DSL Line Synchronisation Optimisation via SNR Monitoring
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Solution Overview
Problem
DSL lines, especially longer rural lines, experience instability due to interference, leading to synchronization losses, and existing Dynamic Line Management (DLM) techniques balance stability with synchronization rate by applying limited and coarse target signal-to-noise ratio (SNR) margins, which can result in suboptimal performance.
Innovation Solution
A method to determine the optimum signal-to-noise ratio (SNR) for synchronization by calculating the sum of the minimum SNR and the target SNR margin, monitoring the line, and synchronizing when the SNR equals this optimum value, thereby maximizing synchronization rate while maintaining stability, using a line optimization unit that gathers and processes SNR data over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high target SNR margin is used to improve line stability, then synchronization losses are reduced, but the synchronization rate decreases
Solution Approach 1:
The patent applies dynamics by making the target SNR margin adjustable and adaptive rather than fixed. The system dynamically modifies the target SNR margin based on measured actual SNR margins and synchronization performance, allowing it to optimize between stability and synchronization rate over time. This is evident in the iterative process where the target margin is increased or decreased based on whether actual margins are consistently above or below desired thresholds.
Solution Approach 2:
The patent changes the parameter of target SNR margin based on observed system performance. By monitoring the relationship between actual SNR margins and synchronization outcomes, the system adjusts the target margin parameter to achieve optimal balance. This includes increasing the target margin when actual margins are too high (reducing sync rate) and decreasing it when actual margins are too low (causing sync losses).
2Productivity
If a low target SNR margin is used to increase synchronization rate, then data transmission speed improves, but line stability decreases leading to more synchronization losses
Solution Approach 1:
The patent implements feedback by continuously monitoring actual SNR margins and synchronization performance, then using this information to adjust the target SNR margin. The system measures whether synchronization losses occur and whether actual margins are consistently above or below target, then modifies the target margin accordingly. This closed-loop feedback mechanism enables the system to self-optimize the balance between synchronization rate and stability.
Solution Approach 2:
The patent applies preliminary action by proactively adjusting the target SNR margin before synchronization problems occur. By monitoring trends in actual SNR margins and predicting potential instability or suboptimal performance, the system modifies the target margin in advance to prevent synchronization losses or maximize synchronization rate, rather than reacting after problems occur.
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AI summary
This invention relates to a method of determining an optimum point at which to synchronise a digital subscriber line in a telecommunications network, with the aim of maximising the resulting synchronisation rate whilst maintaining a stable line. For many lines, the signal to noise ratio (SNR) varies over the course of a day, and recurs on a daily basis. The phenomenon is often referred to as the "diurnal effect". The SNR history for the line is monitored, and the minimum SNR for the line is determined over a 24 hour period to take into account the diurnal effect. The current target SNR margin imposed by DLM on the line is determined, for example, by interrogating the DLM system or by noting the SNR margin on the line immediately after the most recent line synchronisation. The optimum point at which a resynchronisation is to be performed is calculated as point when the SNR on the line is equal to the minimum SNR plus the current target SNR margin. Synchronising when the SNR is at this point should maximise the synchronisation rate, whilst still maintaining a stable line.