Butterfly Neural Filter Applied to Beamforming

The butterfly neural beamformer (NB-Butterfly) is a new adaptive multiple-antenna spatial neural filter inspired on the neural butterfly equalizer (NE-Butterfly), a filter intended to equalize any channel that has real or complex taps, whether linear or nonlinear. Due to the broad use cases of the NE-Butterfly, the objective in this paper is to introduce this novel beamforming filter, the NB-Butterfly and analyze its performance by comparing to other neural and linear beamformers, while also presenting an enhanced training strategy that wasn't present in the butterfly neural architecture before, which is called butterfly neural beamformer with joint error (NB-Butterfly-JE). The proposals are evaluated and compared for different types of channels in order to validate their performance in different use cases.