Predictive Closed Loop Transmitter Power Control

In this paper, a predictive closed power control loop for mobile communication systems is simulated. The system parameters are derived from those used in a CDMA system uplink transmission at urban mobile speeds. This presents no restrictions, however, on using the proposed method in any closed loop control system where the total received power level is to be estimated from noisy measurements. It is shown by COSSAP (Communications Simulation and System Analysis Program of CADIS GmbH, Germany) simulations that when the estimates of the received power level are noisy, and the control loop response is inherently delay-limited, predictive lowpass filtering can be applied to improve the received power level estimates and overall system performance. This method yields better tracking of Rayleigh fading, and improved bit-error-rates (BER), as compared to those achieved with a non-predictive reference controller.