In this letter, we consider the requirement of information freshness in covert communications for the first time. With artificial noise (AN) generated from a full-duplex (FD) receiver, we formulate a covertness maximization problem under the average age of information (AoI) constraint to optimize the transmit probability of information signal. In particular, the transmit probability not only represents the generation rate of information signal but also represents the prior probability of the alternative hypothesis in covert communications, which builds up a bridge between information freshness and communication covertness. Our analysis shows that the best transmit probability is not always 0.5, which differs from the equal prior probabilities assumption in most related works on covert communications. Furthermore, the limitation of average AoI enlarges the transmit probability at the cost of the covertness reduction and leads to a positive lower bound on the information transmit power for non-zero covertness.

中文翻译：

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信息时代受限的隐蔽通信

在这封信中，我们首次考虑了隐蔽通信中信息新鲜度的要求。利用全双工 (FD) 接收器产生的人工噪声 (AN)，我们在平均信息年龄 (AoI) 约束下制定了一个隐蔽最大化问题，以优化信息信号的传输概率。特别是，传输概率不仅代表信息信号的生成率，还代表隐蔽通信中备择假设的先验概率，在信息新鲜度和通信隐蔽性之间架起了一座桥梁。我们的分析表明，最佳传输概率并不总是 0.5，这与大多数隐蔽通信相关工作中的相等先验概率假设不同。此外，