This paper investigates the fundamental covert rate performance in a wireless relaying system consisting of a source-destination pair, a full-duplex (FD) relay and a warden, where the relay can work at either the FD mode or the half-duplex (HD) mode. We first provide theoretical modeling for the instantaneous/average covert rate when the system works solely under the FD mode or HD mode, and then explore the corresponding optimal transmit power control of relay for the covert rate maximization. For an improvement of covert rate, we further propose a joint FD/HD mode that flexibly switches between the FD and HD modes depending on channel state of the relay self-interference channel. Under the joint FD/HD mode, we also examine the related problems of theoretical modeling for covert rate and optimal transmit power control of relay for covert rate maximization. Finally, extensive numerical results are provided to illustrate the covert rate performances of the relaying system under the FD, HD and joint FD/HD modes.

中文翻译：

---

具有功率控制的无线全双工中继系统的隐蔽率最大化


本文研究了由源-目的地对、全双工 (FD) 中继和监护人组成的无线中继系统中的基本隐蔽率性能，其中中继可以工作在 FD 模式或半双工 (HD) 模式。 ） 模式。我们首先对系统单独工作在FD模式或HD模式下的瞬时/平均隐蔽率进行理论建模，然后探索相应的中继最优发射功率控制以实现隐蔽率最大化。为了提高隐蔽率，我们进一步提出了联合FD/HD模式，根据中继自干扰信道的信道状态在FD和HD模式之间灵活切换。在联合FD/HD模式下，我们还研究了隐蔽率理论建模和实现隐蔽率最大化的中继最优发射功率控制的相关问题。最后，提供了大量的数值结果来说明中继系统在 FD、HD 和联合 FD/HD 模式下的隐蔽率性能。