Downlink performance evaluation of UMTS Heterogeneous Network in co-channel deployment

To meet the ever-increasing demand of mobile communication, Heterogeneous Network (HetNet) deployment is considered as an effective approach to enhance the overall system capacity. The performance of radio link is approaching theoretical limits, so the next leap in wireless communication will be in network topology. With a mix of macro and small cells, HetNet enables flexible deployments and can improve the spectral efficiency per unit area. In addition to the research of HetNet actively ongoing in LTE/LTE-A system, the 3rd Generation Partnership Project (3GPP) initiates the study of heterogeneous networks for UMTS system in RAN plenary #57 [1]. The objective is to identify potential issues and solutions of UMTS heterogeneous networks, including studies on performance evaluation, interference management, range expansion techniques, and mobility issues. In this paper, we study the downlink performance of UMTS heterogeneous networks in co-channel deployments. System level simulations are performed to evaluate the potential capacity gains brought by UMTS HetNet.