On the Ergodic Mutual Information of Keyhole MIMO Channels With Finite-Alphabet Inputs

TL;DR

This paper analyzes the ergodic mutual information of keyhole MIMO channels with finite-alphabet inputs, providing insights into high-SNR behavior, the impact of the keyhole effect, and validation through simulations.

Contribution

It extends the analysis of EMI to keyhole MIMO channels with finite-alphabet inputs, including single and multi-stream scenarios, and explores high-SNR asymptotics.

Findings

High-SNR EMI converges to a constant determined by diversity order.

Keyhole effect influences the EMI significantly.

Analytical results are validated by numerical simulations.

Abstract

This letter studies the ergodic mutual information (EMI) of keyhole multiple-input multiple-output channels having finite-alphabet input signals. The EMI is first investigated for single-stream transmission considering both cases with and without the channel state information at the transmitter. Then, the derived results are extended to the scenario of multi-stream transmission. Asymptotic analyses are performed in the regime of high signal-to-noise ratio (SNR). The high-SNR EMI is shown to converge to a constant with its rate of convergence determined by the diversity order. On this basis, the influence of the keyhole effect on the EMI is discussed. The analytical results are validated by numerical simulations.