Hitless Modulation Mode Switching in WDM Networks
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Solution Overview
Problem
Conventional WDM networks waste spectrum resources due to fixed modulation modes and OSNR standards, leading to inefficient bandwidth utilization and complex protocol processing for hitless switching of modulation modes during service data transmission.
Innovation Solution
Implementing a method where the sending end generates and sends invalid data to allow concurrent demodulation by the receiving end to determine the target modulation mode, ensuring seamless switching without requiring protocol processing at either end, thus optimizing spectrum resource usage and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional WDM networks use fixed modulation modes and highest OSNR standards for all paths, then system robustness and upgradability are ensured, but spectrum resources are wasted and bandwidth utilization is inefficient
Solution Approach 1:
The patent implements dynamic modulation mode switching where the system transitions from fixed modulation modes to adaptive modulation modes that can be adjusted according to actual transmission conditions. The receiving end determines the target modulation mode by concurrently demodulating according to all supported modulation modes, and the sending end switches to the target modulation mode for subsequent data transmission, enabling the system to adapt to different path lengths and span numbers.
Solution Approach 2:
The patent changes the modulation mode parameter dynamically based on transmission characteristics. Instead of using a fixed modulation mode for all paths, the system determines the appropriate modulation mode (e.g., QPSK, 16QAM, 64QAM) based on the number of spans and transmission distance, thereby optimizing spectrum efficiency while maintaining system reliability.
2Ease of operation
If overhead bits are inserted to instruct modulation mode switching, then hitless switching of modulation mode is achieved, but protocol processing complexity increases and reliability decreases
Solution Approach 1:
The patent extracts the modulation mode indication function from the protocol overhead bits and implements it through physical layer signaling. Instead of using higher-layer protocol processing to convey modulation mode information, the system uses the modulation mode determination result directly at the physical layer, eliminating the need for complex protocol processing and overhead bit insertion.
Solution Approach 2:
The receiving end autonomously determines the target modulation mode by concurrently demodulating the received signal according to all supported modulation modes and selecting the best match. This self-determination mechanism eliminates the need for the sending end to insert overhead bits to instruct the receiving end, simplifying the overall system architecture and improving reliability.
3Adaptability or versatility
If overhead bits are inserted for modulation mode instruction, then sending and receiving of service data is enabled, but implementation complexity increases and reliability is reduced
Solution Approach 1:
The patent introduces an intermediate mechanism where the receiving end performs concurrent demodulation according to all supported modulation modes to determine the target modulation mode. This intermediary determination process serves as a bridge between the transmitted signal and the actual modulation mode used, enabling reliable modulation mode adaptation without requiring overhead bits or complex protocol processing.
Data Source
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AI summary
Embodiments of the present invention disclose a method, an apparatus, and a system for sending and receiving service data, where the method includes: first, obtaining, by a sending end, a target modulation mode different from a current modulation mode; and then, generating, by the sending end, invalid data, and temporarily storing service data at the same time; and then, performing encapsulation and mapping on the invalid data, switching the current modulation mode to the target modulation mode, modulating encapsulated and mapped invalid data according to the target modulation mode, and sending modulated invalid data to a receiving end; and finally, after the sending end completes the encapsulation and mapping on the invalid data, obtaining, by the sending end, the temporarily stored service data, performing encapsulation and mapping on the temporarily stored service data, modulating encapsulated and mapped service data according to the target modulation mode, and sending modulated service data to the receiving end. The present invention applies to the field of network systems.