Levenberg-Marquardt computation of the Block Factor Model for blind multi-user access in wireless communications

In this paper, we present a technique for the blind separation of DS-CDMA signals received on an antenna array, for a multi-path propagation scenario with Inter-Symbol-Interference. Our method relies on a new third-order tensor decomposition, which is a generalization of the parallel factor model. We start with the observation that the temporal, spatial and spectral diversities give a third-order tensor structure to the received data. This tensor is then decomposed in a sum of contributions, where each contribution fully characterizes one user. We also present an algorithm of the Levenberg-Marquardt type for the calculation of this decomposition. This method is faster than the alternating least squares algorithm previously used.