Effect of carrier-frequency offset on the performance of group-orthogonal multicarrier CDMA systems

In this letter, the downlink performance of a group-orthogonal multicarrier code-division multiple-access (GO-MC-CDMA) system with binary-phase shift keying (BPSK) modulation is investigated, when communicating over Rayleigh fading channels in the presence of carrier-frequency offset (CFO). The bit error rate (BER) performance of the GO-MC-CDMA is compared with that of a conventional MC-CDMA for given system resources and for a given value of the CFO. Our study and results show that the GO-MC-CDMA system is capable of achieving a better BER performance than that of a conventional MC-CDMA scheme in the presence of CFO, when the number of users per group is relatively small. By contrast, when the number of users per group is high, two MC-CDMA systems considered achieve similar BER performance.