Symbol Mapping Circuit for Multi-Dimensional Modulation LUT Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing circuit configurations that use look-up tables (LUTs) to convert transmission data into modulation data for multi-dimensional modulation in optical communication systems require multiple LUTs, leading to increased circuit size due to varying input and output bit lengths, necessitating either two or seven-bit LUTs for different types of modulations.
Innovation Solution
A symbol mapping device that processes two pieces of transmission data, adjusts their length by adding dummy data if necessary, and generates parity-added data, which is then mapped to constellation points, allowing for multiple types of multi-dimensional modulations with different spectral efficiencies while reducing circuit size by using a single set of LUTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple types of LUTs are used to support different bit lengths for multi-dimensional modulation, then adaptability to different modulation schemes is improved, but circuit size increases
Solution Approach 1:
The patent implements a universal LUT structure that can handle multiple bit lengths (2-bit, 3-bit, 5-bit, 6-bit, 7-bit transmission data) through a single circuit design. The LUT is configured with fixed input bits (b0-b5) and output bits (B0-B7), and uses control signals to selectively process different data lengths, eliminating the need for multiple dedicated LUTs for each modulation type.
Solution Approach 2:
The patent changes the operational parameters of the LUT based on the input data length. By using control signals that indicate the transmission data length, the LUT dynamically adjusts its processing behavior - for example, when 2-bit data is input, dummy data is added to reach the required 6-bit input width, and the LUT processes it accordingly. This parameter-based adaptation allows one LUT to replace multiple specialized LUTs.
2Stability of the object's composition
If dummy data is added to transmission data to match LUT input requirements, then processing consistency is improved, but data processing complexity increases
Solution Approach 1:
The patent performs preliminary actions by adding dummy data to transmission data before it enters the LUT, ensuring that the input data always meets the required bit length. This preprocessing step is controlled by control signals that determine whether dummy data needs to be added based on the actual transmission data length, maintaining consistent LUT operation while managing complexity through controlled conditional processing.
Data Source
AI summary
A symbol mapping device includes a transmission data processing unit receiving two transmission data having the same length, and if the length is a first length, uses the two transmission data as two output data without change, and if the length is less than the first length, adds dummy data to the two transmission data to generate two output data, each data having the first length; a parity addition unit generating two parity-added transmission data based on the two output data, where the two parity-added transmission data each contain parity data added to the transmission data and each have a second length; a shuffle unit extracting two modulation data, being data to be mapped, from the two parity-added transmission data generated by the parity addition unit; and a mapping processing unit mapping the two modulation data to two time slots of constellation points.