Performance evaluation of QDPSK over Nakagami fading channels with diversity reception

This paper studies the performance and determine the advantages and limitations of diversity, applied to binary and quadrature differential phase shift keying (DPSK) signals under Nakagami-m (1960) fading in the presence of additive white Gaussian noise. The DPSK signals on the several diversity channels are presumed to be perturbed independently by Nakagami-m fading and additive white Gaussian noise. Also, it is assumed that the fading is slow and frequency nonselective. The postdetection diversity combining method is chosen so that the receiver performs a noncoherent detection, where equal gain combining (EGC) is used. Average bit error probability expressions are derived for both binary and quadrature DPSK. The derived expression for binary DPSK is in closed form, while that of QDPSK is in terms of a finite integral that can be easily computed via numerical integration routines, and, hence, can be usefully exploited in the performance evaluation of digital mobile radio systems.