DSL Transceiver Transmit Power Control for Echo Reduction

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Solution Overview

Problem

Existing DSL transceiver units face challenges in achieving target data rates in both upstream and downstream directions over long lines due to attenuation and echo interference, leading to capacity issues and failure in meeting service requirements, especially in upstream communication.

Innovation Solution

The method involves determining an optimal transmit power that balances capacity between communication paths, reducing echo in one direction to increase SNR and capacity in the other, allowing both directions to meet target data rates by adjusting transmit power based on excess capacity and using channel capacity measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If initial transmit power is used to achieve target data rate in one direction, then capacity in that direction is met, but echo interference increases and capacity in the opposite direction deteriorates

Engineering Contradiction:

Improvedata rateVSAvoidecho interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent dynamically adjusts the transmit power parameter based on measured capacity in both directions. When capacity in one direction exceeds the target data rate, the transmit power is reduced to minimize echo interference in the opposite direction, thereby optimizing the balance between productivity and harmful factors

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements a feedback mechanism where capacity measurements from both upstream and downstream directions are continuously monitored. Based on this feedback, the transmit power is adaptively adjusted to maintain target data rates in both directions while minimizing echo interference, resolving the contradiction between achieving high data rates and reducing harmful echo effects

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If transmit power is reduced to decrease echo interference, then harmful factors in opposite direction are reduced, but capacity in the original direction decreases

Engineering Contradiction:

Improveecho interferenceVSAvoiddata rate

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies partial action by reducing transmit power only to the extent necessary to meet the target data rate in the opposite direction, rather than uniformly reducing power. This allows the system to achieve sufficient echo reduction while maintaining adequate capacity in the original transmission direction

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system dynamically adjusts transmit power based on real-time capacity measurements and target data rate requirements. This dynamic adjustment allows the system to optimize the trade-off between echo interference reduction and maintaining sufficient data rate capacity in both directions

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If flexible frequency band allocation is implemented to increase adaptability, then versatility is improved, but ability to separate echo from far-end signal deteriorates

Engineering Contradiction:

Improvefrequency allocation flexibilityVSAvoidecho separation capability

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary approach by using transmit power adjustment as a control mechanism to compensate for the lack of echo separation capability. Instead of relying on frequency domain separation, the system uses power control as an intermediary means to manage echo interference and maintain target data rates in both directions

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7440411B2Echo reduction to achieve a requested service

Publication Date: 2008.10.21 RPX CORP

AI summary

A method for determining transmission characteristics over a first communication path and a second communication path, while an amount of the signal transmitted over the first communication path couples into the second communication path. In case of excess of capacity over the first communication path and a shortage of capacity over the second communication path, the transmit power over said first communication path is decreased such that the requested service is met over both communication paths. This optimal transmit power can be determined by trying successive transmit power values until the requested service is met, e.g. by means of a dichotomy algorithm or the like. The optimal transmit power value can be computed directly as well, e.g. by making use of the transfer characteristics of the coupling path. A transceiver unit may also be used to implement the present method.