This letter investigates the finite blocklength covert communications where transmitter Alice randomly chooses channel use according to probability $\rho $ in the transmission block. To minimize the decoding error probability of a receiver Bob subject to the covert constraint on a detector Willie, we consider a new scheme that is changing the selection probability $\rho $ . A proof is given for the first time that although Alice randomly chooses channel use for transmission, the received signal of each channel use at Willie in the transmission block satisfies the condition of independent and identical distribution (i.i.d). Subsequently, we examine the effect of channel use selection probability $\rho $ on decoding error probability of Bob. By adjusting $\rho $ , the decoding error probability can be decreased without changing the covert constraints.

中文翻译：

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随机选择信道使用的有限块长度隐蔽通信

这封信研究了有限块长度的隐蔽通信，其中发射机 Alice 根据概率随机选择信道使用 $\rho $ 在传输块中。为了最小化受检测器 Willie 上的隐蔽约束的接收器 Bob 的解码错误概率，我们考虑了一种改变选择概率的新方案 $\rho $ . 首次证明虽然Alice随机选择信道使用进行传输，但在Willie的传输块中每个信道使用的接收信号满足独立同分布（iid）条件。随后，我们检查了信道使用选择概率的影响 $\rho $ 关于 Bob 的解码错误概率。通过调整 $\rho $ ，可以在不改变隐性约束的情况下降低解码错误概率。