Optical Transmission Modulation Switching for Short Data Frames
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Solution Overview
Problem
Conventional optical transmission systems face reduced transmission efficiency when data shorter than the code format are input, as they require inserting fixed values to match the code format, leading to inefficiencies.
Innovation Solution
An optical transmission apparatus that dynamically selects a multilevel modulation scheme based on the length of the information bit sequence, encodes control information with a higher error correction capability, and inserts it into the main signal information to indicate the modulation scheme, allowing flexible mapping and improved transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single predetermined multilevel modulation scheme is used with a fixed code format, then error correction encoding can be performed, but transmission efficiency is lowered when data shorter than the code format are input due to insertion of fixed values
Solution Approach 1:
The patent applies dynamics by making the modulation scheme selectable rather than fixed. The system can dynamically choose between different multilevel modulation schemes (e.g., QPSK, 16QAM, 64QAM, 256QAM) based on the data length and channel conditions, allowing the error correction code format to adapt to the actual data size and eliminate the need for padding with fixed values when data is shorter than the code format
Solution Approach 2:
The patent changes the parameter of modulation scheme selection based on data characteristics. By monitoring the data length and channel quality, the system adjusts the modulation order and corresponding code format parameters, transforming the fixed parameter system into a variable parameter system that optimizes both error correction capability and transmission efficiency for different data sizes
2Reliability
If fixed values are inserted to match data length with code format, then error correction encoding can be performed, but unnecessary fixed values reduce transmission efficiency
Solution Approach 1:
The system dynamically selects the code format length to match the actual data size. When data is shorter than the standard code format, the system chooses a shorter appropriate code format instead of padding with fixed values, thereby utilizing the full information capacity of the transmission channel and avoiding the loss of potential information capacity that would occur with fixed-value insertion
Data Source
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AI summary
An optical transmission apparatus for transmitting a multilevel-modulated optical transmission signal, the optical transmission apparatus including: a control encoding unit (27) that outputs a control information sequence having been encoded, by performing error correction encoding processing on control information, the control information including information on a multilevel modulation scheme to be used for a main signal information sequence; a main encoding unit (25) that generates the main signal information sequence having been encoded, by performing error correction encoding processing on main signal information, the error correction encoding processing corresponding to the multilevel modulation scheme indicated by the control information; a selection circuit (28) that outputs the main signal information sequence after inserting the control information sequence into the main signal information sequence such that the control information sequence indicates the multilevel modulation scheme to be used for the immediately following main signal information sequence; and a mapping unit (29) that generates the multilevel-modulated optical transmission signal by performing mapping processing on the control information sequence by use of a predetermined multilevel modulation scheme, the control information sequence having been output by the selection circuit (28), and performing mapping processing on the main signal information sequence by use of the multilevel modulation scheme indicated by the control information sequence, the main signal information sequence having been output by the selection circuit (28).