A semi-blind algebraic constant modulus algorithm

A modification to the algebraic constant modulus (ACM) algorithm is proposed that exploits the presence of known pilot symbols within the transmitted data. The pilot symbols are used to place soft constraints on the subspace in which the ACM solution should lie, and relax some of the identifiability conditions required by ACM. The primary advantage of the proposed method is that sources transmitting linearly independent pilot data can be separated without resorting to a joint diagonalization procedure, and hence without computing the beamformers of signals that are not of interest.