es. Based on this information, the radio design can be done and the number of network elements, interface capacity, etc., can be designed accordingly. Figure B.6 shows the general dimensioning process. Input Parameters to the Dimensioning Process Traffic Definition Typically traffic is provided as the number of subscribers and the traffic mix per subscriber, or the total amount of traffic in the network. Voice Erlangs and MB for different data services are typically provided. The service distribution in different areas (urban, suburban, etc.) also needs to be specified. In addition, the difference between regular WCDMA and HSDPA traffic needs to be defined. HSDPA Planning and Dimensioning Es_SINR Figure B.7 SINR definition formulas For HSDPA, in addition to the total amount of traffic and service distribution, the average and minimum cell throughput (in Mbps) should also be indicated. Throughput specification is typically a requirement, but in some cases it could also be estimated based on other factors, like the amount of traffic and available power. The total aggregated throughput in the cell will depend on the number of users, the scheduling algorithm and distribution of the 'G factor', which is an indicator of the cell topology and the relation between the power received from the dominant cell and the strongest interferer cells. Air Interface Dimensioning Firstly, the number and type of sites needs to be specified for the air interface (i.e. sectors/site, maximum transmission power, etc.). Then, the average throughput in a certain location should be estimated based on the average SINR (signal-to-interference and noise ratio), which can be used to create the HSDPA link budget. The reason for using SINR instead of Eb/No or Es/No, as done for the DCH, is that it does not depend on the bit rate or number of codes. In the case of HSDPA, the bit rate and code can change in every TTI for each user. Figure B.7 defines the SINR and its relationship to Es/No, where M is the number of HSPDSCH codes used during the TTI. 