VDSL Amplifier Gain Control via Common Mode Signal
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Solution Overview
Problem
DSL systems face limitations in data transmission range due to signal attenuation in metallic twisted pair cables, restricting reliable data services beyond 1.5-2km, and deploying fiber further is costly for a small number of customers.
Innovation Solution
Modulating a common mode voltage signal onto an electrical conductor with operational parameters to determine the gain of an amplifier, allowing it to be operated effectively within the network, thereby extending the VDSL system range without significant infrastructure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If VDSL signals are transmitted over metallic twisted pair cables, then data transmission is enabled, but signal attenuation limits the range to 1.5-2km
Solution Approach 1:
A common mode signal is injected onto the metallic twisted pair cable to carry operational parameters (such as loss values) from the DSLAM to the amplifier. This intermediary signal enables the amplifier to be properly configured and adjusted to compensate for signal attenuation, thereby extending the transmission range beyond the conventional 1.5-2km limit.
2Reliability
If fiber is deployed further into the periphery to serve outlying customers, then reliable data service is provided, but infrastructure cost increases significantly
Solution Approach 1:
The system changes operational parameters (such as amplifier gain and frequency allocation) by injecting a common mode signal that carries loss information from the DSLAM to the amplifier. This allows dynamic adaptation to varying cable conditions, enabling reliable service over extended distances using existing copper infrastructure rather than requiring expensive fiber deployment.
3Power
If amplifier gain is increased to extend transmission range, then signal strength is improved, but interference with existing services may occur
Solution Approach 1:
The system uses feedback by injecting a common mode signal that carries measured loss information from the DSLAM to the amplifier. The amplifier uses this feedback information to automatically adjust its gain and operational parameters, ensuring optimal signal strength while avoiding excessive amplification that could cause interference with existing telephony and DSL services.
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 data services beyond the conventional 1.5-2km range by optimizing amplifier gain based on real-time network data, reducing the need for costly fiber deployments and maintaining interference-free operations.
Implementation Method 1
modulating a common mode voltage signal onto an electrical conductor at a first location, the common mode voltage signal carrying data comprising one or more operational parameters
Implementation Method 2
detecting the common mode voltage signal from the electrical conductor at a second location
Data Source
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AI summary
A method of configuring a network element, for example an amplifier in a VDSL network. Configuration is transmitted to the amplifier using a common mode voltage signal so that there is no interference with the telephony or DSL signals.