Sensitivity of UMTS FDD system capacity and coverage to model parameters

The techniques used for the design and optimisation of WCDMA systems are significantly different from those used in GSM/IS136 systems. It is difficult to consider any part of a WCDMA system in isolation-changes to a part of the system will ripple through the radio network, and may cause changes over a larger area than is the case with GSM/IS136 systems. This high degree of interactivity, together with the limited applicability of analytical techniques (especially for downlink RF performance estimation), makes simulation an essential ingredient in WCDMA system planning. This paper addresses the issue of the sensitivity of the final system capacity to simulation input parameter values. Sensitivity results are presented here for 37-site cell layouts on a regular grid. A Monte Carlo simulation model is described, and the relationship with the physical radio link performance highlighted. The sensitivity of the ultimate capacity and range figures to the values of various propagation and radio link performance parameters is presented, with some surprising conclusions.