UTRA soft handover optimisation

The paper presents a comprehensive analysis of the UTRA (UMTS terrestrial radio access) soft handover performance optimisation based on computer simulations. A system level simulator based on wideband CDMA is applied in a typical UTRA vehicular environment. The effects of different soft handover parameters, i.e. adding and dropping thresholds, time-to-trigger and averaging window size, are investigated. The simulation results show that in soft handover optimisation, all the parameters mentioned have a decisive effect upon the handover performance which has a direct impact on the system, i.e. radio and network resource efficiency and also service quality. Hence, by carefully tuning and setting appropriate values for the handover parameters and therefore a better soft handover optimisation, a higher system performance and capacity can be achieved.