Antenna Array Calibration via Switched Coupler Network
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current antenna array technologies in wireless communication systems face challenges in calibration, particularly during live network traffic, with existing methods either degrading network performance or failing to accurately correct for latency, phase, and amplitude errors across multiple antenna paths.
Innovation Solution
A method and apparatus for calibrating active antenna arrays using a switched coupler structure that allows for simultaneous calibration of receive and transmit paths, employing a common signal processing approach to correct for latency, phase, and amplitude errors, while minimizing impact on live network performance by using a test signal and normalizing measurement values across the array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If calibration is performed using existing methods during live network traffic, then network operations continue, but network performance degrades and calibration accuracy is compromised
Solution Approach 1:
The calibration process is segmented into path-specific calibration steps, where each antenna path is calibrated individually using a switched coupler structure. This allows calibration to be performed on one path at a time while others remain operational, maintaining network continuity while achieving accurate calibration through systematic division of the calibration task.
Solution Approach 2:
A switched coupler structure is introduced as an intermediary component that enables test signal injection and measurement without disrupting live network traffic. The coupler acts as a mediator between the calibration system and the antenna paths, allowing calibration measurements to be taken while maintaining normal network operations on other paths.
2Ease of operation
If conventional beam-forming with fixed beam pattern is used, then simple receive processing is achieved, but signals outside the main lobe are significantly attenuated and calibration errors persist
Solution Approach 1:
The system transitions from fixed beam-forming to dynamic adaptive beam-forming where beam patterns can be adjusted and optimized for different signal conditions. The calibration system enables dynamic compensation of path-specific errors, allowing the beam-forming process to adapt to varying signal environments and improve reception accuracy for signals both within and outside the main lobe.
Solution Approach 2:
The calibration process modifies key parameters including phase, amplitude, and latency for each antenna path based on measured error characteristics. These parameter adjustments enable the system to compensate for path-specific variations and improve signal reception accuracy across different spatial directions, overcoming the limitations of fixed beam patterns.
3Loss of time
If multiple antenna paths are calibrated simultaneously, then calibration time is reduced, but latency, phase, and amplitude errors across paths cannot be accurately corrected
Solution Approach 1:
The calibration process is divided into sequential path-specific steps rather than attempting simultaneous calibration of all paths. Each path is calibrated individually through the switched coupler structure, allowing accurate measurement and correction of latency, phase, and amplitude errors for each path while maintaining overall calibration efficiency through systematic organization.
Solution Approach 2:
The switched coupler structure is temporarily connected to each antenna path during its calibration phase, then switched to the next path. This temporary connection and switching mechanism enables precise per-path calibration measurements to be taken sequentially, recovering accurate error data for each path while minimizing total calibration time through efficient switching between paths.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for calibrating (700) an antenna array comprises a plurality of antenna elements coupled to a plurality of respective receive paths in a wireless communication system. The method comprises, in receive mode, applying a test signal to an individual single receive path (715) of the plurality of receive paths; and feeding back the test signal via a switched coupler network. The method further comprises running a receive calibration measurement routine to determine at least one measurement value used to calibrate the individual signal receive path and waiting for at least one converged measurement value; and extracting (720) the converged measurement value for at least one individual receive path. The steps of applying, running, extracting for a next individual single receive path are repeated until the calibration routine has completed (725). The method further comprises selecting a converged measurement value of at least one individual receive path from a plurality of receive paths (730) to form a reference receiver calibration result (730); normalizing a plurality of at least one measurement values of the plurality of receive paths using the reference receiver calibration result (730); and applying a normalized value to at least one of the plurality of receive paths.