New statistics on FTR fading over dynamic scenario and energy detector performance

This paper examines the detection challenges faced by the cognitive radio network in the scenario where the node position of the secondary user changes rapidly, hence causing a significant amount of large-scale fading. To analyze this we have adopted a natural generalization of the fluctuating two-ray fading (FTR) channel that takes into account the simultaneous effects of both small and large-scale fading. Hence, in this direction, we have presented a composite fading model where small-scale fading is characterized as FTR distributed and large-scale fading as inverse gamma distributed. We derive exact analytical closed-form expressions for the composite probability distribution function (PDF) and cumulative distribution function (CDF) and then obtain a set of new statistical results. These results are further extended to obtain the analytical expressions for (i) Single user detection probability (ii) multi-user detection probability and (iii) average area under the receiver operating characteristic for energy detection-based spectrum sensing. A thorough investigation of the derived expression is used to quantify the degree of deterioration observed in the detection performance due to large-scale fading effects and the extent of performance benefit obtained by exploiting the cooperative spectrum sensing technique under different scenarios. The validity of the derived expressions is verified by Monte-Carlo simulations.