Flexible Position Antennas Enhanced Covert Communications

As a cutting-edge security technology, covert communication aims to hide the transmission behavior rather than the contents. However, its development is facing challenges due to the fact that the conventional fixed-position antennas cannot fully utilize the spatial degrees of freedom. Therefore, an effective way to overcome this challenge is to develop the more efficient flexible position antennas (FlexPAs), which can realize flexible beamforming and spatial multiplexing by dynamically regulating the position, shape or size, providing new solutions to covert communications. In this article, we first investigate three general architectures of FlexPAs and analyze their advantages and disadvantages, especially for covert communications. Then, we briefly review the evolution of covert communications, and illustrate the benefits that FlexPAs can bring. In addition, we present important specific methods to improve the covertness by exploiting FlexPAs with the emphasis on two perspectives, including the transmitter and receiver. Finally, we propose an FlexPAs-aided covert transmission scheme to verify its effectiveness, and future research directions and challenges are discussed.