Abstract
Code Division Multiple Access (CDMA) mobile communication systems has the code division scheme in comparison with traditional frequency division multiple access (FDMA) and time division multiple access (TDMA). Therefore, the system will have additional interference called multiple access interference (MAI). Because interference will restrain the performance of the system, we should consider the interference cancellation scheme when demodulating. This thesis uses multi-carrier transmission and orthogonal frequency division multiplexing (OFDM) to against the frequency-selective fading channel, and uses the parallel interference cancellation (PIC) scheme to improve the performance of receiver. By using the PIC scheme efficiently, the transmitting amplitude for every user and channel gain must be known. However, the receiver receives many replicas of the transmitted signals with slightly time difference and channel gain decay because of the multi-path fading during signal transmission. This may cause the difficulty in estimating the amplitude. A method which can estimate the product of amplitude and channel gain is introduced in this thesis. We can use this information together with the PIC scheme, and the technique of direct combining (DC) or maximum ratio combining (MRC) to obtain a more practical communication receiver.