Staggered Codeword Mapping for Lower-BER Optical Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Higher-order modulation schemes in optical transmission systems result in higher bit error rates and reduced transmission distances, necessitating effective methods to reduce bit error rates and increase transmission distances.
Innovation Solution
A modulation and encoding method that grades to-be-transmitted bits into multiple levels, encodes these levels to obtain codewords, and maps them to symbols in a staggered manner, allowing codewords at different levels to overlap and utilize decoded information for improved demodulation and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher-order modulation schemes are used, then transmission rate is improved, but bit error rate increases and transmission distance decreases
Solution Approach 1:
The patent segments the transmitted signal into multiple codeword levels (first codeword, second codeword, etc.) with different error correction capabilities. Each level is independently encoded and then combined through staggered mapping, allowing the system to achieve high transmission rates while maintaining reliability through hierarchical error protection.
Solution Approach 2:
The patent implements a nested structure where multiple codewords of different lengths and error correction strengths are embedded within a single symbol. The first codeword (longer, stronger error correction) and second codeword (shorter, weaker error correction) are nested together through overlapping mapping, creating a multi-layered error protection mechanism.
2Productivity
If higher-order modulation schemes are used, then transmission rate is improved, but transmission distance decreases
Solution Approach 1:
The patent applies local quality by assigning different error correction strengths to different parts of the transmitted data. The first codeword provides stronger error correction for critical information, while the second codeword provides lighter protection for less critical information. This localized differentiation allows the system to extend transmission distance while maintaining high overall transmission rate.
3Measurement precision
If codewords are mapped in a staggered manner with overlapping, then demodulation accuracy is improved, but system complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-defining the staggered mapping pattern and overlapping structure before transmission. The mapping relationship between first codeword, second codeword, and symbol bits is established in advance, which simplifies the receiver's demodulation process. The receiver can use the predetermined overlapping structure to efficiently combine information from multiple codewords without complex real-time calculations.
Data Source
AI summary
This application discloses a modulation/demodulation and encoding/decoding method and belongs to the field of communication technologies. The modulation and encoding method includes: grading to-be-transmitted bits into a plurality of levels; encoding a plurality of levels of bits obtained through grading to obtain a plurality of levels of codewords; and mapping the plurality of levels of codewords to a symbol in a staggered manner, where the plurality of levels of codewords include a first codeword, the first codeword is located at a Yth level of the plurality of levels of codewords, and the first codeword overlaps at least one codeword at any level other than the Yth level. In this way, codewords at different levels are associated by using a symbol to which the codewords are mapped, and an overlapping part between a plurality of codewords can assist in demodulating the codewords.