Hybrid Adaptive Antenna Array
First Claim
1. A hybrid antenna array comprising:
- (a) a plurality of digital branches, each digital branch including;
(i) an analogue beamforming sub-array, each sub-array having a plurality of antenna elements, a phase shifter adapted to apply a phase shift to the signal from each antenna element, and a combiner adapted to combine the phase shifted signals;
(ii) a signal chain adapted to convert the output of the sub-array to baseband; and
(b) a digital processing module, including;
(i) an angle of arrival estimation sub-module adapted to estimate an angle of arrival of a signal at the antenna elements;
(ii) a phase control sub-module adapted to control the phase shift applied by each phase shifter depending on the estimated angle of arrival; and
(iii) a digital beamformer adapted to combine the baseband signals from the digital branches using a weight vector to form an output signal.
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Accused Products
Abstract
Disclosed is a hybrid antenna array (100) comprising a plurality of digital branches (145), each digital branch including an analogue beamforming sub-array (e.g. 110-1), each sub-array having a plurality of antenna elements (120), a phase shifter (130) adapted to apply a phase shift to the signal from each antenna element, and a combiner (e.g. 135-1) adapted to combine the phase-shifted signals. Each digital branch also includes a signal chain (e.g. 140-1) adapted to convert the output of the sub-array to baseband. The hybrid antenna array also comprises a digital processing module (150), including: an angle of arrival estimation sub-module (155) adapted to estimate an angle of arrival of a signal at the antenna elements; a phase control sub-module (170) adapted to control the phase shift applied by each phase shifter depending on the estimated angle of arrival; and a digital beamformer (165) adapted to combine the baseband signals from the digital branches using a weight vector to form an output signal (180).
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Citations
13 Claims
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1. A hybrid antenna array comprising:
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(a) a plurality of digital branches, each digital branch including; (i) an analogue beamforming sub-array, each sub-array having a plurality of antenna elements, a phase shifter adapted to apply a phase shift to the signal from each antenna element, and a combiner adapted to combine the phase shifted signals; (ii) a signal chain adapted to convert the output of the sub-array to baseband; and (b) a digital processing module, including; (i) an angle of arrival estimation sub-module adapted to estimate an angle of arrival of a signal at the antenna elements; (ii) a phase control sub-module adapted to control the phase shift applied by each phase shifter depending on the estimated angle of arrival; and (iii) a digital beamformer adapted to combine the baseband signals from the digital branches using a weight vector to form an output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of estimating the angle of arrival of a signal at an antenna array comprising a plurality of digital branches and a digital beamformer, the method comprising:
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(a) cross-correlating the baseband signals from adjacent digital branches; (b) for a plurality of candidate beams, (i) setting the phase shifts using the arguments of the cross-correlation values; and (ii) computing the power of the output signal of the digital beamformer; (c) determining the candidate beam giving the maximum output power; and (d) estimating the angle of arrival from the cross-correlation values of the determined candidate beam.
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12. A method of calibrating an antenna array comprising a plurality of digital branches and a digital beamformer, the method comprising:
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(a) estimating the expected phase difference between the baseband signals from adjacent digital branches; (b) determining the phase deviation of each digital branch as the difference between the expected phase difference and an actual phase difference between the baseband signals from a digital branch and an adjacent previously calibrated digital branch; and (c) applying each phase deviation to the baseband signal from the corresponding digital branch.
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13. A method of calibrating an antenna array comprising a plurality of analogue branches, each analogue branch comprising an antenna element and a phase shifter, the method comprising:
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(a) optimising the phase shifts applied b the phase shifters to an input signal to the array so as to obtain a maximum-power output signal from the array; (b) determining expected values of the phase shifts using an angle of arrival of the input signal; (c) determining the phase deviation for each analogue branch in the array as the difference between the expected phase shift and the optimised phase shift for the analogue branch; and (d) applying each phase deviation to adjust the phase shift applied by the corresponding phase shifter.
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Specification