Access Network Clock Synchronization Using Shared GNSS Error Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing clock synchronization methods in communication systems using GNSS receivers for access network devices suffer from errors due to atmospheric and satellite system inaccuracies, which are not adequately addressed by current precision correction techniques, especially for high-accuracy applications like inter-site coordination.
Innovation Solution
A method for clock synchronization between apparatuses within an access network device using time differences calculated from pulse signals and satellite information to adjust local clocks, eliminating common errors and improving synchronization accuracy without relying on a backhaul network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple communication methods (2PC, 3PC, Paxos) are used for clock synchronization, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a primary clock device as an intermediary that centralizes the synchronization function. Instead of having multiple devices directly communicate using complex protocols like 2PC or Paxos, the primary clock device acts as a mediator that distributes time information to secondary clock devices, thereby maintaining reliability while reducing overall system complexity.
Solution Approach 2:
The patent inverts the traditional distributed consensus approach by designating one device as the primary clock authority. Rather than having all devices participate equally in consensus protocols (which increases complexity), one device is elevated to authority status, simplifying the synchronization mechanism while maintaining reliability through centralized time distribution.
2Reliability
If active standby mechanism is used for primary clock device failure, then reliability is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent implements a self-service mechanism where secondary clock devices automatically detect primary clock device failures and elect a new primary from among themselves. This automatic self-healing process eliminates the need for complex manual intervention or pre-configured active standby systems, reducing device complexity while maintaining reliability through automatic failover.
Solution Approach 2:
The patent creates a dynamic system where the primary clock device role is not fixed but can transition between devices based on operational status. This dynamic role assignment allows the system to adapt to failures automatically, improving reliability without requiring static active standby configurations, thereby reducing overall system complexity.
3Measurement precision
If frequent clock information updates are sent, then synchronization precision is improved, but network bandwidth consumption increases
Solution Approach 1:
The patent implements periodic clock information updates where the primary clock device sends time synchronization data at regular intervals rather than continuously. This periodic transmission maintains synchronization precision by providing regular updates while significantly reducing network bandwidth consumption compared to continuous real-time streaming of clock information.
Solution Approach 2:
The patent ensures continuous clock synchronization functionality through periodic updates by maintaining the useful action of time distribution without interruption. The periodic nature of the updates ensures that synchronization remains effective while optimizing network resource usage, achieving continuity of the synchronization service with reduced bandwidth demands.
Data Source
Figure 1~2A
Figure 2B
Figure 3
AI summary
Embodiments of this application provide a clock synchronization method, an apparatus, and a system. The method includes: A first apparatus obtains a first time difference and a second time difference. The first time difference is a time difference between the first apparatus and a satellite, and the first time difference is determined based on a first pulse signal and information about the satellite. The second time difference is a time difference between the second apparatus and the satellite, and the second time difference comes from the second apparatus. The first apparatus and the second apparatus belong to a same access network device. The first apparatus obtains clock synchronization information of the first apparatus based on the first time difference and the second time difference. According to the foregoing method, the first apparatus can eliminate a part of common errors in satellite transmission based on calculation of the first time difference and the second time difference, and improve accuracy of clock synchronization. In addition, the method can be applied in an access network range, so that clock synchronization can be implemented without relying on a backhaul network.