Dynamic Frequency Allocation for DSL Crosstalk Reduction

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Solution Overview

Problem

The existing Access Network Frequency Plan (ANFP) reduces crosstalk on higher-tier DSL connections but inefficiently decreases the capacity of lower-tier DSLAMs, and manual resource allocation in DSL networks leads to significant delays and service disruptions due to crosstalk noise and interference issues, particularly exacerbated by the deployment of G.fast technology.

Innovation Solution

A method and apparatus for dynamically adjusting the power spectral density of lower-tier DSL lines based on noise measurements and characteristics, such as Quiet Line Noise, to determine non-overlapping frequency ranges that avoid interference with higher-tier lines, allowing for more efficient bandwidth use and higher data rates while minimizing crosstalk interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the Access Network Frequency Plan (ANFP) is used to reduce crosstalk on higher-tier DSL connections, then crosstalk interference is reduced, but the capacity of lower-tier DSLAMs decreases significantly

Engineering Contradiction:
Improvecrosstalk interferenceVSAvoidnetwork capacity
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent implements dynamic frequency allocation where lower-tier DSLAMs can flexibly use frequencies based on real-time availability. Instead of static frequency plans, the system continuously monitors and adjusts frequency usage, allowing lower-tier DSLAMs to access frequencies currently unused by higher-tier DSLAMs, thereby maximizing network capacity while preventing interference.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of frequency allocation from fixed to variable. Lower-tier DSLAMs dynamically adjust their operating frequencies based on the current state of higher-tier DSLAM usage, transforming the frequency spectrum from a static resource division to a dynamic shared resource that adapts to changing network conditions.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If manual resource allocation is performed to manage crosstalk noise and interference, then interference issues are addressed, but significant delays and service disruptions occur

Engineering Contradiction:
ImproveinterferenceVSAvoidservice disruption time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where lower-tier DSLAMs continuously monitor the frequencies used by higher-tier DSLAMs and automatically adjust their own frequency allocation in response. This closed-loop system eliminates the need for manual intervention, as the network self-regulates to prevent interference while maintaining optimal capacity utilization.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system enables lower-tier DSLAMs to autonomously manage their own frequency allocation by detecting and avoiding frequencies currently in use by higher-tier DSLAMs. This self-service capability removes the need for external manual configuration and eliminates service disruptions associated with manual resource reallocation.

Inventive Principle:
Principle #25Self-service

3Productivity

If lower-tier DSLAMs use full power transmissions to maximize their capacity, then data rates are improved, but high levels of crosstalk are caused on higher-tier subscriber lines

Engineering Contradiction:
Improvedata rateVSAvoidcrosstalk
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different transmission characteristics to different tiers of DSLAMs based on their location and role in the network hierarchy. Lower-tier DSLAMs transmit at full power when frequencies are available, while higher-tier DSLAMs use reduced power on overlapping frequencies to minimize crosstalk. This localized quality adjustment optimizes both capacity and interference management.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3127312B1Resource allocation in a digital communication network
Publication Date: 2020.02.12 BRITISH TELECOM PLC
  • EP3127312B1 patent drawingFigure 1
  • EP3127312B1 patent drawingFigure 2
  • EP3127312B1 patent drawingFigure 3

AI summary

Methods and apparatus are disclosed for allocating resources in a Digital Subscriber Line (DSL) network, the network comprising at least one lower-tier digital subscriber line (15d, 15e) carrying signals according to a first protocol between a transceiver device (22) at a lower-tier network node (20) and a subscriber (10d, 10e) transceiver device and further comprising at least one higher-tier digital subscriber line (15a, 15b, 15c) carrying signals according to a second protocol between a transceiver device (32) at a higher-tier network node (30) and a subscriber (10a, b, 10c) transceiver device, the first protocol permitting signals to be carried at frequencies in a range having a higher upper limit than the second protocol.