Constellation Diagram Simulation for Signals Traversing AWGN and Rayleigh Fading Channels

This MATLAB-based program simulates constellation diagrams for QPSK and 16QAM modulated signals passing through additive white Gaussian noise (AWGN) and Rayleigh fading channels. The simulation implements core communication algorithms including modulation/demodulation routines, channel modeling functions, and constellation plotting modules. During simulation, users can observe performance differences between modulation schemes and analyze their impact on signal quality through visualized constellation points distribution and rotation patterns. The program employs MATLAB's communication toolbox functions for accurate channel modeling and provides practical insights into modulation and transmission processes for real-world system design references.

The program features extensive parameter configuration options including channel model selection (AWGN/Rayleigh fading), modulation scheme switching (QPSK/16QAM), signal power adjustment, and SNR settings. The code architecture uses modular design with separate functions for channel generation, signal processing, and visualization. Users can flexibly configure parameters through GUI interfaces or script modifications and observe real-time constellation diagram variations across different parameter sets. Comparative analysis of simulation results helps deepen understanding of signal transmission characteristics and optimization strategies for modulation schemes through quantitative BER calculations and qualitative constellation degradation patterns.

Beyond constellation diagram simulation, the program incorporates additional functional modules for bit error rate (BER) performance analysis using Monte Carlo simulation methods and channel capacity calculations based on Shannon's theorem. These modules employ statistical processing algorithms and performance metric computations, enabling comprehensive evaluation of communication system performance through integrated analysis workflows.

In summary, this program serves as a robust and comprehensive simulation tool that implements advanced communication algorithms to analyze different modulation schemes under various channel conditions. The code structure facilitates easy extension to additional modulation types (like 64QAM) and channel models (like Rician fading), helping users deeply understand communication system working principles and performance characteristics. Simultaneously, it provides valuable references and guidance for practical communication system design and optimization through configurable simulation scenarios and performance benchmarking capabilities.