An Iterative Algorithm for Computing a Spatial Whitening Filter

In this paper, we describe a simple technique to estimate the spatial covariance of the interference at the receiver, using pilot signals from the transmitter, and propose an iterative algorithm to compute a spatial whitening filter for the estimated covariance. Unlike well-known techniques for computing such a whitening filter (e.g., inverting the lower-triangular Cholesky factor of the covariance), the algorithm we propose requires only matrix additions and multiplications, and no nontrivial division or square root operations, making it well suited to fixed-point implementation.