Central-Side RoF Communication Device for Nonlinear Compensation
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Solution Overview
Problem
Conventional radio over fiber (RoF) systems face issues with nonlinear distortion in signal conversion, requiring complex feedback links and additional optical fibers to compensate for distortion, leading to increased complexity and cost.
Innovation Solution
A communication device and system that compensates for nonlinear distortion by establishing a feedback link within the central-side communication device, utilizing digital processing apparatuses and optical splitters to perform nonlinear compensation without the need for additional optical fibers, simplifying the setup and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electro-optical signal conversion apparatus is integrated into the remote-side communication device to compensate for nonlinear distortion, then the signal quality is improved, but the device complexity and system cost increase due to requiring additional optical fibers and control logic
Solution Approach 1:
The patent extracts the electro-optical signal conversion apparatus from the remote-side communication device and relocates it to the central-side communication device. This extraction eliminates the need for feedback optical paths from remote to central, removing the complexity of bidirectional optical fiber configuration while maintaining the distortion compensation function at its source.
Solution Approach 2:
Instead of the conventional approach where the remote device sends feedback signals back to the central device for distortion analysis, the patent inverts the architecture: the central device performs self-diagnosis by analyzing its own transmitted signals after they reflect off remote devices. This inversion eliminates the need for complex feedback control logic at both ends.
2Measurement precision
If additional optical fibers are deployed to establish a feedback link for distortion compensation, then the nonlinear distortion compensation accuracy is improved, but the system cost and installation complexity increase
Solution Approach 1:
The patent makes the existing optical fibers bidirectional by using optical circulators and switches, allowing the same physical infrastructure to serve both forward signal transmission and backward reflection collection. This multi-functionality eliminates the need for dedicated feedback optical fibers, reducing installation complexity while maintaining compensation accuracy.
Solution Approach 2:
The patent uses optical circulators to create isolated feedback paths that copy the transmitted signal's reflection characteristics without requiring separate physical fibers. The circulator directs reflected signals from the remote device back to the central device through a controlled path, achieving accurate distortion measurement using existing infrastructure.
3Ease of manufacture
If optical signals and uplink data share the same link to avoid additional optical fibers, then the system cost is reduced, but additional control logic is required which increases device complexity
Solution Approach 1:
The patent uses optical switches at the central device to pre-establish dedicated feedback paths for distortion compensation signals before transmission occurs. By separating the feedback path setup from the data transmission path, the system avoids the need for complex dynamic switching control logic while still achieving path isolation using existing optical fiber infrastructure.
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 effectively compensates for nonlinear distortion in RoF networks by eliminating the need for additional optical fibers and complex control logic, enhancing signal quality and reducing setup complexity.
Implementation Method 1
an optical splitter is further connected to the second processing apparatus. The optical splitter is configured to split an received optical signal into a first optical signal and a second optical signal
Implementation Method 2
The central-side communication device converts a generated baseband signal into a radio frequency signal, converts the radio frequency signal into an optical signal by using the electro-optical signal conversion apparatus
Implementation Method 3
The remote-side communication device converts the received optical signal into a radio frequency signal by using the optical-electro signal conversion apparatus
Data Source
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Figure 3
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AI summary
Embodiments of this application provide a communication device and system. In embodiments of this application, a feedback link is established in a central-side communication device. The feedback link is used to feed back a baseband signal that has nonlinear distortion and that is processed by a component in the central-side communication device. The central-side communication device may compensate for nonlinear distortion of the baseband signal based on a generated baseband signal and the signal fed back through the feedback link. This improves signal transmission quality. Nonlinear distortion in a RoF network system mainly occurs in the central-side communication device. Therefore, in a structure of the central-side communication device in embodiments of this application, nonlinear distortion in the RoF network system can be compensated for, an additional optical fiber does not need to be disposed, and complex control logic can be avoided when the feedback link needs to be established between the central-side communication device and a remote-side communication device. This simplifies a disposing manner on a remote side.