Beamforming devices and methods
AssigneeHobbit Wave, Inc.
InventorHarvey C. Woodsum
Life of this patent
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Abstract
Devices and methods are provided for directionally receiving and/or transmitting acoustic waves and/or radio waves for use in applications such as wireless communications systems and/or radar. High directional gain and spatial selectivity are achieved while employing an array of receiving antennas that is small as measured in units of the wavelength of radio waves being received or transmitted, especially in the case of spatially oversampled arrays. Frequency/wavenumber, multi-dimensional spectrum analysis, as well as one-dimensional frequency spectrum analysis can be performed.
Claims28
A device for receiving signals comprising:
- an array of N signal-receiving elements for receiving N signals, where N is a natural number greater than or equal to three;
- sampling circuitry for sampling the N signals and providing output samples for the N signals;
- a processor for receiving and processing signals derived from the output samples, the processing including using a non-diagonal N×M matrix to produce a set of M beams, where M is a natural number greater than N, each of the M beams corresponding to a particular direction of signal arrival relative to the signal-receiving elements, the N×M non-diagonal matrix being derived in advance to increase the signal for each one of the M beams and to reduce the signal each of the other M−1 beams, for each of the M beams the processor producing an output of M beam vectors.
A method for receiving signals comprising:
- receiving a set of N signals, where N is a natural number greater than or equal to three;
- sampling the N signals and providing output samples for the N signals;
- receiving and processing signals derived from the output samples, the processing including using a non-diagonal N×M matrix to produce a set of M beams, where M is a natural number greater than N, each of the M beams corresponding to a particular direction of signal arrival relative to the signal-receiving elements, the N×M non-diagonal matrix being derived in advance to increase the signal for each one of the M beams and to reduce the signal each of the other M−1 beams, for each of the M beams producing an output of M beam vectors.
A device for receiving signals from a transmitting device, the device comprising:
- an array of N elements receiving N signals, where N is a natural number greater than or equal to three;
- sampling circuitry for deriving digital data from the N elements;
- a spatial filter for obtaining signals from a desired sector;
- a spatial interpolator for receiving signals derived from the digital data and providing M interpolated signals, where M>N, M representing a set of beams;
- and
- a selector for selecting one or the beams to identify a location of the transmitting device.
A method for receiving signals from a transmitting device, the method comprising:
- receiving N signals with an array of N signal elements, where N is a natural number greater than or equal to three;
- sampling the signals to derive digital data from the N elements;
- spatial filtering for obtaining signals from a desired sector;
- spatially interpolating the N signals to provide M interpolated signals, where M>N, M representing a set of beams;
- and
- selecting one or the beams to identify a location of the transmitting device.
A processing system for use with a radiotelephone device including one of a base station and a handset and having antennas for receiving wireless signals, the system comprising:
- a processor for receiving sampled signals and for transforming signals derived from the received signals from a first state in which the signals represent signals received from N antennas into a second state in which signals output from the processor represent M beams, where M>N, and where the second state is different from the first state,
- wherein the processing includes determine a non-diagonal matrix W:
- Σ(θ1,θ2,θ3, . . . )W*V(θm)=ρ(θm);
- wherein Σ(θ1,θ2,θ3, . . . ) is a matrix with each row constructed as a matched filter for an arriving wave;
- V(θ) is a signal vector that is an N×1 matrix of complex values and representing a set of received voltages produced by the N antennas in response to a pressure wave with harmonic time dependence arriving from a particular direction indicated by the arrival angle θ;
- wherein the matrix W is derived by using a least squares technique to solve for a matrix W that makes a beam response β(θ) close to a reference vector ρ(θ),
- wherein for each of a set of chosen beam directions {θ1,θ2,θ3, . . . }, a reference vector ρ(θm) has dimensions N×1 and is chosen to have zeroes in all rows, except for a row corresponding to the one selected beam direction, θm, in which row is placed a unity value to derive an ideal beam response, with response only in the desired direction, θm, and zero response elsewhere,
- the processor being implemented in a radiotelephone device.
A processing system for use with a radiotelephone device including one of a base station and a handset and having antennas for receiving wireless signals, the system comprising:
- a processor for receiving sampled signals and for transforming signals derived from the received signals from a first state in which the signals represent signals received from N antennas into a second state in which signals output from the processor represent M beams, where M>N, and where the second state is different from the first state,
- wherein the processing includes determine a non-diagonal matrix wherein the a non-diagonal matrix is determined based on:
- H=ΣHW
- where the Σ matrix has a set of columns, each column being made up of a set of complex phasors that serve as spatial matched filters to an incoming signal from a specified beam direction, ΣH is the complex conjugate transpose of the Σ matrix, and W is a full-rank N×N pre-set complex valued matrix;
- wherein the solution for W is found by solving in a least-squares sense, the following equation:
- ΣHWΣ=CI
- where C is a scaling constant and I is a reference response.
Dependencies are inferred from the claim text.