Physical layer security in SWIPT-based cooperative vehicular relaying networks

Unlike prior works assuming perfect attack detection, this paper investigates the physical layer security of a simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided network under a full-duplex active eavesdropper in the more realistic scenario where its jamming remains undetected by the legitimate transmitter. Assuming Nakagami-m fading channels, we first derive the probability density functions (PDFs) of the signal-to-interference ratios (SIRs) at both the legitimate user and the eavesdropper. Then, using the PDFs, we obtain novel closed-form expressions for key secrecy metrics, including the probability of nonzero secrecy capacity (PNSC), secrecy outage probability (SOP), and average secrecy capacity (ASC). Moreover, the asymptotic PNSC, SOP, and ASC at high signal-to noise ratio (SNR) are also derived. Based on those asymptotic expressions, we present compact expressions for several key performance indicators: 1) the secrecy diversity order and the secrecy array gain of the SOP, and 2) the high SNR slope and the high SNR power offset of the ASC. Results demonstrate that, compared to the passive eavesdropper scheme, the active jamming attack carried out by Eve will not cause any loss in secrecy diversity gain and high SNR slope, but only result in the loss of secrecy array gain and high SNR power offset. Finally, we verify our analytical results via simulations.

This paper studies the physical layer security of uplink (UL) transmission in simultaneous wireless information and power transfer (SWIPT) deployed in wireless sensor networks (WSNs). Firstly, we model the random network as Poisson cluster process (PCP) to focus on the case where eavesdroppers hide around certain targets to intercept the confidential information successfully. Then, the communication model of time division multiple access (TDMA) is established to avoid inter-node interferences and extend the time for energy harvesting (EH). After that, aiming at the sensor nodes that work in “harvesting-transmitting” (H-T) mode with time switching (TS) receiver, we derive the energy outage probabilities (EOP), connection outage probabilities (COP) and secrecy outage probabilities (SOP) through comprehensive analysis on downlink (DL) and UL transmissions, based on which the uplink secrecy throughput (STP) is obtained to characterize the overall performance. Finally, our theoretical derivations are verified and the influences of various parameters on uplink STP are revealed by the simulation results, which indicate the existence of an optimal energy threshold and a partition coefficient of DL and UL period that can achieve the best secrecy performance.

Secrecy outage analysis of imperfect MRC in SWIPT systems with a random eavesdropper

Simultaneous wireless information and power transmission (SWIPT)-enabled vehicle-to-vehicle (V2V) systems use radio frequency (RF) signals for both information transmission and power. It reduces energy consumption, increases spectrum efficiency, and optimizes resource allocation to improve overall system performance. In this article, we investigate the physical-layer security (PLS) for a SWIPT enabled V2V cooperative communication system in which a source vehicle (S) transmits information to a destination vehicle (D) through an intermediate vehicle treated as relay node (R). During analysis, it is assumed that two independent vehicular nodes in the same road, i.e., eavesdroppers (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E_{1}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E_{2}$ </tex-math></inline-formula>) are trying to intercept the information from different legitimate channels. The communication links are assumed to follow the double Nakagami-m (DNm) fading distribution. The study examines the security performance of the networks by calculating the secrecy outage probability (SOP), strictly positive secrecy capacity (SPSC), intercept probability (IP), and connection outage probability (COP). Next, we extend to the analysis of tradeoff between security and reliability as well as tradeoff between secrecy rate and secrecy outage which are termed as security and reliability tradeoff (SRT) and effective secrecy throughput (EST). For a comprehensive analysis, the results are produced for different values of the fading parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(m)$ </tex-math></inline-formula>, power splitting factor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(\rho)$ </tex-math></inline-formula>, and secrecy thresholds. The results clearly indicate that an increase in m leads to an enhancement in the secrecy performance. Additionally, the results show that secrecy performance improves as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rho $ </tex-math></inline-formula> decreases. Finally, the Monte-Carlo simulation results are presented to verify our proposed analytical models.

