Covert communications with channel inversion power control in uplink NOMA systems

Abstract

Abstract Covert communications hide the very existence of wireless transmissions and thus can address privacy and security issues in non‐orthogonal multiple access (NOMA) systems. In this paper, we investigate covert communications in uplink NOMA systems with channel inversion power control (CIPC), where a public user's transmission is exploited to confuse a warden's detection on a covert user's communication behaviour. More precisely, the public link with CIPC causes the channel uncertainty of received signals at the warden. Specifically, the warden's detection error probability is derived and a guideline to make the optimal choice of CIPC parameters to obtain the maximum covert rate is proposed. The analysis and simulation results show that the covert rate is restricted by the interference between two users when the public user's CIPC parameter is relatively large.

Keywords

• Electromagnetic compatibility and interference
• Multiple access communication
• Radio links and equipment
• Mobile radio systems
• Power and energy control
• Data security