Multi-carrier DS-CDMA is considered to be an efficient scheme to minimize multiple access interference by moving the signals ' orthogonality property to the frequency domain. Nevertheless, due to the smaller bandwidth, the multi-carrier approach results in non-selective frequency fading in sub-channels. In this paper we will propose using a soft decision decoding Reed Muller code to recover the corresponding quality loss and compare the resulting system with a single carrier DS-CDMA system.