Simulation of Carrier-Based QPSK Signal Transmission over Rayleigh Channels

In this paper, we present a comprehensive simulation of carrier-based QPSK signal transmission over Rayleigh fading channels. The study begins with an explanation of QPSK modulation fundamentals and its applications in wireless communication systems. We then detail the characteristics and mathematical modeling of Rayleigh fading channels, including how multipath propagation and Doppler effects create specific impacts on QPSK signal integrity. The simulation methodology section covers practical implementation aspects: using I/Q component generation for QPSK symbol mapping, creating Rayleigh channel models with complex Gaussian random variables, and implementing matched filtering with raised-cosine pulse shaping. Performance evaluation techniques include calculating bit error rate (BER) versus signal-to-noise ratio (SNR) curves using Monte Carlo simulations and analyzing constellation diagram distortions. The results analysis examines fading-induced performance degradation and discusses enhancement strategies such as channel equalization techniques and diversity combining methods. This research provides valuable insights into QPSK transmission characteristics under Rayleigh fading conditions, offering practical references for wireless system design and optimization.