Optical Transmission Coding With Adaptive Multilevel Modulation
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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, inserts control information indicating the scheme, and performs error correction encoding to generate a multilevel-modulated optical transmission signal, allowing flexible adaptation to varying data lengths.
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 fixed value insertion
Solution Approach 1:
The patent applies dynamics by making the modulation scheme and code format selectable rather than fixed. The system dynamically chooses between multiple multilevel modulation schemes (e.g., 16QAM, 64QAM, 256QAM) and corresponding code formats based on the data length, allowing the error correction code format to adapt to the actual data size and avoid fixed value insertion for short data
Solution Approach 2:
The patent changes the parameter of code format to match the data length. By selecting different code formats (e.g., 2544, 1824, 1008, 576, 432, 288, 216, 144, 72, 60, 48, 36, 24, 12, 6, 4, 2, 1) based on the information bit sequence length, the system ensures that the code format matches the data size, eliminating the need to insert fixed values and improving transmission efficiency
2Reliability
If fixed values are inserted to match data length with code format, then error correction encoding can be performed, but unnecessary data transmission occurs reducing overall efficiency
Solution Approach 1:
The system changes the code format parameter to exactly match the data length, eliminating the need for fixed value insertion. By selecting from multiple code formats that correspond to different data length ranges, the system ensures that the encoded data length matches the original data length, preventing transmission waste
Data Source
AI summary
An optical transmission apparatus including: a control encoding unit that outputs a control information sequence by performing error correction encoding processing on control information including information on a multilevel modulation scheme to be used for a main signal information sequence; a main encoding unit that generates the main signal information sequence by performing error correction encoding processing on main signal information, the error correction encoding processing corresponding to the multilevel modulation scheme; a selection circuit that outputs the main signal information sequence after inserting the control information sequence into the main signal information sequence; and a mapping unit that generates the multilevel-modulated optical transmission signal by performing mapping processing on the control information sequence by using the multilevel modulation scheme, the control information sequence having been output by the selection circuit, and performing mapping processing on the main signal information sequence by using the multilevel modulation scheme.