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This paper presents a study of the impact of different types of waveform jamming schemes against remote detonation communication devices based on Long term evolution (LTE) technology. Two main categories of waveform jamming signals (single-carrier and multi-carriers) were used. Also, two jamming scenarios against LTE-based remote detonation devices (jamming the whole LTE frame and jamming the LTE synchronization channel) were investigated. The key point of evaluating the effectiveness of the presented waveform jamming signals is by measuring their ability to successfully cut off the connection between the transmitter and the LTE-based remote detonation device. This is achieved by verifying that the remote detonation device is unable to successfully receive the transmitted information (Deny of Service (DOS) mode). To this end, emulations of these scenarios are held using two Keysight software-defined radio software programs (SystemVue 2015 and VSA 89600). Finally, a real practical experiment of the impact of different waveform jamming schemes against LTE-based remote detonation devices is emulated to present the optimal waveform jamming scheme against these types of devices. [ABSTRACT FROM AUTHOR]

In 5G, users can easily enjoy services by accessing the edge devices (EDs) deployed around the base stations. Generally, due to the uneven distribution and mobility of users, one ED is required to serve multiple users simultaneously, that results in the ED overload, seriously affecting the quality of experience (QoE) of the users. By responding to users' requests, service migration realizes the cross edge device migrations, that dynamically provides services for mobile users, which effectively improves the resource utilization rate of edge servers and the QoE of users. However, during the service migrations, malicious users may deploy pseudo base stations, gateways and other devices to illegally eavesdrop or tamper with user service data, that causes user information loss or disclosure. To prevent these security issues, a fountain-coding based cooperative jamming strategy is proposed in this paper. Specifically, the fountain coding technology is introduced to construct a three-node transmission model, including an original node, a target node and a malicious node, to realize the secure data transmission process in service migration. Besides, a group of relay nodes are employed to carry out cooperative jamming, that deteriorate the illegal eavesdropping quality of malicious nodes on service data. Then secrecy rate and outage probability are utilized to evaluate the security and reliability of the whole service migration. Finally, the theoretical analysis is shown by simulation results. [ABSTRACT FROM AUTHOR]

Aiming at the problems of complex networking, high power consumption, and short communication distance of the communication technology used in the existing multi-loom data monitoring system, this paper adopts a LoRa technology with the advantages of strong anti-jamming ability, low operating power consumption, and long communication distance, and proposes a multi-loom data monitoring system program based on LoRa technology. Due to the large number of looms in the industrial field, multiple LoRa terminal nodes need to report data to the LoRa gateway nodes at the same time, the transmission frequency is relatively high and the channel load is heavy, and there is the problem of low channel utilization under the traditional data anti-collision algorithm. Aiming at the above problems, this paper proposes a communication mechanism based on the combination of binary tree conflict decomposition algorithm and TDMA, which can ensure that the communication of static time-slot type terminal nodes is free of data collision and reduce the node's power consumption, and at the same time, it can ensure that the terminal nodes that do not receive the receive answer frame can use the competition to report the data again within the dynamic time-slot assigned, so that the packets involved in the collision can be successfully transmission. In this paper, the remote monitoring system is designed in terms of both hardware and software systems. In order to prove the feasibility of the solution, practical tests show that the terminal nodes and gateway nodes can realize 100% no packet loss within 400 m in the loom industrial field environment, and the designed terminal nodes have low power consumption. It has some reference value in loom data monitoring. [ABSTRACT FROM AUTHOR]

Interrupted-sampling repeater jamming (ISRJ) is a type of intra-pulse coherent jamming that poses a significant threat to radar detection and tracking of targets. This paper proposes an ISRJ suppression method based on frequency agile waveform and sparse recovery, starting from the temporal discontinuity and modulation characteristics of ISRJ. This method is particularly suitable for scenarios with high jamming duty ratio (JDR) and high jammer sampling duty ratio (SDR). By dividing the transmitted waveform into sub-pulses with different carrier frequencies and applying a two-round block sparse algorithm, the method accurately recovers three parameters of ISRJ, achieving effective jamming identification, reconstruction, and cancellation. Additionally, a target detection technique based on robust sparse recovery is proposed, significantly improving the stability and accuracy of target detection. Comparative experimental results conducted in three scenarios confirm the effectiveness and superiority of this method under high JDR and SDR conditions. [ABSTRACT FROM AUTHOR]

