Performance of UWB DS-CDMA/OFDM/MC-CDMA system

In this paper, we purports to compare ultra-wide band (UWB) DS-CDMA with OFDM system, both of which are currently drafted in standardization. Although MC-CDMA is not in standard, this paper proposes that it is a potential candidate for standardization because MC-CDMA may provide certain qualities that the other system may not support. UWB system operates in the indoor wireless environment wherein channel suffers from frequency-selective fading. Accordingly, DS-CDMA must use many rake fingers that increase system complexity. Further, it uses MBOK to raise data rate, but it has not shown good performance, based on the results of simulations shown in this paper. OFDM system is relatively simple as compared with the DS-CDMA, but it is not able to resolve a power problem; in other words, power is generated in excess of the standard as provided by the FCC regulations. Because MC-CDMA does not require RAKE receiver, it is simpler than DS-CDMA and it shows better performance than OFDM at low signal power. The BER performance of each system in downlink channel with S-V channel is compared by computer simulation.