Frequency-Domain Calibration for Beamforming Antennas

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Solution Overview

Problem

Current calibration methods for beamforming antennas in wireless communication systems, particularly in 5G networks, face challenges such as frequency-selectivity, high signal processing effort, and incompatibility with multi-carrier signals due to the use of time-domain calibration signals, which can lead to distortion and inefficiency.

Innovation Solution

The implementation of frequency-domain calibration signals that are generated and overlaid on operational signals, allowing for more accurate phase and amplitude adjustments, reducing computational complexity, and enabling detailed characterization of signal paths without interfering with operational signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If time-domain calibration signals are used for beamforming antenna calibration, then calibration can be performed, but frequency-selectivity causes distortion and high signal processing effort is required

Engineering Contradiction:
Improvecalibration accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the domain parameter from time-domain to frequency-domain for calibration signals. This transformation allows the calibration system to handle frequency-selective channels more effectively, reducing distortion while lowering computational complexity through efficient frequency-domain processing operations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If time-domain calibration signals are used, then calibration is achieved, but compatibility with multi-carrier signals is poor leading to interference

Engineering Contradiction:
Improvecalibration reliabilityVSAvoidcompatibility with multi-carrier signals
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the calibration approach from time-domain to frequency-domain, which naturally aligns with the frequency-based structure of multi-carrier signals like OFDM. This parameter change enables the calibration signals to coexist with operational multi-carrier signals without causing time-domain interference, improving both reliability and adaptability.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If calibration signals are injected into the antenna during operation, then measurement of antenna performance is possible, but operational signals are masked by calibration signals

Engineering Contradiction:
Improveantenna performance measurementVSAvoidoperational signal quality
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces frequency-domain calibration signals as an intermediary that operates in a separate domain from operational signals. This mediator approach allows calibration measurements to be performed without directly interfering with operational signals in the time domain, as the calibration signals are distinguished through their frequency-domain characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If conventional test equipment is used to evaluate antenna signals, then basic parameters can be measured, but detailed measurements of individual antenna ports are not provided

Engineering Contradiction:
Improvebasic parameter measurementVSAvoiddetailed antenna port characterization
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the calibration and measurement process to operate independently for each antenna port in the frequency domain. This segmentation enables detailed characterization of individual antenna ports while maintaining compatibility with multi-carrier signal structures, providing granular measurement capability that conventional equipment lacks.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3734865B1Beamforming antenna, measurement device and method
Publication Date: 2022.03.30 XILINX INC
  • EP3734865B1 patent drawingFigure 1
  • EP3734865B1 patent drawingFigure 2
  • EP3734865B1 patent drawingFigure 3

AI summary

The present invention provides a beamforming antenna (100, 200) for multi-carrier transmission with multiple sub-carriers, the beamforming antenna (100, 200) comprising a number of signal paths (101, 102, 103, 571, 572) configured to transmit and receive communication signals, a calibration signal (108, 109, 110, 111, 208, 211, 308) generator (107, 207) that is configured to generate for the signal paths (101, 102, 103, 571, 572) a number of calibration signals (108, 109, 110, 111, 208, 211, 308) with the sub-carriers of the multi-carrier transmission in the frequency domain, the calibration signals (108, 109, 110, 111, 208, 211, 308) comprising a calibration sub-signal in at least one of the sub-carriers of the respective calibration signal (108, 109, 110, 111, 208, 211, 308), and a supply element (112, 113, 114, 115, 212, 213, 214) configured to supply the calibration signals (108, 109, 110, 111, 208, 211, 308) to the respective signal paths (101, 102, 103, 571, 572). Further, the present invention provides a respective measurement device (680) and a respective method.