A Lazy Caching Location Strategy with Bypass Pointers in PCS
Sing-Ling Lee, Hwa-Chuan Lin, Pei-Xian Kou · 2004
In this paper we propose an efficient tracking strategy, called the Precache strategy, for a hierarchical database architecture in Personal Communication Services (PCS). The main goal of our strategy is to reduce the overloads of a PCS system in the following two situations: (1) when a callee receives calls frequently, and (2) when a user crosses many registration area (RA) boundaries with the characteristic of locality. The Precache strategy keeps a callee’s bypass pointers when he/she moves around neighboring RAs. A threshold to predict and confine the roaming regions is used to estimate the trade-off of maintaining bypass pointers. The purpose of setting the value of a threshold is to avoid updating and reading location databases frequently when users move around in certain fixed regions (RAs). We also discuss how to set the threshold value to determine a user’s roaming regions and where to set the bypass pointers. Through mathematical cost analysis and experimental simulation, we demonstrate that the Precache strategy, without employing any users ’ profile information, can reduce more traffic impacts than the traditional Basic and Caching strategies.