Optical Node WDM Switching for Protocol Transparency

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Solution Overview

Problem

Existing optical networking solutions for fronthaul networks in cellular communication systems face limitations in scalability, flexibility, and power efficiency, particularly due to the need for hardware replacement or reconfiguration with evolving transport and interface protocols, and increased power consumption with Optical-Electro-Optical (OEO) conversion.

Innovation Solution

An optical node with Wavelength Division Multiplexing (WDM) capabilities, featuring wavelength selective switches, node optical combiners, and switching units that provide add/drop, internal, and external bypass functionalities, along with amplification stages for tailored signal amplification, enabling non-blocking local and remote connectivity without wavelength contention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Optical-Electro-Optical (OEO) conversion is used for existing optical networking solutions, then transport and switching capabilities are provided, but power consumption increases and hardware replacement is required for future protocol evolution

Engineering Contradiction:
Improveprotocol transparencyVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the traditional OEO conversion approach with a fully optical switching mechanism. The optical circuit switch fabric performs switching operations directly in the optical domain without converting to electrical signals, eliminating the need for OEO conversion equipment and reducing power consumption while maintaining protocol transparency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical circuit switch fabric is designed to be protocol-agnostic and bitrate-transparent, providing universal switching capabilities that can handle different protocols and bitrates without requiring hardware replacement. This multi-functional design allows the same infrastructure to serve evolving communication protocols

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

2Adaptability or versatility

If OEO conversion equipment is deployed in hub nodes, then scalability and flexibility are achieved, but operating costs increase due to extra power requirements

Engineering Contradiction:
Improvenetwork scalabilityVSAvoidoperating cost
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The invention substitutes OEO conversion equipment with an all-optical circuit switch fabric that performs switching operations directly in the optical domain. This eliminates the need for optical-to-electrical-and-back conversion equipment in hub nodes, maintaining network scalability while significantly reducing power consumption and operating costs

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If electrical switching at hub node is implemented, then high degree of scalability and flexibility are achieved, but hardware replacement may be required for future network evolution

Engineering Contradiction:
Improveprotocol transparencyVSAvoidhardware reconfiguration requirement
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces electrical switching with optical circuit switching performed directly in the optical domain. The optical circuit switch fabric maintains scalability and flexibility while being inherently transparent to protocol changes, eliminating the need for hardware replacement during future network evolution

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical circuit switch fabric provides dynamic routing capabilities that can adapt to different traffic patterns and protocol requirements without physical reconfiguration. This dynamic optical switching maintains the flexibility previously achieved through electrical switching while avoiding hardware replacement requirements

Inventive Principle:
Principle #15Dynamics

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

The optical node enhances scalability, flexibility, and power efficiency by allowing transparent operation to bit rates and protocols, supporting longer distances and future protocol evolution, while reducing the need for hardware changes and power consumption.

Implementation Method 1

a wavelength selective switch coupled between the first and second line ports and configured to drop optical signals from a WDM signal traversing the optical node

Methodology Applied
Scientific EffectWavelength Division Multiplexing:

Implementation Method 2

a node optical combiner coupled between the first and second line ports and configured to add optical signals to a WDM signal traversing the optical node

Methodology Applied
Scientific EffectWavelength Division Multiplexing:

Data Source

PatentEP3198758B1Optical node
Publication Date: 2020.01.22 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3198758B1 patent drawingFigure 1~2
  • EP3198758B1 patent drawingFigure 3
  • EP3198758B1 patent drawingFigure 4

AI summary

An optical node (100) is disclosed. The optical node (100) comprises first and second line ports (104, 106) for Wavelength Division Multiplexing (WDM) signals and first and second pluralities of local add/drop ports (108, 110) for optical signals. The optical node further comprises a wavelength selective switch (112), coupled between the first and second line ports (104, 106) and configured to drop optical signals from a WDM signal traversing the optical node between the first and second line ports (104, 106), and a node optical combiner (114) coupled between the first and second line ports (104, 106) and configured to add optical signals to a WDM signal traversing the optical node between the first and second line ports (104, 106). The optical node also comprises first and second switching units (116, 118), each switching unit coupled to the wavelength selective switch(112), the node optical combiner (114), a respective one of the first and second pluralities of local add/drop ports (108, 110) and the other of the first and second switching units (116, 118). Each of the first and second switching units (116, 118) is configured to distribute dropped optical signals from the wavelength selective switch (112) to its coupled plurality of local add/drop ports and to provide optical signals from its coupled plurality of local add/drop ports to the node optical combiner (114). Each of the first and second switching units (116, 118) is also configured to distribute optical signals from its coupled plurality of local add/drop ports to the other of the first and second switching units (116, 118) and to distribute optical signals from the other of the first and second switching units to its coupled plurality of local add/drop ports.