Optical Data Transmission Using Interleaved Even-Odd Constellation Schemes
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Solution Overview
Problem
Existing optical data transmission methods are limited in granularity for increasing data rate and are sensitive to noise artefacts, leading to reduced transmission distances when switching between modulation formats.
Innovation Solution
The method involves generating data symbols using multiple constellation schemes, alternating between even and odd data bit representations, and interleaving them in time, allowing for finer granularity in data rate increase while reducing sensitivity to noise artefacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a modulation format with an increased number of constellation points is used to increase data rate, then the data rate is improved, but the distance to other constellation points is decreased making it more sensitive to noise artefacts
Solution Approach 1:
The data stream is segmented into even and odd data bit sets, with even bits modulated using a first constellation scheme and odd bits using a second constellation scheme. This segmentation allows each subset to use optimized modulation formats, balancing data rate and noise sensitivity independently.
Solution Approach 2:
Different constellation schemes are applied to different data bit positions (even vs odd), allowing each group to have optimized local properties. The first constellation scheme optimizes for certain characteristics while the second optimizes for others, achieving overall system optimization.
2Productivity
If the number of constellation points is increased to represent more data bits per symbol, then the data rate is improved, but the transmission reach is reduced due to increased sensitivity to transmission artefacts
Solution Approach 1:
By dividing data bits into even and odd groups with different modulation schemes, the system achieves higher effective data rate without requiring a single high-order constellation that would reduce transmission reach.
Solution Approach 2:
The system uses a composite modulation approach, combining multiple constellation schemes (e.g., QPSK and 8QAM) to create an effective modulation format that achieves high data rate while maintaining the robustness of lower-order schemes for parts of the data stream.
3Ease of operation
If a single modulation format is used for all data symbols, then the system is simple to operate, but the granularity for increasing data rate is limited
Solution Approach 1:
The data stream is divided into even and odd bit groups that can be independently modulated, enabling fine-grained control of data rate by adjusting the mix of modulation schemes used on each group, while maintaining relatively simple system operation.
Solution Approach 2:
The system dynamically selects and applies different constellation schemes to different data bit groups, allowing flexible and granular adjustment of data rate without requiring complete system reconfiguration or complex multi-format switching.
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 enables a higher data rate with improved resistance to transmission artefacts, achieving longer distances than using a single higher modulation format while maintaining lower bit error ratios.
Implementation Method 1
modulating the phase and/or the amplitude of an optical carrier signal in dependence on the set of data bits
Implementation Method 2
modulating the phase and/or the amplitude of an optical carrier signal
Data Source
AI summary
A method and device for optical data transmission are disclosed. Data bits are transmitted in the form of data symbols, by modulating an optical signal in dependence on the data bits and in accordance with two or more constellation schemes. The data bits are transmitted, by generating first data symbols, which represent respective sets of data bits containing an even number of data bits. The first data symbols are generated, by modulating the optical signal in accordance with a first constellation scheme. Furthermore, the data bits are transmitted, by generating second data symbols, which represent respective sets of data bits having an odd number of data bits. The second data symbols are generated, by modulating the optical signal in accordance with a second constellation scheme. The first and the second data symbols are generated at a predefined symbol rate, such that the first and the second data symbols are interleaved in time.