Performance of cognitive spatial modulation MIMO systems under transceiver hardware impairments

In this work, the performance of spatial modulation (SM) for multiple-input multiple output (MIMO) underlay cognitive radio systems is studied under the effect of channel and hardware impairments. Specifically, a closed-form expression of the average pairwise error probability (APEP), an asymptotic APEP, and a tight upper bound of the average bit error rate (ABER) are derived for Rayleigh fading channels. Useful remarks are highlighted on the system diversity and on the impact of channel and hardware impairments. Numerical results, which are corroborated through simulations, show that the ABER performance saturates to a constant value in the high power region due to the effects of channel and hardware impairments.