Exact expressions are derived for the performance of predetection maximal ratio combiner diversity reception with L correlated branches in Nakagami fading. Bit error rates are evaluated for both coherent and noncoherent binary phase-shift-keying and frequency-shift-keying signals, starting from the L-variate moment generating function of the random input power vector. The new formulation presented for the bit error rate, in which the covariance matrix of the fading at the L branches explicitly appears, allows arbitrary branch correlation to be taken into account for any diversity order in the case of identical fading severity on the branches. Results are presented for evaluation of the outage probability, for integer values of fading severity, as well as for the effect of the presence of unbalanced channels with arbitrary correlation.

The paper deals with the detection of binary signals operated by diversity systems to counteract signal power fading. The statistical model of the fading is assumed to be in accordance with the general Nakagami distribution. A predetection selection diversity combiner (SDC) is analyzed in the case of detection of binary digital signals. Error probability for the detection of signals in additive white Gaussian noise is provided in four cases: NCFSK, DCPSK, CFSK and CPSK. Performance is analytically derived, giving a compact general formula; numerical results are presented for equal branch signal to noise ratio and fading severity. The analysis carried out allows to define those operational situations where diversity can operate successfully to counteract the degrading effects of short-term fading.

The structure of the locally optimum space-diversity detector for coherent detection of a bandpass signal subject to amplitude fluctuations in the presence of narrow-band non-Gaussian noise is derived and its large-sample performance is evaluated. For easy implementation a suboptimum structure is proposed. It consists of local detectors performing independent local decisions and of a central processor that, working according to simple logical schemes (OR or AND), performs the global decision based on the local ones. Numerical results and a comparison between the performances of both proposed structures are presented and discussed.