Performance analysis of MIMO systems with cochannel interference over Rayleigh fading channels

Relying on the Khatri distribution of the largest eigenvalue of certain quadratic forms in complex Gaussian vectors, we develop an analytical framework for the performance analysis of multiple-input-multiple output (MIMO) systems subject to cochannel interference and operating over Rayleigh fading channels. We consider interference limited systems in which the number of interferers exceeds or is equal to the number of receiving antenna elements and we present new closed-form expressions for the probability density function of the output signal-to-interference ratio and for the MIMO system outage probability. When applicable, these expressions are compared to the special case which dealt with the performance of single-input-multiple-output (SIMO) systems (see Shah, A. and Haimovich, A.M., IEEE Trans. Commun., vol.46, p.473-9, 1998). These analytical results are validated by Monte-Carlo simulations and as an illustration of the mathematical formalism some numerical examples for particular cases of interest are plotted and discussed. The results show that, given a fixed number of total antenna elements and cochannel interferers, (i) SIMO systems always outperform multiple-input-single-output systems and (ii) it is preferable to distribute the number of antenna elements evenly between the transmitter and the receiver for optimum performance