Prediction of received signal power in CDMA cellular systems

Abstract

The prediction of signal power in code division multiple access (CDMA) systems in urban radio channels is investigated. We focus on the processing of the measured input signal for power control purposes in a mobile station receiver. Predictive filtering based on a polynomial signal model is proposed, and a class of FIR-type polynomial filters is investigated with simulations. Two alternative schemes are examined; direct prediction of the squared power signal, and prediction of the in-phase and quadrature signal components separately. The simulations show that FIR polynomial predictors can provide smoothed signal power samples with the signal-to-noise ratio (SNR) improved by ca.5 dB, without any delaying of the signal. The results show that polynomial prediction is potential tool for delayless filtering of additive noise and smoothing of fast fading of the signal.