ers) increases the rate reduction factor and reduces the effective throughput per user or QoS. Capacity Planning Summary of GPRS and EGPRS Traffic Dimensioning Basic guidelines have been outlined for dimensioning a mixed circuit switched and GPRS/EGPRS network. These should be treated as a 'rule of thumb' to enable initial designs to be performed. As the data network is deployed and carrying live traffic, two key "assumptions" require re-visiting and quantification for calibrating and re-dimensioning: data and traffic profiles: Data profiles. Initially, it is assumed that the majority of users will be using EGPRS for web brows- ing and email applications. This implies relatively large message sizes (typically upwards of several kilobits). The QoS requirements for these applications may differ somewhat from those associated with other applications, such as those involving short messaging. Should the application profile change significantly from that assumed in the simulation work performed, then, for example, it may be pos- sible to relax the EGPRS loading constraints, allowing for higher channel loading and higher EGPRS throughput. Traffic profiles. Dimension a data network on the assumption that the circuit switched and EGPRS traffic peaks simultaneously may result in a degree of over dimensioning. Dimensioning should be adjusted based on revisiting this assumption through live traffic profiling as the heavy data cells start loading EGPRS traffic. For the busiest cells, the overall peak hour of primary concern SO dimensioning should reflect this. 2.6.3 Capacity Planning in WCDMA Networks Capacity planning in WCDMA networks is much more complicated than in GSM/EGPRS. Factors that affect the coverage calculations are load, interference, traffic behaviour, speed of subscribers, etc. Uplink WCDMA is an interference system limited by the air interface. Hence, capacity planning would need to calculate the interference and the cell capacity, i.e. the amount of traffic that is supported by a base station. The amount of 