Study of SM-MIMO system combining opportunistic scheduling with zero-forcing receivers

To utilize the multiuser diversity efficiently in multiuser MIMO systems, opportunistic scheduling is employed, where the user with largest SNR is adaptively selected according to channel state information feedback from the receive side and in the meantime, and to utilize the multiplexing gain effectively and improve the capacity, a novel scheme of MIMO systems combining opportunistic scheduling and spatial multiplexing with zero-forcing receiver is presented under Rayleigh channel. Using the direct method based on polynomial expansion, the expressions of error rate with M-QAM and M-PSK modulations, the diversity gain and the sum-rate capacity under different channel conditions are got, respectively, and the asymptotic forms are derived based on Taylor series. The correctness of theoretical analysis is verified by the corresponding Monta-Carlo simulation results which indicate that the scheme with multiuser diversity provides much larger diversity and higher capacity than that without opportunistic scheduling.