Optical Receiver Frame Detection Using Composite Header

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Solution Overview

Problem

Current optical communication systems face challenges in distinguishing between polarized optical signals due to distortion from chromatic dispersion and polarization-dependent impairment, making it difficult to achieve high data transmission rates and accurate polarization separation.

Innovation Solution

An optical receiver is designed with a frame detector and time-domain equalizer (TDEQ) that uses a composite header with a post-amble, pre-amble, and header to identify and separate frames in polarized signals, leveraging auto-correlation and cross-correlation properties to achieve frame detection and polarization separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data streams are modulated using multiple polarizations to increase transmission rates, then data transmission rate is improved, but signal distortion from chromatic dispersion and polarization-dependent impairment increases making frame detection and polarization separation more difficult

Engineering Contradiction:
Improvedata transmission rateVSAvoidframe detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by inserting a composite header (containing pre-amble, header, and post-amble sequences) at the beginning of each frame before transmission. This pre-configured structure enables the receiver to perform frame detection and polarization separation using correlation operations on known sequences, overcoming the difficulty of distinguishing distorted polarized signals during transmission.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If data streams are modulated using multiple polarizations to increase transmission rates, then data transmission rate is improved, but polarization separation difficulty increases

Engineering Contradiction:
Improvedata transmission rateVSAvoidpolarization separation difficulty
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses the composite header as an intermediary element that facilitates polarization separation. The known pre-amble, header, and post-amble sequences act as reference signals that the receiver correlates with the received polarized signals, enabling accurate separation of multiple polarized data streams despite chromatic dispersion and polarization-dependent impairment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If optical signals pass through optical links subject to chromatic dispersion and polarization-dependent impairment, then signal transmission is achieved, but signal distortion increases affecting reception quality

Engineering Contradiction:
Improvesignal transmissionVSAvoidreception quality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the receiver uses the composite header sequences to train a time-domain equalizer (TDEQ). The TDEQ adjusts its coefficients based on correlation results between the received signals and the known header sequences, continuously adapting to compensate for chromatic dispersion and polarization-dependent impairment, thereby maintaining reliable reception.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2532104B1Method and apparatus for frame detection and polarization separation
Publication Date: 2017.09.13 HUAWEI TECH CO LTD
  • EP2532104B1 patent drawingFigure 1
  • EP2532104B1 patent drawingFigure 2
  • EP2532104B1 patent drawingFigure 3

AI summary

An optical receiver comprising a frame detector configured to receive a polarized signal comprising a first bit stream and a second bit stream, and further configured to identify a plurality of frames in the first bit stream and the second bit stream using a composite header, and a time- domain equalizer (TDEQ) configured to separate the first bit stream and the second bit stream using a portion of the composite header.