In this paper, the effect of the antenna array (AA) on the performance of the uplink synchronous orthogonal multicarrier DS-CDMA RAKE system is investigated. The bit error rate performance is evaluated under multipath Rayleigh fading channels in terms of the number of antennas, the number of users, and the diversity order. The resultant BER performances are compared to those of the corresponding asynchronous uplink with the A A. The numerical results demonstrate that the additional performance improvement can be obtained by the AA in the synchronous uplink. However, the performance difference between synchronous and asynchronous transmissions decreases as the number of the antennas increases. The capacity of AA- aided orthogonal MC DS-CDMA RAKE systems can be further improved by employing the frequency domain diversity in the synchronous uplink rather than the time domain diversity.