating frequently called mobile users. However, when the cache information is obsolete, it results in much more signaling traffic than that of the IS-41. In order to solve this problem, we propose a new location caching scheme called the PB-Cache scheme, which exploits a user’s movement locality as well as call locality. Even if the cached information is not up-to-date, the called user can be found by tracing forwarding pointers in the VLR’s without querying the HLR. Thus, the PB-Cache scheme can effectively reduce the signaling traffic for location management, and makes it possible to establish a rapid call setup. Besides, it distributes the signaling and database access load on the HLR to the VLR’s. The analytical results indicate that the PB-Cache scheme significantly outperforms the other schemes when a user’s call-to-mobility ratio is high or the signaling traffic to the HLR is heavy.

This work was funded by the University Research Program supported by Ministry of Information & Communication in South Korea.