Performance of multicarrier spread spectrum CDMA system with transmit diversity

In this paper, an advanced multicarrier transmit diversity scheme is presented for code division multiple access (CDMA) technique. The proposed system is applied for the reverse link in case of a slowly-varying multipath Rayleigh fading channel. It combines both multicarrier spread spectrum CDMA (MC-SS-CDMA) scheme and delay transmit diversity (DTD) scheme. So, it is called "MC-SS-CDMA/DTD" system. Moreover, it exploits the RAKE receiver to retrieve the multipath components of the channel and achieve the multipath diversity gain in addition to both the transmit diversity gain and the frequency diversity gain. Also, this paper examines the proposed system for both urban environment and suburban environment and it compares the results of both environments together using a computer simulation. As will be shown, the proposed system can achieve a spectral efficiency and much better performance than that obtained in both MC-SS-CDMA system without transmit diversity and DTD system. Besides, the system performance in case of urban areas is better than that in case of suburban areas.