Active Antenna Calibration Using Coupler Network Phase Compensation
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Solution Overview
Problem
Current antenna calibration methods for active antenna systems in 5G technology are costly and complex, requiring stringent hardware guarantees or cascading calibration methods that involve complicated setups and are prone to calibration errors.
Innovation Solution
A method for antenna calibration that generates test signals based on multi-carrier code division multiple access (MC-CDMA) and uses a root sequence transformed by inverse fast Fourier transformation, transmitted over multiple antennas, with calibration information determined by phase difference analysis between received signals from the antennas and coupler network, allowing for accurate compensation of coupler network influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cascading calibration methods are used, then calibration can be performed, but the setup becomes complicated and calibration errors increase
Solution Approach 1:
The calibration process is segmented into distinct phases: test signal generation at baseband, transmission through the coupler network, feedback reception, and calibration parameter calculation. This segmentation allows each component to be calibrated independently using simplified procedures rather than requiring complex cascading setups.
Solution Approach 2:
A feedback signal path is introduced as an intermediary mechanism that carries calibration information from the antenna output back to the baseband processor. This feedback loop enables the system to self-calibrate by measuring the actual transmitted signals and adjusting parameters accordingly, eliminating the need for complex external calibration equipment.
2Measurement precision
If stringent hardware guarantees are required, then calibration accuracy improves, but system cost increases
Solution Approach 1:
The system performs self-calibration by using its own transmitted test signals as the reference for calibration. The baseband processor generates test signals, transmits them through the coupler network via antennas, receives feedback, and automatically calculates calibration parameters without requiring external calibration equipment or stringent hardware guarantees.
Solution Approach 2:
The calibration method changes the operational parameters of the system by injecting known test signals with specific characteristics (training sequences, spreading codes) and measuring the actual transmitted signals. By comparing expected versus actual parameters, the system dynamically adjusts calibration parameters to compensate for coupler network variations without requiring expensive precision hardware.
3Reliability
If phase alignment is achieved through traditional methods, then beamforming effectiveness improves, but the calibration process becomes time-consuming
Solution Approach 1:
The calibration process is designed to be continuous and integrated with normal system operation. Test signals are generated and processed through the same signal path used for actual beamforming operations, allowing calibration to be performed without interrupting system functionality and enabling rapid phase alignment adjustment.
Solution Approach 2:
Calibration parameters are calculated in advance during system initialization or maintenance periods using the feedback mechanism. Once determined, these calibration parameters are stored and applied to subsequent beamforming operations, eliminating the need for repeated time-consuming calibration processes while maintaining phase alignment accuracy.
Data Source
AI summary
A method for antenna calibration for an active antenna system is disclosed. According to an embodiment, test signals are generated for multiple antennas of the active antenna system. The test signals are transmitted via the multiple antennas. A first signal that results from the transmission of the test signals is received over the air. A second signal is received from a coupler network of the active antenna system. The coupler network is configured to generate coupled signals of the test signals and combine the coupled signals into the second signal. Calibration information for compensating an influence of the coupler network is determined based on the first and second signals. An active antenna system is also disclosed for use in antenna calibration.