Full Duplex DOCSIS Modem Synchronization via Advance Warning Signals

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Solution Overview

Problem

In full duplex cable modem communication networks, upstream and downstream signals share the same frequency band, leading to interference that causes neighboring modems to 'blind' and lose synchronization, resulting in degraded signal quality and increased recovery time, which hampers efficient network operation.

Innovation Solution

A head-end equipment generates an advanced warning signal for modems in an interference group about upcoming upstream transmissions, allowing them to take protective actions such as suspending downstream communications during upstream bursts, thereby maintaining synchronization and reducing interference effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full duplex communication is implemented where upstream and downstream signals share the same frequency band, then network capacity and efficiency are improved, but neighboring modems experience interference that causes them to lose synchronization and go out of lock

Engineering Contradiction:

Improvenetwork capacityVSAvoidsynchronization

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The head-end equipment sends advance warning signals to modems before upstream transmissions begin. These warning signals allow modems to prepare protective actions in advance, such as suspending downstream communications or adjusting receiver settings, thereby preventing loss of synchronization rather than reacting after interference occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies counter-actions before harmful interference can take effect. By warning modems of upcoming upstream transmissions, the system enables modems to take protective measures that counteract the potential blinding effect, maintaining their lock state despite the interference that would otherwise occur

Inventive Principle:

Principle #9Preliminary anti-action

2Use of energy by moving object

If upstream transmission bursts are allowed in the same frequency band as downstream communication, then spectral efficiency is improved, but received signal quality degrades causing modems to go out of lock

Engineering Contradiction:

Improvespectral efficiencyVSAvoidreceived signal quality

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The head-end equipment provides advance warning to modems before upstream transmissions begin, allowing them to prepare protective actions that maintain received signal quality despite the upcoming interference from upstream bursts in the same frequency band

Inventive Principle:

Principle #10Preliminary action

3Productivity

If modems remain synchronized during upstream transmissions, then network operation efficiency is improved, but interference from upstream bursts still occurs in the shared frequency band

Engineering Contradiction:

Improvenetwork operation efficiencyVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system converts the potentially harmful upstream transmission bursts into beneficial scheduled communications. By coordinating upstream transmissions with advance warnings, the system ensures that interference occurs only when modems are prepared, transforming what would be harmful random interference into controlled, manageable events that maintain overall network efficiency

Inventive Principle:

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

Data Source

PatentUS11902218B2Signaling method to enable full duplex in next generation docsis cable modem standard

Publication Date: 2024.02.13 INTEL CORP

AI summary

A head-end equipment associated with a communication system configured to interface with an interference group (IG) composed of two or more modems is disclosed. The head-end equipment comprises a memory configured to store a plurality of instructions; and one or more processors configured to retrieve the plurality of instructions from the memory. In some embodiments, the one or more processors, upon execution of the plurality of instructions from the memory, is configured to generate an advanced warning signal to be provided to one or more modems associated with the IG. In some embodiments, the advanced warning signal comprises an information that a select modem, different from the one or more modems, in the IG will be initiating an upstream communication in a select frequency band, as well as information on a start time and a duration of the upstream communication.