The MIMOME Channel

TL;DR

This paper characterizes the secrecy capacity of the MIMOME Gaussian wiretap channel, establishing a saddle-point formulation, identifying when secure communication is possible, and analyzing large antenna array implications.

Contribution

It introduces a minimax characterization of the secrecy capacity for the MIMOME channel and provides conditions for zero secrecy capacity.

Findings

Secrecy capacity is the saddle-value of a minimax problem.

Gaussian distribution maximizes the secrecy capacity.

Conditions for zero secrecy capacity are explicitly derived.

Abstract

The MIMOME channel is a Gaussian wiretap channel in which the sender, receiver, and eavesdropper all have multiple antennas. We characterize the secrecy capacity as the saddle-value of a minimax problem. Among other implications, our result establishes that a Gaussian distribution maximizes the secrecy capacity characterization of Csisz{\'a}r and K{\"o}rner when applied to the MIMOME channel. We also determine a necessary and sufficient condition for the secrecy capacity to be zero. Large antenna array analysis of this condition reveals several useful insights into the conditions under which secure communication is possible.