Principles and Implementation of Quadrature Amplitude Modulation (QAM) with Performance Analysis

This article primarily introduces the principles and implementation of Quadrature Amplitude Modulation (QAM) modulation and demodulation, performance comparisons between MQAM, OFDM, and MPSK modulation schemes, as well as MQAM performance in disturbed channels and corresponding improvement methods including channel coding and frequency-domain equalization. Simulations are performed on communication channels with known characteristics to verify the feasibility and effectiveness of MQAM. Furthermore, the application scope of MQAM is explored, covering areas such as wireless communications and wired communications. Through in-depth study of MQAM, researchers can better understand its underlying principles and performance characteristics, providing valuable references and guidance for communication system design and optimization in related fields. Implementation-wise, MQAM modulation can be achieved using constellation mapping algorithms where binary data is mapped to complex symbols, while demodulation employs maximum likelihood detection. Channel coding enhancements typically involve convolutional or LDPC codes, and frequency-domain equalization can be implemented using FFT-based techniques to combat inter-symbol interference.