Enhancing information security has become increasingly significant in the digital age. This paper investigates the concept of physical layer security (PLS) within a relay-aided power line communication (PLC) system operating over a multiple-input multiple-output (MIMO) channel based on MK model. Specifically, we examine the transmission of confidential signals between a source and a distant destination while accounting for the presence of multiple eavesdroppers, both colluding and non-colluding. We propose a two-phase jamming scheme that leverages a full-duplex (FD) amplify-and-forward (AF) relay to address this challenge. Our primary objective is to maximize the secrecy rate, which necessitates the optimization of the jamming precoding and transmitting precoding matrices at both the source and the relay while adhering to transmit power constraints. We present a formulation of this problem and demonstrate that it can be efficiently solved using an effective block coordinate descent (BCD) algorithm. Simulation results are conducted to validate the convergence and performance of the proposed algorithm. These findings confirm the effectiveness of our approach. Furthermore, the numerical analysis reveals that our proposed algorithm surpasses traditional schemes that lack jamming to achieve higher secrecy rates. As a result, the proposed algorithm offers the benefit of guaranteeing secure communications in a realistic channel model, even in scenarios involving colluding eavesdroppers. [ABSTRACT FROM AUTHOR]

Free-space optical (FSO) communication systems are a promising technology for future smart cities due to their cost-effective installation, high data throughput, extensive reach, and minimal latency. However, these systems are vulnerable to potential intrusions, particularly jamming. The limited wavelengths of FSO systems, typically around 1300 nm or 1550 nm, make them accessible to potential adversaries. The wide field-of-view (FoV) of FSO receivers is important for dealing with changing weather conditions. However, jammers can use this to their advantage, lowering security or stopping FSO links from working. Even in terrestrial applications, FSO transceivers, often situated at significant heights, are vulnerable to jamming. A jammer can transmit disruptive optical pulses to the FSO receiver, making it difficult to distinguish between legitimate signals and jammed interference, posing a significant risk to communication integrity. Addressing jamming in FSO communication systems is crucial, especially in scenarios demanding secure and reliable communication, such as military applications. Understanding jamming and developing effective countermeasures is essential to ensuring the security and reliability of future communication networks as FSO technology continues to evolve. [ABSTRACT FROM AUTHOR]

Background: One of the biggest challenges in soft robotics is the variability and controllability of stiffness. Jamming-based approaches have been of interest to change stiffness dramatically by increasing friction between grains, layers, or fibers. Besides, magnetorheological elastomers (MREs) that exhibit magnetic field-dependent viscoelasticity have significant potential as a stiffness variation material. This study investigates the unique mechanics of magnetic jamming of MRE sheets exploring stiffness change both due to jamming and variable viscosity. Methods: Sample MREs and flexible neodymium-iron-boron (NdFeB) magnets are manufactured. Uniaxial tensile tests supported with digital image correlation are performed to characterize the materials. Multi-layer jamming structures comprised of MREs and NdFeB magnets are developed and validated through 3-point bending experiments and finite element simulations. Results: Results show that the stiffness of the multi-layer structure is higher under magnetic field. Furthermore, the stiffness change is increased when MREs are used instead of PDMS as layers. Conclusion: This study proves the concept of magnetic jamming of MRE layers. The results are crucial for the possible soft robotic implementation of the proposed hybrid stiffening approach combining jamming with viscoelasticity modification. [ABSTRACT FROM AUTHOR]

This work aims at achieving the secrecy rate (SR) enhancement in amplify-and-forward (AF) relay-aided simultaneous wireless information and power transfer (SWIPT)-NOMA network via control-jamming (CJ) whilst satisfying the constraints on total transmit power budget. Here, in order to coordinate the information processing and energy-harvesting (EH), power-splitting (PS) protocol is deployed at the relay. For comparison purposes, in addition to CJ, the SR of with-jamming (J) and without-jamming (WJ) conditions are also highlighted in the existence of an eavesdropper (Eve). Moreover, the analytical expression for Ergodic SR is evaluated at the NOMA users under the CJ scenario. Next, to maximize the SR of the users further, an optimal power allocation (OPA) scheme has been adopted, which involves both particle swarm optimization (PSO) and Lagrangian multiplier (LM)-based approaches to acquire the optimized power factors of various nodes of the network. In addition, we analyzed the affect of major parameters such as: J → E v e distance, transmit signal-to-noise ratio (SNR), and R → E v e distance on the SR by exploiting distinct jamming scenarios. Finally, a significant secrecy performance gain in terms of SR is verified with proposed CJ over other jamming conditions and OPA over the fixed power allocation (FPA) and it is confirmed through Monte-Carlo based simulations. [ABSTRACT FROM AUTHOR]

