A Closed-Form Approximate BEP Expression for Cooperative IDMA Systems over Multipath Nakagami- $m$ Fading Channels

In this letter, a closed-form approximate bit error probability (BEP) expression is derived for cooperative interleave-division multiple access systems with decode-and forward relaying subject to multipath Nakagami-m fading channels. The BEP expression is obtained by using the exponential-type approximation of Gaussian Q-function. Then, the derived expression is used to analyze system performance for different parameters, such as number of relays and Nakagami-m fading parameter. The accuracy of theoretical derivation is extensively validated through comprehensive computer simulations. It is shown that the results obtained by the proposed expression are in well agreement with the simulation results.