FDD-UMTS which is based on W-CDMA is an interference limited system. Therefore the system can only be driven close to the capacity limit, if the transmit power of the individual users is minimized with the constraint, that the link quality (SIR) for the requested data rate is ensured.
To reach this goal in time-varying fading channels a closed loop power control is utilized. Its limiting factors are fixed stepsizes and a feedback delay. The goal of our project is to analyze the system and develop optimal power control strategies for the base station concerning the global (multi-user) interference situation.