ANTENNA ARRAY CALIBRATION USING TRAFFIC SIGNALS
First Claim
1. A method for calibrating an antenna array of a base station to remove distortion incurred by transmit paths in abuse station, the antenna array including a plurality of sub-arrays coupled to the transmit paths for transmitting outbound traffic signals to a wireless network, the method comprising the steps of:
- combining the outbound traffic signals in respective ones of the sub-arrays into a feedback signal by a combiner in the antenna array;
capturing the outbound traffic signals simultaneously for use as reference signals before the outbound traffic signals enter the transmit paths, each of the reference signals being one of the outbound traffic signals that is to be transmitted via one of the sub-arrays;
performing an impairment estimation for each of the outbound traffic signals based on the feedback signal and the reference signals; and
applying an approximate inverse of the impairment estimation to the outbound traffic signals before the outbound traffic signals enter the transmit paths to thereby remove the distortion incurred by the transmit paths.
1 Assignment
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Accused Products
Abstract
An antenna array of a base station is calibrated using outbound traffic signals. The antenna array includes a number of sub-arrays. A combiner in the antenna array combines the outbound traffic signals in the sub-arrays into a feedback signal. The outbound traffic signals are captured simultaneously for use as reference signals before the outbound traffic signals enter transmit paths in a radio unit of the base station. Each of the reference signals is one of the outbound traffic signals that is to be transmitted via one of the sub-arrays. An impairment estimator of the base station estimates the impairment for each of the outbound traffic signals based on the feedback signal and the reference signals. An approximate inverse of the impairment estimation is applied to the outbound traffic signals by a number of equalizers before the outbound traffic signals enter the transmit paths.
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Citations
22 Claims
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1. A method for calibrating an antenna array of a base station to remove distortion incurred by transmit paths in abuse station, the antenna array including a plurality of sub-arrays coupled to the transmit paths for transmitting outbound traffic signals to a wireless network, the method comprising the steps of:
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combining the outbound traffic signals in respective ones of the sub-arrays into a feedback signal by a combiner in the antenna array; capturing the outbound traffic signals simultaneously for use as reference signals before the outbound traffic signals enter the transmit paths, each of the reference signals being one of the outbound traffic signals that is to be transmitted via one of the sub-arrays; performing an impairment estimation for each of the outbound traffic signals based on the feedback signal and the reference signals; and applying an approximate inverse of the impairment estimation to the outbound traffic signals before the outbound traffic signals enter the transmit paths to thereby remove the distortion incurred by the transmit paths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A base station that performs calibration of an antenna array to remove distortion incurred by transmit paths in the base station, the antenna array including a plurality of sub-arrays coupled to the transmit paths for transmitting outbound traffic signals to a wireless network, the base station comprising:
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a combiner in the antenna array adapted to combine the outbound traffic signals in respective ones of the sub-arrays into a feedback signal; a feedback receiver adapted to receive the feedback signal from the combiner; an impairment estimator coupled to the feedback receiver, the impairment estimator adapted to receive the outbound traffic signals that are simultaneously captured before entering the transmit paths for use as reference signals, and to perform an impairment estimation for each of the outbound traffic signals based on the feedback signal from the feedback receiver and the reference signals, wherein each of the reference signals is one of the outbound traffic signals that is to be transmitted via one of the sub-arrays; and a plurality of equalizers coupled to the impairment estimator, the plurality of equalizers adapted to apply an approximate inverse of the impairment estimation to the outbound traffic signals before the outbound traffic signals enter the transmit paths to thereby remove the distortion incurred by the transmit paths. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification