Analysis of soft-handover characteristics in realistic urban UMTS radio networks

This work presents a comprehensive simulation study on the soft hand over (SHO) related system characteristics in UMTS radio networks using a new dynamic simulation approach. This approach is better suited for many planning tasks than the conventional dynamic system level approaches as it allows inclusion of only as much detail as required for specific planning jobs. In contrast to existing radio planning tools, it can easily integrate the effects due to dynamic phenomena such as user mobility. In this study, a pixel oriented mobility model, which permits detailed modeling of user movements, is used to obtain characteristic quantities such as the overall SHO rate, mean duration in SHO, mean active set size and mean number of branch additions and deletions. Simulation results are presented for a regular hexagonal cell layout and also for the "Alexander Platz" in the city of Berlin, which is representative for a realistic dense urban scenario. Further investigations are conducted to evaluate the impact of different SHO related parameters on system performance and cell dimensioning in the selected scenarios.