Investigating MC-CDMA system performance using measurement-based channel models

This paper investigates the performance of the downlink in Multi Carrier CDMA (MC-CDMA) systems using a channel model from in-the-field propagation measurements. Results are presented also for channel models having non-exponentially decaying profiles. Channel coherence bandwidth (B_c) is incorporated within the analysis in order to demonstrate the effect of channel frequency selectivity on system performance. The effect of transmission bandwidth, number of users and number of sub-carriers on system performance is analyzed. Our simulation results show that B_c values for correlation coefficients of 0.75 or 0.9 can be used to represent the channel properties to investigate the required number of subcarriers. The level of multiple access interference is also shown to be related to the B_c value for correlation coefficient of 0.5. Performance was analyzed for transmission bandwidths of 20 MHz and 40 MHz. Our results show that for some channels, performance is improved by using narrower transmission bandwidth and by selecting the band of transmission within the available band.