To Improve Performance and Analysis of Multi - Carrier Direct Sequence (MC DS) CDMA with Fading

Abstract

The performance of an MC DS CDMA wireless communication system over a Rayleigh Fading Channel is
analyzed in the presence of Multiple Access Interference (MAl) and Inter-Carrier Interference (ICI). The Signal to
Interference plus Noise Ratio (SINR) is derived in this environment. The analysis is also extended to MC-DS-CDMA system
with Rake Receiver. The performance results are evaluated numerically in terms of SINR and BER considering several
system parameters like number of users, processing gain, number of sub-carriers and number of rake fingers. The result
shows that there are significant deterioration in SINR and BER performance due to fading. Optimum system design
parameters are determined from the analytical results for a given performance level.
We use band limited spreading waveforms to prevent self-interference, and we evaluate system performance over a
frequency selective Rayleigh channel in the presence of partial band interference. There is no interference from the CDMA
signals to the existing microwave systems. Thus, there is no need for either a narrowband suppression filter at the receiver or
a notch filter at the transmitter. Simulation results compare system performance with that of a single-carrier RAKE system