Performance of diversity receivers in generalised gamma fading channels

The performance of M-ary modulation schemes operating in a generalised gamma fading environment in the presence of additive white Gaussian noise is studied. The multipath fading channel is modelled by the three-parameter generalised gamma distribution, which includes the Rayleigh, Nakagami and Weibull distributions as special cases and the log-normal distribution as a limiting case. The Suzuki distribution can also be adequately approximated by the generalised gamma distribution. The performances of the selection combining (SC), equal gain combining (EGC) and maximal ratio combining (MRC) diversity schemes are considered. Specifically, the exact average symbol error rates (ASER) for coherent multilevel modulation schemes with SC and MRC are derived using the moment generating function-based approach, while the ASER of EGC is obtained by employing the characteristic function-based approach. The analytical results are validated by computer simulation.