Average Secrecy Throughput Research Articles

Secure short-packet transmission in uplink massive MU-MIMO assisted URLLC under imperfect CSI

Ultra-reliable and low-latency communication (URLLC) is still in the early stage of research due to its two strict and conflicting requirements, i.e., ultra-low latency and ultra-high reliability, and its impact on security performance is still unclear. Specifically, short-packet communication is expected to meet the delay requirement of URLLC, while the degradation of reliability caused by it makes traditional physical-layer security metrics not applicable. In this paper, we investigate the secure short-packet transmission in uplink massive multiuser multiple-input-multiple-output (MU-MIMO) system under imperfect channel state information (CSI). We propose an artificial noise scheme to improve the security performance of the system and use the system average secrecy throughput (AST) as the analysis metric. We derive the approximate closed-form expression of the system AST and further analyze the system asymptotic performance in two regimes. Furthermore, a one-dimensional search method is used to optimize the maximum system AST for a given pilot length. Numerical results verify the correctness of theoretical analysis, and show that there are some parameters that affect the tradeoff between security and latency. Moreover, appropriately increasing the number of antennas at the base station (BS) and transmission power at user devices (UDs) can increase the system AST to achieve the required threshold.

URLLC-oriented secure communication for UAV relay-assisted network

In this paper, we investigate the unmanned aerial vehicle (UAV) relay-assisted secure short packet communication. The UAV acts as a decode-and-forward relay to transmit control signals from the source to the actuators in the presence of a ground eavesdropper (EV) whose imperfect channel state information is available at the UAV. Specially, non-orthogonal multiple access is adopted in our work to achieve more connections and improve the fairness of communication and the short packets are employed for data transmission to reduce the latency. Explicitly, we maximize the minimum average secrecy throughput among all actuators by jointly optimizing the UAV trajectory, transmit power and blocklength allocation, which generates a challenging optimization problem. Therefore, we propose an iterative algorithm based on block coordinate descent method and successive convex approximation technique to handle the non-convex problem. Numerical results show that the proposed scheme has better performance compared to the benchmark schemes.

Optimal Channel Training Design for Secure Short-Packet Communications.

Physical layer security is a promising technique to ensure the confidentiality of short-packet communications, since no additional channel uses are needed. Motivated by the fact of finite coding blocklength in short-packet communications, we attempt to investigate the problem of how many the channel uses utilized for channel training should be allocated to perform secure communications. Based on the finite blocklength information theory, we derive a closed-form expression to approximate the average achievable secrecy throughput. To gain more insights, we also present the asymptotic average secrecy throughput under two special cases, i.e., high signal-to-noise ratio (SNR) and infinite blocklength. Moreover, we determine the optimal channel training length to maximize the average secrecy throughput under the reliability constraint and given blocklength. Numerical results are provided to validate the analysis and demonstrate that the performance gain achieved by the optimal channel training length is remarkable, relative to other benchmark schemes.

Performance Analysis of Short Packet Communications With Multiple Eavesdroppers

This paper studies the performance of short packet communications in the presence of multiple eavesdroppers. We start our investigation by examining the fading wiretap channel, where the communication is overheard by multiple non-colluding single antenna eavesdroppers. A closed-form expression for the average secrecy throughput is derived, when the transmitter has a single antenna. The Monte-Carlo simulations show a close match of the analytical expression with the numerical results. Moreover, the optimal blocklength value that maximizes the secrecy throughput is determined, when the communication is observed by single and multiple eavesdroppers. We then extend our analysis for the case of a multiple-antenna transmitter and consider artificial noise (AN) to confuse the eavesdroppers. A closed-form expression for the average secrecy throughput is obtained for the scenario of a two-antenna transmitter and two eavesdroppers with a single antenna. The results demonstrate the validity of the approximation when compared with Monte-Carlo simulations. The results further reveal that an increased number of antennas at the transmitter is associated with higher average secrecy throughput and applying AN helps to eliminate the harm of the eavesdroppers.

Relay-assisted secure short-packet transmission in cognitive IoT with spectrum sensing

Cognitive Internet of Things (IoT) has attracted much attention due to its high spectrum utilization. However, potential security of the short-packet communications in cognitive IoT becomes an important issue. This paper proposes a relay-assisted maximum ratio combining/zero forcing beamforming (MRC/ZFB) scheme to guarantee the secrecy performance of dual-hop short-packet communications in cognitive IoT. This paper analyzes the average secrecy throughput of the system and further investigates two asymptotic scenarios with the high signal-to-noise ratio (SNR) regime and the infinite blocklength. In addition, the Fibonacci-based alternating optimization method is adopted to jointly optimize the spectrum sensing blocklength and transmission blocklength to maximize the average secrecy throughput. The numerical results verify the impact of the system parameters on the tradeoff between the spectrum sensing blocklength and transmission blocklength under a secrecy constraint. It is shown that the proposed scheme achieves better secrecy performance than other benchmark schemes.

