Cell Site Clock Synchronizer Multi-Source Switching
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Solution Overview
Problem
Conventional cell site devices face challenges in maintaining stable clock synchronization between processing circuits, especially when GPS signals are blocked or weak, leading to synchronization issues that affect communication with user equipment.
Innovation Solution
A cell site device with a clock synchronizer and multiple processing circuits that can switch between GPS, PTP, syncE, and oscillator-based clock synchronization sources, ensuring continuous synchronization by prioritizing GPS, then PTP, syncE, and finally an internal oscillator for reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS signal is used for clock synchronization, then synchronization accuracy is improved, but reliability deteriorates when GPS signal is blocked or weak
Solution Approach 1:
The patent combines multiple clock synchronization sources (GPS receiver, network interface circuit, and local oscillator) into a unified synchronization system. The clock synchronizer integrates signals from different sources and selectively switches between them, merging the advantages of high-accuracy GPS synchronization with the reliability of alternative sources when GPS is unavailable.
Solution Approach 2:
The system dynamically changes the synchronization source parameter based on signal availability. When GPS signal quality deteriorates or becomes unavailable, the system switches from GPS-based synchronization to network-based or oscillator-based synchronization, altering the operational parameter to maintain reliable timing.
2Reliability
If multiple clock synchronization sources are integrated, then reliability is improved, but device complexity increases
Solution Approach 1:
The clock synchronizer is designed as a universal component that can handle multiple types of synchronization inputs (GPS, network protocols like PTP/syncE, and local oscillator signals). This multi-functional design consolidates what could be separate complex systems into a single versatile synchronization unit, managing diversity without proportionally increasing overall complexity.
Solution Approach 2:
The clock synchronizer acts as an intermediary component between various synchronization sources and the processing circuits. It mediates the selection and switching between different sources, absorbing the complexity of multi-source management within a dedicated component rather than distributing complexity throughout the entire system.
3Measurement precision
If GPS antenna is used for receiving GPS signal, then synchronization accuracy is improved, but reliability deteriorates in indoor or blocked environments
Solution Approach 1:
The system performs preliminary actions by maintaining a local oscillator that can immediately provide synchronization when GPS signal is lost. The oscillator is pre-configured and ready to take over without interruption, ensuring continuous operation in environments where GPS reception may be blocked or unreliable.
Data Source
AI summary
A cell site device and an associated clock synchronization method are provided. The cell site device includes a clock synchronizer, a first processing circuit, and a second processing circuit. The clock synchronizer generates a first operation clock and a second operation clock. The first operation clock and the second operation clock have a specific synchronous relationship, and the clock synchronizer is adjusted by a synchronizer setting signal. The first processing circuit generates the synchronizer setting signal according to one of an external clock synchronization source and an internal clock signal. The clock synchronizer respectively transmits the first operation clock and the second operation clock to the first processing circuit and the second processing circuit. The first processing circuit generates a cross-unit periodic synchronization signal and transmits the cross-unit periodic synchronization signal to the second processing circuit.