Power amplifier dimensioning for WCDMA-systems

This paper focuses on power amplifier dimensioning applied to WCDMA wireless networks. First a modeling of the downlink capacity is given which allows determination of the relationship between the signal to interference ratio and required downlink power per user. In the second part, following a similar methodology to those presented in Sipila et al. (2000) and Hiltunen et al. (2000), an average approach to estimate the total Node B output power according to design and capacity requirements is presented This method is based on assumptions, which could differ from real network situations. Therefore in a third part, the difference between the previous average approach and extended simulations is studied in different cases: mobiles are randomly drawn in the cell and parameters such as orthogonality and frequency reuse factor are not constant. It is shown that Node B power, at the Node B antenna connector, determined by the average approach is not enough to guarantee desired capacity. This comparison leads us to define margins, which are mandatory to ensure the capacity with the required quality of service (QoS).