Adaptive robust power control for WCDMA systems

Large variations of signal strength due to Rayleigh fading radio channel are observed in cellular radio communication systems. Power control (PC) is needed to mitigate this effect. It is essential in WCDMA, where many users share the same transmission medium simultaneously. Difficulties arise in power control because the conditions of radio channels change very rapidly. In this paper we propose a new adaptive robust algorithm for closed-loop power control for WCDMA systems, suitable for real implementation. The scheme relies on the generalized predictive controller (GPC), which is known to be able to control very difficult processes, and an adaptive self-tuning control strategy to automatically adjust the controller parameters. The approach was shown in simulations to outperform the conventional bang-bang controller.