Dual-band Line Interface Circuit for Multi-mode DSL Interference Reduction

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Solution Overview

Problem

VDSL and ADSL modems face interference and performance degradation due to their wide frequency ranges and different standards, making it challenging to design a single hardware platform that can efficiently operate in multiple DSL modes without compromising performance in either VDSL or ADSL modes.

Innovation Solution

A DSL communication device with a line interface circuit incorporating a hybrid circuit and separate transmit filters for lowpass and highpass frequency bands, optimized transformers for each band, and a parallel configuration to reduce interference, allowing the device to operate in multiple DSL modes with improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single hardware platform is designed to support multiple DSL modes (VDSL and ADSL), then adaptability is improved, but performance degradation occurs due to interference between frequency bands

Engineering Contradiction:

Improvemulti-mode operation capabilityVSAvoidcommunication performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The transmit path is segmented into separate lowpass and highpass filter channels, each optimized for its specific frequency band. This segmentation allows independent optimization of filter characteristics for VDSL and ADSL modes while maintaining a unified hardware platform, thereby achieving multi-mode adaptability without performance degradation from frequency band interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different quality characteristics are applied to different parts of the system: the lowpass filter is optimized for VDSL performance in the lower frequency band, while the highpass filter is optimized for ADSL performance in the higher frequency band. This local optimization ensures that each frequency band operates at peak performance levels when its corresponding mode is active.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If separate lowpass and highpass filters are used for different frequency bands, then interference between bands is reduced, but device complexity increases

Engineering Contradiction:

Improveinterference between frequency bandsVSAvoidfilter and transformer configuration

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The lowpass and highpass filters are combined in a parallel configuration where both filters operate simultaneously on the same transmit path. This merging approach reduces inter-band interference by isolating frequency bands while maintaining a compact hardware structure that avoids the need for completely separate transmit paths, thus balancing complexity reduction with interference mitigation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The filter system is designed with universal functionality to handle both VDSL and ADSL modes through a single integrated architecture. The parallel lowpass and highpass filters serve multiple purposes: they enable multi-mode operation, reduce interference, and maintain compatibility with both DSL standards, thereby reducing overall device complexity compared to separate dedicated systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If transformer parameters are optimized for a wide frequency range, then adaptability is improved, but performance in specific frequency bands deteriorates

Engineering Contradiction:

Improvefrequency band coverageVSAvoidfilter optimization accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The transformer system is segmented into separate lowpass and highpass transformer sections, each with parameters specifically optimized for its designated frequency band. This segmentation enables precise optimization of transformer characteristics for VDSL and ADSL modes independently, achieving high manufacturing precision and performance in each band while maintaining overall adaptability through the unified parallel structure.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS7907659B2Dual-band line interface circuit capable of multi-band communication

Publication Date: 2011.03.15 COMMSCOPE TECHNOLOGIES LLC

AI summary

In an embodiment, a DSL communication device comprising a line interface circuit is disclosed. The line interface circuit includes a hybrid circuit to interface the communication device to a communication line, a lowpass transmit filter to pass signals in a first frequency band, and a highpass transmit filter to pass signals in a second frequency band, where the second frequency band is higher in frequency than the first frequency band. The outputs of the highpass and lowpass filters are coupled in parallel to the communication line. The lowpass and highpass filters as well as the low and highpass transformers are optimized for their frequency bands. Further, the edges of the low and high frequency bands are sufficiently separated to reduce interference from the other frequency band. These factors, in part, allow a multiple tone communication device to be capable of operating in multiple modes of operation with multiple DSL varieties.