Comparison of frequency-domain and time-domain diversity for uplink synchronous orthogonal multicarrier DS-CDMA systems in multipath rayleigh fading channels

In this paper, the effects of frequency-domain and time-domain diversity on the performance of the uplink synchronous orthogonal multicarrier DS-CDMA system are investigated. The bit error rate performance is evaluated under multipath Rayleigh fading channels in terms of the diversity order and the number of users. The resultant performances are compared to those of the corresponding asynchronous uplink. The numerical results demonstrate that the additional performance improvement can be obtained by the frequency-domain diversity in the synchronous uplink. However, as the number of users increases, the synchronous transmissions become a major factor in determining the performance improvement rather than the diversity gain.