On Achievable Covert Communication Performance under Practical Imperfect CSI

Sa Xiao, Yafu Lai, Jianquan Wang +3 more

Xi Peng, Jianquan Wang, Sa Xiao +1 more

This paper considers the problem of covert communication over a multiple-input single-output channel (MISO) in the case of the imperfect channel state information. The transmitter wants to communication with the receiver while the eavesdropper detects the existence of the transmission. We first study the scenario that the accurate channel state information (CSI) is known and show that the condition achieving the positive rate by the beamforming vector. However, because of the non-cooperation between the transmitter and the eavesdropper, we consider the CSI is imperfect. There are estimation errors for the transmitter. When the positive rate can not be achieved, the objective is to maximize the communication rate. We discuss the deterministic bounded CSI errors for the covert communication. Robust beamforming and the transmitter power is investigated, which can be transformed as a second order cone programming (SCOP) problem. We consider the line-of-sight (LoS) channel and the linear array antenna model. Comparing with the perfect CSI, the results show that the strategy of the transmitter is more conservative under the imperfect CSI. The capacity declines by the estimation errors.

Emmanuel Kwaning Kwakye, Taehoon Kim, Inkyu Bang

In covert communication, adaptive power control can help balance reliability and covertness, particularly when working with a cooperative jammer. Recent studies considering adaptive power control in covert communications typically assume perfect channel estimation at the transmitter. However, channel estimation is imperfect in practice, resulting in inaccurate power allocation with degraded covertness performance. This paper investigates the effect of channel estimation error on jammer-assisted covert communication. We model channel estimation error in covert communication and analyze its impact on the covertness throughput. Simulation results show that estimation uncertainty leads to degraded throughput compared to perfect channel state information (CSI).

Yinuo Zhao, Enyu Li, Xiaofei Zhai +2 more

Hien Quang Ta, Quoc‐Viet Pham, Khuong Ho‐Van +1 more

Moslem Forouzesh, Paeiz Azmi, Ali Kuhestani +1 more

In this article, we investigate joint information-theoretic secrecy and covert communication in a single-input-multioutput (SIMO) system where a transmitter (Alice) is communicating with two legitimate users (Bob and Carol). We consider that an untrusted user and a warden node are also present in the network attempting to attack the secure and covert communications to Bob and Carol, respectively. Specifically, Bob requires secure communications such that his messages from Alice are not decoded by the untrusted user, while Carol requires covert communications such that her messages from Alice are not detected by the warden. To do so, we consider that Alice transmits Carol's messages during selected time slots to hide them from the warden while also transmitting Bob's messages in each time slot contentiously. We formulate an optimization problem with the aim of maximizing the average rate subject to a covert communication requirement and a secure communications constraint. Since the proposed optimization problem is nonconvex, we utilize successive convex approximation to obtain a tractable solution. Moreover, we extend our proposed system model to multiple antenna Alice scenario and find beamforming vectors so that the average sum rate is maximized. Furthermore, we consider practical assumptions that Alice has imperfect knowledge of the warden's location and imperfect channel state information (CSI) of Bob and Carol. Our numerical examples highlight that the imperfect CSI at Carol has a more detrimental impact on the average rate compared to imperfect CSI at Bob.