Lower bound on the ergodic capacity of distributed MIMO systems over K fading channels

Abstract

This paper presents ergodic capacity analysis of distributed multiple-input multiple-out (D-MIMO) systems over non-correlated K fading (Rayleigh/Gamma) channels. With the aid of Minkowski inequality, we first derive the analytical closed-form expression of the lower bound on the ergodic capacity for D-MIMO systems over non-correlated K fading channels. The proposed lower bound becomes tight at high signal-to-noise ratio (SNR) regime and when the number of receive antennas grows large. To intuitively reveal the impacts of system and fading parameters on the ergodic capacity, we deduce asymptotic approximations in the high SNR regime. Finally, we pursue the large systems analysis for the lower bound and derive closed-form expressions when the number of antennas at BS grows large, and when the number of antennas at transceiver becomes large with a fixed and finite ratio. It is demonstrated that the proposed expressions on the ergodic capacity accurately match with the theoretical analysis.