SEP of rectangular QAM in composite fading channels

In this paper, we analytically evaluate the average symbol error probability (SEP) of rectangular quadrature amplitude modulation (QAM) signalling in composite fading channels modelled by the generalized-K (KG) distribution. The analysis is based on a fast converging infinite series representation of the average of the product of two Gaussian-Q functions over KG fading that has been extracted. Considering integer and a half values for the distribution's shaping parameters, exact closed-form expressions have been also derived. Numerical evaluated results, complemented by equivalent computer simulated ones, are presented to verify the accuracy of the proposed analysis.