Secrecy Probability Research Articles

Physical Layer Security in IRS-Assisted Cache-Enabled Satellite Communication Networks

This paper presents a comprehensive analysis of the physical layer security performance of a cache-enabled satellite communication network that incorporates intelligent reflecting surfaces (IRS) in the presence of a passive eavesdropper. In the proposed system, content caches are deployed at both the ground station and the satellite, which can improve system performance by reducing latency and transmission overhead. Moreover, the use of IRS provides an additional layer of security by enabling the manipulation of the reflected signals to impede eavesdropping. Practical channel models are used to derive connection probability and secrecy probability for both the ground station-IRS-user and the satellite-IRS-user links. The obtained results are then used to evaluate the system’s secure transmission probability, which is maximized subject to the caching probabilities and transmission rate constraints. The paper presents numerical results to demonstrate the accuracy of the analysis and the effectiveness of deploying IRS and caching to support secure content delivery. The findings provide valuable insights into the potential benefits of utilizing IRS and caching technologies in satellite communication networks for improved physical layer security.

Joint Secure Offloading and Resource Allocation for Vehicular Edge Computing Network: A Multi-Agent Deep Reinforcement Learning Approach

The mobile edge computing (MEC) technology can simultaneously provide high-speed computing services for multiple vehicular users (VUs) in vehicular edge computing (VEC) networks. Nevertheless, due to the open feature of the wireless offloading channels and the high mobility of the vehicles, the security and stability of the offloading process would be seriously degraded. In this paper, by utilizing the physical layer security (PLS) technique and spectrum sharing architecture, we propose a deep reinforcement learning based joint secure offloading and resource allocation (SORA) scheme to improve the secrecy performance and resource efficiency of the multi-user VEC networks, where the VU offloading links share the frequency spectrum preoccupied with the vehicle-to-vehicle (V2V) communication links. We use Wyner’s wiretap coding scheme to obtain the achievable secrecy rate and guarantee that confidential information cannot be decoded by multiple mobile eavesdroppers. We aim at minimizing the system processing delay while securing the wireless offloading process, by jointly optimizing the transmit power, the frequency spectrum selection and the computation resource allocation. We formulate the optimization problem as a multi-agent collaborative optimal decision problem and solve it with a double deep Q-learning algorithm. Besides, we set a punishment mechanism for the rate degradation to guarantee the communication quality of each V2V link. Simulation results demonstrate that multiple VU agents adopting the SORA scheme can rapidly adapt to the highly dynamic VEC networks and cooperate to improve the system delay performance while increasing the secrecy probability.

Secrecy outage probability and limiting threshold criteria in an optimal SNR regime by maximizing desired transfer rate

In this paper, the optimum secrecy probability has been calculated using a reduction function that optimizes the transfer rate of the user's signal for a given average broadcast power while minimizing the transfer rate of the eavesdropper's signal to ensure safe transmission. In this work, the signal-to-noise ratio (SNR) of the eavesdropper signal and the received signal are accurately estimated using matrix theory. These approximated SNRs have been studied in relation to the outage probability. By making three distinct assumptions about channel correlation, it has been possible to determine the precise secrecy outage probability. In correlated multi-antenna transmit and receive channels, this research investigates the secrecy performance of three popular diversity combining strategies—maximum ratio combining (MRC), selection combining (SC), and equal gain combining (EGC). In this research, we consider a Rayleigh fading channel with overhead communication between the transmitter and recipient. In this research, we also propose a limiting bounds condition to improve the limits on the outage probability for the Rayleigh fading environment using the three diversity combining methods. Our restricting distribution is threshold-based in order to generate precise limits on the probability of secrecy outage. An application case has been presented which discusses the impact of the proposed model for device to device communication application scenario. Our findings demonstrate that channel correlation substantially influences the probability of a secrecy outage.

Optical HAPS Eavesdropping in Vertical Heterogeneous Networks

In the next generation (6G) wireless networks, the integration of terrestrial and non-terrestrial networks is essential to provide flawless connectivity over the globe. The vital element of this architecture is the high altitude platform station (HAPS) systems, which can provide reliable and ubiquitous connectivity among satellites, unmanned aerial vehicles (UAVs), and terrestrial users. Motivated by the importance of HAPS systems, in this paper, we provide three different use-cases for HAPS eavesdropping scenarios and investigate their physical layer security (PLS) performances. To quantify the PLS performance of the proposed setups, we perform secrecy outage probability (SOP), probability of positive secrecy (PPSC), average secrecy capacity (ASC), and secrecy throughput (ST) analyses. Furthermore, we also provide important design guidelines that can be beneficial for secure HAPS systems.

