Low complexity frequency-domain despreading for cyclic-prefix CDMA systems

In this letter, a frequency-domain despreading method for the cyclic-prefix code-division multiple-access (CP-CDMA) system is introduced. Using the orthogonality transformation property of the discrete Fourier transform (DFT), we can despread the received CP-CDMA, signals in the frequency domain. Moreover, we propose an efficient architecture for the proposed frequency-domain despreader. Comparison with the conventional time-domain despreading approach shows that the proposed architecture can save a large amount of computation. The proposed scheme is therefore suitable for efficient implementation of CP-CDMA receivers that adopt frequency-domain equalization and despreading.