In this letter, we consider the physical-layer security (PLS) in full-duplex (FD) multiuser multiple-input-multiple-output (MIMO) short-packet communications, where a base station (BS) transmits precoded signals for secure downlink multicast while receiving signals from uplink users. To quantify the PLS performance in the worst-case scenario, we consider the possible maximum wiretapping capability of a multi-antenna eavesdropper. Taking into account the self-interference (SI) in FD mode and the co-channel interference (CCI) from uplink to downlink, we analyst the secrecy throughput in finite blocklength regime and obtain its analytic expression, which perfectly matches asymptotic and simulation results in various scenarios. Moreover, the investigations on secrecy throughput substantiate that the FD multiuser MIMO systems outperform their half-duplex counterparts given the SI being sufficiently suppressed and the CCI being well managed.

中文翻译：

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全双工多用户 MIMO 短包通信中的保密吞吐量

在这封信中，我们考虑了全双工 (FD) 多用户多输入多输出 (MIMO) 短数据包通信中的物理层安全性 (PLS)，其中基站 (BS) 为安全下行链路传输预编码信号组播同时接收上行用户的信号。为了量化最坏情况下的 PLS 性能，我们考虑了多天线窃听者可能的最大窃听能力。考虑到FD模式下的自干扰（SI）和上行到下行链路的同信道干扰（CCI），我们分析了有限块长机制下的保密吞吐量并得到了其解析表达式，与渐近和仿真结果完美匹配各种场景。而且，