Thermal Noise Mutual Coupling Effect on the Capacity of MIMO Wireless Systems

In this paper we analyze the impact of mutual coupling on MIMO channel capacity, considering its effect on both, signal and thermal noise. We calculate noise correlation matrix in the multi-antenna system with closely spaced antennae by applying the Nyquist’s thermal noise theorem. Then, we employ noise correlation matrix in channel capacity formula, that enables the identification of thermal noise correlation contribution on the MIMO channel capacity. In addition, we examine thermal noise correlation due to mutual coupling effect. Our simulation results confirm theoretical analysis that mean and outage MIMO channel capacity is underestimated if noise correlation due to mutual coupling effect is not accounted for.