Distributed Reference Clock for DAS Signal Synchronization
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Solution Overview
Problem
Distributed Antenna Systems (DAS) face challenges in synchronizing digital and analog domains for efficient wireless signal distribution in substantially closed environments, leading to signal loss and distortion over long distances.
Innovation Solution
A communication system with a master host unit, hybrid expansion unit, and remote antenna unit that uses digital and analog communication links to synchronize digital master reference clock signals, converting between analog and digital spectra, ensuring accurate signal conversion and recovery across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If analog signals are transmitted over long distances in closed environments, then wireless coverage is extended, but signal loss and distortion increase
Solution Approach 1:
The system divides the transmission path into multiple segments with distributed antenna units (DAUs) positioned throughout the closed environment. Each DAU acts as an independent transmission node, converting the single long-distance transmission problem into multiple short-distance transmissions, thereby maintaining signal quality while extending overall coverage distance.
Solution Approach 2:
The patent introduces digital signal processing intermediaries between the source and destination. Digital-to-Analog Converters (DACs) and Analog-to-Digital Converters (ADCs) are positioned at strategic points to convert signals between domains, allowing digital processing and regeneration of analog signals to compensate for transmission losses over distance.
2Measurement precision
If digital and analog domains are synchronized, then signal conversion accuracy is improved, but system complexity increases
Solution Approach 1:
The system implements feedback mechanisms where the master host unit receives status information from distributed antenna units and adjusts timing and frequency parameters accordingly. This closed-loop synchronization approach maintains conversion accuracy while automating the complexity of coordination between digital and analog domains.
Solution Approach 2:
The patent combines the synchronization functions into a centralized master host unit that manages all DAUs. By merging timing and frequency control into a single authoritative source, the system achieves precise synchronization across domains without requiring complex distributed synchronization protocols at each conversion point.
Data Source
AI summary
A communication system includes master host unit, hybrid expansion unit, and remote antenna unit. Master host unit communicates analog signals with service provider interfaces. Master host unit and hybrid expansion unit communicate N-bit words of digitized spectrum over communication link. Hybrid expansion unit converts between N-bit words and analog spectrum. Hybrid expansion unit and remote antenna unit communicate analog spectrum over analog communication medium. Remote antenna unit transmits and receives wireless signals over air interfaces. Master host unit includes master clock distribution unit that generates digital master reference clock signal. Master host unit communicates digital master reference clock signal over communication link. Hybrid expansion unit receives digital master reference clock signal from master host unit over communication link and generates analog reference clock signal based on digital master reference clock signal. Hybrid expansion unit sends, and remote antenna unit receives, analog reference clock signal across analog communication medium.