Virtual Noise Mask for DSL Synchronization Stability
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Solution Overview
Problem
High bandwidth DSL systems face significant cross-talk noise issues due to variations in neighboring lines' power modes, leading to synchronization failures and connection drops, as the noise environment changes dramatically when lines transition between low and high power modes.
Innovation Solution
A method for calculating a virtual noise mask based on combined noise measurements taken during quiet line phases, applied only after multiple resynchronizations occur within a predetermined period, using a peak detection algorithm to select break points for the mask, which is transmitted to a central management device or processed by transceivers to stabilize DSL connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If virtual noise mask is applied during resynchronization, then synchronization stability is improved, but system complexity increases due to additional calculations and measurements
Solution Approach 1:
The patent performs preliminary noise measurements during quiet line phases before actual data transmission begins. By pre-calculating the virtual noise mask during the training phase and storing it in MIB, the system prepares synchronization parameters in advance, avoiding the need for complex real-time noise calculations during active transmission, thus improving synchronization stability without proportionally increasing system complexity
Solution Approach 2:
The system uses its own quiet line phases to self-measure noise characteristics without requiring external intervention. The transceiver automatically performs noise measurements during its own training phase, calculates virtual noise masks, and applies them to its synchronization process, reducing the need for external management system intervention while improving reliability
2Measurement precision
If virtual noise mask calculation is performed for all lines, then synchronization accuracy is improved, but processing time and computational resources are wasted on stable lines
Solution Approach 1:
The patent applies virtual noise mask calculation selectively only to lines that require it - specifically those experiencing synchronization issues or during initial training phases. Stable lines continue to use standard synchronization procedures without the additional computational overhead of virtual noise mask calculations, thereby improving synchronization accuracy where needed while avoiding unnecessary processing time consumption on already stable connections
3Use of energy by moving object
If low power modes are used to reduce energy consumption, then energy efficiency is improved, but cross-talk noise varies significantly causing connection drops
Solution Approach 1:
The system performs preliminary noise measurements during quiet line phases before data transmission begins, capturing the noise environment when neighboring lines are in low power modes. This pre-measured noise data is used to calculate virtual noise masks that account for the quieter noise environment during energy-saving modes, allowing the system to maintain reliable connections at lower power consumption levels by having advance knowledge of the reduced noise conditions
Solution Approach 2:
The patent implements dynamic power management where the system can operate in different power modes (low power or high power) depending on traffic conditions. By using virtual noise masks calculated from measurements taken in low power modes, the system can dynamically switch to energy-saving modes while maintaining connection stability, as the virtual noise mask compensates for the varying cross-talk noise environment that occurs during power mode transitions
Data Source
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AI summary
A digital subscriber line management system is provided. It comprises a device for calculating a set of values specifying a virtual noise mask. The device includes a receiver (136) for receiving or otherwise obtaining a set of measurements of noise levels experienced at a digital subscriber line transceiver at each of a plurality of frequencies at different times, and a processor (131) for calculating, in respect of each frequency, a combined value based on a plurality of measurements taken at different times, and for generating the set of values specifying a virtual noise mask in dependence upon the combined values.