1588 Time Synchronization Offset Compensation for Asymmetric Delays
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Solution Overview
Problem
Current time synchronization methods based on the IEEE 1588 protocol face challenges in achieving high precision due to errors caused by asymmetric delays in optical fibers and internal device offsets, which are not effectively addressed by existing solutions, particularly in advanced communication systems like LTE and 5G that require synchronization precision beyond microseconds.
Innovation Solution
A method and apparatus for adjusting the 1588 time synchronization offset by determining and compensating for asymmetrical delays and internal offsets, using GPS time as a reference to improve precision, and sharing offset values between terminals and management devices to reduce labor costs and enhance network deployment efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time synchronization is performed based on the IEEE 1588 protocol, then time synchronization can be achieved, but synchronization precision is limited to microseconds or less due to asymmetric delays and internal offsets
Solution Approach 1:
The patent introduces a terminal device as an intermediary that performs additional compensation operations. The terminal device calculates a second time offset value based on uplink and downlink time difference information, and uses this to compensate for the first time offset value obtained from the 1588 protocol. This intermediary compensation mechanism addresses the precision limitations of the standard 1588 protocol by adding a correction layer that accounts for asymmetric delays and internal offsets.
Solution Approach 2:
The patent replaces the purely protocol-based time synchronization mechanism (1588 protocol) with a hybrid approach that combines protocol-based synchronization with calculation-based compensation. Instead of relying solely on the mechanical/protocol-based 1588 time offset, the system substitutes in a calculated compensation value derived from measuring actual uplink and downlink time differences, thereby achieving higher precision.
2Measurement precision
If standard 1588 protocol is used for time synchronization, then implementation is simple, but synchronization precision cannot meet the requirements of LTE and 5G services which require precision better than microseconds
Solution Approach 1:
The patent segments the time synchronization process into two distinct parts: the first time offset value obtained from the 1588 protocol and the second time offset value calculated from uplink-downlink time differences. By dividing the compensation process into these separate segments, the system can apply different methods to different parts of the offset calculation, maintaining simplicity where possible while adding precision where needed.
Solution Approach 2:
The patent performs preliminary measurement of uplink and downlink time differences to calculate the second time offset value before applying the final compensation. This preliminary action of measuring and calculating the compensation value in advance allows the system to prepare accurate correction data that can be applied to improve synchronization precision without adding complex real-time processing requirements during critical synchronization events.
Data Source
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AI summary
Embodiments of this application provide a time synchronization offset adjustment method and apparatus, a terminal, and an access layer device. The method includes: compensating, on a 1588 terminal or an access layer device based on a 1588 time offset value, for a 1588 time obtained through synchronization. This reduces an error caused by asymmetric delays on transmit and receive links, and improves precision of the 1588 time obtained through synchronization.