MATLAB Implementation of 4PAM Modulation and Demodulation with Performance Analysis

This paper presents a MATLAB implementation of 4PAM modulation and demodulation with comprehensive bit error rate simulation analysis. First, we explain the fundamental principles and application scenarios of 4PAM modulation. Then, we detail the design and implementation steps of the MATLAB-based transceiver system, including signal generation using random bit streams, modulation mapping (typically assigning symbols like [-3, -1, 1, 3] to binary pairs), channel simulation with AWGN (Additive White Gaussian Noise) modeling, and demodulation using threshold detection algorithms. The implementation employs key MATLAB functions such as randi() for bit generation, pammod() and pamdemod() for symbol mapping/demapping, and awgn() for channel noise simulation. We conducted extensive Monte Carlo simulations to analyze the BER performance under varying SNR conditions, comparing practical results with theoretical values derived from Q-function calculations. Finally, we summarize the simulation outcomes and suggest potential optimizations including adaptive threshold adjustment, error correction coding integration, and multipath channel extensions. This research provides valuable insights into 4PAM modulation characteristics and offers practical guidance for related communication system applications.