The Role of Large-Scale Fading in Uplink Massive MIMO Systems

TL;DR

This paper investigates how large-scale fading impacts the ergodic capacity of uplink massive MIMO systems, deriving new bounds and analyzing the effects of perfect and imperfect channel state information.

Contribution

It introduces novel lower bounds for ergodic capacity considering large-scale fading effects in massive MIMO systems with both perfect and imperfect CSI.

Findings

Large-scale fading significantly influences ergodic capacity in massive MIMO.

Derived new lower bounds for capacity under different CSI conditions.

Simulation results confirm the accuracy of the analytical bounds.

Abstract

In this correspondence, we analyze the ergodic capacity of a large uplink multi-user multiple-input multiple-output (MU-MIMO) system over generalized-$K$ fading channels. In the considered scenario, multiple users transmit their information to a base station equipped with a very large number of antennas. Since the effect of fast fading asymptotically disappears in massive MIMO systems, large-scale fading becomes the most dominant factor for the ergodic capacity of massive MIMO systems. Regarding this fact, in our work we concentrate our attention on the effects of large-scale fading for massive MIMO systems. Specifically, some interesting and novel lower bounds of the ergodic capacity have been derived with both perfect channel state information (CSI) and imperfect CSI. Simulation results assess the accuracy of these analytical expressions.