Optical Super-Frame Symbol Layout for DC-Balanced Polarization Recovery
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Solution Overview
Problem
Conventional optical communication systems face challenges in adapting to scenarios beyond 400 Gbps and suffer from poor cross-correlation between symbol sequences in different polarization directions, leading to signal distortion and poor signal quality.
Innovation Solution
A transmission and reception method for optical communication that includes generating super-frames with specific distributions of training and pilot symbols in each polarization direction, ensuring balanced quantities and direct current balance, and using target polynomials to generate pilot symbols, thereby improving signal quality and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional transmission symbol sequences are used for 400-Gbps scenario, then the system works for current data rates, but it cannot adapt to future scenarios of over 400 Gbps (600 Gbps, 800 Gbps, and the like)
Solution Approach 1:
The patent designs a universal symbol sequence structure that can be applied across multiple data rate scenarios (400 Gbps, 600 Gbps, 800 Gbps, and beyond). The super-frame structure with configurable sub-frames and symbol distributions allows the same basic framework to serve multiple future-proof data rate requirements without requiring complete redesign for each scenario.
Solution Approach 2:
The patent introduces dynamic configurability in the symbol sequence design, where the quantities of training symbols and pilot symbols can be adjusted based on the specific data rate scenario. The use of mathematical formulations with variables (NTS, NPS, A, aj) allows the system to adapt its parameters dynamically to match different transmission requirements while maintaining the same underlying structure.
2Reliability
If fixed symbol sequences are added to combat signal distortion, then long-distance transmission is maintained, but the cross-correlation between transmission symbol sequences in different polarization directions becomes poor
Solution Approach 1:
The patent applies asymmetric design in the polarization domain by using different symbol distributions for different polarization directions. Specifically, it rotates the constellation diagram by 45 degrees and assigns different quantities of training and pilot symbols to different polarization directions, creating an asymmetric structure that improves cross-correlation properties while maintaining signal integrity.
Solution Approach 2:
The patent optimizes the local properties of symbol sequences in different polarization directions by assigning specific quantities of training symbols and pilot symbols to each direction based on local requirements. The formulation allows different polarization directions to have tailored symbol distributions (with NTS and NPS parameters) that optimize their respective cross-correlation characteristics while contributing to overall system reliability.
3Adaptability or versatility
If training symbols and pilot symbols are increased to improve signal restoration, then the adaptability to higher data rates improves, but the symbol sequence length increases
Solution Approach 1:
The patent segments the transmission frame into a super-frame structure containing multiple sub-frames, with training symbols and pilot symbols distributed across different sub-frames. This segmentation allows the system to achieve the benefits of having numerous training and pilot symbols for high data rate adaptability while organizing them in a structured, manageable way that avoids excessive overall sequence length through efficient distribution.
Data Source
AI summary
A transmission method for optical communication and a related device and system are provided, which may be applied to various scenarios such as a metropolitan area network, a backbone network, and data center interconnect of over 400 Gbps (including 600 Gbps, 800 Gbps, and the like). The method includes: generating a super-frame including a plurality of sub-frames; and transmitting the super-frame, wherein each sub-frame includes training symbols and pilot symbols, and each of the training symbols and the pilot symbols is one of −A−Aj, −A+Aj, A−Aj, and A+Aj, A being a real number. In addition, in the training symbols and the pilot symbols included in each sub-frame, quantities of −A−Aj, −A+Aj, A−Aj, and A+Aj in two mutually perpendicular polarization directions meet specific requirements, so that direct current balance can be achieved, which helps a receiver end restore a signal.