Performance of a multi-carrier code division multiple access frequency domain RAKE receiver

A multi-carrier code division multiple access system with a frequency domain RAKE receiver is described. We compare multi-carrier and direct sequence CDMA systems using frequency and time domain RAKE receivers in the downlink of a mobile cellular system. No guard interval or interleaving is used in our multi-carrier system and in this way the multi-carrier and direct sequence systems occupy the same bandwidth. The modulation scheme is differential phase shift keying. The results are presented as received bit error rates from Monte Carlo simulations. The simulations are conducted in a multipath channel with Rayleigh fading characterised by a 300 Hz classical Doppler spectrum with additive white Gaussian noise. In the multipath fading channel the performance of the direct sequence CDMA system is superior to the multi-carrier CDMA RAKE receiver for multiple users using the architectures described.