Time Synchronization in Distributed Base Station Networks
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Solution Overview
Problem
Current distributed base station networks face challenges in maintaining consistent time synchronization between radio equipment control (REC) and radio equipment (RE) units, which is crucial for ensuring accurate air interface frequency and communication delay stability, especially when using optical fibers for connectivity.
Innovation Solution
A time synchronization method and system where network devices connected to REC and RE record and transmit time stamps and system clocks to maintain synchronization, allowing for the calculation and compensation of transmission delays to ensure consistent communication delay across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time synchronization is maintained between REC and RE through optical fiber connection, then communication delay stability is improved, but system complexity increases due to the need for time stamp recording and transmission
Solution Approach 1:
The patent introduces time stamp messages as intermediary elements that carry timing information between REC and RE. These time stamp messages act as mediators that enable synchronization without requiring direct complex interaction between the main devices, thus improving reliability while managing complexity through standardized messaging protocols
Solution Approach 2:
The patent implements a feedback mechanism where time stamp messages are exchanged bidirectionally between REC and RE. Each device records reception time stamps and transmits them to the other device, creating a closed-loop feedback system that continuously monitors and maintains synchronization, thereby ensuring communication delay stability
2Measurement precision
If time stamp recording and transmission is implemented between network devices, then time synchronization accuracy is improved, but information processing overhead increases
Solution Approach 1:
The patent extracts only the essential timing information (time stamp values) from the complex synchronization problem and transmits only this extracted data between devices. By taking out and transmitting only the necessary timing parameters rather than complete synchronization state information, the system achieves high measurement precision while minimizing information processing overhead
Solution Approach 2:
The patent transforms the synchronization problem into parameter comparison by converting time measurements into numerical time stamp parameters. This parameter transformation allows for precise mathematical comparison and calculation of communication delays, improving measurement precision while enabling efficient digital processing that reduces information overhead
3Manufacturing precision
If communication delay compensation is performed based on time stamps, then air interface frequency accuracy is improved, but calculation complexity increases
Solution Approach 1:
The patent performs preliminary action by having devices record time stamp information at the moment of message transmission and reception. This advance recording of timing data allows for subsequent delay calculations to be performed using simple subtraction operations on pre-captured time values, thereby achieving high frequency accuracy without increasing real-time calculation complexity
Data Source
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AI summary
Embodiments of the present invention provide a time synchronization method and system, and a network device. The method includes: receiving, by a second network device, a first packet sent by a first network device, where the first packet includes a first service frame and a first time stamp T1, the first service frame is sent by an REC to the first network device, the first service frame carries a system clock of the REC, and the first time stamp is a time stamp at which the first network device receives the first service frame; obtaining, by the second network device, the system clock of the REC according to the first packet; sending, by the second network device according to the system clock of the REC, the first service frame extracted from the first packet to an RE; recording, by the second network device according to a system time of the second network device, a second time stamp T2 at which the first service frame is sent; and determining, by the second network device, a transmission delay T=T2-T1 between the first network device and the second network device. This solution helps ensuring that a delay between the REC and the RE remains unchanged.