Unbiased power prediction of Rayleigh fading channels

Abstract

Prediction of the rapidly fading envelope of a mobile radio channel enables a number of capacity improving techniques like fast resource allocation or fast adaptive modulation. Some power prediction algorithms are based on linear prediction of the taps of the complex impulse response and then forming the power prediction as the sum of the absolute square of the prediction of the taps in the impulse response. This will render a biased power predictor, that generally underestimates the power. We propose a bias compensated power predictor and derive the optimal prediction coefficients for the Rayleigh fading channel. The importance of efficient noise reduction of channel samples that are used as inputs to the predictor is also emphasized. A performance evaluation of the prediction algorithm is carried out on measured broadband mobile radio channels.