DSL Modem Rate Adaptation Without Re-synchronization

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Solution Overview

Problem

Current DSL systems cannot dynamically adjust data rates in response to changing line conditions or user service needs without disrupting ongoing communications sessions, leading to inefficient bandwidth usage and service interruptions.

Innovation Solution

Implement a method where DSL modems continuously monitor line characteristics like SNR and attenuation, allowing for seamless adjustments of data rates up or down in 32 Kbps increments without re-initialization or resynchronization, and enable dynamic service level changes through the provisioning system to match varying user demands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a full initialization operation is performed to provision a higher service rate, then the service rate is improved, but ongoing communications sessions are interrupted

Engineering Contradiction:

Improvedata rateVSAvoidservice continuity

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system dynamically adjusts the data rate during ongoing communications sessions without requiring full re-initialization. The DSL modem continuously monitors line conditions and modifies transmission parameters in real-time, allowing service rate changes while maintaining active connections. This dynamic adaptation resolves the contradiction by making the system flexible rather than static.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system performs preliminary monitoring of line conditions (SNR, attenuation) before initiating rate changes. By continuously assessing line quality in advance, the system can determine optimal moments for rate adjustments that minimize disruption to ongoing sessions. This preliminary assessment enables smooth transitions without forcing full re-initialization.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If the line rate is fixed based on initial conditions, then service stability is maintained, but the system cannot adapt to changing line conditions or user needs

Engineering Contradiction:

Improveservice stabilityVSAvoidrate adaptability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The system changes transmission parameters (data rate, modulation scheme) based on monitored line conditions. By continuously measuring SNR and attenuation, the system adjusts operational parameters to match current line quality and user demands. This parameter adaptation maintains stability through controlled changes rather than fixed configurations.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements continuous feedback loops where line conditions are monitored and used to automatically adjust data rates. The feedback mechanism compares current line quality against thresholds and triggers appropriate rate adjustments, enabling the system to adapt to changing conditions while maintaining stable communications. This closed-loop control resolves the contradiction between stability and adaptability.

Inventive Principle:

Principle #23Feedback

3Reliability

If resynchronization is performed due to poor line conditions, then communication reliability is maintained, but the data rate decreases over time

Engineering Contradiction:

Improvecommunication reliabilityVSAvoiddata rate

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The system performs preliminary adjustments to data rates before complete loss of synchronization occurs. By monitoring line conditions and proactively reducing rates when degradation is detected, the system maintains continuous communication without full re-initialization. This prevents the ratcheting down effect by avoiding multiple resynchronization cycles.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous data transmission while adapting rates to line conditions. Rather than interrupting communications for resynchronization, the system continuously adjusts parameters to preserve the communication session. This continuous operation prevents the cumulative rate reduction that occurs with repeated resynchronization events.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS8457181B2Rate agile rate-adaptive digital subscriber line

Publication Date: 2013.06.04 INTELLECTUAL VENTURES II LLC

AI summary

Methods and apparatus for maintaining the maximum achievable data rate on a DSL line, up to and including a rate to which a user subscribes is described. Performance monitoring is conducted on the DSL line on an ongoing basis to determine noise margins in each direction. Each noise margin is compared against pre-determined decreasing/increasing thresholds to determine whether the line characteristics dictate a data rate change without loss of synchronization. The invention supports dynamic provisioning changes including application driven service level change requests, e.g., new bandwidth-on demand services. In some embodiments, a combination of existing and new embedded operations channel (EOC) messages are used to implement the modem data rate changes. New EOC messages may be implemented using some of the reserved and/or vendor proprietary Opcodes currently permitted. Modem assigned data rate changes are implemented without a disruption of service, e.g., without the need for re-initialization and/or re-synchronization.