Covert MIMO Communications under Variational Distance Constraint

TL;DR

This paper characterizes the maximum reliable communication rate over MIMO AWGN channels under strict covertness constraints, considering static and partially unknown channel matrices to enhance covert communication strategies.

Contribution

It provides the first characterization of covert capacity for MIMO AWGN channels under variational distance constraints, including scenarios with partial channel knowledge.

Findings

Covert capacity is explicitly characterized for static MIMO channels.

Extension of capacity results to channels with uncertain adversary's channel matrix.

Analysis demonstrates the impact of channel knowledge on covert communication limits.

Abstract

The problem of covert communication over Multiple-Input Multiple-Output (MIMO) Additive White Gaussian Noise (AWGN) channels is investigated, in which a transmitter attempts to reliably communicate with a legitimate receiver while avoiding detection by a passive adversary. The covert capacity of the MIMO AWGN is characterized under a variational distance covertness constraint when the MIMO channel matrices are static and known. The characterization of the covert capacity is also extended to a class of channels in which the legitimate channel matrix is known but the adversary's channel matrix is only known up to a rank and a spectral norm constraint.