On the Interference Reduction Factor in Massive MIMO System over Rician Fading Channels

Massive Multiple-Input and Multiple-Output (M-MIMO) is considered a key technique in fifth-generation (5G) and beyond 5G (B5G) standards. Among the various benefits that M-MIMO provides for wireless systems, the fact that it allows reducing interference levels stands out, which can be translated into an spectral efficiency (SE), energy efficiency (EE) and hardware efficiency (HE) improvement. In this sense, this work analyzes the interference reduction factor (IRF) in the uplink of M-MIMO systems over uncorrelated Rician fading channels. Exact closed-form and asymptotic expressions are derived to evaluate the IRF, which are validated via Monte-Carlo simulations in some representative scenarios. The results show that the IRF behavior is different in Rayleigh and Rician fading channels. In particular, increasing the specular component power, or equivalently, the Rician K factor, affects drastically the IRF, i.e., the capability of the M-MIMO system to reduce interference is affected.