PERFORMANCE AND ANALYSIS OF OFDM SYSTEMS USING 4-PSK AND 8-PSK MODULATION TECHNIQUES

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is a highly efficient multicarrier modulation technique that converts a high-rate data stream into multiple parallel low-rate subcarriers to achieve high-speed transmission in delay dispersive, multipath fading channels. This paper delivers a rigorous comparative analysis and systematic evaluation of an OFDM system framework implemented using M-ary Phase Shift Keying (MPSK) schemes, specifically focused on 4-PSK (QPSK) and 8-PSK configurations. The comprehensive communication chain—comprising pseudorandom binary sequence generation, digital symbol mapping, Inverse Fast Fourier Transform (IFFT) processing, cyclic prefix insertion, Additive White Gaussian Noise (AWGN) channel emulation, receiver-side Fast Fourier Transform (FFT) processing, Euclidean distance optimal demodulation, and automated Bit Error Rate (BER) evaluation—is engineered and evaluated in MATLAB®. Performance benchmarks are strictly analyzed using theoretical thresholds, simulated BER versus Signal-to-Noise Ratio (SNR) curves, received constellation scattering charts, and spectral efficiency trade-offs. The empirical results demonstrate that while OFDM4PSK provides exceptional noise margin robustness and minimizes communication degradation under low SNR environments, OFDM-8PSK offers a 50% enhancement in data throughput and spectral efficiency at the expense of higher SNR prerequisites to maintain matching error bounds.