On the physical layer security of hybrid RF-FSO system in presence of multiple eavesdroppers and receiver diversity

In this paper, the physical layer security (PLS) analysis for a decode-and-forward (DF) protocol based multi-hop hybrid radio frequency (RF)/ free space optics (FSO) is presented. Herein, two different scenarios are considered for detecting the secured information at the destination. In the first scenario, at each hop, the received signals with higher secrecy capacity are selected. However, in the second scenario, the RF and FSO signals are simply decoded and forwarded to the next hop and selection is done at the last hop only. Each node in the system is connected to its subsequent node through parallel RF and FSO links. The FSO links and RF links are characterized by Málaga ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathcal {M}$</tex-math></inline-formula> ) and Nakagami- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$m$</tex-math></inline-formula> composite distributions respectively. For both scenarios, the secrecy outage probability (SOP), strictly positive secrecy capacity (SPSC), intercept probability (IP), and effective secrecy throughput (EST) are obtained as performance metrics. These performance metrics are obtained by considering pointing error, different optical signal detection methods, turbulence effect, and the RF link fading parameter ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$m$</tex-math></inline-formula> ). Using the results, the security and reliability trade-off analysis is discussed for two scenarios. In addition, the asymptotic results are also obtained to study the system in depth. Further, the secrecy diversity order (SDO) and secrecy coding gain (SCG) are obtained to analyse the system in depth. Finally, Monte-Carlo Simulation is performed to verify the obtained results. The results manifest that the scenario with selection at each hop provides better secrecy performance than the scenario with selection at the last hop.

In this paper, we investigate physical layer security for multiple decode-and-forward (DF) relaying underlay cognitive radio networks (CRNs) with fixed transmit power at the secondary network against passive eavesdropping attacks. We propose a simple relay selection scheme to improve wireless transmission security based on the instantaneous channel information of all legitimate users and the statistical information about the eavesdropper channels. The closed-form expressions of the probability of non-zero secrecy capacity and the secrecy outage probability (SOP) are derived over independent and non-identically distributed Rayleigh fading environments. Furthermore, we conduct the asymptotic analysis to evaluate the secrecy diversity order performance and prove that full diversity is achieved by using the proposed relay selection. Finally, numerical results are presented to verify the theoretical analysis and depict that primary interference constrain has a significant impact on the secure performance and a proper transmit power for the second transmitters is preferred to be energy-efficient and improve the secure performance.

In this paper, we investigate secure communication for a dual-hop multiuser relay network, where a source communication with N ( N ≥ 1 ) destinations via an untrusted variable gains relay. To exploit multiuser diversity while protecting source’s confidential message, we first propose a joint destination-based jamming and opportunistic scheduling (DJOS) scheme. Then, we derive closed-form approximated and asymptotic expressions of the secrecy outage probability (SOP) for the considered system with DJOS. Furthermore, we determine an asymptotical optimal power allocation (OPA), which minimizes the asymptotic SOP, to further improve the secrecy performance. Our analytical results show that the achievable secrecy diversity order in terms of SOP with fixed power allocation is min ( 1 , N 2 ) , whereas, with OPA, the achievable secrecy diversity order can be improved up to min ( 1 , 2 N N + 2 ) . This interesting result reveals that OPA can improve the secrecy diversity order of the single-user network. This is intuitive since full diversity order of 1 cannot be achieved when N = 1 , thus leaving some space for OPA to improve the diversity order. Nevertheless, for N ≥ 2 , the effect of OPA is to increase the secrecy array gain rather than the secrecy diversity order since full diversity order 1 has been achieved by the OS scheme. Finally, simulation results are presented to validate our analysis.

Vehicle to vehicle (V2V) communications under dense urban scenarios are usually influenced by keyhole effect, which leads to rank deficiency and diminishes communication security. This paper investigates the physical layer security (PLS) in V2V communications with keyhole effect, where multiple-input multiple-output (MIMO) is involved in both legitimate and wiretap channels. Secrecy performance of the considered MIMO-V2V systems is evaluated by deriving closed-form expressions of the probability of non-zero secrecy capacity, secrecy outage probability (SOP) and average secrecy capacity (ASC), respectively. The analytical results are validated by numerical simulations and are in excellent agreement.

Recently, simultaneous wireless information and power transfer (SWIPT) has emerged as a potential solution for improving energy efficiency. However, it is also unavoidable to be eavesdropped on by security threats. In this paper, we investigate the secure transmission of the SWIPT system where a user is equipped with power-splitting (PS) scheme while an eavesdropper (Eve) tries to listen to the private information of the transmitter-user communication link. Our objective is to optimize the system secrecy rate while satisfying the requirements on energy harvesting (EH) at the user and transmit power at the transmitter. For solving the optimization problem, we utilize the feasible point pursuit (FPP) technique and the successive convex approximation (SCA) iterative-based algorithm. Although this algorithm can effectively solve our non-convex problem, it is often quite complex and time-consuming due to the many mathematical transformations and the need for the number of iterations to be converged to the optimal solutions. Therefore, we also consider the deep learning (DL)-based approach which helps the optimization problem to achieve an efficient solution in terms of the computation time. The simulation results validate the proposed scheme significantly improve the system secrecy rate. Moreover, the DL scheme achieved similar performance to the optimization algorithm, but with low computation time.

