Optical Frequency Slot Fragmentation Reduction
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Solution Overview
Problem
The existing WDM and flex grid technologies lead to a messy distribution of optical signal spectra in optical fibers due to the generation of numerous OFS fragments during cross transmission through multiple nodes, resulting in reduced spectrum resource utilization.
Innovation Solution
A method involving the selection of at least two optical carriers corresponding to optical frequency slots with a vacant slot between them, modulation of data information onto these carriers to form a channel occupying multiple slots, and subsequent combination of signals to insert vacant slots, allowing flexible arrangement of spectrum blocks and reducing OFS fragments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flex grid technology is used to accommodate high rate signals with wide spectrum, then signals can be transmitted at higher bit rates (400 Gbit/s, 1 Tbit/s), but optical frequency slots are wasted when low rate signals occupy the same wide slots
Solution Approach 1:
The patent segments the optical frequency spectrum into finer granularity slots (e.g., 6.25 GHz or 12.5 GHz) instead of using fixed 50 GHz or 100 GHz slots. This segmentation allows low-rate signals to occupy only the necessary number of small slots, preventing spectrum waste while high-rate signals can still access multiple slots when needed. The spectrum is divided into reusable time-frequency blocks that can be dynamically allocated.
Solution Approach 2:
The patent implements dynamic slot allocation where the number and position of optical frequency slots assigned to each signal are not fixed but can be adjusted based on real-time spectrum availability and signal requirements. This dynamic approach allows efficient packing of both low-rate and high-rate signals without permanent reservations, resolving the contradiction between supporting high bit rates and preventing spectrum waste.
2Ease of operation
If consecutive optical frequency slots are allocated to a channel, then the channel can occupy a continuous spectrum bandwidth, but cross transmission through multiple nodes generates numerous OFS fragments causing messy spectrum distribution
Solution Approach 1:
The patent introduces a time dimension to the frequency-slot allocation by creating reusable time-frequency blocks. Instead of permanently assigning consecutive frequency slots to a channel (which causes fragmentation issues in the frequency dimension), the system allocates blocks that can be reused across different time slots. This transforms the problem from a purely frequency-domain allocation to a time-frequency domain allocation, reducing spectrum fragmentation and management complexity.
3Ease of manufacture
If a fixed optical frequency grid is used, then network design and signal distribution are simplified, but high rate signals with spectrum width exceeding grid spacing cannot be transmitted
Solution Approach 1:
The patent makes the optical frequency grid dynamic by allowing flexible adjustment of slot boundaries and allocations based on signal requirements. Instead of a rigid fixed grid, the system can dynamically configure the number, position, and width of frequency slots to match the actual spectrum needs of different signal rates, from 10 Gbit/s to 1 Tbit/s and beyond.
Solution Approach 2:
The patent changes the fundamental parameters of the frequency grid by introducing variable slot widths (e.g., 6.25 GHz, 12.5 GHz, 25 GHz, 50 GHz, 100 GHz) and allowing these parameters to be adjusted based on signal characteristics. This parameter flexibility enables the network to accommodate both simple fixed-grid scenarios and complex high-rate signal transmissions with varying spectrum widths.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures a more efficient use of spectrum resources by arranging optical signals closely in the optical fiber, minimizing OFS fragments and enhancing resource utilization during cross transmission.
Implementation Method 1
modulating data information onto the at least two optical carriers to form a channel of optical signals
Data Source
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Figure 6b~7
AI summary
A method, a system, and an apparatus for transmitting data information by using optical signals are disclosed. The method includes: selecting at least two optical carriers, where the at least two optical carriers correspond to at least two optical frequency slots, and a vacant optical frequency slot or an optical frequency slot occupied by other optical signals exists between the two optical frequency slots; modulating data information onto the at least two optical carriers to form a channel of optical signals, so that the channel of optical signals occupies the at least two optical frequency slots, and a vacant optical frequency slot or an optical frequency slot occupied by other optical signals exists between the two optical frequency slots; and sending the channel of optical signals. In implementation manners in embodiments of the present invention, a spectrum corresponding to a channel of optical signals occupies at least two OFSs, and a vacant OFS or an OFS used by other optical signals exists between the two OFSs. In this case, after cross transmission is performed through multiple nodes on a transmission network, flexible arrangement may be performed according to the size of an OFS block, so that spectra in an optical fiber are arranged closely, thereby reducing OFS fragments, and increasing the utilization of the spectra in the optical fiber.