MIMO Channel Characterization Through Electromagnetic Analysis

Massive multiple-input multiple-output (MIMO) is a key technology in 5G, which enhances the spectral efficiency and enlarges the capacity of MIMO by adopting orthogonal frequency division multiplexing (OFDM). In this paper, we proposed a simple MIMO model, which consists of point sources and point receivers. Then, we introduce the scalar Green’s function and dyadic Green’s function and derive the channel matrix H from the scalar Green’s function and the dyadic Green’s function, respectively. Furthermore, we calculate the capacity of MIMO system through channel matrix H with a water injection method and compare it with a traditional equal power method. The water injection method achieves the maximum channel capacity by optimizing power distribution. Finally, the effects of the distance, SNR and permittivity on capacity of MIMO are derived. In all cases studied, the capacity derives from water injection method is better than equal power method.