Dual diversity reception of M-ary DPSK signals over Nakagami fading channels

In the field of radio communication systems, the received signal strength is usually affected by fade phenomena due to multipath propagation. The paper deals with the reception of M-ary differential phase-shift keying modulated signals in the presence of additive white Gaussian noise and Nakagami slow and nonselective fading. With reference to dual diversity, predetection maximal ratio combining and predetection selection diversity combining techniques are analysed. Two situations are considered, namely, independent fading fluctuations with different severity parameters over the branches and correlated fading fluctuations with the same severity parameter. Average symbol error rate formulas are derived (to evaluate the performance of digital mobile radio systems) and numerical results are presented to single out those operational situations where dual diversity can successfully counteract short-term fading