Abstract
Code Division Multiple Access (CDMA) has become an important access scheme in recent years because of its several advantages such as higher capacity than TDMA system, anti-multipath fading, etc.. However, one of the significant disadvantages of CDMA system is multiple access interference (MAI). This happens because of the multiple users simultaneously using the same frequency band in the CDMA system. In order to overcome the MAI problem, multiuser detector is commonly used.Several multiuser detection schemes have been proposed in the literatures. In this thesis, a new structure of multiuser detector using interference projection method for CDMA system is constructed. In this approach, the MAI is estimated first. Then, the received signal is modified to improve the performance of the system. The performance (bit error rate) of the proposed receiver is evaluated by computer simulations and compared with other receivers published in literatures, including conventional receiver, minimum mean square error receiver, optimum maximum-likelihood receiver and Hopfield neural network receiver.