New handoff strategies in microcell/macrocell overlaying systems

Abstract

To cope with the increasing demand of mobile and personal communications, two-tier cellular systems are likely to be deployed in major city center. Reservation schemes are consequently to be adapted to such a context: forced call terminations due to handoff call blocking are generally more objectionable than new call blocking. In order to maintain an acceptable call dropping probability rate, we propose, below, a new adaptive guard channel scheme: Hierarchical Predictive Reserva-tion Policy (HPRP). In this scheme, the number of reserved channels depends on the actual number of calls in progress in the neighboring cells. In micro/macrocells systems, users are assigned to a given level of the hierarchy according to their speed. In this paper, three schemes are proposed and compared by discrete event simulations. The efficiency of the proposed methods is emphasized on a complex configuration.