Dynamic Spectrum Control-Assisted Secure and Efficient Transmission Scheme in Heterogeneous Cellular Networks

Abstract Heterogeneous cellular networks (HCNs) are envisioned as a promising architecture to provide seamless wireless coverage and increase network capacity. However, the densified multi-tier network architecture introduces excessive intra- and cross-tier interference and makes HCNs vulnerable to eavesdropping attacks. In this article, a dynamic spectrum control (DSC)-assisted transmission scheme is proposed for HCNs to strengthen network security and increase the network capacity. Specifically, the proposed DSC-assisted transmission scheme leverages the idea of block cryptography to generate sequence families, which represent the transmission decisions, by performing iterative and orthogonal sequence transformations. Based on the sequence families, multiple users can dynamically occupy different frequency slots for data transmission simultaneously. In addition, the collision probability of the data transmission is analyzed, which results in closed-form expressions of the reliable transmission probability and the secrecy probability. Then, the upper and lower bounds of network capacity are further derived with given requirements on the reliable and secure transmission probabilities. Simulation results demonstrate that the proposed DSC-assisted scheme can outperform the benchmark scheme in terms of security performance. Finally, the impacts of key factors in the proposed DSC-assisted scheme on the network capacity and security are evaluated and discussed.

Secrecy‐oriented user association in ultra dense heterogeneous networks against strategically colluding adversaries

Network densification is recognized as the key technology to meet the ever growing demand of data traffic in next generation wireless networks. However the proliferation of small cell base stations (SCBSs) introduces vulnerabilities to information security, as they are prone to eavesdropping attacks. In this paper, it is studied how user association strategies can be specifically tailored to meet this security challenge in a ultra dense heterogeneous cellular network(UDHCN) with a group of colluding eavesdroppers. In particular, the situation is considered where eavesdroppers may have limited capabilities in intercepting and decoding data traffic. In this setting each eavesdropper has to make its own decision on eavesdropping targets, and they are able to take concerted actions to sabotage information security. To address this challenge, a zero sum game framework to reflect the conflicting interests of users and eavesdroppers is proposed and a user association scheme is devised that aims to maximize system sum secrecy rate against these adversaries whose actions intend to minimize sum secrecy rate. The case that all adversaries have limited eavesdropping capabilities is first considered, and it is shown that the corresponding zero sum game is indeed a bilinear game, and its Nash equilibrium solution can be readily approximated using a saddle point Frank Wolfe(SP-FW)algorithm. Then the framework is extended to the case where adversaries with a diverse configuration of eavesdropping capabilities exist. In this case, it is shown that the underlying minimax optimization problem is indeed a nonsmooth convex-nonconcave one. A two stage method is proposed by first smoothing the objective function with a Hermite cubic polynomial approximation, and then obtaining a nearly stationary solution via a recently proposed proximal point gradient descent method. Simulation results show that the proposed framework leads to significant increases in sum secrecy rate and secrecy probability against both the capability-limited adversaries and a hybrid type of adversaries.

Secure UAV Random Networks With Minimum Safety Distance

In this correspondence, we study the physical layer security in a stochastic unmanned aerial vehicles (UAVs) network from a network-wide perspective, where the locations of UAVs are modeled as a Mat$\acute{\text{e}}$rn hard-core point process (MHCPP) to characterize the minimum safety distance between UAVs, and the locations of users and eavesdroppers are modeled as a Poisson cluster process and a Poisson point process, respectively. UAVs adopt zero-forcing precoding to serve multiple ground users and emit artificial noise to combat eavesdropping. We derive the approximations for the coverage probability and secrecy probability of a typical user, with which we derive the secrecy throughput of the whole network. Numerical results show the analytical results can well approximate the simulation results. Impacts of parameters on the secrecy performance are shown.

