MIMO Multiuser Detection for CDMA Systems

To combine presented MIMO scheme with multiuser detectors for uplink will suffer from the problems of high computation complexity and channel coherency. So, in this paper we propose a MIMO multiuser detection (MUD) scheme that reduces considerably the system computation complexity. The proposed algorithm adopts inverse channel matrix for MIMO decoding, which is not sensitive to the coherency of channels. Because of the scattering characteristic of the MIMO channel, the inverse channel matrices are always nonsingular, which keeps the receivers can get stable spatial diversity gain. The MUD algorithms can be realized using a parallel modular architecture. MUD is based on a minimum mean square error (MMSE) algorithm. Simulation results show that our MIMO-MUD performs much better than presented MIMO-MUD for the same order of complexity, though the MIMO CDMA system has only two antennas at each BS and two antennas at each mobile station