Terrestrial Broadcast Synchronization for LTE Base Stations
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Solution Overview
Problem
Existing WiMAX and LTE macro-network base stations rely on GPS signals for synchronization and stability, which can be unreliable in locations without a line-of-sight view of GPS satellites, necessitating alternative methods for frame-start synchronization and local oscillator stabilization.
Innovation Solution
Implementing a terrestrial broadcast signal with a subcarrier phase-locked to a GPS signal to stabilize local oscillators and provide timing information for frame-start synchronization, allowing base stations to operate without GPS signals, and using non-GPS based techniques for location determination and time-of-day information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS signals are used for synchronization and local oscillator stabilization, then reliability of timing reference is improved, but adaptability to environments without GPS access deteriorates
Solution Approach 1:
The patent introduces an intermediary system consisting of a master clock at a network operations center and distributed slave clocks at base stations. This intermediary time distribution network replaces direct GPS dependency at each base station, allowing synchronization through networked time transfer protocols that work in environments where GPS is unavailable.
Solution Approach 2:
The network operations center master clock serves multiple functions: it acts as the primary time reference for the entire network, provides timing synchronization to all base stations, and enables location determination through time-of-flight calculations. This multi-functional approach replaces the need for each base station to independently acquire GPS signals for all these purposes.
2Adaptability or versatility
If terrestrial broadcast signals with subcarriers are used for local oscillator stabilization, then GPS signal dependency is reduced, but signal acquisition complexity increases
Solution Approach 1:
The patent extracts the timing reference function from GPS satellite signals and implements it through terrestrial broadcast infrastructure. By taking out the essential timing function and placing it in the terrestrial broadcast domain with phase-locked subcarriers, the system achieves GPS independence while using existing broadcast infrastructure rather than creating entirely new signaling mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable operation of WiMAX and LTE base stations in areas without GPS access, ensuring stable signal transmission and synchronization, while providing redundancy and flexibility in location determination and time management.
Implementation Method 1
receiving a terrestrial broadcast signal with a subcarrier phase-locked to a GPS signal to stabilize local oscillators
Data Source
AI summary
Disclosed herein are methods and systems that may help a base station provide high-speed data communication under a protocol such as LTE or WiMAX, even when a GPS signal is not available to the base station.