Digital Pre-Distortion and Echo Cancellation for Cable Network Full Duplex

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Solution Overview

Problem

Cable network operators face significant costs due to high electrical power consumption by HFC amplifiers, which is not proportionally offset by increased throughput, and existing technologies struggle to implement full duplex communication effectively in cable networks, leading to bandwidth limitations and interference issues.

Innovation Solution

The implementation of a system architecture that includes digital pre-distortion (DPD) and echo cancellation mechanisms, utilizing high-speed analog-to-digital converters, advanced algorithms, and machine learning to optimize amplifier efficiency and suppress interference, enabling full duplex communication while reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If HFC amplifiers are deployed to boost signal power throughout the cable network, then signal coverage and throughput are improved, but electrical power consumption increases significantly

Engineering Contradiction:

ImprovethroughputVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies digital pre-distortion (DPD) technology to pre-compensate amplifier non-linearity and saturation effects before signal amplification. By digitally adjusting signal characteristics in advance, the system reduces the need for excessive power amplification, thereby lowering power consumption while maintaining throughput performance

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts amplifier operating parameters including power levels, frequency allocations, and modulation schemes based on real-time network conditions. This optimization allows amplifiers to operate at lower power levels while maintaining required throughput, directly addressing the power-consumption versus productivity contradiction

Inventive Principle:

Principle #35Parameter changes

2Productivity

If full duplex communication is implemented in cable networks, then bandwidth capacity is increased, but interference and distortion issues worsen

Engineering Contradiction:

Improvebandwidth capacityVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful self-interference signal into a useful reference signal for echo cancellation. By capturing the transmitted signal and using it to generate an accurate echo model, the system subtracts the interference from the received signal, thereby enabling full duplex operation with reduced interference

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements echo cancellation mechanisms that use feedback from the transmitted signal to dynamically adjust and cancel out self-interference in real-time. This feedback loop continuously optimizes interference suppression, allowing full duplex communication to achieve high bandwidth capacity without being overwhelmed by interference

Inventive Principle:

Principle #23Feedback

3Productivity

If amplifier power is increased to improve throughput, then signal strength is enhanced, but power efficiency deteriorates

Engineering Contradiction:

ImprovethroughputVSAvoidpower efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent applies digital pre-distortion to pre-compensate for amplifier non-linearity and saturation effects before signal amplification. By digitally adjusting signal characteristics in advance, the system reduces the need for excessive power amplification, thereby lowering power consumption while maintaining throughput performance

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10797750B2System architecture for supporting digital pre-distortion and full duplex in cable network environments

Publication Date: 2020.10.06 CISCO TECHNOLOGY INC

AI summary

An example apparatus for supporting digital pre-distortion (DPD) and full duplex (FDX) in cable network environments is provided and includes a first path for signals being transmitted out of the apparatus, a second path for signals being received into the apparatus, a DPD actuator located on the first path, an amplifier located on the first path, an echo cancellation (EC) actuator located on the second path, and a data interface including a plurality of channels connecting the apparatus to a signal processor. DPD coefficients, EC coefficients and delay parameters are provided over the data interface from the signal processor to the apparatus. The DPD actuator predistorts signals on the first path using the DPD coefficients compensating for distortions introduced by the amplifier, and the EC actuator reduces interferences in signals on the second path using the EC coefficients and the delay parameters, facilitating FDX communication by the apparatus.