Effects of user distribution on multiuser MIMO-OFDM channel capacity in rural area

Multi-user multiple-input multiple-output orthogonal frequency division multiplexing (MU-MIMO-OFDM) is a promising technology to improve the spectrum efficiency of fixed wireless broadband access systems in rural areas. When MU-MIMO is deployed in predominantly line-of-sight (LoS) environments, for instance in rural areas, the problem of ill-conditioned channels may occur. This letter investigates the effects of capacity degradation with user distribution angle from 10° to full azimuthal angle, based on the results of a deterministic model. The deterministic model developed for rural MU-MIMO-OFDM has been validated with the experimental data. Furthermore, the validated deterministic model has been used to study the optimal distribution of users in a rural MU-MIMO-OFDM system. The optimum capacity has been observed for a user distribution with an angle between 180° and 360° around the access point.