Effects of outdated channel state information on user scheduling in MRC MIMO systems with antenna selection

- In this paper, the effects of outdated CSI on the system performance of MRC MIMO employing user scheduling and antenna selection have been analyzed and evaluated.
- Absolute-SNR scheduling and normalized-SNR scheduling schemes have been considered for i.i.d-users and i.ni.d-users scenarios, respectively.
- A transmit antenna selection scheme has been employed to overcome the drawback of channel hardening in multiuser MIMO systems, and also to improve the system performance.
- Closed-form expressions are derived to quantify the degradation caused by the outdated CSI on the average channel capacity, outage probability, and the average BER of the system.

This paper presents an analysis for evaluating the effects of outdated channel state information (CSI) on the performance of multiuser MRC MIMO systems with antenna selection. Two user scheduling schemes: absolute-SNR scheduling and normalized-SNR scheduling schemes are employed. For the independent and identically distributed users-i.i.d. scenario, the absolute-SNR scheduling scheme is used, and for the independent and non-identically distributed users-i.ni.d. scenario, the normalized-SNR scheduling scheme is employed. Mathematical expressions are derived to evaluate the performance degradation of the outage probability, average channel capacity, and average bit error rate for the presented scheduling schemes under outdated channel information over Rayleigh fading channels. Numerical evaluation results are presented to show the effects of various parameters on the system performance, where the accuracy of the analytical results are also verified by Monte-Carlo simulations.