Linear Pre-coded Multicarrier Signal for Optical Network Element
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Solution Overview
Problem
Existing optical systems face challenges in achieving high spectral efficiency without increasing complexity, particularly at high data rates, due to the need for advanced digital signal processing and the use of digital coherent detection.
Innovation Solution
A method involving linear pre-coding of multicarrier signals, which doubles spectral efficiency while maintaining low system complexity, allowing for direct detection compatibility without the need for polarization multiplexing or complex digital signal processing, using differential or amplitude modulation, and enabling transmission over dispersion-unmanaged links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If advanced modulation formats (multilevel modulation, polarization multiplexing, OFDM) are used to increase spectral efficiency, then spectral efficiency is improved, but device complexity increases due to the need for digital coherent detection and complex digital signal processing
Solution Approach 1:
The patent extracts and removes the need for digital coherent detection and complex DSP algorithms from the system. By using linear pre-coded multicarrier signals with direct detection, it eliminates the requirement for digital coherent detection while maintaining high spectral efficiency through the linear pre-coding structure that allows simple detection methods to achieve performance comparable to complex modulation formats
Solution Approach 2:
The patent substitutes the mechanical/electronic complex DSP system with a simpler optical processing approach. Linear pre-coding in the optical domain replaces the need for complex digital signal processing, transforming the problem from the digital domain to the optical domain where it can be solved with simpler components
2Productivity
If digital coherent detection with complex DSP algorithms is implemented, then spectral efficiency is improved, but energy consumption increases significantly
Solution Approach 1:
The patent removes the energy-intensive digital coherent detection and complex DSP algorithms from the system. By using linear pre-coded multicarrier signals compatible with direct detection, it eliminates the need for high-power digital processing while maintaining high spectral efficiency through optical-domain pre-coding
3Device complexity
If direct detection is used to reduce complexity, then device complexity is reduced, but spectral efficiency decreases due to the need for reference carrier and guard bands
Solution Approach 1:
The patent applies preliminary linear pre-coding to the multicarrier signal before modulation and transmission. This pre-coding structure is designed to be compatible with direct detection, allowing the signal to maintain its spectral efficiency properties while being detectable by simple direct detection receivers without requiring reference carriers or guard bands
Data Source
AI summary
A method for processing data in an optical network element is provided, wherein a multicarrier signal is linear pre-coded, and wherein the linear pre-coded signal is modulated. An according optical network element is also suggested.