Optical Network Design Apparatus for Baud Rate and Modulation Selection
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Solution Overview
Problem
In digital coherent optical transmission systems, there is a challenge in manually selecting the optimum combination of baud rate and multi-level modulation system due to the trade-off between pass band narrowing and optical signal-to-noise ratio (OSNR) tolerance, making it difficult for network designers to achieve proper network design.
Innovation Solution
A network design method that calculates the bandwidth narrowing caused by wavelength filters and selects combinations of modulation systems and baud rates based on minimum OSNR tolerance, ensuring the bandwidth is equal to or less than the narrowed bandwidth, thereby optimizing the selection of baud rate and modulation system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a higher baud rate is set to increase the number of bits per symbol, then the transmission speed is improved, but the bandwidth of the optical signal becomes wider and the influence of pass band narrowing increases
Solution Approach 1:
The patent changes the parameter of multi-level degree in the multi-level modulation system to resolve the contradiction. By adjusting the multi-level degree, the system can achieve the desired transmission speed while controlling the bandwidth and pass band narrowing influence. The network design apparatus calculates optimal parameters by considering both transmission speed requirements and pass band characteristics.
2Reliability
If a lower multi-level degree is selected to improve OSNR tolerance, then the optical signal-to-noise ratio tolerance is improved, but the number of bits per symbol becomes smaller requiring a higher baud rate
Solution Approach 1:
The patent adjusts the multi-level degree parameter to balance OSNR tolerance and baud rate requirements. By optimizing this parameter, the system achieves sufficient OSNR tolerance while maintaining the required transmission speed, resolving the contradiction between reliability and speed.
3Adaptability or versatility
If manual selection of baud rate and modulation system is performed, then flexibility in design is maintained, but the complexity of network design increases and optimal selection becomes difficult
Solution Approach 1:
The network design apparatus automatically performs the selection of optimal baud rate and multi-level modulation system combinations by calculating and evaluating multiple parameters. This self-service approach reduces design complexity while maintaining adaptability, as the apparatus independently determines the optimal configuration based on system requirements.
Solution Approach 2:
The apparatus uses feedback from parameter calculations and evaluations to determine the optimal configuration. By continuously assessing the impact of different parameter combinations on transmission performance, the system automatically converges on the optimal setting, simplifying the design process while maintaining flexibility.
Data Source
AI summary
A network design method includes calculating, from the number of wavelength filters on a transmission route of an optical signal, a bandwidth of the optical signal after narrowing by the wavelength filters, selecting, from a plurality of combinations of a multi-level modulation system and a baud rate about the optical signal set in a transmitting apparatus, one or more first combinations about which a lower-limit value of the bandwidth of the optical signal in each of the combinations is equal to or smaller than the bandwidth of the optical signal after narrowing, and selecting a second combination from the one or more first combinations based on a minimum value of an OSRN of the optical signal in the selected combinations.