An OTA test system supporting full vehicle 5G MIMO measurement
An intelligent connected vehicle (ICV) is fitted with a myriad of wireless systems (V2X, cellular, Bluetooth, satellite navigation). To ensure the reliability and integrity of vehicle operation, engineers must perform full vehicle communication performance testing in a real environment. The two major challenges of the test are how to perform a near field antenna and EIRP/EIS test under the eccentric condition, and how to rebuild a real-world transmission environment in the lab and execute the MIMO performance test. GTS overcome these challenges with RayBow, an Arc + Arms-based automotive OTA solution, where multiple probes are fixed using electrical switching, and coordinate with the rotation of the vehicle on the turntable to perform 3D wireless performance test.
Test Technology – New
- Spherical near-field scanning + near-to-far-field transformation
Test speed – Fast
- Duration of parallel testing with 8 passive antennas: 45 minutes
- Duration of long-term testing for active antenna SISO: 10 minutes
Test Accuracy – High
- System mechanical accuracy: ±0.02°
- Antenna testing accuracy: ±0.5dB (typical value)
- SISO testing accuracy: ±0.8dB (typical value)
- MIMO testing accuracy: ±1dB (typical value)
Measurable items – All
- Passive measurement
- ICV SISO
- ICV MIMO measurement (patented) option
- EMC test (patented) option
Innovative patented technology to achieve high-precision testing
In order to ensure the accuracy of the measurement results, the main lobe of the test probe must effectively irradiate (that is, full coverage) the radiation position of the antenna under test (often the entire vehicle), as shown in the figure:
In order to achieve high-precision testing, Universal Test has designed a special measurement probe for automobiles. The indicators are as shown in the figure below:
According to the characteristics of the vehicle test, a special MIMO test scheme is designed, and the two-step radiation method is used to achieve accurate and efficient vehicle multi-antenna wireless performance test under complex electromagnetic environment. This solution supports 2×2/4×4 MIMO performance evaluation and is suitable for LTE and 5G sub6G (NSA/SA) communication systems. With the wireless channel emulator, dynamic MIMO tests under standard channel models can be performed, and even environmental simulations of rain, fog, terrain, dynamics, etc., as well as scenario road conditions can be simulated.
The near-far field conversion algorithm is the core of the spherical near-field test system. The general test optimizes the traditional near-far field conversion process, and with the unique probe design, creatively solves the three major challenges of vehicle OTA testing:
- Eccentricity near and far field of large DUT
- Probe Effective Illumination, Cross Polarization, Symmetry Issues
- Probe factor calibration problem in near and far field restoration
When the car is driving, various internal subsystems will affect each other, and the receiving sensitivity of the wireless communication system will be interfered by various noises, and all sensitivity-related tests can use the Desense interference test method. In order to accurately analyze the influence of each module in the car and improve the wireless communication performance of the car, Desense test has become a key indicator of the whole vehicle test.
- Influence of vehicle status on various communication performance
- Influence of in-vehicle equipment on various communication performance
- Influence of vehicle power supply on various communication performance
- Dynamic influence
GTS’s full range of products use high-performance, environmentally friendly fourth-generation absorbing materials based on the world’s leading technology – Universal Testing’s patented polypropylene foam (EPP) absorbing material, which is unmatched by traditional polyurethane sponge (PU) materials. Advantages: moisture-proof, flame-retardant, stable and environmentally friendly.
To meet the sampling requirement of high precision (≥0.1°) for vehicle measurement, GTS has designed an efficient persistent data model to ensure the accuracy and stability of the measurement process and provide users with the most reliable measurement. At the same time, to improve the testing speed and reduce testing costs, the system uses fast measurement algorithms, which can complete the testing in the shortest possible time while ensuring the reliability of the results.
Wavex® Auto also provides result analysis and comparison tool dedicated to automotive testing, which can be used to analyze and compare many kinds of test results on a common computer, including：
- NF test data and FF transformed data comparison
- Different vehicles test data comparison
- Simulated data and tested data comparison
- Different angles 2D and 3D comparison
- Multi-angle and multi-frequency data comparison
- Customized comparison