MM-OFDM-IM Coding Method with Symmetrical Constellation Mode Permutations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing MM-OFDM-IM systems face challenges with low reliability and insufficient communication performance in complex and changeable wireless channel environments.
Innovation Solution
A coding method and device based on MM-OFDM-IM that divides the coded bit sequence into an index-layer sequence and a symbol-layer sequence, determining constellation modes and symbols for each subcarrier to achieve symmetrical constellation mode permutations, thereby enhancing channel polarization and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MM-OFDM-IM encoding is used, then the system achieves basic transmission functionality, but the transmission reliability is low in complex wireless channel environments
Solution Approach 1:
The coded bit sequence is divided into two distinct layers: index-layer sequence and symbol-layer sequence. This segmentation allows independent optimization of each layer's encoding strategy, with the index-layer handling constellation mode selection and the symbol-layer handling constellation symbol mapping, thereby improving reliability without overwhelming complexity
Solution Approach 2:
The patent introduces a new dimensional structure by creating a two-layer encoding framework. The index-layer operates in the constellation mode selection dimension while the symbol-layer operates in the constellation symbol mapping dimension. This dimensional separation enables the system to achieve enhanced reliability through diversified encoding paths without linearly increasing overall complexity
2Productivity
If full permutations of constellation modes are transmitted as index information, then spectrum efficiency is improved, but communication performance becomes insufficient under complex channel conditions
Solution Approach 1:
The transmission information is segmented into two functional components: index information conveying constellation mode permutation (index-layer) and symbol information conveying constellation symbol data (symbol-layer). This segmentation enables the system to maintain high spectrum efficiency through full permutation transmission while improving communication performance by dedicating separate processing and optimization to each information type
Solution Approach 2:
Different encoding and processing qualities are applied to different parts of the transmitted information. The index-layer receives optimized processing tailored for constellation mode identification, while the symbol-layer receives processing optimized for symbol recovery. This local quality differentiation ensures that each component achieves its optimal performance contribution to overall system reliability
Data Source
AI summary
A coding method based on multiple-mode orthogonal frequency division multiplexing with index modulation (MM-OFDM-IM) is provided. A coded bit sequence is divided into an index-layer sequence and a symbol-layer sequence. According to the index-layer sequence and the symbol-layer sequence, a plurality of constellation modes respectively corresponding to the plurality of subcarriers and which one of a plurality of constellation symbols respectively corresponding to the plurality of constellation modes is carried by each of the plurality of subcarriers are determined. A constellation mode permutation corresponding to each of the plurality of subcarriers is in a symmetrical distribution. The coded bit sequence is converted into the plurality of constellation symbols. The plurality of constellation symbols are respectively loaded to the plurality of subcarriers. A coding device based on MM-OFDM-IM is also provided.