Antenna array calibration method and apparatus
First Claim
1. A time domain calibration method to compensate for signal impairment in transmit paths in a transmitter configured to drive an antenna array, the method comprising:
- receiving a feedback signal formed from a combination of a plurality of outbound signals couple-able to a plurality of antenna ports;
capturing at least one outbound signal as a reference signal before the at least one outbound signal is input to a transmit path;
performing an impairment estimate based on the at least one reference signal and the feedback signal;
wherein performing the impairment estimate includes implementing a conjugate gradient method to produce an impairment vector, H, the impairment vector H usable to determine the phase compensation;
determining a phase compensation from the impairment estimate for each of the at least one outbound traffic signal; and
applying the phase compensation to a respective one of the at least one outbound traffic signal before the at least one outbound traffic signal is input to the transmit path and before the at least one outbound traffic signal is captured to form the at least one reference signal.
1 Assignment
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Accused Products
Abstract
A method and system for time domain calibration to compensate for signal phase impairment in transmit paths in a transmitter configured to drive an antenna array are disclosed. According to one aspect, a base station is configured to compensate for signal impairment in transmit paths feeding an array of antenna elements in which the compensation is performed in the time domain. The base station includes a combiner configured to combine signals output from the transmit paths to form a feedback signal. An impairment estimator is configured to receive the feedback signal and outbound traffic signals and to determine a phase compensation value for each impairment path. A multiplier is provided for each transmit path, the multipliers configured to multiply the outbound traffic signals by respective phase compensation values.
6 Citations
22 Claims
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1. A time domain calibration method to compensate for signal impairment in transmit paths in a transmitter configured to drive an antenna array, the method comprising:
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receiving a feedback signal formed from a combination of a plurality of outbound signals couple-able to a plurality of antenna ports; capturing at least one outbound signal as a reference signal before the at least one outbound signal is input to a transmit path; performing an impairment estimate based on the at least one reference signal and the feedback signal;
wherein performing the impairment estimate includes implementing a conjugate gradient method to produce an impairment vector, H, the impairment vector H usable to determine the phase compensation;determining a phase compensation from the impairment estimate for each of the at least one outbound traffic signal; and applying the phase compensation to a respective one of the at least one outbound traffic signal before the at least one outbound traffic signal is input to the transmit path and before the at least one outbound traffic signal is captured to form the at least one reference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A transmitter configured to compensate for signal impairment in transmit paths of the transmitter that couple outbound traffic signals to antennas of an antenna array, the compensation being performed in a time domain, the transmitter comprising:
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a plurality of transmit paths, each transmit path coupling an outbound traffic signal to a port of an antenna element of the antenna array; a combiner switch configured to combine signals output from the transmit paths to form a feedback signal; an impairment estimator unit configured to produce a phase compensation value based on at least one reference signal and the feedback signal, the at least one reference signal being an outbound traffic signal after being multiplied by the phase compensation value and wherein the impairment estimator unit implements a conjugate gradient method to produce an impairment vector, H, the impairment vector H usable to determine the phase compensation value; and at least one multiplier device configured to multiply each of at least one outbound traffic signal by a phase compensation value before the at least one outbound traffic signal is coupled to a respective transmit path. - View Dependent Claims (12, 13, 14, 15)
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16. A base station configured to compensate for signal phase impairment in transmit paths feeding an array of antenna elements, the compensation being performed in a time domain, the base station comprising:
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a combiner switch configured to combine signals output from the transmit paths to form a feedback signal; an impairment estimator unit configured to receive the feedback signal and outbound traffic signals and to determine a phase compensation value for each impairment path wherein the impairment estimator unit implements a conjugate gradient method to produce an impairment vector, H, the impairment vector H usable to determine the phase compensation value; and a multiplier device for each transmit path, the multipliers device configured to multiply the outbound traffic signals by respective phase compensation values. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification