Estimation of additive noise variance for multiuser CDMA systems

In this paper, a novel additive noise variance estimation algorithm is proposed for multiuser CDMA systems experiencing time varying and frequency selective fading. The algorithm is developed by exploring the eigenstructure of the receive signal correlation matrix, which is characterized by the statistical properties of both the fading channel and the additive white Gaussian noise. Relying only on the knowledge of the receiver signal samples, the algorithm can accurately estimate the variance of the additive noise present at the receiver of multiuser CDMA systems. The estimated noise variance can be employed along with other receiver algorithms to improve system performance.