This paper studies the secrecy performance of short-packet communications in dual-hop cooperative Internet-of-Things (IoT) networks in the presence of multiple eavesdroppers. The best node selection (BNS) scheme is proposed to select the best IoT node for improving secure packet transmissions from a source to a robot destination under two intercepting scenarios at eavesdroppers such as non-colluding and colluding. Closed-form expressions for the average secrecy block error rate (SBLER) and secrecy throughput (STP) of the BNS scheme are derived, based on which the asymptotic analysis at high signal-to-noise ratio (SNR) regimes is also carried out. Simulation results show that the proposed BNS scheme outperforms the random selection one in terms of SBLER and STP. Moreover, the impacts of average SNR and the number of blocklengths on the system STP are also evaluated.
This paper studies the secrecy performance of short-packet communications in dual-hop cooperative Internet-of-Things (IoT) networks in the presence of multiple eavesdroppers. The best node selection (BNS) scheme is proposed to select the best IoT node for improving secure packet transmissions from a source to a robot destination under two intercepting scenarios at eavesdroppers such as non-colluding and colluding. Closed-form expressions for the average secrecy block error rate (SBLER) and secrecy throughput (STP) of the BNS scheme are derived, based on which the asymptotic analysis at high signal-to-noise ratio (SNR) regimes is also carried out. Simulation results show that the proposed BNS scheme outperforms the random selection one in terms of SBLER and STP. Moreover, the impacts of average SNR and the number of blocklengths on the system STP are also evaluated.
This paper proposes a best node and random jammer (bN-rJ) scheme for multi-hop Internet-of-Things (IoT) networks under imperfect channel state information (CSI) and non-colluding eavesdroppers. Approximate and asymptotic closed-form expressions for the secrecy block-error rate (SBLER) and secrecy throughput (STP) of the bN-rJ scheme are derived, thereby guiding useful insights into system designs. Numerical results reveal that: 1) For perfect CSI cases, the bN-rJ scheme offers better secrecy improvement than the benchmark ones, especially saving over 10 dB power for SBLER transmission and increasing at least 0.5 bit per channel use in STP performance; 2) For imperfect CSI (iCSI), SBLER can be reduced significantly when using node selection strategy, for example, on average reduction of 2×10-1 with 10 nodes at an iCSI level of 0.6; 3) The optimal transmission hop of the bN-rJ scheme under perfect CSI is always larger than its counterpart under iCSI at least 1 hop in STP evaluation.
In this paper, we propose a best node and friendly jammer (bN-fJ) scheme for secure short-packet multi-hop communications in Internet-of-Things (IoT) networks. Under imperfect channel state information (CSI) conditions, the best IoT node is chosen for data transmission and a friendly jammer is chosen later to confuse the received signals at a multi-antenna eavesdropper. Approximate and asymptotic closed-form expressions for the secrecy throughput of the bN-fJ scheme are obtained, offering valuable insights into the system designs. Numerical results show that the proposed bN-fJ scheme achieves much better performance than benchmarking schemes, especially with 1 more bit/channel use and 9.4 dB enhancement in communication reliability measure. Moreover, under imperfect CSI and large antennas at the eavesdropper, the secrecy throughput and communication reliability of the system can be improved by employing the proposed node selection, e.g., a 12.5 dB improvement at 10 antennas at Eve and the imperfect CSI of 0.8. Finally, the secrecy throughput is presented as a concave curve for the number of hops and blocklengths, which enables us to identify the optimal hops and blocklength for secure multi-hop short-packet transmissions.
In this work, we exploit a multi-antenna cooperative jammer to enable secure short packet communications in Internet of Things (IoT) networks. Specifically, we propose three jamming schemes to combat eavesdropping, i.e., the zero forcing beamforming (ZFB) scheme, null-space artificial noise (NAN) scheme, and transmit antenna selection (TAS) scheme. Assuming Rayleigh fading, we derive new closed-form approximations for the secrecy throughput with finite blocklength coding. To gain further insights, we also analyze the asymptotic performance of the secrecy throughput in the case of infinite blocklength. Furthermore, we investigate the optimization problem in terms of maximizing the secrecy throughput with the latency and reliability constraints to determine the optimal blocklength. Simulation results validate the accuracy of the approximations and evaluate the impact of key parameters such as the jamming power and the number of antennas at the jammer on the secrecy throughput.
An aim of Internet-of-Things (IoT) networks is to enable smart cities by connecting billions of devices for various applications. Such a massive connectivity can face many vital challenges, one of which is security. Accordingly, we propose a Cooperative Jamming (CJ) scheme for multihop IoT networks, where each transmitted symbol is protected by two hybrid-duplex jamming nodes from randomly located colluding eavesdroppers. Our proposed scheme provides a significant performance enhancement compared to a conventional Single Jamming (SJ) approach, at no additional power cost. In particular, to achieve a secrecy outage probability of 10−1, and assuming the number of hops is 8, the proposed CJ scheme outperforms the SJ case by 3.5 dB of jamming Signal-to-Noise Ratio (SNR). Integral closed-form expressions are derived for the secrecy outage probability and verified via Monte Carlo simulations.
This paper investigates the secure transmission for buffer-aided relay networks in the Internet of Things (IoT) in the presence of multiple passive eavesdroppers. For security enhancement, we adopt the max-link relay selection policy and propose three secure transmission schemes: (1) non-jamming (NJ); (2) source cooperative jamming (SCJ); and (3) source cooperative jamming with optimal power allocation (SCJ-OPA). Moreover, to analyze the secrecy performance comprehensively, two eavesdropping scenarios, i.e., non-colluding eavesdroppers (NCE) and colluding eavesdroppers (CE) are considered. Based on this, by modeling the dynamic buffer state transition as a Markov chain, we derive the exact closed-form expressions of the secrecy outage probability, the average secrecy throughput, and the end-to-end delay for each schemes. The analytical analysis and simulation shows that the SCJ-OPA scheme achieves similar performance as the NJ scheme when the total transmit power is small. On the other hand, when the transmit power is high, the performance achieved by SCJ-OPA is similar to that of SCJ. Thereby, the SCJ-OPA scheme can achieve better performance across the entire total transmit power, which makes up the defects of NJ and SCJ exactly.
In applications of the Internet of Things (IoT), the use of short packets is expected to meet the stringent latency requirement in ultra-reliable low-latency communications; however, the incurred security issues and the impact of finite blocklength coding on the physical-layer security are not well understood. This paper investigates the performance of secure short-packet communications in a mission-critical IoT system with an external multi-antenna eavesdropper. An analytical framework is proposed to approximate the average achievable secrecy throughput of the system with finite blocklength coding. To gain more insight, a simple case with a single-antenna access point (AP) is considered first, in which the secrecy throughput is approximated in a closed form. Based on that result, the optimal blocklengths to maximize the secrecy throughput with and without the reliability and latency constraints, respectively, are derived. For the case with a multi-antenna AP, following the proposed analytical framework, closed-form approximations for the secrecy throughput are obtained under both beamforming and artificial-noise-aided transmission schemes. The numerical results verify the accuracy of the proposed approximations and illustrate the impact of the system parameters on the tradeoff between transmission latency and reliability under a secrecy constraint.