Hardware Clock Time Stamping for Wireless Delay Measurement
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Solution Overview
Problem
Current wireless communication systems lack an effective method to accurately determine the delay time between communication entities, which is crucial for verifying communication technology performance, especially in high-speed applications like autonomous driving, where minimal processing and propagation delays are necessary.
Innovation Solution
A method and system utilizing time stamp devices with synchronized hardware clocks, integrated with global navigation satellite system (GNSS) units, to provide precise timing information for data packets, allowing for the determination of both processing and propagation delays by comparing time stamps on the transmitting and receiving sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hardware time stamping is used to improve measurement precision, then delay time measurement accuracy is improved, but device complexity increases due to additional hardware clock and GNSS unit
Solution Approach 1:
The hardware clock is designed to serve multiple functions: it provides timing for time stamping data packets, synchronizes with GNSS master clock for global time reference, and enables both processing delay and propagation delay measurements through a single integrated timing mechanism
Solution Approach 2:
The GNSS master clock acts as an intermediary reference that synchronizes multiple hardware clocks across different wireless communication entities, enabling accurate delay measurement without requiring direct complex synchronization between all entities
2Device complexity
If time stamping is performed at higher layers to simplify device structure, then device complexity is reduced, but measurement precision deteriorates due to additional delay and jitter during processing
Solution Approach 1:
The time stamping function is extracted from higher protocol layers and placed at the physical layer where data packets first enter the system, eliminating the additional delay and jitter that would occur during processing at higher layers
3Reliability
If continuous synchronization is performed to improve reliability, then timing accuracy is improved, but loss of time increases due to iterative synchronization intervals
Solution Approach 1:
The hardware clock performs synchronization with the GNSS master clock at periodic intervals rather than continuously, maintaining timing accuracy while reducing the time overhead associated with constant synchronization operations
Data Source
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AI summary
A method for determining a delay time between two wireless communication entities (12, 16) is described, with the following steps: - Synchronizing a global navigation satellite system clock (42) of a global navigation satellite system unit (34) with a global navigation satellite system master clock (48), said global navigation satellite system unit (34) being allocated to a first wireless communication entity (12); - Synchronizing said global navigation satellite system clock (42) with a hardware clock (32) in a first payload data interface unit (30) by using a clock synchronization protocol; - Routing at least one data packet from a second payload data interface unit (31) to said first payload data interface unit (30) or vice versa; and - Providing a first time stamp of said data packet by using said hardware clock (32). Further, a time stamp device (28) and a system (10) are described.