le TTI. The maximum number of soft channel bits over all the HARQ processes; HSDPA Traffic Definition Air-Interface Dim Node -B config RNC config lub config/sizing Figure B.6 Dimensioning process If the UE supports 16-QAM (e.g. code efficiency limitation); Parameters are also available for specification of the L2 buffer capability (RLC+MAC). A UE with a low number of soft channel bits will not be able to support IR for the highest peak data rates and its performance will thus be slightly lower than for a UE supporting a larger number of soft channel bits. B.5 HSDPA Planning and Dimensioning B.5.1 Planning Basics Since HSDPA is a shared data channel, the end user throughput will depend on the total number of HSDPA users in the cell. Capacity planning and dimensioning is therefore different in the case of HSDPA compared with the regular WCDMA DCH. However, as power and codes are shared between all users, overall cell capacity will be considered when doing the analysis. There are several aspects that should be considered, especially for HSDPA planning. In the first place, HSDPA throughput depends on the SINR conditions in the UE. The transmission power of the HSPDSCH is constant and reserved, SO it cannot be used by the DCH (i.e. link adaptation is used instead of power control). Secondly, the uplink transmission is done with a normal UL NRT DCH bearer. In addition, the higher bit rates require a review of the lub and RNC capacity, which need to be dimensioned accordingly. B.5.2 HSDPA Dimensioning There are different approaches that can be used for HSDPA dimensioning, assuming that DCH dimen- sioning has already been done. The first one would use the remaining power, not used for the DCH, and obtain HSDPA and cell throughput as a result. The second option would take the desired HSDPA throughput as the input and use it to determine the required transmission power. The dimensioning process requires different inputs from the operator, who needs to provide the ex- pected traffic distribution and expected throughputs rat