TD-LTE Base Station Standing-Wave Ratio Detection Using Downlink OFDM Signals
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Solution Overview
Problem
Current methods for detecting standing-wave ratio in TD-LTE base station systems using Frequency Domain Reflectometry technology require a specific training sequence, which causes interference and limits frequent or real-time detection, affecting transmission quality.
Innovation Solution
The method employs a downlink OFDM-modulated signal from a TD-LTE base station system to detect standing-wave ratio by extracting feedback signals, performing Fast Fourier Transform, and determining reflection coefficients, thereby avoiding additional interference and enabling fast and accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a specific training sequence is transmitted for standing-wave ratio detection using Frequency Domain Reflectometry, then measurement accuracy is improved, but additional interference is generated with the communication system
Solution Approach 1:
The downlink OFDM signal serves dual purposes: it is both the communication signal for normal base station operation and the measurement signal for standing-wave ratio detection. By utilizing the existing OFDM signal structure (specifically the cyclic prefix portion) for both communication and measurement functions, the patent eliminates the need for separate training sequences, thereby avoiding additional interference while maintaining measurement capability
Solution Approach 2:
The base station uses its own transmitted downlink OFDM signal to perform self-diagnosis of the antenna system. The reflection signal is extracted from the same signal that the base station is already transmitting for communication purposes, allowing the system to monitor its own health status without requiring external test equipment or additional test signals that would interfere with normal operation
2Measurement precision
If a specific training sequence is transmitted for standing-wave ratio detection, then detection accuracy is improved, but detection frequency is reduced due to interference
Solution Approach 1:
The standing-wave ratio detection is performed continuously on every downlink OFDM signal transmission. Since the downlink signal is continuously transmitted for communication purposes, the detection can also continuously monitor the antenna system status without interruption, achieving real-time monitoring capability that was not possible with periodic training sequence-based detection
Solution Approach 2:
By making the downlink OFDM signal serve both communication and measurement functions simultaneously, the patent enables continuous detection at the same rate as communication transmissions, eliminating the trade-off between detection frequency and system interference
3Measurement precision
If Frequency Domain Reflectometry technology is used for standing-wave ratio detection, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the necessary components for detection from the downlink OFDM signal - specifically isolating the cyclic prefix portion and the corresponding reflection signal - and processes only these extracted components. This selective extraction approach maintains the accuracy benefits of Frequency Domain Reflectometry while reducing computational complexity by avoiding processing of the entire OFDM signal
Solution Approach 2:
The detection process is segmented into distinct processing stages: extracting the cyclic prefix signal, performing FFT transformation, calculating reflection coefficient, and determining standing-wave ratio. This segmentation allows each stage to be optimized independently and facilitates implementation using existing signal processing blocks already present in the base station
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
This approach allows for frequent and accurate detection of standing-wave ratio in real-time, reducing interference and ensuring precise calibration of the base station system without additional hardware costs or cumbersome instruments.
Implementation Method 1
performing Fast Fourier Transform on the feedback signals of the OPD and the feedback signals of the RPD in each period of time respectively, and determining spectrum characteristics of the feedback signals of the OPD and the spectrum characteristics of the feedback signals of the RPD
Data Source
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AI summary
Disclosed are a method and device for detecting a standing-wave ratio, which are used for realizing quick and accurate detection of the standing-wave ratio by only using a downlink service signal transmitted by a TD-LTE base station system, thereby preventing a special training sequence from causing additional interference to the base station system. The method comprises: capturing output power detection data (OPD) of a service signal transmitted by the base station system and reflection power detection data (RPD) of a device to be detected in a base station; within a first preset bandwidth range, respectively extracting feedback signals of the OPD and feedback signals of the RPD within a plurality of periods of time according to a preset data length; determining spectrum characteristics of the feedback signals of the OPD and spectrum characteristics of the feedback signals of the RPD respectively corresponding to each period of time, and determining the reflection coefficient of the base station system according to the spectrum characteristics of the feedback signals of the OPD and the spectrum characteristics of the feedback signals of the RPD respectively corresponding to each period of time; and determining the standing-wave ratio of the base station system within the first preset bandwidth range according to the reflection coefficient of the base station system.