OTN Transmission via Virtual Lanes and Stuff Insertion
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Solution Overview
Problem
Current technologies face challenges in transmitting high-speed signals exceeding 100 Gbps over OTN due to limitations in increasing symbol rates of hardware circuits, making it difficult to achieve a symbol rate of 100 Gbaud or more.
Innovation Solution
The method involves generating and transmitting optical signals through multiple virtual lanes using dual polarization and multi-level modulation, where frame signals are adjusted in frequency by inserting 'stuff' to accommodate different symbol rates, allowing for efficient transmission of high-speed data without the need for dedicated circuitry for each transmission rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single high-speed circuit is used to transmit data at 100 Gbps or more, then the transmission capacity is improved, but the hardware circuit speed limit makes it difficult to achieve the required symbol rate
Solution Approach 1:
The patent divides a single high-speed transmission channel into multiple parallel virtual lanes (e.g., 4 lanes for ODU4C4). Each lane operates at a lower, achievable symbol rate (e.g., 25-50 Gbaud), while collectively providing the required high transmission capacity (100 Gbps or more). This segmentation resolves the contradiction by trading single-channel high speed for multi-channel parallel operation at moderate speeds.
Solution Approach 2:
The patent transitions from a single-dimensional high-speed transmission approach to a multi-dimensional parallel transmission structure using virtual lanes. By adding the dimension of parallelism (multiple lanes), the system achieves high aggregate throughput without requiring any single lane to operate at prohibitively high symbol rates.
2Productivity
If multiple virtual lanes are used to transmit high-speed data, then the transmission capacity exceeds 100 Gbps, but the frequency synchronization between lanes becomes complex
Solution Approach 1:
The patent employs a universal frequency adjustment mechanism (stuff insertion) that can be applied to all virtual lanes regardless of their specific frequency offsets. This universal approach simplifies the overall system design compared to implementing lane-specific synchronization circuits, reducing equipment complexity while maintaining multi-lane high-capacity transmission.
Solution Approach 2:
The patent dynamically adjusts the frequency parameter of each virtual lane by inserting stuff bytes, allowing each lane to be tuned to its optimal operating frequency while maintaining synchronization with the overall system clock. This parameter adjustment approach provides flexible frequency management across multiple lanes without requiring complex hardware synchronization.
3Device complexity
If frame signals are read from memory at a unified frequency, then the clock synchronization is simplified, but the frequency difference between input and output frames must be adjusted
Solution Approach 1:
The patent introduces stuff bytes as an intermediary mechanism between the input frame signals (with their original frequency characteristics) and the output frame signals (read at unified memory frequency). These stuff bytes act as a buffer that absorbs frequency differences, allowing the memory to operate at a unified frequency while still accommodating the varying input frequencies without data loss or corruption.
Data Source
AI summary
A transmission method that transmits an optical signal via a plurality of virtual lanes in dual polarization or multi-level modulation includes: receiving a first frame signal of a first frequency and a second frame signal of a second frequency, and storing the first and second frame signals on a memory; reading out the first frame signal from the memory at a third frequency, and inserting a stuff into the first frame signal such that a difference between the first frequency and the third frequency is adjusted to generate a third frame signal; reading out the second frame signal from the memory at the third frequency, and inserting a staff into the second frame signal such that a difference between the second frequency and the third frequency is adjusted to generate a fourth frame signal; and transmitting the third and fourth frame signals respectively via different virtual lanes.