Network Node Transmission Method for Passive Optical Network

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Solution Overview

Problem

The existing network architectures for gigabit access technologies, such as Fiber to the Distribution Point (FTTdp), require complex OFDM modulation and demodulation processes, leading to increased operation and maintenance costs due to the need for two sets of OFDM operations in the passive optical network.

Innovation Solution

A method and apparatus that simplifies the network node transmission by performing OFDM modulation and multiplexing on downlink data, allowing direct demultiplexing to obtain OFDM symbols for each customer premises equipment (CPE), reducing the complexity to a single set of OFDM operations and enhancing transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two sets of OFDM modulation and demodulation are performed in the passive optical network, then the signal transmission can be completed, but the device complexity and operation and maintenance costs increase

Engineering Contradiction:
Improvesignal transmission completionVSAvoidOFDM operation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the optical domain signal processing with the electrical domain OFDM processing into a unified hybrid system. The OOLT performs OFDM modulation on electrical signals, converts them to optical signals, and the optical hybrid receiver simultaneously performs optical-to-electrical conversion and OFDM demodulation. This merging eliminates the need for separate optical domain modulation/demodulation stages, reducing device complexity while maintaining transmission reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical hybrid receiver is designed with multi-functionality, serving both as an optical-to-electrical converter and as an OFDM demodulator. This universal device handles multiple functions that would traditionally require separate components, thereby reducing the overall device complexity and operation and maintenance costs while ensuring reliable signal transmission.

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

2Reliability

If two sets of OFDM modulation and demodulation are performed in the passive optical network, then the signal transmission can be completed, but the operation and maintenance costs increase

Engineering Contradiction:
Improvesignal transmission completionVSAvoidoperation and maintenance costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the optical domain signal processing with the electrical domain OFDM processing into a unified hybrid system. The OOLT performs OFDM modulation on electrical signals, converts them to optical signals, and the optical hybrid receiver simultaneously performs optical-to-electrical conversion and OFDM demodulation. This merging eliminates the need for separate optical domain modulation/demodulation stages, reducing device complexity while maintaining transmission reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical hybrid receiver is designed with multi-functionality, serving both as an optical-to-electrical converter and as an OFDM demodulator. This universal device handles multiple functions that would traditionally require separate components, thereby reducing the overall device complexity and operation and maintenance costs while ensuring reliable signal transmission.

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

3Reliability

If complex OFDM modulation and demodulation processes are used, then the transmission can be achieved, but the transmission speed over the downlink optical channel decreases

Engineering Contradiction:
Improvetransmission achievementVSAvoiddownlink optical channel transmission speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent replaces complex mechanical/optical domain modulation and demodulation processes with an electrical domain OFDM system. The OOLT performs OFDM modulation on electrical signals before optical conversion, and the optical hybrid receiver performs OFDM demodulation after optical-to-electrical conversion. This substitution of electrical processing for optical processing reduces complexity and improves transmission speed while maintaining reliable transmission achievement.

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

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

This approach simplifies the DPU structure, reduces costs and power consumption, and improves transmission speed over the downlink optical channel by eliminating the need for redundant OFDM processes, thereby lowering operation and maintenance costs.

Implementation Method 1

performing optical-to-electrical conversion and analog-to-digital conversion on the downlink optical signal

Methodology Applied
Scientific EffectOptical-to-electrical conversion: Photoelectric Effect

Implementation Method 2

performing optical-to-electrical conversion and analog-to-digital conversion on the downlink optical signal

Methodology Applied
Scientific EffectAnalog-to-digital conversion:

Implementation Method 3

perform digital-to-analog conversion on the downlink OFDM symbols of each CPE

Methodology Applied
Scientific EffectDigital-to-analog conversion:

Data Source

PatentEP2988437B1Network node transmission method, and device and system thereof
Publication Date: 2017.11.01 HUAWEI TECH CO LTD
  • EP2988437B1 patent drawingFigure 1
  • EP2988437B1 patent drawingFigure 2
  • EP2988437B1 patent drawingFigure 3

AI summary

Embodiments of the present invention provide a network node transmission method, apparatus, and system. The method includes: receiving a downlink optical signal sent by an OLT, where the downlink optical signal is obtained through digital-to-analog conversion and electrical-to-optical conversion performed by the OLT on a first downlink multiplexing digital signal, and in the first downlink multiplexing digital signal, multiple customer premises equipments CPE correspond to respective OFDM symbol timeslots and/or subcarriers; and performing optical-to-electrical conversion and analog-to-digital conversion on the downlink optical signal to obtain a second downlink multiplexing digital signal, demultiplexing the second downlink multiplexing digital signal to obtain downlink OFDM symbols for each CPE of the multiple CPEs, and performing digital-to-analog conversion on the downlink OFDM symbols of each CPE to obtain a downlink analog signal of each CPE. Embodiments of the present invention require only one set of OFDM modulation and demodulation, which can reduce operation and maintenance costs.