Full Duplex Expander for Same-Band Signal Isolation

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Solution Overview

Problem

The transition to full duplex communications in cable networks is hindered by the need to replace legacy analog amplifiers with FDX nodes, which increases costs and deployment time due to the requirement for fiber connections, as analog amplifiers are not compatible with full duplex transmission in the same frequency band.

Innovation Solution

The introduction of FDX expanders that can amplify full duplex signals by separating and isolating downstream and upstream signals in the same frequency band, allowing for continued use of analog connections and avoiding the need for FDX node replacements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If legacy analog amplifiers are replaced with FDX nodes to enable full duplex transmission, then full duplex capability is achieved, but cost and deployment time increase due to fiber connection requirements

Engineering Contradiction:

Improvefull duplex capabilityVSAvoidinfrastructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system segments the full duplex signal into upstream and downstream components, separating them in the frequency domain using guard bands. This allows legacy amplifiers to process each direction independently while maintaining full duplex operation, avoiding the need for complete infrastructure replacement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A frequency domain intermediary layer is introduced between the legacy amplifier and the full duplex transmission requirement. By inserting guard bands and frequency separation mechanisms, the system mediates between the legacy amplifier's limitations and the full duplex capability requirement, enabling both to coexist.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If legacy analog amplifiers are replaced with FDX nodes, then full duplex transmission is enabled, but deployment time increases due to coaxial cable replacement with fiber

Engineering Contradiction:

Improvefull duplex transmission capabilityVSAvoiddeployment time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system performs preliminary frequency domain configuration by establishing guard bands and frequency allocation schemes before deployment. This preliminary setup allows legacy amplifiers to be retrofitted with frequency separation capabilities without requiring physical infrastructure changes, significantly reducing deployment time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention creates a virtual frequency domain copy of the transmission medium, where upstream and downstream signals are separated through frequency multiplication and guard band insertion. This virtual copying approach allows full duplex operation over existing coaxial infrastructure without physical fiber replacement.

Inventive Principle:

Principle #26Copying

3Reliability

If diplex filters are used in legacy amplifiers for frequency separation, then upstream and downstream isolation is achieved, but oscillation prevention is compromised in full duplex same-band transmission

Engineering Contradiction:

Improvesignal isolationVSAvoidsame-band transmission compatibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system changes the frequency domain parameters by introducing guard bands between upstream and downstream frequencies. This parameter modification allows legacy amplifiers to maintain signal isolation without diplex filters, enabling same-band full duplex transmission while preventing oscillation through frequency separation rather than filtering.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables full duplex traffic transmission without replacing legacy analog amplifiers, reducing costs and deployment time by maintaining coaxial cable connections and providing efficient signal amplification and isolation.

Implementation Method 1

separating, by the computing device, the downstream signal and the upstream signal into a first path and a second path

Methodology Applied

Scientific EffectFrequency separation:

Implementation Method 2

amplifying, by the computing device, the downstream signal using the first path and the upstream signal using the second path

Methodology Applied

Scientific EffectSignal amplification:

Implementation Method 3

isolating, by the computing device, the downstream signal and the upstream signal from one another

Methodology Applied

Scientific EffectSignal isolation:

Data Source

PatentEP4125223A1Full duplex expander in a full duplex network

Publication Date: 2023.02.01 ARRIS ENTERPRISES LLC

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AI summary

In one embodiment, a method receives a downstream signal and an upstream signal in a same frequency band. The downstream signal and the upstream signal are separated into a first path and a second path. The downstream signal using the first path and the upstream signal using the second path are amplified in an analog domain. The method isolates the downstream signal and the upstream signal from one another and sends the downstream signal downstream to a subscriber device and sends the upstream signal towards a full duplex node.