Secure transmission for heterogeneous cellular network with limited feedback

We study physical layer secure transmission with limited feedback in heterogeneous cellular networks. A transmission protocol is designed to obtain more secure and accurate channel state information (CSI) for enhancing the secrecy performance. Under the proposed protocol, we derive expressions of coverage probability and secrecy outage probability to analyze the security performance with different system parameters such as feedback CSI length and number of antennas. Furthermore, an iteration algorithm is proposed to balance the tradeoff between the feedback and transmission time, and maximize the average secrecy throughput under coverage and secrecy outage constrains. Numeric results demonstrate the optimal feedback overhead and the maximum average secrecy throughput are influenced by the number of antennas.

Buffer-Aided Secure Relay Networks With SWIPT

In this paper, we propose the use of data and energy buffering in wireless powered relays, while we also design scheduling schemes, with the aim to increase the secrecy throughput. More specifically, it is assumed that Alice transmits information to Bob by using half-duplex randomize-and-forward relaying with simultaneous wireless information and power transfer, under the existence of a passive eavesdropper. First, considering a conventional system, i.e., without energy and data buffering, an optimal baseline policy is designed. Then, focusing on buffer-aided relaying, we maximize the average secrecy throughput under the stability requirement for data and energy queues by using the framework of Lyapunov optimization, according to which, we transform the initial stochastic optimization problem into a sequence of online subproblems. The proposed online adaptive transmission policy dynamically allocates the available resources, i.e., time and power, with respect to the channel state information, as well as the states of the buffers. In addition, our analysis reveals the existence of an interesting trade-off between the average secrecy throughput and the average queue delay. Simulation results validate the analysis and demonstrate that the proposed buffer-aided scheme significantly improves the average secrecy throughput compared to the baseline one.

Secure Transmission for Buffer-Aided Relay Networks in the Internet of Things

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.

Enhancing Physical Layer Security of DF Buffer-Aided Relay Networks With Small Buffer Sizes

In this paper, we propose a novel max-weight secure link selection (MWSLS) scheme to enhance physical layer security of decode-and-forward (DF) buffer-aided relay networks. The MWSLS scheme can select the link with the largest weight among all secure and available source-to-relay and relayto-destination links. By modeling the dynamic buffer state transitions as a Markov chain, we derive the closed-form expressions of the secrecy outage probability, the secrecy diversity gain, the average secrecy throughput and the end to end delay, which provide a comprehensive and effective way to evaluate the impacts of different parameters on the secrecy performance. The results of this paper reveal that: 1) For the case with small buffer sizes, a significant enhancement on the secrecy outage performance can be observed compared with the popular max-link secure link selection (MLSLS) scheme. 2) When L ≥ 3, the secrecy diversity gain of the system can achieve 2M, while the MLSLS scheme achieves the same secrecy diversity gain only when L → ∞ (where M denotes the number of relays and L is the buffer size). 3) The MWSLS scheme outperforms the MLSLS scheme in terms of the average secrecy throughput and the end to end delay in the low signal-to-noise ratio (SNR) regime, and obtain the same performance as the latter in the high SNR regime.

Security of an Ordered-Based Distributive Jamming Scheme

This letter proposes a new efficient yet simple distributed ordered-based jamming scheme for securing a legitimate transmission and powering a wireless receiver equipped with a nonlinear energy harvester. A legitimate source node (Alice) communicates with one legitimate receive node (Bob) and one legitimate radio-frequency energy-harvesting node (Dana) in the presence of an eavesdropping node (Eve). A set of cooperative nodes (Jims) are deployed in the network to power Dana and secure the legitimate transmissions by jamming Eve. In each time slot, only one Jim is selected. Our proposed scheme does not require the instantaneous channel state information (CSI) of Eve’s links or the global CSI of the legitimate nodes at a legitimate central unit. The numerical results demonstrate that our scheme achieves higher average secrecy throughput than that achieved by the best-jammer scheme.

Impact of Artificial Noise on Cellular Networks: A Stochastic Geometry Approach

This paper studies the impact of artificial noise (AN) on the secrecy performance of a target cell in multi-cell cellular networks. Although AN turns out to be an efficient approach for securing a pointto-point/single cell confidential transmission, it would increase the inter-cell interference in a multi-cell cellular network, which may degrade the network reliability and secrecy performance. For analyzing the average secrecy performance of the target cell which is of significant interest, we employ a hybrid cellular deployment model, where the target cell is a circle of fixed size and the base stations (BSs) outside the target cell are modeled as a homogeneous Poisson point process (PPP). We investigate the impact of AN on the reliability and security of users in the target cell in the presence of pilot contamination using a stochastic geometry approach. The analytical results of the average connection outage and the secrecy outage of its cellular user (CU) in the target cell are given, which facilitates the evaluation of the average secrecy throughput of a randomly chosen CU in the target cell. It shows that with an optimized power allocation between the desired signals and AN, the AN scheme is an efficient solution for securing the communications in a multi-cell cellular network.