Optical Burst Receiver Modulation Format Detection
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Solution Overview
Problem
Current all-optical switching networks face challenges in supporting multiple modulation formats, particularly non-equal-amplitude QAM signals, due to limitations in existing coherent burst receivers that rely on constant modulus algorithms applicable only to equal-amplitude modulation formats.
Innovation Solution
The introduction of a label-based system within the optical burst packet header allows the receiver to identify modulation formats by determining polar radius values of labeled constellation points, enabling the use of corresponding demodulation schemes for different-order amplitude modulation signals, such as BPSK, QPSK, 8QAM, and 16QAM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If constant modulus algorithm (CMA) is used for channel equalization in coherent burst receivers, then convergence speed is improved for equal-amplitude modulation formats, but the receiver cannot support non-equal-amplitude QAM signals
Solution Approach 1:
The patent implements a dynamic demodulation scheme selection mechanism that adapts to different modulation formats. The receiver dynamically switches between CMA (for equal-amplitude formats like PSK) and RLS algorithms (for non-equal-amplitude formats like QAM) based on the detected modulation type, ensuring optimal performance for each format while maintaining broad compatibility
Solution Approach 2:
The patent changes the demodulation algorithm parameter based on the modulation format. By detecting whether the signal uses equal-amplitude or non-equal-amplitude modulation, the system selects appropriate algorithms (CMA or RLS) with different mathematical characteristics, thereby resolving the contradiction between versatility and reliability
2Adaptability or versatility
If multiple demodulation algorithms are supported for different modulation formats, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a modulation format detection module as an intermediary that identifies the signal type before routing to the appropriate demodulation algorithm. This mediator simplifies the system architecture by using a centralized detection mechanism rather than requiring multiple parallel demodulation paths, thereby reducing overall system complexity while maintaining multi-format support
Solution Approach 2:
The demodulation system is segmented into distinct functional modules: a detection module that identifies modulation format, and separate processing paths for different formats. This segmentation allows each module to be optimized independently and simplifies the overall control logic, reducing device complexity while supporting multiple formats
Data Source
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AI summary
The present invention discloses data receiving and sending methods and apparatuses and a system, and relates to the field of communications technologies. The data receiving method includes: receiving a data carrier; deciding polar radius values of multiple labeled constellation points carried at a pre-determined location in the data carrier, to determine a numerical value indicated by a polar radius value of each labeled constellation point in the multiple labeled constellation points; determining, according to a sequence including numerical values indicated by polar radius values of all the labeled constellation points in the multiple labeled constellation points, a demodulation scheme of a constellation point, other than the multiple labeled constellation points, carried in the data carrier; and demodulating, according to the determined demodulation scheme, the constellation point, other than the multiple labeled constellation points, carried in the data carrier. According to the data receiving and sending methods and apparatuses and the system, the data receiving apparatus can receive different-order amplitude modulation signals, and perform processing by using corresponding demodulation formats.