A robust space time co-channel interference mitigation and detection technique for Multiuser MIMO Multicarrier DS/CDMA systems

In this paper a multiuser multi input multi output (MIMO) multicarrier (MC) DS CDMA system with co-channel interference mitigation technique is investigated. The future generation (4G) wireless networks aim at offering very high data rates and flexibility by supporting multiple users by adopting multicarrier (MC) transmissions. Multicarrier (MC) DS CDMA system possesses all these attributes and thus proves to be a promising air interface for 4G. In spite of these advantages MC DS CDMA system suffers from interferences which limits its capacity. We consider MIMO MC DS CDMA systems, with N_T transmit antennas for each asynchronous users and N_R receive antennas at the base station over quasi static Rayleigh fading channel. The performance of the improved MMSE IC and ML decoding for MC DS/CDMA system is envisaged. Improved MMSE interference cancellation (IC) and Maximum Likelihood (ML) detection for k - asynchronous users is employed at the receiver. The MMSE estimation considered here is adaptive in nature. Simulation results divulge that MIMO MC DS CDMA system with Improved MMSE IC and ML decoding provides better interference suppression in a multiuser environment.