A Block Component Model-Based Blind DS-CDMA Receiver

In this paper, we consider the problem of blind multiuser separation-equalization in the uplink of a wideband DS-CDMA system, in a multipath propagation environment with intersymbol-interference (ISI). To solve this problem, we propose a multilinear algebraic receiver that relies on a new third-order tensor decomposition and generalizes the parallel factor (PARAFAC) model. Our method is deterministic and exploits the temporal, spatial and spectral diversities to collect the received data in a third-order tensor. The specific algebraic structure of this tensor is then used to decompose it in a sum of user´s contributions. The so-called block component model (BCM) receiver does not require knowledge of the spreading codes, the propagation parameters, nor statistical independence of the sources but relies instead on a fundamental uniqueness condition of the decomposition that guarantees identifiability of every user´s contribution. The development of fast and reliable techniques to calculate this decomposition is important. We propose a blind receiver based either on an alternating least squares (ALS) algorithm or on a Levenberg-Marquardt (LM) algorithm. Simulations illustrate the performance of the algorithms.