Trends in multi-layer cellular system design and handover design

This paper presents an overview of current research and published work on the performance of multi-layer cellular architectures and the handover performance in such networks. In a multi-layer cellular network, macrocells with a large coverage area, overlay microcells or picocells with smaller coverage areas. This network architecture, if well engineered, can provide improved QoS and higher capacity over the traditional single-tier cellular network under the same resource constraints. The small coverage of microcells/picocells, and the consequent multipath and shadow fading characteristics, mean that handover events in future systems will occur at a much higher rate. Therefore efficient handover algorithms are a cost-effective way of enhancing the capacity and QoS of cellular systems. This paper describes several methods that can be used for the evaluation of handover-related system performance