MIMO channel spatial covariance estimation: Analysis using a closed-form model

In this paper, we propose a closed-form model that allows estimation of the full MIMO covariance (as opposed to the more traditional one-sided or separable covariance [1]) based on knowledge of the power angular spectrum (PAS) of the channel and the antenna radiation patterns. Comparison of covariance matrices computed using this model and those estimated from observed channel samples reveals the appropriate window over which the covariance should be estimated for non-WSS time-varying channels.