5G UE Propagation Delay Compensation for TSN Synchronization
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Solution Overview
Problem
The 5G system faces challenges in achieving stringent time synchronization accuracy for Time Sensitive Networks (TSN) due to increased uncertainty when TSN Grandmaster clocks are located at end stations connected to user equipment (UE) with different gNodeBs, leading to higher propagation delays and synchronization errors.
Innovation Solution
The UE provides information to the gNB to preferentially use Timing Advance (TA) or Round-Trip Time (RTT) based propagation delay estimation methods for accurate clock synchronization, allowing the UE or gNB to perform propagation delay compensation, thereby reducing synchronization errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TSN Grandmaster clocks are located at end stations connected to different gNodeBs, then the 5G system can support distributed time-sensitive applications, but propagation delay uncertainty increases leading to synchronization errors
Solution Approach 1:
The patent implements a feedback mechanism where the UE measures the actual propagation delay between itself and the gNB, then reports this measurement back to the gNB. The gNB uses this feedback information to adjust timing parameters and compensate for propagation delays, thereby maintaining synchronization accuracy in distributed TSN scenarios with multiple gNBs.
Solution Approach 2:
The patent replaces traditional TSN synchronization mechanisms (which rely on IEEE 802.1AS Grandmaster clocks and PTP protocols) with a 5G-native synchronization approach using NR SSB (Synchronization Signal Block) timing information. This substitution leverages the inherent timing precision of 5G NR synchronization signals to achieve accurate time synchronization without relying on external TSN Grandmaster clocks, thereby reducing propagation delay uncertainty.
2Measurement precision
If propagation delay compensation is performed using traditional TSN methods, then time synchronization can be achieved, but system complexity and power consumption increase
Solution Approach 1:
The patent enables the UE to autonomously measure its own propagation delay to the gNB using downlink synchronization signal timing information, without requiring complex external TSN synchronization infrastructure. The UE performs self-service timing measurements and reports results to the gNB, which then applies compensation, significantly reducing overall system complexity compared to traditional TSN Grandmaster clock architectures.
Solution Approach 2:
The patent makes the 5G NR synchronization system multi-functional by using the same NR SSB synchronization signals for both initial access/cell search and propagation delay measurement for TSN time synchronization. This universal use of synchronization signals eliminates the need for separate dedicated synchronization channels or external TSN Grandmaster clocks, thereby reducing device complexity and power consumption while maintaining synchronization accuracy.
Data Source
AI summary
A method (1600) implemented by a terminal device (600) is provided. The method includes transmitting (1602) information about a first preference of the terminal device to use a timing advance, TA, based propagation delay estimation or a round-trip time, RRT, based propagation delay estimation. For example, the first preference may include at least one of: a preference of the terminal device for at least one downlink reference signal; a preference of the terminal device for at least one uplink reference signal; and a preference of the terminal device for at least one physical random access channel, PRACH, transmission on an uplink. As another example, the first preference indicates a preference of the terminal device to use a network node based propagation delay estimation or a terminal device based propagation delay estimation.