Closed Form Secrecy Capacity of MIMO Wiretap Channels with Two Transmit Antennas

TL;DR

This paper derives a closed-form expression for the secrecy capacity of a MIMO wiretap channel with a two-antenna transmitter, providing a precise measure of secure communication potential.

Contribution

It presents the first closed-form solution for the secrecy capacity in a MIMO wiretap channel with two transmit antennas, advancing understanding of secure MIMO communications.

Findings

Closed-form secrecy capacity expression derived.

Optimal input covariance matrix identified.

Enhances design of secure MIMO systems.

Abstract

A Gaussian multiple-input multiple-output (MIMO) wiretap channel model is considered. The input is a two-antenna transmitter, while the outputs are the legitimate receiver and an eavesdropper, both equipped with multiple antennas. All channels are assumed to be known. The problem of obtaining the optimal input covariance matrix that achieves secrecy capacity subject to a power constraint is addressed, and a closed-form expression for the secrecy capacity is obtained.