Error Probability Analysis of Combining Space-Time Block Coding and Scheduling in MIMO Systems

In this paper, we investigate a joint diversity scheme combining space-time block coding (STBC) and opportunistic scheduling in a multiple-input multiple-output (MIMO) system. In this scheme, the user with the maximum effective signal-to-noise ratio (SNR) is adaptively selected, and the closed-form symbol error rate (SER) of the joint diversity scheme is presented. The exact SER of the joint diversity scheme can then be derived for M-ary QAM and M-ary PSK modulations in flat Rayleigh fading channels. Furthermore, using asymptotic analysis, we approximate the SER and clearly quantify both the diversity order and SNR gain for the joint diversity scheme. Based on this analysis, we show that the diversity order of the joint diversity scheme is improved in proportion to multiuser diversity (MUD) and spatial diversity, whereas the SNR gain worsens as spatial diversity increases. Finally, analytical results are verified through Monte-Carlo simulation results.