Non-Uniform Constellation Mapping for Phase-Noise-Robust 802.11
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current communication systems using uniform constellations face limitations in maximizing coding and modulation capacity and robustness against phase noise, particularly in high-frequency bands like 60 GHz, where phase noise significantly affects signal quality.
Innovation Solution
The implementation of non-uniform constellations (NUCs) optimized for AWGN and AWGN+PN channels, featuring quadrant and octant symmetry, which are designed to maximize BICM capacity and robustness by strategically placing constellation points and assigning bit labels, allowing for better phase noise compensation and improved signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform constellations are used for modulation, then the system structure is simple and easy to implement, but the coding and modulation capacity is not maximized and the bit error rate is higher
Solution Approach 1:
The patent applies asymmetry by transitioning from uniform constellations to non-uniform constellations where constellation points are asymmetrically distributed in the complex plane. This asymmetric distribution optimizes the mapping between coded bits and modulation symbols, thereby maximizing coding and modulation capacity while maintaining reasonable implementation complexity.
Solution Approach 2:
The patent changes the fundamental parameter of constellation distribution from uniform to non-uniform. By optimizing the positions of constellation points in the complex plane, the system achieves higher coding and modulation capacity. The non-uniform constellation parameters are specifically designed to maximize the gain while managing implementation complexity.
2Ease of operation
If uniform constellations are used for modulation, then the implementation is straightforward, but the robustness against phase noise is reduced
Solution Approach 1:
The non-uniform constellation introduces asymmetric point distribution that provides inherent robustness against phase noise. The asymmetric arrangement optimizes the geometric relationships between constellation points, making the modulation more resilient to phase perturbations while maintaining ease of operation through systematic design.
Solution Approach 2:
By changing the constellation distribution parameter from uniform to non-uniform, the system achieves improved phase noise robustness. The optimized non-uniform parameters create better noise immunity characteristics without significantly complicating the operation, as the new constellation structure is systematically designed for both performance and operability.
3Productivity
If non-uniform constellations are used, then the coding and modulation capacity is maximized and bit error rate is reduced, but the system complexity increases
Solution Approach 1:
The patent optimizes constellation parameters to achieve maximum coding and modulation capacity. By carefully designing the non-uniform constellation parameters, the system maximizes performance gains while controlling the increase in system complexity. The parameter optimization ensures that the complexity increase is justified by the significant improvements in capacity and error rate.
4Reliability
If non-uniform constellations are used, then the robustness against phase noise is improved and SNR gain is achieved, but the implementation complexity increases
Solution Approach 1:
The patent implements non-uniform constellation parameter optimization to achieve improved phase noise robustness and SNR gain. The parameter design balances the increased implementation complexity with significant performance improvements, ensuring that the complexity is necessary and justified by the enhanced reliability and noise immunity.
Data Source
AI summary
A coding and modulation apparatus and method are presented, particularly for use in a system according to IEEE 802.11. The apparatus comprises an encoder configured to encode input data into cell words according to an LDPC code and a modulator configured to modulate said cell words into constellation values of a non-uniform constellation and to assign bit combinations to constellation values of the used non-uniform constellation. The modulator is configured to use a non-uniform constellation and bit labeling from one of the several groups of constellations, which constellation show quadrant and octant symmetry.