Bit-error probabilities for 2- and 4-DPSK in general Nakagami fading channels with correlated Gaussian noise

Exact bit-error probability (BEP) expressions are derived for 2- and 4-ary differential phase shift keying (2- and 4-DPSK) with post-detection equal gain combining (EGC) in arbitrarily correlated slow Nakagami fading channels. Unlike previous work, the effect of noise correlation between adjacent symbol intervals is considered and shown explicitly in the BEP expressions. The characteristic function method is used to give a BEP expression in a general form for 2- and 4-DPSK. Furthermore, closed-form BEP expressions are derived for 2-DPSK with coloured noise, and for 4-DPSK with white noise and integer fading parameter m. The theoretical result is demonstrated by analysing two antenna configurations, giving some interesting findings