Outage Analysis of Cooperative CDMA Systems in Nakagami- $m$ Fading Channels

The performance of uplink cooperative code-division multiple-access (CDMA) systems using adaptive decode-and-forward (DF) relaying is investigated over Nakagami-
m
fading channels. A closed-form expression for the outage probability for a multirelay system with relay selection is derived. Our method is based on the moment-generating function (MGF) for the total signal-to-noise ratio (SNR) at the base station where the cumulative density function (cdf) is obtained. We also examine the asymptotic performance of the system at high SNR from which we evaluate the achievable diversity gain for different system parameters. Both simulations and analytical results are presented for performance evaluation.