EURASIP Journal on Wireless Communications and Networking 
Volume 2004 (2004), Issue 2, Pages 261-272
doi:10.1155/S1687147204406112

Robust Downlink Power Control in Wireless Cellular Systems

Mehrzad Biguesh,1 Shahram Shahbazpanahi,1,2 and Alex B. Gershman1,2

 1Department of Communication Systems, University of Duisburg-Essen, Bismarckstrasse 81, Duisburg 47057, Germany
2Department of Electrical & Computer Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
Received 30 November 2003; Revised 13 July 2004

Abstract

A serious shortcoming of current downlink power control methods is that their performance may be severely degraded when the downlink channel information is known imprecisely at the transmitter. In this paper, a computationally and implementationally simple centralized downlink power control method is proposed for cellular wireless communication systems using code division multiple access (CDMA) or space division multiple access (SDMA). Our method provides a substantially improved robustness against imperfect knowledge of the wireless channel by means of maintaining the required quality of service for the worst-case channel uncertainty. In the SDMA case, the proposed technique can be straightforwardly combined with any of the existing transmit beamforming methods. Simulation results validate substantial robustness improvements achieved by our approach.