Performance analysis of general coherent MRC receivers in Nakagami-m fading channels

We refine the exact expressions of the average symbol error rate (SER) of several coherent, L-branched maximal-ratio-combining (MRC) receivers in a set of correlated Nakagami-m (1960) fading channels with additive white Gaussian noise (AWGN). These expressions can be applied to study the performance for M-PSK or M-QAM receivers with any number of diversity branches, with an arbitrary SNRs correlation function between branches, with any constellation size, and with any fading severity parameter m rational. In addition, we analyze the channel capacity of the M-PSK system with MRC receivers for the case of balanced branches (i.e. all branches have the same average SNR per symbol) for arbitrary SNR correlation functions. The results of this analysis can guide the design in realizing the systems that dynamically adapt modulation schemes to the time-varying channel conditions in order to maintain the data link´s quality of service (QoS)