Performance Analysis of Differential Phase Shift Keying Communication Systems under AWGN and Rayleigh Fading Channels

DPSK (Differential Phase Shift Keying) is a modulation method used in the case when it is more difficult to keep the phase of the carrier signal synchronized with one another. The paper presents a performance analysis of DPSK when demodulation is performed (for simulated) by using the AWGN (Additive White Gaussian Noise) channel, the flat Rayleigh fading channel, and the time varying Rayleigh fading channel. Analysis includes BER (Bit Error Rate), constellation diagram behaviour, eye diagrams, phase trajectory and Doppler effects for the various modulations (DBPSK, DQPSK and D8PSK). This analysis was completed as a parameter sweep of the results with respect to how noise level (SNR) and how much time of day affects the performance characteristics of the DPSK receiver systems. Although DPSK demodulation has benefits to ease the receiver design (because of the non-coherency of the carrier phase demodulation); as the fading increases in severity and/or mobility increases, the performance of the DPSK system decreases.