# Covert Transmission with Antenna Selection and Using an External Jammer

## TL;DR

This paper investigates how antenna selection and external jamming can improve covert communication rates in wireless networks, analyzing different scenarios and optimizing power and antenna choices.

## Contribution

It introduces a novel approach combining antenna selection and jamming strategies, with optimization solutions for maximizing covert rates under various conditions.

## Key findings

- More antennas lead to higher covert rates.
- Difference of Convex method effectively solves non-convex optimization.
- Convex optimization applies when the destination cancels jamming.

## Abstract

This paper adopts the antenna selection technique to enhance the covert rate in a wireless communication network comprised of a source, a destination , an external jammer and an eavesdropper. In the covert communication, the level of transmit power is low and hence a source with multiple antennas can be adopted to send the information toward the single antenna destination while concurrently, the jammer transmits an artificial noise signal. For this system model, we consider a scenario where the source is forced to select one or several of its antennas to transmit its confidential information due to its limited RF chains. Furthermore, we consider two different jamming scenarios to support our covert communication: 1) The destination is unable to cancel the jamming signal, 2) The destination can subtract the jamming signal. For such a communication network, our aim is to maximize the covert rate subject to power constraint and covert communication requirement. In the first scenario, the optimization problem is non-convex, and hence, it can be solved through using Difference of Convex function (DC) method while the optimization problem of the second scenario is intrinsically convex. Our numerical results show that the higher the number of selected antennas at the transmitter, the higher the covert rate will be achieved.