Multistage Adaptation for Large Digital Arrays

Daniel Rabideau
MIT Lincoln Laboratory
244 Wood St.
Lexington, MA  02173
Phone: (781) 981-2892

Abstract This work is concerned with efficient techniques for adaptive interference cancellation, and their application to very large digital arrays. Such arrays provide many Degrees of Freedom (DOFs) that can be used for filtering. However, the processing hardware required to fully utilize these DOFs (i.e., in a simultaneous, data-adaptive fashion) is prohibitive. To address this problem, we suggest two adaptive beamforming frameworks: feed-forward multistage adaptation, and closed-loop multistage adaptation. We demonstrate the capabilities of these new signal processing architectures. In typical applications, multistage adaptive beamforming is shown to potentially result in one of the following desirable results: (1) a large reduction in both hardware and processing for a given performance level. (2) a large improvement in interference rejection for a given number of instantaneously adaptive DOFs.

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