Analytical characterization of the soft handover gain in UMTS

Abstract Soft handover is one of the key features in UMTS networks. For a sophisticated network planning it is necessary to understand the influence of soft handover on the capacity and coverage of UMTS systems which is expressed by the soft handover gain. In this paper we derive a method for computing interference distributions for UMTS networks with and without soft handover. Thus, we are able to show the benefit of soft handover resulting in an increased coverage area. Furthermore, the soft handover gain is characterized for both homogeneous and inhomogeneous UMTS networks with hexagonal as well as with irregular BS layouts. In particular, it is shown that the soft handover gain is increasing with the degree of inhomogeneity of the traffic intensity. Soft handover is one of the key features in UMTS networks. For a sophisticated network planning it is necessary to understand the influence of soft handover on the capacity and coverage of UMTS systems which is expressed by the soft handover gain. In this paper we derive a method for computing interference distributions for UMTS networks with and without soft handover. Thus, we are able to show the benefit of soft handover resulting in an increased coverage area. Furthermore, the soft handover gain is characterized for both homogeneous and inhomogeneous UMTS networks with hexagonal as well as with irregular BS layouts. In particular, it is shown that the soft handover gain is increasing with the degree of inhomogeneity of the traffic intensity.