This paper presents the concept and studies of federated deep reinforcement learning (DRL) based anti-jamming communication in softwarization UAV network (SUNET). First, task-driven SUNET framework is presented and joint beamforming and power control (JBPC) based multidomain anti-jamming model is built to balance the spectrum efficiency (SE) and energy efficiency (EE) of the SUENT. Then a weighted dueling DQN (wDDQN) learning algorithm with upper confidence bound (UCB) action exploration is provided to handle the formulated model. Further, we propose federated wDDQN-UCB (F-wDDQN) based JBPC anti-jamming strategy to tackle the challenge of agent training would consume a large of communication resources, and design the link state aware quantity of service (LSAQ) routing of SUNET to reduce transmission delay of the model parameters during F-wDDQN training. Simulation results validate that the spectrum-energy efficiency and convergence performance achieved by the F-wDDQN based JBPC anti-jamming strategy is superior to existing DRL methods, and the LSAQ routing is benefit to reduce the transmission delay of the F-wDDQN learning strategy and accelerate its convergence. [ABSTRACT FROM AUTHOR]

This paper proposes a adaptive reaching law-based sliding mode control (SMC) method for maintaining favorable velocity control performance of permanent magnet synchronous motors (PMSMs) under internal and external perturbations. An adaptive switching power reaching law (ASPRL) is designed, which contains adaptive terms and state variables of the sliding mode surface function. This augmented reaching law decreases the chatter of the control system and increases the rate at which the state variables of the system reach the sliding mode surface. Additionally, a Luenberger observer load torque (LOLT) is designed to observe the external load and provide feedback to the velocity controller, reducing the impact of load disturbances and improving the jamming performance of the controller. Simulation experiments confirm that ASPRL reduces buffeting, decreases overshoot, and shortens response time, demonstrating its advantages in PMSM control. [ABSTRACT FROM AUTHOR]

The adaptive interference cancellation technique has been widely utilized in radar, GPS, data link, etc., systems to address challenges from external interference, such as co-site and hostile interference. Since the anti-jamming performance of the adaptive interference cancellation technique is sensitive to group delay mismatch between channels, the group delay mismatch becomes one of the main factors that limit the system's anti-jamming capability. However, the traditional adaptive interference cancellation system's mathematical model cannot quantitatively characterize the group delay mismatch effect on the wideband interference cancellation performance. In this paper, the mathematical model of the wideband adaptive spatial interference cancellation (ASIC) system is established, which considers the group delay mismatch, to quantitatively analyze the impact of group delay mismatch on the hostile interference cancellation. The mathematical model utilizes the weighted multi-tone signals to fit the wideband interference, and then, delay differences are attached to each tone signal to simulate the group delay mismatch. Then, the analytic expressions of weight and interference cancellation ratio are derived, which consider the interference bandwidth and group delay mismatch, to quantitatively analyze the group delay mismatch effect on the anti-jamming performance of the wideband ASIC system. Simulation results indicate that the theoretical analysis based on the mathematical model of wideband ASIC system are accurate, which can achieve the quantitative analysis of the group delay mismatch effect on the WIC performance. [ABSTRACT FROM AUTHOR]

