Performance analysis of multicarrier DS-CDMA with imperfect power control and variable spreading factors

The MC-DS-CDMA possesses the advantages of the immunity against multipath dispersion of orthogonal frequency division multiple access (OFDM) and the flexibility of the time-domain and frequency-domain spreading technique. However, power control errors (PCE) may significantly degrade the performance of the MC-DS-CDMA system. In this paper, we propose an easily computed analytical method to evaluate the bit error rate performance of the multi-rate MC-DS-CDMA system with the time/frequency 2-domain spreading subject to PCE. Furthermore, the proposed analysis also considers the effect of multiple access interference (MAI) from all the subcarriers in the multi-rate MC-DS-CDMA system. We find that power control errors will offset the gain of frequency domain spreading. More importantly, the larger the value of frequency domain spreading, the more the sensitivity to PCE.