Expected likelihood-based detection-estimation of multirank signals

Even for the simple rank-one plane-wave model, the accurate maximum-likelihood (ML) solution of the detection-estimation problem is infeasible, mainly because the multivariate likelihood function is non-convex and multi-extremal. For this reason, a number of "ML-proxy" routines have been developed that, in some important practical cases, approach the efficiency of the ML performance benchmark (Cramer-Rao bound, CRB), for sufficiently large sample volume T and/or signal-to-noise ratio (SNR).