GNSS Propagation Delay Testing for 5G Grandmaster Timing
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Solution Overview
Problem
Current methods fail to accurately account for propagation delays in Global Navigation Satellite System (GNSS) antenna to Grandmaster Clock (GM) communication paths, leading to reduced precision in 5G Radio Access Network (RAN) timing synchronization, which is critical for achieving stringent time error requirements.
Innovation Solution
A test device is used to determine unknown propagation delays in the GNSS signal distribution system (GSDS) between a GNSS antenna and a GM, allowing for precise programming of a GM offset to correct timing accuracy in 5G RANs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If propagation delays in GNSS signal distribution system are not measured and compensated, then device complexity is reduced, but timing precision in 5G RAN deteriorates
Solution Approach 1:
A test device is introduced as an intermediary between the GNSS antenna and the Grandmaster Clock to measure propagation delays. This separate measurement device allows timing precision to be improved without permanently increasing the complexity of the main synchronization system, as the test device can be removed or deactivated when not in use.
Solution Approach 2:
Propagation delays are measured and compensated in advance before actual 5G RAN operations begin. The test device performs preliminary characterization of the GNSS signal distribution system, and the measured delay values are stored for later compensation during normal operation, eliminating the need for continuous complex measurements.
2Measurement precision
If propagation delays are accurately measured and compensated, then timing precision is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The test device serves as a specialized intermediary instrument designed specifically for measuring propagation delays in GNSS signal distribution systems. This dedicated measurement tool simplifies the detection and measurement process compared to using general-purpose equipment, as it is purpose-built for this specific measurement task.
Solution Approach 2:
The patent replaces complex manual measurement procedures with an automated test device that electronically measures propagation delays. The system uses signal processing and electronic timing mechanisms rather than manual observation and calculation, significantly reducing the difficulty of detection and measurement.
3Measurement precision
If GM offset is programmed to correct timing accuracy, then timing precision is improved, but loss of time occurs during programming and configuration
Solution Approach 1:
Propagation delays are measured and GM offset values are calculated in advance during system installation or maintenance windows. Once determined, these offset values are programmed into the Grandmaster Clock and remain valid for extended periods, eliminating the need for frequent re-programming and reducing time loss during normal operations.
Solution Approach 2:
The test device provides feedback about the actual propagation delays measured in the GNSS signal distribution system. This feedback information is used to calculate appropriate GM offset values that compensate for the measured delays, creating a closed-loop system that improves timing precision through informed configuration rather than trial and error.
Data Source
AI summary
A test device determines a Global Navigation Satellite System (GNSS) signal propagation delay in a GNSS signal distribution system (GSDS) for a radio access network, and can further perform long-term tests on a GSDS without having access to a GNSS satellite. The test device includes a GNSS receiver and a clock that can be re-tuned to accommodate performing tests on the GSDS.