FDD Signal Path Calibration Using Variance Thresholds

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Solution Overview

Problem

In Frequency Division Duplex (FDD) systems, signal processing paths require calibration to match electrical parameters like magnitude, phase, and bulk delay within specified tolerances, but existing methods struggle to ensure precise matching across multiple paths without impacting regulatory spectral emission masks and spurious emissions.

Innovation Solution

A method involving a beamforming calibration system that calculates calibration weights and applies them to signal processing paths, using calibration data to adjust phase and magnitude variations, ensuring compliance with tolerance thresholds and regulatory specifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If calibration is performed to match electrical parameters within tight tolerances, then manufacturing precision is improved, but device complexity increases due to multiple signal processing paths requiring separate calibration

Engineering Contradiction:

Improveparameter matching precisionVSAvoidsignal processing path complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The calibration process is segmented into multiple independent calibration paths, each handling specific signal processing routes separately. This allows precise calibration of each path while managing the overall complexity through modular organization of calibration procedures

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A reference signal is introduced as an intermediary element to facilitate calibration across multiple paths. The reference signal serves as a common benchmark that enables comparison and matching of electrical parameters across different signal processing paths without requiring direct comparison between all paths

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If signal processing paths are calibrated to match characteristics within tolerance, then reliability is improved, but the calibration process becomes more difficult to detect and measure

Engineering Contradiction:

Improvesignal path matching reliabilityVSAvoidcalibration measurement difficulty

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The system employs feedback mechanisms where calibration results are measured and used to adjust calibration weights iteratively. The reference signal provides a feedback reference that enables detection of parameter mismatches and guides the calibration process to achieve reliable matching within tolerances

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

Traditional physical measurement methods are replaced with signal processing-based measurement techniques. Electrical parameters are measured and compared through digital signal processing of the reference signal, making the calibration measurement process more precise and easier to detect than physical mechanical measurements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If calibration weights are applied to multiple signal processing paths, then productivity is improved through efficient signal processing, but loss of information increases due to potential mismatches in magnitude, phase, and delay

Engineering Contradiction:

Improvesignal processing efficiencyVSAvoidsignal parameter distortion

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

Different calibration weights are applied to different signal processing paths based on their specific characteristics. Each path receives customized calibration parameters (magnitude, phase, delay adjustments) tailored to its local requirements, preventing information loss while maintaining processing efficiency

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The calibration process dynamically adjusts electrical parameters (magnitude, phase, bulk delay) of calibration weights based on measured deviations from the reference signal. By changing these parameters iteratively, the system compensates for path-specific distortions and preserves signal information integrity

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8179314B2Enhanced calibration for multiple signal processing paths in a frequency division duplex system

Publication Date: 2012.05.15 VIAVI SOLUTIONS INC(US)

AI summary

Calibrating signal processing paths for a plurality of transmission devices by obtaining calibration data for at least one of the signal processing paths for each of the transmission devices and determining a plurality of calibration weights from the calibration data for each of the transmission devices. A calibration variance is calculated between the plurality of calibration weights and it is determined if the calibration variance is below a calibration variance threshold. Additionally, a phase variation and a magnitude variation are calculated from the calibration data for each of the transmission devices and it is determined for each of the transmission devices if the phase variation is below a phase variation threshold and if the magnitude variation is below a magnitude variation threshold. Further, if the calibration variance is below the calibration variance threshold, and the phase variation is below the phase variation threshold and the magnitude variation is below the magnitude variation threshold for each of the transmission devices, then the plurality of calibration weights are applied to the at least one of the signal processing paths of each of the transmission devices.