The performance of bit-interleaved coded modulation-iterative decoding (BICM-ID) based cooperative network is analyzed over Rayleigh and Nakagami-m fading channels. The relays are assumed to be operating in amplifyand-forward (AF) configuration. The bit error rate (BER) bounds of single-relay cooperative system with the serial concatenated BICM-ID using the 8-PSK modulations with maximal ratio combining (MRC) at the destination is obtained. For the numerical results of the union bound on BER, moment generating function (MGF) based approach is used and the closed-form MGF expression of the branch metric is derived. The comparisons of theoretical and simulation results are also shown.