Reverse Power Feed Disconnection for Accurate Line Testing
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Solution Overview
Problem
Reverse Power Feed (RPF) in xDSL network systems prevents Metallic Line Testing (MELT) by introducing a voltage source that interferes with resistance and capacitance measurements, necessitating a mechanism to disconnect power during testing without affecting network node operations.
Innovation Solution
A network node and apparatus configuration that allows for disconnection from the transmission line during MELT by applying an invalid signature or violating power constraints, enabling measurements without impacting power supply, and subsequent reconnection using predefined signals or impedance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Reverse Power Feed is deployed to power DPUs from customer premises, then power supply capability is improved, but MELT test execution is prevented
Solution Approach 1:
The system performs preliminary detection of test conditions before executing MELT tests. The DPU detects when a line is in test mode and proactively disconnects the RPF voltage source before the test begins, preventing interference with resistance and capacitance measurements while maintaining power supply capability for normal operations
Solution Approach 2:
The RPF voltage source is made dynamically controllable, allowing it to be connected during normal operation and disconnected during MELT tests. The system transitions the RPF circuit between connected and disconnected states based on operational mode, enabling both power supply and measurement functions to operate effectively at different times
2Power
If RPF voltage source is connected to provide DC power, then power delivery is improved, but line measurement accuracy deteriorates
Solution Approach 1:
The RPF voltage source is extracted or removed from the line connection specifically during MELT test execution. The system separates the power delivery function from the measurement function by disconnecting the voltage source when measurements are required, ensuring accurate resistance and capacitance readings without power source interference
Solution Approach 2:
The system introduces a control mechanism that acts as an intermediary between the RPF voltage source and the transmission line. This controller monitors test conditions and mediates the connection state, disconnecting the voltage source during tests and reconnecting during normal operation, thereby resolving the conflict between power delivery and measurement accuracy
Data Source
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AI summary
The present document discloses network nodes and apparatuses deployable in network systems. The network node may be coupleable via a transmission line to the apparatus. In particular, the network node may comprise means for receiving supply power from the apparatus via the transmission line; performing a line measurement on the transmission line; and signaling to the apparatus to disconnect from the transmission line, wherein the means may be further configured to perform the line measurement on the transmission line during a period of time when the apparatus is disconnected from the transmission line. The apparatus may comprise means for providing supply power to the network node; monitoring at least one electrical parameter of the transmission line; and disconnecting the apparatus from the transmission line if a predetermined line condition or a power violation is detected such that the network node can perform a measurement on the transmission line.