  In this paper, we analyze the performance of cognitive radio (CR) systems
over different composite generalized multipath /shadowed fading scenarios. The
\k{appa}-{\mu} shadowed and Fisher-Snedecor F fading channels which are
proposed as a simple and high accurate distributions in comparison with
generalized-K (KG) and Nakagami-m shadowed conditions are used in this
analysis. For the \k{appa}-{\mu} shadowed, a novel simple exact closed-form
analytic expression for the probability density function (PDF) and the
cumulative distribution function (CDF) are introduced by assuming the fading
parameters are integer numbers. To this end, the detection performance metrics,
namely, the average detection probability and the average area under the
receiver operating characteristics curve (AUC) which are used in the analysis
of energy detection and the effective rate and the effective rate are derived.
To validate the results of this work, comparisons between the simulated and
numerical results as well as with various conventional channel models and
scenarios are given.
