Separation of correlated signals using signal canceler constraints in a hybrid CM array architecture

In this paper, we present a hybrid implementation of the multistage constant modulus (CM) array for separating correlated signals. Using a cascade architecture of the CM array with a series of adaptive signal cancelers, we derive a parallel set of constrained beamformers. The canceler weights provide estimates of the direction vectors of the captured signals across the cascade stages, which are used in a parallel implementation of the linearly constrained CM (LCCM) array. Since the direction vectors are obtained directly fromthe 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 completely cancel the captured signals, and previous versions of the parallel CMarray do not always capture different sources across the stages. These problems are handled by the proposed hybrid LCCM architecture based on the signal canceler constraints. Computer simulations for example cochannel scenarios are provided to illustrate some properties of the system.