Physical Layer Security Enhancement Using Artificial Noise in Cellular Vehicle-to-Everything (C-V2X) Networks

The secure transmission of confidential information in cellular vehicle-to-everything (C-V2X) communication networks is vitally important for user's personal safety. However, for C-V2X there have not been much studies on the physical layer security (PLS). Since artificial noise (AN) and secure beamforming are popular PLS techniques for cellular communications, in this paper we investigate the potential of these PLS techniques for enhancing the security of C-V2X networks. In particular, leveraging stochastic geometry, we study the PLS of an AN assisted C-V2X network, where the locations of legitimate vehicular nodes, malicious vehicular nodes and road side units (RSUs) are modeled by Cox processes driven by a common Poisson line process (PLP), and the locations of cellular base stations (BSs) are modeled by a two-dimensional (2D) Poisson point process (PPP). Based on the maximum signal-to-interference-ratio (SIR) association scheme, we calculate the coverage probability of the network. We also derive bounds on the secrecy probability, which are validated by simulation results. Moreover, we obtain an analytical result of the effective secrecy throughput for characterizing the reliability and security of wiretap channels. Simulation results are given to validate the analytical result, and provide interesting insights into the impact of network parameters on the achievable secrecy performance. Simulation results show that a larger array antenna can provide a better robustness of the secure transmission strategy, and the optimal power allocation ratio between confidential information and AN remains almost unchanged for different numbers of antennas.

Physical layer security in hybrid TPSR two-way half-duplex relaying networks over rayleigh fading channel: non-zero secrecy probability analysis

In this paper, we proposed and investigated the Hybrid TPSR Two-Way Half-Duplex (HD) Relaying Communication Networks Over Rayleigh Fading Channel in the presence of the Eavesdropper (E). The system model consists of two sources A and B communicate with each other with helping of intermediate Relay (R). For the system performance analysis, we analyzed and derived the exact and approximate integral-form of the system Non-zero secrecy probability (NZSP) in the case that the E uses the MRC (maximal ratio combining) technique. In addition, the effect of the main system parameters on the system performance is investigated. Finally, all the research results are convinced by the Monte Carlo Simulation. This paper can provide a novel recommendation for relaying communication network manufacture.In this paper, we proposed and investigated the Hybrid TPSR Two-Way Half-Duplex (HD) Relaying Communication Networks Over Rayleigh Fading Channel in the presence of the Eavesdropper (E). The system model consists of two sources A and B communicate with each other with helping of intermediate Relay (R). For the system performance analysis, we analyzed and derived the exact and approximate integral-form of the system Non-zero secrecy probability (NZSP) in the case that the E uses the MRC (maximal ratio combining) technique. In addition, the effect of the main system parameters on the system performance is investigated. Finally, all the research results are convinced by the Monte Carlo Simulation. This paper can provide a novel recommendation for relaying communication network manufacture.

Intelligent Spectrum Control in Heterogeneous Networks With High Security Capability

In this letter, an intelligent spectrum control (ISC) scheme is proposed to enhance the communication security performance in heterogeneous networks (Het-Nets), where the available spectrum can be efficiently managed by avoiding interferences flexibly with the aid of spectrum sensing technique. We analyze the security performance for the Het-Nets, and derive the closed-form expressions for the reliable transmission probability and the secrecy probability of the authorized user. Our numerical simulation results validate the accuracy of the analytical expressions, and imply that the Het-Nets with the ISC scheme can achieve a high security performance.

Average secrecy rate and probability of non-zero secrecy capacity of wiretap generalised gamma fading channels

Average secrecy rate and probability of non-zero secrecy capacity of wiretap generalised gamma fading channels

Average secrecy rate and probability of non-zero secrecy capacity of wiretap generalised gamma fading channels

In this paper, secrecy performance is studied for the classic Wyner's wiretap channel which follows Generalised Gamma (GG) distribution. In order to evaluate the secrecy performance, we derived the exact Average Secrecy Rate (ASR) and closed form expression for the Probability of Non-Zero Secrecy Capacity (PNZSC) for different fading parameters corresponding to main and eavesdropper's channels. The results are then simulated and verified. It has been observed that the ASR of GG fading increases with the increase in the fading constant of the main channel.

