Covert Communication in Integrated High Altitude Platform Station Terrestrial Networks

Abstract

In recent years, Internet of Things (IoT) technology has emerged and gradually sprung up. As the needs of largescale IoT applications cannot be satisfied by the fifth generation (5G) network, wireless communication network needs to be developed into the sixth generation (6G) network. However, with the increasingly prominent security problems of wireless communication networks such as 6G, covert communication has been recognized as one of the most promising solutions. Covert communication can realize the transmission of hidden information between both sides of communication to a certain extent, which makes the transmission content and transmission behavior challenging to be detected by noncooperative eavesdroppers. In addition, the integrated high altitude platform station (HAPS) terrestrial network is considered a promising development direction because of its flexibility and scalability. Based on the above facts, this article investigates the covert communication in an integrated HAPS terrestrial network, where a constant power auxiliary node is utilized to send artificial noise (AN) to realize the covert communication. Specifically, the covert constraint relationship between the transmitting and auxiliary nodes is derived. Moreover, the closed-form expressions of outage probability (OP) and effective covert communication rate are obtained. Finally, numerical results are provided to verify our analysis and reveal the impacts of critical parameters on the system performance.