PHY Circuit Dynamic Data Rate Adjustment for Category 5e Cable Length

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Solution Overview

Problem

Current cabling infrastructures, such as Category 5e copper cables, are limited in supporting 10G Ethernet data rates at 100m cable lengths due to bandwidth and insertion loss constraints, restricting data rates to 1G over longer distances.

Innovation Solution

The system modifies the 10G physical layer (PHY) circuit to dynamically adjust data rates between 10M and 10G by using new auto-negotiation messages and 10G training, allowing support for 2.5G and 5G data rates over 100m of Category 5e cable by reducing bandwidth and adjusting the reference clock, while maintaining power over Ethernet (PoE) capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If 10G Ethernet data rate is used over Category 5e cable, then data transmission speed is improved, but cable length is limited due to bandwidth and insertion loss constraints

Engineering Contradiction:
Improvedata transmission speedVSAvoidcable length
Core Design Contradiction:
SpeedVSLength of stationary object

Solution Approach 1:

The system dynamically adjusts the data transmission rate based on cable length and quality. The PHY circuit can operate at multiple data rates (10G, 2.5G, 1G) and automatically selects the appropriate rate based on link training results, allowing 10G operation over shorter cables while falling back to lower rates for longer cables.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the physical layer by introducing intermediate data rates (2.5G, 5G) between 1G and 10G. This allows the system to optimize performance for specific cable lengths by selecting the appropriate data rate, effectively extending the usable range of Category 5e cables.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If data rate is increased from 1G to 10G over Category 5e cable, then communication efficiency is improved, but signal loss increases due to bandwidth limitations

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidsignal loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system uses dynamic rate adaptation where the data transmission rate is adjusted based on the actual link conditions. The link training process evaluates signal quality and selects the highest achievable data rate, ensuring optimal communication efficiency while maintaining acceptable error rates.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention introduces intermediate data rates (2.5G, 5G) that represent partial steps between 1G and 10G. This allows the system to achieve better than 1G performance without fully committing to 10G, which would require excessive signal quality and result in high loss for longer cables.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If fixed data rate of 1G is used for long cable lengths, then reliability is maintained, but adaptability to different cable lengths and qualities is reduced

Engineering Contradiction:
Improveconnection reliabilityVSAvoidadaptability to cable variations
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The PHY circuit is designed to support multiple data rates (10G, 2.5G, 1G) within the same hardware infrastructure. This multi-functionality allows a single device to adapt to various cable lengths and qualities, maintaining reliable connections across different scenarios without requiring specialized hardware for each data rate.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements dynamic rate selection through link training, where the data rate is not fixed but determined based on actual link conditions. This allows the system to maintain reliability by selecting appropriate rates while adapting to different cable characteristics.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3085028B1Adjustable data rates
Publication Date: 2020.05.06 CISCO TECHNOLOGY INC
  • EP3085028B1 patent drawingFigure 1
  • EP3085028B1 patent drawingFigure 2
  • EP3085028B1 patent drawingFigure 3

AI summary

Adjustable data rate data communications may be provided. First, a plurality of remote data rates at which a remote device is configured to operate may be received. Then, a plurality of local data rates at which a local device is configured to operate may be received. A greatest one of the plurality of local data rates may comprise a cable data rate comprising a greatest rate supported by a length of cable connecting the local device and the remote device. Next, an operating data rate may be determined. The operating data rate may comprise a highest one of the plurality of local data rates that has a corresponding equivalent within the plurality of remote data rates. The local device may then be operated at the operating data rate.