Physical Layer Security in Nonorthogonal Multiple Access Wireless Network with Jammer Selection

The physical layer security of downlink nonorthogonal multiple access (NOMA) network is analyzed. In order to improve the secrecy probability, friendly jammers are jointed in the NOMA network. Two jammer schemes are proposed in the NOMA network. All the jammers transmit jamming signal without jammer selection in the first scheme (NO JS scheme). Jammers are selected to transmit jamming signal if their interfering power on scheduled users is below a threshold in the second scheme (JS scheme). A stochastic geometry approach is applied to analyze the outage probability and the secrecy probability. Compared with the NO JS scheme and traditional scheme (without jointing jammers), the jammer selection scheme provides a good balance between the user outage probability and secrecy probability. Numerical results demonstrate that the security performance of the two proposed schemes can be improved by jointing the jammers in the NOMA wireless network.

Effective User-Pair Association Schemes for Relay-Based Multi-tier Heterogeneous Networks with Physical Layer Security

This paper focuses on relay-assisted multi-tier heterogeneous networks (HetNets) in term of feasible user-pair association (UPA) criterions and physical layer secrecy analysis. In the interesting relay-assisted multi-tier HetNets, the randomly located mobile user-pair communicates with the help of the relay of its associated tier. We model the locations of all network elements as independent Poisson point process. For such relay-assisted HetNets, similar to the nearest relay defined for user association in traditional single-hop HetNets, we define the so-called best relay in each tier for a typical mobile user-pair by using the equivalent end-to-end biased received power (BRP). Then based on the defined best-relay, we first propose the max–min user-pair association (MM-UPA) criterion. Due to the fact that the MM-UPA criterion is dominated by the bottleneck link’s BRP and does not exploit the joint effect of both the source-relay and relay-destination links, we present the maximum harmonic mean user-pair association (MHM-UPA) criterion, again. For the two UPA criterions, by using feasible mathematical analysis, we derive the corresponding UPA probabilities. Finally, as an implement of the two proposed UPA criterions, by using stochastic geometry, we perform the secrecy performance analysis of the considered relay-assisted multi-tier HetNets. The presented numerical analysis first validates our derivations through the comparison analysis with traditional single-hop user association criterion. At the same time, we also present the comparison analysis between the two proposed MM-UPA and MHM-UPA criterions. It is found that when the transmission power $$P_{R(S)}^{k}$$ is small, the MHM-UPA scheme outperforms the MM-UPA one in term of UPA probability. On the contrary, the two schemes achieve approximately the same UPA probability. For the total secrecy probability, we find that when transmit power is small, the MHM-UPA achieves the higher secrecy probabilities. Moreover, the achieved gain by MHM-UPA is increasing with the decrease of transmission power. Contrarily, when the transmission power is large, although the MM-UPA outperforms the MHM-UPA, the achieved gain by MM-UPA cover MHM-UPA is small.

Secure Transmissions in Wireless Information and Power Transfer Millimeter-Wave Ultra-Dense Networks

The millimeter-wave (mmWave) ultra-dense networks are more suitable for wireless power transfer, since the short-distance transmissions experience less pathloss and the base station (BS) packed with large-scale antenna arrays can achieve significant array gains. However, the secrecy performance of the simultaneous wireless information and power transfer (SWIPT) mmWave ultra-dense networks has not been investigated so far. In this paper, we consider the secure communications in downlink SWIPT mmWave ultra-dense networks, where the energy-constrained users extract energy and information from the mmWave signals in the presence of multiple eavesdroppers. First, the analytical expressions of the energy-information coverage probability are derived for both power splitting and time switching policies using stochastic geometry. Then, we derive the closed-form expressions of the secrecy probability in the presence of multiple independent or colluding eavesdroppers. Finally, the effective secrecy throughput (EST), which can measure the network energy coverage, secure, and reliable transmission performance in a unified manner, is derived. Theoretical analysis and simulation results reveal that the EST first increases and then decreases with the increasing of the transmit power, power/time splitting ratio, codeword transmission rate, and confidential information rate. Furthermore, reducing the beamwidth of the signal at BSs can decrease the information leakage and improve the EST.

