Optical Digital Transmission System with Stuff Control Bytes
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Solution Overview
Problem
Current optical digital transmission systems face challenges in accommodating client signals with higher bit rate accuracy, particularly those with ±100 ppm, in multiplexing and transmitting them as OTU frames, due to limitations in wavelength division multiplexing systems of the 10 Gb/s and 40 Gb/s classes.
Innovation Solution
The system introduces additional stuff control bytes and bits in specific positions within the OTU frame to accommodate client signals with higher bit rate accuracy, allowing for the multiplexing and transmission of ODU2e signals with ±100 ppm accuracy by adjusting the frame structure and bit rates, while maintaining compatibility with ±20 ppm signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the OTU frame structure is used with standard stuff control bytes, then compatibility with existing systems is maintained, but client signals with ±100 ppm bit rate accuracy cannot be accommodated
Solution Approach 1:
The patent segments the stuff control mechanism into multiple independent components: existing JC1/NJO1/PJO1 bytes are separated from newly added JC2/NJO2/PJO2 bytes. This segmentation allows the system to independently control stuff operations for different client signal types, enabling simultaneous support for both ±20 ppm and ±100 ppm accuracy requirements without compromising existing system compatibility.
Solution Approach 2:
The patent extends the stuff control dimension by adding a second set of control bytes (JC2, NJO2, PJO2) alongside the existing first set (JC1, NJO1, PJO1). This dimensional extension creates independent control pathways, allowing the system to handle client signals with different bit rate accuracy requirements through selective activation of appropriate control sets, thereby resolving the contradiction between compatibility and precision.
2Measurement precision
If additional stuff control bytes are added to accommodate ±100 ppm signals, then bit rate accuracy is improved, but frame structure complexity increases
Solution Approach 1:
The patent extracts the stuff control functionality into separate, modular byte components (JC, NJO, PJO sets) that can be independently managed. By taking out the control logic into discrete extractable units, the system can selectively apply stuff operations based on client signal requirements, reducing the effective complexity for each specific application while maintaining the capability for high precision control.
Solution Approach 2:
The patent implements partial action by allowing the system to activate only the necessary stuff control set (either the first or second set, or both) depending on the specific client signal requirements. This partial activation approach avoids the full complexity of always processing all control bytes, enabling precise control for ±100 ppm signals while maintaining simplicity for standard ±20 ppm signals.
Data Source
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AI summary
An optical digital transmission system of the present invention newly defines one second negative stuff byte in an overhead area for accommodation of the client signals with multiplexing into the OTU frame, newly defines one third positive stuff byte in a corresponding tributary slot in a payload area for accommodation of client signals with multiplexing, newly defines stuff control bits that is used for decision of the use of the second negative stuff byte and the third positive stuff byte in three different places in the overhead area for client signal accommodation with multiplexing, performs control by using the newly defined stuff control bits when accommodation of the client signal with the third positive stuff byte or the second negative stuff byte is required, and performs stuff control without using the newly defined stuff control bits when accommodation of the client signal by the third positive stuff byte and the second negative stuff byte is not required.