Multicarrier code division multiple access   (MC-CDMA) systems are more sensitive to the carrier frequency offset than single carrier systems. Carrier frequency offset destroys the orthogonality among subcarriers in MC-CDMA systems and degrades the system performance seriously. To mitigate the effect of carrier frequency offset, it should be estimated and compensated before demodulation. An efficient algorithm has been proposed to estimate Carrier Frequency Offset in MC-CDMA systems to enhance the performance of the system. The scheme is based on locating spectral minima’s within null subcarriers embedded in the spectrum. This is done by scaling the frequency axis to acquire a smaller part of the spectrum at a higher resolution. The significant feature of this algorithm is, it can be repeated to achieve accuracy. This method is suitable for systems with continuous transmission.

Index terms — CFO, MC-CDMA, DFT, OFDM.