d interference analysis. Along with this, the all-important process of defining parameter settings takes place. The detailed planning process is sometimes referred to as pre-launch optimisation, and radio network planning tools have an important role in this. Some data collected from drive tests is also used. 7.6.1 Coverage and Capacity The foremost aspect of detailed planning is more accurate coverage and capacity plans. This starts with performance analysis of the radio links. The power budgets are analysed by taking some data from actual drive tests results. Factors that commonly cause a deviation of the practical link budget (i.e. the power actually received) from the theoretical calculations are: the propagation model link budget parameters propagation conditions. All these factors are inter-dependent. Fine-tuning of the propagation model is necessary under actual propagation conditions, as far as possible. A network covering a big region will require analysis for each part of the region separately, as propagation conditions (apart from topography) will change from one region to another. This leads to changes in the propagation model parameters, such as clutter type corrections, diffraction, topographical corrections, etc. One big change in a WCDMA radio network's link performance analysis is the fact that data play an important role. The types of data and their individual delay characteristics makes it impossible to define one set of parameters for the whole network. Each of the data types will have individual coverage probability requirements. This analysis leads to results that give quite accurate antenna heights, antenna tilts, bearing, location of sites, etc. Both the uplink and downlink transmitted power need to be ascertained, after which the number of mobile subscribers can be more accurately predicted. An accurate prediction of the number of subscribers will lead to a more accurate inter- ference analysis compared to the results in the pre-planning phase. The frequency re-use DETAILED PLANNING Figur