Secrecy Outage Probability of Conventional and Modified TAS/Alamouti-STBC Schemes With Power Allocation in the Presence of Feedback Errors

Modified transmit antenna selection (M-TAS)/Alamouti space-time block coding (STBC) schemes have been shown to achieve superior error performance together with a reduced feedback load in the presence of feedback errors (FEs) when compared to the conventional TAS/Alamouti-STBC schemes. By shifting the focus of the investigation, this paper answers the query on whether the modified schemes with power allocation (PA) provide enhancements in the secrecy outage probability (SOP) performance of multi-antenna schemes in wiretap channels. The exact expressions of the SOP and non-zero secrecy probabilities for both the conventional and modified schemes in Rayleigh fading channels have been derived and validated via Monte Carlo simulations. With the help of high signal-to-noise ratio approaches and approximations, the asymptotic secrecy diversity order analysis has been carried out. Besides, by providing a simulation-based examination on the inclusion of a different TAS criterion before STBC transmission, the additional advantages on the secrecy performance have been exhibited. The extensive investigation and comparisons have shown that M-TAS/PA/Alamouti-STBC schemes provide considerable enhancements in the secrecy rates of wireless communications systems in the presence of FEs.

Physical Layer Security in <inline-formula> <tex-math notation="LaTeX">$K$ </tex-math> </inline-formula>-Tier Heterogeneous Cellular Networks Over Nakagami-<inline-formula> <tex-math notation="LaTeX">$m$ </tex-math> </inline-formula> Channel During Uplink and Downlink Phases

In this paper, we study the physical layer security performance under K-tier heterogeneous cellular network during both downlink and uplink phases. Especially, Nakagami-m fading is used to capture the characteristics of line-of-sight (LoS) propagation. Using stochastic geometry tool, tractable expressions of connection probability are derived accordingly. Upper-bound expression of secrecy probability is derived through only considering the closest eavesdropper, whose rationality is validated theoretically. While lowerbound expression of secrecy probability is derived through using Jensen's inequality. Moreover, we demonstrate the effects of parameter setting upon network connection and secrecy performances through numerical simulation. For example, Rayleigh fading and LoS scenario (an extreme Rician case) can be regarded as special cases of this paper through properly setting m 0 value. Connection probability is insensitive to BS density during downlink phases, while it is an increasing function of BS density during the uplink phase. We also find that connection probability is an increasing function of m 0 value. Secrecy probability is insensitive to m 0 value, while it is an increasing function of BS density during both downlink and uplink phases.

Delivery-Secrecy Tradeoff for Cache-Enabled Stochastic Networks: Content Placement Optimization

Wireless caching has been widely recognized as a promising technique for efficient content delivery. In this paper, by taking different file secrecy levels into consideration, physical-layer security oriented content placement is optimized in a stochastic cache-enabled cellular network. We propose an analytical framework to investigate the nontrivial file delivery-secrecy tradeoff. Specifically, we first derive the closed-form expressions for the file hit and secrecy probabilities. The global optimal probabilistic content placement policy is then analytically derived in terms of hit probability maximization under file secrecy constraints. Numerical results are demonstrated to verify our analytical findings and show that the targeted file secrecy levels are crucial in balancing the file delivery-secrecy tradeoff.

Secure User Association in Two-Tier Heterogeneous Cellular Networks With In-Band Interference

In this paper, we address the issue of security-concerned user association in two-tier heterogeneous cellular networks with in-band interference. Different from the maximum secrecy capacity association (max-SC), which studied multi-tier heterogeneous networks without in-band interference, we consider the max-SC problem with in-band interference. Considering the intractability of the max-SC scheme under in-band interference scenario, we derive a simplified max-SC scheme based on the Maclaurin formulation. Network connection and secrecy probability, as well as network secrecy throughput, are analyzed under our association scheme through stochastic geometry. Simulation results demonstrate that the proposed scheme can approach the performance of the max-SC association, in terms of secrecy probability and network secrecy throughput, and performs better in terms of connection probability. Comparing with the previous work, the proposed scheme performs better in connection, secrecy probability, and secrecy throughput.

Physical Layer Security in Heterogeneous Networks With Jammer Selection and Full-Duplex Users

In this paper, we enhance physical layer security for downlink heterogeneous networks by using friendly jammers and full-duplex users. The jammers are selected to transmit jamming signal if their interfering power on the scheduled users is below a threshold, meanwhile the scheduled users confound the eavesdroppers using artificial noise by full-duplexing. Using the tools of stochastic geometry, we derive the expressions of connection probability and secrecy probability. In particular, the locations of active jammers are modeled by a modified Poisson hole process. Determining the jammer selection threshold is further investigated for connection probability maximization subject to the security constraints. A greedy algorithm is proposed to efficiently solve this problem. The accuracy of the theoretical analysis and the efficiency of the proposed algorithm are evaluated by numerical simulations.