Asymptotic Outage Probability for Amplify-and-Forward CDMA Systems over Nakagami-m Fading Channels

In this paper, we address the performance of cooperative code-division multiple-access (CDMA) systems using amplify-and-forward (AF) relaying over independent nonidentical (i.ni.d) Nakagami-m fading channels. The outage probability of the system is investigated using the moment generating function (MGF) of the total signal-to-noise ratio (SNR) at the base station. Since it is complicated to derive a closed form expression of the outage probability, we derive an approximation for the probability density function (PDF) of the total SNR which in turn enables us to derive the asymptomatic outage probability for any value of the fading parameter m. Simulation results are presented to assess the accuracy of our analytical results. Furthermore, using the derived outage probability, we investigate the diversity advantage of the cooperative system under different system settings.