Analysis of Polarization Diversity Gain at Base Station in W-CDMA System

There have been many theoretical and experimental investigations on polarization diversity reception characteristics at base stations. The diversity gain was evaluated based on the distribution of the instantaneous received power in these investigations. The mainstream mobile communication systems are shifting to standardized IMT-2000 systems and the W-CDMA system is one of them. The effect using base station polarization diversity in WCDMA must be evaluated by considering not only antenna diversity, but also RAKE reception / path diversity. Furthermore, Transmit Power Control (TPC) is applied to overcome the near-far problem of mobile units that maintain a fixed reception power level in W-CDMA systems. Therefore, traditional diversity gain cannot be used as an evaluation indicator. In this paper, we propose a theoretical analysis method for diversity gain using base station polarization diversity in W-CDMA. We also clarify the analytical results of practical diversity gain and verify the evaluation model used for theoretical analysis through a comparison with the experimental results.