Wireless TSN Time Synchronization Using Low-Variability UE Selection
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Solution Overview
Problem
The existing 5G network infrastructure struggles to deliver highly accurate timing information to TSN endpoints, leading to inaccuracies in time synchronization due to the variability of radio links between redundant UEs, which exceed the 1-microsecond end-to-end requirement for demanding industrial applications.
Innovation Solution
Implementing a method to select a UE with the least variability in timing measurements for TSN message timestamping, using RTT-based DL PD compensation and error reduction techniques to minimize errors in the radio links, ensuring accurate delivery of TSN GM clock timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple redundant UEs are used for TSN message delivery, then reliability is improved, but time synchronization accuracy deteriorates due to radio link variability
Solution Approach 1:
The patent implements a feedback mechanism where the RAN node receives timing measurement information from multiple UEs, evaluates their performance based on variability metrics, and dynamically selects the UE with the least variability for TSN message delivery. This feedback loop ensures that the system continuously optimizes time synchronization accuracy while maintaining reliability through redundant UE availability.
Solution Approach 2:
The patent changes the operational parameter of UE selection based on timing measurement variability. By monitoring and comparing timing measurement values from different UEs, the system dynamically identifies and selects the UE exhibiting the least variability, thereby optimizing time synchronization accuracy while maintaining the reliability benefits of having multiple redundant UEs available.
2Measurement precision
If RTT-based DL PD compensation is implemented, then time synchronization accuracy is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary compensation mechanism where the RAN node performs RTT-based downlink propagation delay compensation on behalf of the UEs. The RAN node receives timing measurement information from UEs, calculates the propagation delay compensation, and applies it to the TSN message timestamps before delivery. This intermediary approach improves time synchronization accuracy while distributing the computational complexity to the network infrastructure rather than requiring complex processing at each UE.
Data Source
AI summary
Embodiments include methods for a controller of a plurality of user equipment (UEs) that are served by a radio access network (RAN) node. Such methods include receiving information about the following from each of the UEs: first measurements, UEDL,RX, of respective timing events of the radio link between the UE and the RAN node; and second measurements, UERxTxDiff, of respective time differences between the UE receiving a downlink reference signal, RS, and transmitting a corresponding uplink RS. Such methods also include, based on the received information, selecting one of the plurality of UEs to provide a time-sensitive network (TSN) end station with a TSN message timestamped by a system clock time that is associated with the RAN and that is based on at least one first measurement and at least one second measurement. Other embodiments include complementary methods for a UE, and controllers and UEs configured to perform such methods.