Wireless TSN Time Sync Using UE Selection and Delay Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless networks face inaccuracies in time synchronization due to radio links of redundant UEs, which are major contributors to errors in delivering TSN GM clock timing information, particularly in 5G-TSN integrated networks, failing to meet the stringent 1-µs end-to-end accuracy requirements for demanding industrial applications.
Innovation Solution
Implementing methods for a controller to select a UE with the least variability in radio link measurements, such as UE DL,Rx and UE RxTxDiff, to provide a timestamped TSN message based on system clock time, and compensating for propagation delays to reduce timing errors, thereby improving time synchronization accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time synchronization is achieved through wireless network messages between distributed clocks, then time synchronization can be maintained across the network, but time synchronization accuracy is insufficient for certain applications
Solution Approach 1:
A reference clock device is introduced as an intermediary between GPS satellites and distributed clocks. The reference clock receives precise time from GPS and distributes it to other clocks through wireless messages, serving as a mediator that bridges satellite-based time and network-based time distribution to achieve both high accuracy and reliability
Solution Approach 2:
The reference clock pre-processes and stores time synchronization data received from GPS satellites before distributing it to distributed clocks. By preparing time data in advance and maintaining a local time reference, the system ensures continuous high-accuracy synchronization even when GPS signals are temporarily unavailable
2Measurement precision
If multiple messages are used for time synchronization, then synchronization can be maintained, but the time required to achieve synchronization increases
Solution Approach 1:
The reference clock pre-calculates and stores time offset values and synchronization data from GPS before they are needed by distributed clocks. This preliminary preparation allows distributed clocks to quickly obtain accurate time information without requiring multiple iterative message exchanges, significantly reducing synchronization time
Solution Approach 2:
The time synchronization process is segmented into independent operations: GPS time reception by the reference clock, local time processing and storage, and distributed time delivery to client clocks. This segmentation allows each component to operate independently and efficiently, reducing overall synchronization time while maintaining accuracy
Data Source
Figure 1
Figure 2
Figure 3~4
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, UE DL,RX, of respective timing events of the radio link between the UE and the RAN node; and second measurements, UE RxTxDiff, 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.