Oscillator Supervision via Backhaul Network Clock Correlation
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Solution Overview
Problem
Existing methods for supervising free-running oscillators in telecommunications networks are expensive, impractical, and inefficient, particularly in detecting small frequency offsets or wander, which can lead to operational failures and legal violations due to inaccurate RF spectrum compliance.
Innovation Solution
A system and method that distributes a reference clock to oscillators, measures frequency offsets, and correlates these offsets to identify faulty oscillators without requiring additional hardware, using the backhaul network as a common time reference, allowing for remote supervision and detection of frequency deviations in near real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an additional oscillator is added to compare frequencies, then frequency offset detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses the backhaul network as an intermediary reference clock to detect oscillator frequency offsets. Instead of adding another oscillator at each base station, the system uses the existing backhaul network clock as a mediator reference that can be compared against local oscillators, thereby achieving detection capability without increasing device complexity
Solution Approach 2:
The patent creates a virtual copy of the reference clock by distributing the backhaul network clock signal to multiple base stations. This allows each base station to have a local reference without physically installing additional high-precision oscillators, reducing device complexity while maintaining measurement precision through correlation analysis
2Reliability
If a second oscillator is deployed for comparison, then frequency supervision is improved, but cost increases
Solution Approach 1:
The backhaul network clock serves multiple functions simultaneously: it acts as the timing reference for transmission networks, provides a reference for oscillator supervision, and enables frequency offset detection across multiple base stations. This multi-functionality eliminates the need for dedicated supervision oscillators, reducing cost while maintaining reliability
Solution Approach 2:
The system uses existing infrastructure (backhaul network clocks) to provide the reference signal needed for supervision. Rather than requiring separate dedicated reference clocks or additional oscillators at each site, the system makes the existing backhaul network serve the dual purpose of data transmission timing and frequency supervision reference
3Measurement precision
If GPS receivers are installed at each base station, then frequency accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the frequency supervision function with the existing backhaul network timing infrastructure. Instead of installing separate GPS receivers and reference clock systems at each base station, the system combines oscillator supervision with the already-deployed backhaul network clock distribution, eliminating redundant equipment and reducing device complexity
4Quantity of substance
If backhaul network clock is used as reference, then equipment cost is reduced, but measurement precision deteriorates due to network clock instability
Solution Approach 1:
The patent applies partial correction by using the backhaul network clock as a reference and then applying correlation-based offset compensation. The system doesn't require the backhaul clock to be perfectly stable, but rather uses statistical correlation across multiple measurements to extract accurate frequency offset information, compensating for the reference clock's instability
Solution Approach 2:
The system implements feedback through correlation analysis of frequency offsets measured at multiple base stations. By continuously monitoring and correlating offset measurements, the system can distinguish between actual oscillator failures and backhaul network clock variations, maintaining measurement precision even when using a less stable reference clock
5Difficulty of detecting and measuring
If two oscillators are used for comparison, then frequency offset detection is enabled, but reliability decreases due to doubled failure probability
Solution Approach 1:
The patent extracts the reference clock function from the local base station equipment and places it in the centralized backhaul network. This eliminates the need for redundant local oscillators and their associated failure modes, while maintaining frequency offset detection capability through the distributed comparison of local oscillators against the centralized reference
Data Source
Figure 1~2
AI summary
The present invention relates to a system and method for supervising a plurality of oscillators in a network, in particular a telecommunications network. The invention can preferably be applied to the supervision of wireless base station oscillators. A system for supervising a plurality of oscillators in a network comprises a reference clock for generating a reference clock signal; clock distribution means for distributing the reference clock signal in the network; measuring means for measuring the oscillator offsets by determining the difference between the oscillator frequencies and the frequency of the reference clock signal; and a control unit for correlating the frequency offsets of the oscillators to determine whether an oscillators operates with a frequency which is different from a nominal frequency.