Open‐loop power control performance in DS‐CDMA networks with frequency selective fading and non‐stationary base stations

Abstract

In this paper, we study the performance of a simple and easy‐to‐implement distributed power control strategy applicable to direct sequence code division multiple access (DS‐CDMA) networks. The scheme makes use of the received power measurements made on the forward link at individual mobile units to control the transmit powers on their reverse links. The algorithm, which effectively compensates for the slowly varying distance and shadow losses (due to their high correlation on both forward and reverse links), attempts to minimize the effect of fast multipath fading by averaging it out. We adopt a quasi‐analytic approach to estimate the reverse link capacity performance of an open‐loop power control scheme in both a single cell and a multi‐cell environment, and we do this for both a fixed base station and a moving base station scenario. Non‐stationary base stations are typical in tactical and emergency communications scenarios where the base stations could be mounted on moving platforms (e.g., tanks, jeeps, unmanned airborne vehicles). We estimate the capacity degradation, when base stations move relative to other cells, as a function of the amount of cell overlap and the standard deviation of the power control error. We also provide a comparison of the performance of the open‐loop power control strategy with that of a closed‐loop power control strategy.