Separation of correlated signals using signal canceler constraints in a hybrid CM array architecture
V. Venkataraman, John J. Shynk · 2006
In this paper, we present a hybrid implementation of the mul-tistage constant modulus (CM) array for separating corre-lated signals. Using a cascade architecture of the CM array with a series of adaptive signal cancelers, we derive a par-allel set of constrained beamformers. The canceler weights provide estimates of the direction vectors of the captured sig-nals across the cascade stages, which are used in a parallel implementation of the linearly constrained CM (LCCM) ar-ray. Since the direction vectors are obtained directly from the canceler weights, the hybrid implementation does not require prior knowledge of the array response matrix. If the source signals are sufficiently separated in angle, then they can be captured individually across the parallel stages. When the sources are correlated, the cascade CM array does not com-pletely cancel the captured signals, and previous versions of the parallel CM array do not always capture different sources across the stages. These problems are handled by the pro-posed hybrid LCCM architecture based on the signal can-celer constraints. Computer simulations for example cochan-nel scenarios are provided to illustrate some properties of the system. 1.