Virtual Cable Calibration for Accurate FR2 OTA Conformance Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining a valid virtual cable calibration (VCC) matrix in over the air (OTA) testing are computationally complex and time-consuming, making it difficult to achieve accurate conformance testing for multi-Rx reception in FR2 due to unguided wireless channels causing crosstalk and interference.
Innovation Solution
A method where the device under test (DUT) estimates an overall channel using downlink training signals and transmits a representation of this channel to the test equipment, allowing the test equipment to derive a virtual cable calibration matrix for pre-compensating the OTA channel portion, thereby establishing a wireless/virtual cable connection for conformance testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional conducted testing methods using transmission lines are used for FR1, then measurement precision is improved, but device complexity increases and ease of operation deteriorates when applied to FR2
Solution Approach 1:
The patent replaces the mechanical cable connection system with an over-the-air wireless testing system. Instead of using physical transmission lines (coaxial cables) to connect the DUT to the test system, the invention uses wireless signal transmission through probes positioned in a testing chamber. This substitution enables FR2 testing without requiring physical connectors, which are incompatible with bonded mmWave antennas, while maintaining measurement precision through careful channel estimation and compensation.
2Ease of operation
If over the air testing approaches are used for FR2, then ease of operation is improved, but measurement precision deteriorates due to unguided wireless channels causing crosstalk and interference
Solution Approach 1:
The patent applies preliminary action by performing channel estimation and virtual cable calibration before the actual conformance testing. The DUT first estimates the OTA channel characteristics using training signals transmitted from the probes. This preliminary channel information is then used to derive a virtual cable calibration matrix that compensates for crosstalk and interference. By preparing the channel compensation in advance, the system eliminates measurement precision deterioration during the actual testing phase while maintaining the ease of operation of OTA testing.
Solution Approach 2:
The patent implements feedback through the channel estimation and compensation mechanism. The DUT estimates the OTA channel based on training signals and feeds back this channel information to the test equipment. The test equipment then uses this feedback to derive a virtual cable calibration matrix that compensates for channel imperfections. This feedback loop enables the system to adapt to the actual wireless channel conditions and maintain measurement precision despite the unguided nature of OTA transmission.
3Measurement precision
If virtual cable calibration is performed using existing methods, then measurement precision is improved, but productivity deteriorates due to computational complexity and time consumption
Solution Approach 1:
The patent applies self-service by enabling the DUT to autonomously estimate the OTA channel using training signals received from the probes. Instead of requiring the test equipment to perform complex channel estimation and calibration calculations, the DUT itself performs the channel estimation and transmits the estimated channel information back to the test equipment. This self-service approach significantly reduces the computational burden on the test system and accelerates the calibration process, thereby improving productivity while maintaining measurement precision.
Data Source
AI summary
Various example embodiments relate to devices, methods, apparatuses and computer readable mediums for virtual cable calibration in over the air conformance testing. In an example embodiment, a terminal device may receive training signals from at least four probes, estimate a channel based on the received training signals, and transmit a representation of the estimated channel to a test equipment coupled to the at least four probes. The terminal device and the at least four probes are positioned in a testing chamber. The estimated channel includes an over the air, OTA, channel portion between the at least four probes and the terminal device. The representation of the estimated channel is transmitted to the test equipment for compensation of the OTA channel portion.