Abstract: A method of generating a reference signal for transmission over a wireless communication channel comprises generating a first signal of a first characteristic, generating a second signal with second characteristic, scaling the second signal at least in time and an amplitude to form a scaled signal and iteratively adding the scaled signal to the first signal to generate the reference signal. The iteratively adding comprises time indexing the first signal with plurality of time points, adding the scaled signal to first signal at each time point in the plurality of time points, computing a cost function to determine the cost of adding the scaled signal at each time point in the plurality of time points, selecting a set of time points that indicate reduction in the cost when the scaled signal is added and adjusting the amplitude of the scaled signal at each time point in the set of time points to reduce the cost.

Abstract: A radio frequency receiver comprises a set of antennas for receiving an RF signal over a communication channel represented by a channel matrix Hd, a plurality of analog beamformer for generating plurality of analog beams, wherein each analog beam former is coupled to a subset of antennas comprising a fewer number antennas in the set of antennas, a mixer for combining the plurality of analog beams to provide a down converted signal, and a digital beam former for generating a plurality of digital beams, wherein a set of analog weights (FR) of the plurality of analog beamformer and a set of digital weights (FB) of the digital beamformer are selected such that effective beam formed by their product FB FR is orthogonal and spans the same space as columns of the channel matrix Hd.

Abstract: A radio frequency receiver comprises a set of antennas for receiving an RF signal over a communication channel represented by a channel matrix Hd, a plurality of analog beamformer for generating plurality of analog beams, wherein each analog beam former is coupled to a subset of antennas comprising a fewer number antennas in the set of antennas, a mixer for combining the plurality of analog beams to provide a down converted signal, and a digital beam former for generating a plurality of digital beams, wherein a set of analog weights (FR) of the plurality of analog beamformer and a set of digital weights (FB) of the digital beamformer are selected such that effective beam formed by their product FB FR is orthogonal and spans the same space as columns of the channel matrix Hd.