Handoff analysis of the hierarchical cellular system

Abstract

As the mobile teletraffic demands increase dramatically, interest in the cellular system with the hierarchical structure has emerged. The hierarchical cellular system can provide high system capacity, efficient channel utilization, and inherent load-balancing capability. In the hierarchical system, the blocked calls rejected in a microcell are overflowed to an overlaying macrocell. Whereas, in the case that the overflowed calls in a macrocell could not be returned to a microcell, the channels of macrocell would be exhausted by overflowed calls. Thus we propose the hierarchical cellular system with the underflow scheme, which permits the overflowed calls to return to microcells. In this paper, we model the underflow traffic and analyze the system performance. To manage mobile users having different mobility in the hierarchical cellular system, it is assumed that the low mobility users are dedicated to microcells and the high mobility users are dedicated to macrocells. We take into consideration the multiple high mobility users who are served in one vehicle at the same time and analyze the macrocell-to-macrocell handoffs of the multiple calls for the high mobility users.