Xn/X2 RTT Sampling for Accurate Inter-Site Synchronization
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Solution Overview
Problem
In a 5G era, TDD systems face synchronization issues leading to interference between out-of-synchronization and synchronized base stations, exacerbated by burst or congestion jitter affecting inter-site synchronization offset measurements.
Innovation Solution
Obtain N pieces of first round-trip time in a first periodicity, determine a minimum first round-trip time reference value, and use it to calculate the inter-site synchronization offset value, reducing errors due to jitter and congestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inter-site synchronization offset measurement is performed using Xn/X2 interface, then synchronization status can be determined, but large error is caused to offset measurement result when burst/congestion jitter occurs on transmission network
Solution Approach 1:
The patent applies preliminary action by obtaining multiple RTT values in advance (N pieces of first round-trip time) before performing the offset measurement. By collecting multiple samples beforehand and selecting the minimum value, the system prepares robust measurement data that is not easily affected by transient jitter conditions during the actual measurement process.
Solution Approach 2:
The patent converts the harmful effect of jitter into a beneficial filtering mechanism. By obtaining multiple RTT values and selecting the minimum one, the system transforms the random jitter variations into a useful selection criterion - the minimum RTT value represents the best-quality measurement path, effectively using the jitter data to identify and select the most accurate measurement instance.
2Measurement precision
If multiple RTT values are obtained in first periodicity, then accuracy of offset measurement is improved, but measurement time is increased
Solution Approach 1:
The patent applies partial action by obtaining N pieces of RTT data (where N>1) - more data than a single measurement would provide - and then using only the minimum value from this set for the final offset calculation. This partial/excessive action approach ensures that even if some measurements are affected by jitter, the minimum value represents a reliable measurement, achieving high accuracy without requiring all N measurements to be perfect.
Data Source
AI summary
Example data processing methods, network devices, and media are disclosed. One example method includes obtaining, by a first network device, N pieces of first round-trip time in a first periodicity. The first round-trip time is time consumed when the first network device and a second network device each transmit a packet once through an Xn/X2 interface. A minimum first round-trip time reference value is determined based on the N pieces of first round-trip time. The minimum first round-trip time reference value is a smallest value of the N pieces of first round-trip time. An inter-site synchronization offset value of the first periodicity is determined based on the minimum first round-trip time reference value. The inter-site synchronization offset value of the first periodicity is an inter-site synchronization offset value that exists when the first network device and the second network device transmit packets through the Xn/X2 interface.