Dong Ruonan, Li Baogang, Yan Binyang
Department of Electronic and Communication Engineering, North China Electric Power University, No. 619, Yong Hua Street, Baoding 071003, China.
Sensors (Basel). 2019 Jul 9;19(13):3031. doi: 10.3390/s19133031.
The Internet of Things (IoT) will feature pervasive sensing and control capabilities via the massive deployment of machine-type communication devices in order to greatly improve daily life. However, machine-type communications can be illegally used (e.g., by criminals or terrorists) which is difficult to monitor, and thus presents new security challenges. The information exchanged in machine-type communications is usually transmitted in short packets. Thus, this paper investigates a legitimate surveillance system via proactive eavesdropping at finite blocklength regime. Under the finite blocklength regime, we analyze the channel coding rate of the eavesdropping link and the suspicious link. We find that the legitimate monitor can still eavesdrop the information sent by the suspicious transmitter as the blocklength decreases, even when the eavesdropping is failed under the Shannon capacity regime. Moreover, we define a metric called the effective eavesdropping rate and study the monotonicity. From the analysis of monotonicity, the existence of a maximum effective eavesdropping rate for a moderate or even high signal-to-noise (SNR) is verified. Finally, numerical results are provided and discussed. In the simulation, we also find that the maximum effective eavesdropping rate slowly increases with the blocklength.
物联网（IoT）将通过大规模部署机器类型通信设备来实现广泛的传感和控制能力，从而极大地改善日常生活。然而，机器类型通信可能会被非法使用（例如，被犯罪分子或恐怖分子利用），且难以监控，因此带来了新的安全挑战。机器类型通信中交换的信息通常以短数据包的形式传输。因此，本文研究了在有限码长情况下通过主动窃听实现的合法监测系统。在有限码长情况下，我们分析了窃听链路和可疑链路的信道编码率。我们发现，即使在香农容量条件下窃听失败，随着码长的减小，合法监测器仍能窃听可疑发射机发送的信息。此外，我们定义了一个称为有效窃听率的指标并研究其单调性。通过对单调性的分析，验证了在中等甚至高信噪比（SNR）情况下存在最大有效窃听率。最后，给出并讨论了数值结果。在仿真中，我们还发现最大有效窃听率随码长缓慢增加。
