Outage performance in cooperative CDMA systems over nakagami-m fading channels

The performance of decode-and-forward (DAF) cooperative code-division multiple-access (CDMA) systems is analyzed in Nakagami fading channels. A closed-form expression for the cumulative distribution function (CDF) is derived based on of the sum of two independent non-identical distributed gamma random variables (RV). This expression is then used to obtain the outage probability. In our analysis we consider both perfect and non-perfect inter-user channels. We also investigate the behavior of the system at high signal-to-noise ratio (SNR) where we obtain asymptotically the achievable diversity order for various system parameters. Simulation results are presented to assess the accuracy of our analytical results.