Node Unit Delay Measurement in Distributed Antenna Systems
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Solution Overview
Problem
In distributed antenna systems, accurate transmission delay measurement is crucial for maintaining orthogonality in OFDM-based signal transmission systems like LTE and WIBRO, but existing methods are inadequate for automatic delay measurement and compensation, affecting the quality of mobile communication services.
Innovation Solution
A node unit capable of measuring transmission delay is introduced, which automatically measures delays in the signal transmission system and performs delay compensation, using a method that involves transmitting a test signal through the transport medium, detecting loop-back signals, and adjusting for round trip delays to synchronize service times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual delay measurement methods are used in distributed antenna systems, then delay equalization processing can be performed, but automatic delay measurement and compensation capability is lacking, affecting service quality
Solution Approach 1:
The node unit automatically measures transmission delay by generating a test signal, detecting the loop-back signal, and calculating the round trip delay without external intervention. The system self-calibrates by using its own transmitted signal as the reference, enabling automatic delay measurement and compensation that improves service quality while maintaining high measurement precision.
2Reliability
If delay equalization processing is implemented in OFDM-based systems, then orthogonality between carrier waves is maintained, but transmission delay must be accurately measured as a precondition
Solution Approach 1:
The node unit transmits a test signal through the transport medium and detects the loop-back signal to measure the round trip delay. This feedback mechanism provides accurate transmission delay measurement by comparing the transmitted and received signals, enabling precise delay equalization processing that maintains orthogonality in OFDM-based systems.
3Adaptability or versatility
If multiple node units are branch-connected in a distributed antenna system, then signal distribution is achieved, but transmission delay varies across different branches requiring synchronization
Solution Approach 1:
Before providing mobile communication services, the node unit performs preliminary delay measurement by transmitting a test signal and detecting the loop-back signal to determine the round trip delay. This preliminary action enables the system to compensate for transmission delay variations across different branches, ensuring synchronized service times while maintaining the adaptability of signal distribution in distributed antenna systems.
Data Source
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AI summary
A node unit branch-connected to another communication node unit through a transport medium, the node unit includes a delay measuring part configured to transmit a test signal for delay measurement to an upper adjacent node unit branch-connected to the node unit through the transport medium, and detect a loop-back signal where the test signal is looped back via the upper adjacent node unit, thereby measuring a round trip delay between the node unit and the upper adjacent node unit, and a delay providing part disposed on a signal transmission path through which a test signal for delay measurement, to be transmitted from a lower adjacent node unit branch-connected to the node unit, is to be looped back to the lower adjacent node unit, the delay providing part providing a delay corresponding to the round trip delay measured by the delay measuring part.