abstract

Bit-error rate (BER) is a core performance measure of the strength of the modern digital communication systems under the influence of noise. The present article carries out a cross-frequency analysis of the BER of four widely used modulation strategies, namely, Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), 16-Quadrature Amplitude Modulation (16-QAM), and 64-QAM with respect to three of the traditional channel models, that is, Additive White Gaussian Noise (AWGN), Rayleigh fading and Rician fading. The same theoretical expressions of the BER obtainable by probability density functions (PDFs) and the Q-function are demonstrable and, subsequently, the MATLAB simulations confirm it over SNR range of 0 dB to 20 dB. With the Monte Carlo structure, the simulations availed in MATLAB give statistically sound performance at various noise levels. The results show the tradeoff between spectral efficiency and noise immunity in state of the art digital communication platforms: on the one hand, the BPSK and QSPK modulations are seen to perform better on fading channels but on the other hand the QAM of higher order is much better in very high SNR environments. The outcomes help shed light on factors that have to be considered when trying to maximize modulation schemes when designing communication systems.