In Cooperative Networks based on simultaneous wireless information and power transfer (SWIPT), relay nodes collect the energy of radio signals received from source node and transmit the information of source nodes to destination nodes, which not only prolongs the service life of energy-constrained nodes, but also improves the ability of long-distance transmission of information. Due to the openness of energy harvesting, there may be eavesdropping users with malicious decoding. In order to study the security performance of the Cooperative Networks based on SWIPT, this paper mainly studies the physical layer security performance of this network, derives and simulates the expression of system security outage probability and throughput. The simulation results show that the system security performance is mainly influenced by time allocation parameter of SWIPT and decreases with the increase of target rate.

The main challenges of sensing in harsh industrial and biological environments are the limited energy of sensor nodes and the difficulty of charging sensor nodes. Simultaneous wireless information and power transfer (SWIPT) is a non-invasive option to replenish energy. SWIPT harvests energy and decodes information from the same RF signal, which is influencing the design of a wireless sensor network. In multi-hop multi-flow wireless sensor networks, interference generally exists, and the interference has a different influence on SWIPT. Route, interference and SWIPT are dependent. However, existing works consider SWIPT link resource allocation with a given route or only select path for one flow without interference. Therefore, this paper firstly analyzes the influence of interference on SWIPT, and select the SWIPT routing with interference. We design an interference-based information and energy allocation model to maximize the link capacity with SWIPT. Then, we design an interference-aware route metric, formulate SWIPT routing problem, and design an interference-aware SWIPT routing algorithm. The simulation results show that as the number of flows increases, there is more likely to obtain performance gains from interference and SWIPT.

We analyze the impact of outdated Channel State Information (CSI) on the secrecy performance of Multi-input, Multi-output, Multi-eavesdropper (MIMOME) system over Nakagami-m fading channels, where Transmit Antenna Selection (TAS) is used at the transmitter and Maximal-ratio Combination (MRC) is used at the desired receiver and the eavesdropper. In our analysis, new closed-form expressions for the probability of the existence of positive secrecy capacity and the secrecy outage probability are derived. We also derive the asymptotic secrecy outage probability, in which the secrecy diversity order and the secrecy array gain are revealed. Furthermore, the -outage secrecy capacity is characterized. Our results demonstrate that due to the outdated CSI, the secrecy performance sufiers from great loss, and the transmit diversity order is reduced to one, while the receive diversity order is not afiected.

In this paper, we provide a comprehensive literature survey on simultaneous wireless information and power transfer (SWIPT) in multi-antenna systems. We first review recent contributions on the theory analysis of SWIPT from information theoretic standpoint and introduce the tradeoff between information transfer and power transfer under various settings. Then, we focus on the utilization of multi-antenna techniques to solve existing problems of SWIPT. Contributions on the implementation aspects of multi-antenna SWIPT are summarized. The performance of SWIPT is evaluated by different metrics, therefore, we review the works on dynamic SWIPT optimization based on objective function using multi-antenna techniques. In addition, the implementation of SWIPT brings up secure issue. Thus, we summarize recent works on secure SWIPT. Finally, we present researches combining SWIPT with state-of-the-art techniques due to potential application in different scenarios.

This paper studies the physical-layer security (PLS) of a system model consisting of a transmitter, a receiver, and multiple eavesdroppers. Cascaded general fading channel, which is the κ-μ distribution is assumed at the main and the wiretap links of the network. The impacts of the cascade level, the number of eavesdroppers attempting to overhear the confidential information, and the wiretap channel's parameters on the system's secrecy are investigated. Two of the main secrecy metrics are used to evaluate the secrecy level of the system, which are the secrecy outage probability (OP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sec</sub> ) and the probability of non-zero secrecy capacity (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nsc</sub> ). Exact and asymptotic form expressions for (OP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sec</sub> ) and (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nsc</sub> ) are derived. Asymptotic analysis is performed to gain a clear vision about the impact of some key parameters over the secrecy. The results show that the fading channel cascade level has a significant effect on the system's secrecy. Also, the results show that the system is less protected when increasing the number of eavesdroppers or when improving the wiretap channel's conditions. Analytical results are validated using Monte-Carlo simulations.