Delay Offset for TSN Synchronization Error
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Solution Overview
Problem
In 5G wireless communications, the inaccuracy of clock synchronization in time-sensitive networks (TSN) due to radio frequency propagation delay is not adequately addressed by existing methods, particularly in industrial IoT applications, where precise timing is crucial for factory automation and other use cases.
Innovation Solution
A method is introduced where network nodes determine and transmit a common delay offset based on the cell's radius or average distance to wireless devices, incorporating a non-line-of-sight factor, to compensate for propagation delay errors, using system information blocks (SIB) and radio resource control (RRC) messages, allowing devices to adjust their clock synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 1/2 timing advance (TA) is used to mitigate RF propagation delay, then synchronization error is reduced, but TA accuracy is insufficient for accurate end-to-end timing delivery in TSN networks due to its design purpose for aligning uplink transmissions with Cyclic Prefix error independent of RF path distance
Solution Approach 1:
The patent changes the parameter used for delay compensation from timing advance (designed for uplink alignment with CP error) to a downlink-specific delay offset based on cell radius and propagation speed. This parameter change addresses the mismatch between TA's original purpose and TSN timing requirements, providing accurate end-to-end timing delivery by using parameters specifically designed for downlink clock synchronization.
2Measurement precision
If a common delay offset based on cell radius is applied to all wireless devices, then timing accuracy is enhanced for the majority of devices, but devices at different distances from the network node experience varying levels of synchronization accuracy
Solution Approach 1:
The patent applies local quality by determining delay offset based on the specific cell's radius and characteristics rather than using a universal compensation value. The network node calculates a common delay offset tailored to its coverage area, and devices apply this offset specific to their local cell environment. This provides optimized synchronization for each cell while maintaining simplicity, balancing local accuracy with broader applicability.
3Measurement precision
If delay offset information is transmitted to wireless devices, then propagation delay errors are compensated, but system overhead increases due to additional signaling in SIB and RRC messages
Solution Approach 1:
The patent achieves universality by integrating delay offset information into existing SIB and RRC message structures already used for system information broadcast and device management. Rather than creating separate dedicated signaling channels, the delay compensation data is embedded in multi-purpose messages that devices already receive for other functions, thereby providing delay compensation without adding separate signaling overhead.
Data Source
AI summary
A method, system and apparatus are disclosed for a network node configured to communicate with a wireless device (WD). In some embodiments, the network node includes processing circuitry configured to cause the network node to determine delay offset information based at least in part on a common distance for a cell, the delay offset information indicating a common temporal delay offset and transmit the delay offset information to the WD in at least one of a system information block, SIB, and a radio resource control, RRC, message. In some embodiments, a wireless device includes processing circuitry configured to cause the wireless device to receive delay offset information in at least one of a system information block, SIB, and a radio resource control, RRC, message, the delay offset information being based at least in part on a common distance and the delay offset information indicating a common temporal delay offset.