Performance of DS-CDMA and MC-CDMA systems in Gaussian and Rayleigh fading channels

This paper investigates multiple-access performance of odd degree Gold codes in DS-CDMA and MC-CDMA systems in Gaussian, flat-fading and frequency-selective Rayleigh channels. The influence of code length on the system performance is investigated for a given number of tones and data rate. Simulation results show that the code performance does not saturate even when the system is heavily loaded to full system capacity. The results also show that in a flat-fading channel, the codes provide a constant coding gain close to that obtainable in a Gaussian channel. Furthermore, in a frequency-selective channel, frequency diversity associated with the use of longer codes makes the system resilient to multipath effects, resulting in lowering of error floor.