Indoor CBSD Timing Distribution via Wireless Sync Monitoring
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Solution Overview
Problem
The traditional method for providing synchronization information to indoor CBRS TD-LTE radios, which relies on GPS signals and a GrandMaster and boundary clock approach, is costly and ineffective in building environments where GPS signals are weak.
Innovation Solution
A method where devices in a campus network monitor for wireless synchronization signals, generate and send timing signal accuracy reports, and an intelligent switch selects the best sync source, designating a master device to propagate synchronization information to other devices within the network, eliminating the need for expensive GPS receivers and time sync servers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional GPS receiver and time sync server approach is used, then synchronization accuracy is improved, but system cost increases significantly
Solution Approach 1:
The patent extracts the synchronization function from expensive hardware components (GPS receiver, time sync server) and implements it through software-based wireless signal monitoring and processing. CBSDs monitor wireless signals for sync information and report accuracy metrics to IDF switches, which select the best sync source and designate master devices, eliminating the need for costly traditional synchronization infrastructure.
Solution Approach 2:
The patent replaces expensive, complex synchronization hardware with inexpensive wireless communication capabilities. Instead of requiring $25,000-30,000 per site for GPS receivers and time sync servers, the system uses standard wireless signals and processing logic already present in CBSDs and IDF switches to achieve synchronization.
2Measurement precision
If GPS signals are used for synchronization, then timing accuracy is improved, but signal reliability deteriorates in building environments
Solution Approach 1:
The patent introduces wireless signals as an intermediary carrier for synchronization information. Instead of relying directly on GPS signals that cannot penetrate buildings, the system uses wireless communications between CBSDs and IDF switches to distribute timing information, with CBSDs monitoring wireless signals for embedded sync data and reporting accuracy metrics for processing.
Solution Approach 2:
The patent transitions from satellite-based three-dimensional GPS signaling to two-dimensional wireless signal-based synchronization within the network infrastructure. CBSDs monitor wireless signals in the local network dimension, and IDF switches process the accuracy reports to select optimal sync sources, creating a localized synchronization dimension that works reliably indoors.
Data Source
AI summary
Devices including a wireless receiver, e.g., indoor CBSDs, in a local network, e.g. a campus network, monitor for wireless signals conveying synchronization information. Different devices in the local area network may detect wireless signals conveying synchronization information from one or more different sources. A device detecting a source of synchronization information generates and sends a timing signal accuracy report to a switch, e.g. an intelligent IDF switch, included in the local network. The switch receives multiple timing signal accuracy reports, selects a “best” sync source and designates the particular device, e.g., particular CBSD, which reported the best sync source, to be the current master timing device for the local network. The switch communicates the address, e.g., IP address, of the selected master to the devices within the local network.