Wireless Clock Synchronization via UPF Delay Compensation
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Solution Overview
Problem
Current wireless communication systems, particularly 5G networks, face challenges in providing clock synchronization across terminals, which is typically supported in wired networks but not effectively in wireless environments, leading to propagation delay asymmetry issues between uplink and downlink air links.
Innovation Solution
The implementation of a method and apparatus in wireless communication systems that receive parameters for packet delay budget, loss tolerance, and priority to schedule packets and perform clock synchronization, utilizing a user plane function (UPF) and terminal processors to manage link delay times, residence times, and backhaul delays for accurate synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless communication systems use conventional packet scheduling without clock synchronization, then system simplicity is maintained, but propagation delay asymmetry between uplink and downlink causes timing errors and synchronization failures
Solution Approach 1:
The system performs preliminary measurements of air interface propagation delays and pre-calculates compensation values before actual packet transmission. The network entity stores these pre-computed timing adjustment parameters and applies them automatically during packet scheduling, eliminating the need for real-time synchronization calculations while maintaining accurate timing alignment between uplink and downlink transmissions
Solution Approach 2:
A network entity acts as an intermediary between the terminal and the packet scheduling system. This intermediary measures propagation delays, calculates compensation parameters, and provides timing adjustment information to the scheduler. By introducing this intermediate layer, the system achieves precise clock synchronization without requiring complex modifications to the existing packet scheduling architecture
2Measurement precision
If the system implements precise packet scheduling based on multiple delay parameters, then clock synchronization accuracy is improved, but the complexity of parameter management and processing increases
Solution Approach 1:
The system combines multiple delay parameters (air interface propagation delay, processing delay, transmission delay) into a single composite timing adjustment parameter. By merging these separate measurements and calculations into one unified compensation value, the system achieves precise delay compensation while simplifying the parameter management process and reducing the computational burden on network entities
Solution Approach 2:
The system transforms complex multi-parameter delay measurements into simplified timing adjustment parameters that can be directly applied during packet scheduling. By changing the form and representation of delay parameters from multiple separate values to consolidated timing offsets, the system maintains measurement precision while reducing processing complexity
3Adaptability or versatility
If wireless networks support time-sensitive applications requiring clock synchronization, then adaptability to TSN requirements is improved, but propagation delay asymmetry causes synchronization failures
Solution Approach 1:
The system performs preliminary measurements of air interface propagation delays and pre-calculates compensation parameters to counteract the asymmetric delay effects before time-sensitive packets are transmitted. By applying these pre-computed timing adjustments in advance, the system eliminates synchronization errors that would otherwise occur during actual TSN operation, ensuring reliable clock synchronization for time-sensitive applications
Data Source
AI summary
The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as long term evolution (LTE). According to various embodiments of the disclosure, an operating method of a user plane function (UPF) in a wireless communication system and an apparatus therefor are provided. The operating method includes receiving a first parameter for clock synchronization from a base station, and performing the clock synchronization with a neighboring network system using the received first parameter and a second parameter. The first parameter may include information relating to a link delay time between the neighboring network system and a network system comprising the UPF, and a residence time of a terminal, a base station and the UPF of the network system comprising the UPF, and the second parameter may include information relating to a backhaul delay time between the base station and the UPF.