Accurate parameter estimation in radar systems is critically hindered by multipath interference, a challenge that is amplified in complex and dynamic environments. Traditional methods for parameter estimation, which concentrate on single parameters and rely on statistical assumptions, often struggle in such scenarios. To address this, the deep adaptive temporal network (DAT-Net), an innovative deep learning model designed to handle the inherent complexities and non-stationarity of time series data, is proposed. In more detail, DAT-Net integrates both the pruned exact linear time method for effective time series segmentation and the exponential scaling-based importance evaluation algorithm for dynamic learning of importance weights. These methods enable the model to adapt to shifts in data distribution and provide a robust solution for parameter estimation. In addition, DAT-Net demonstrates the capability to comprehend inherent nonlinearities in radar multipath interference signals, thereby facilitating the modeling of intricate patterns within the data. Extensive validation experiments conducted across parameter estimation tasks and demonstrates the robust applicability and efficiency of the proposed DAT-Net model. The architecture yield root mean squared error scores as low as 0.0051 for single-parameter estimation and 0.0152 for multiple-parameter estimation. [ABSTRACT FROM AUTHOR]

This paper investigates the adverse effects of co-channel interference (CCI) on the secrecy achievable rate (SAR) performance of illegitimate decode-and-forward full-duplex two-way relaying in power-domain non-orthogonal multiple access network. So as to minimize the information leakage, the investigation considers that illegitimate relay terminals are affected by a limited number of friendly jammers. In an effort to minimize the system overhead, the investigation activates a single illegitimate relay terminal by selecting a relay, which has the minimum secrecy achievable rate and maximizing. Obtained results reveal that while the CCI has adverse effects on system SAR performance, the friendly jammer helps to enhance the system performance. Monte-Carlo-based extensive simulations verify the numerically obtained results. [ABSTRACT FROM AUTHOR]

Radio jamming represents a serious threat in wireless networks that can cause denial of service (DoS) attacks for the network users. The jammer transmits jamming signals to disrupt the normal operation of the wireless networks. With proliferation of unmanned aerial vehicle (UAV)-based wireless networks and Internet of Things technologies, jamming attacks have become a major challenge to the practical adoption of these technologies. In this paper, we investigate the problem of optimizing the performance of the UAV data collection from ground IoT devices in presence of a malicious jammer. The IoT devices are clustered, and the UAV collects the data from the cluster heads (CHs) such that the harmful effect of the jammer is mitigated. The objective is to minimize the flight time of the UAV while collecting the data from the ground IoT devices in presence of the jamming attack. We modeled our problem mathematically as an integer linear program (ILP). Due to the difficulty of solving the optimization problem when the scale of the problem is large, we proposed Jamming-Aware UAV Routing and IoT Devices Clustering Algorithm (JA-RC). This algorithm is Genetic-based and can solve the original optimization problem in a more efficient way. Then, we investigate the performance of the proposed algorithm under different settings and scenarios. [ABSTRACT FROM AUTHOR]

With the development of modern electronic countermeasure technology, the fight between radar jamming and anti-jamming has become increasingly fierce. Experts have done a lot of highly effective work on radar anti-jamming performance. However, the emergence of various new complex interferences has rendered existing methods unable to meet the needs. In this manuscript, we consider the measurement and evaluation method of radar anti-jamming effectiveness based on principal component analysis and machine learning. Firstly, taking into account the diversity of variables in radar countermeasure experiments and the complexity of constraints between variables, we propose a bipartite covering array for the experimental scheme, which requires that each level combination of any radar parameter and jammer parameter occurs at least once, to ensure the rationality of the experiments. Secondly, according to the characteristics of multiple jammers and the analysis of impacts on radar performances, we combine the existing indicators and use the principal component analysis method to obtain two comprehensive indicators, which better reflect radar performances. Finally, we select the best model as a prediction for radar comprehensive indicators by comparing several machine learning algorithm models, including classification and regression tree, random forest, xgboost, and SVM. Additional experiments verify the effectiveness of the resulted model. [ABSTRACT FROM AUTHOR]

Secrecy performance of a cooperative communication network is analyzed in which source transmits information to a destination via multiple relays, assisted with multiple antennas, where an eavesdropper is able to eavesdrop the information signal from relay only. The direct link does not exist between source and destination due to deep fading and shadowing effect and transmission of a signal from source to destination is completed in two phases; first is the broadcasting phase and other is the relaying phase. Each relay follows decode and forward protocol and receives the information signal with multiple antennas. A selected relay harvests energy from received multiple signals through multiple antennas. Both information and jamming signals are transmitted by the selected antenna of a selected relay. It has been seen that a selected relay harvests energy 0.3706 joule with an array of 5 antennas when the source transmits the information signal with 5 dBW power. We have also observed that the performance increased by 99.24 % in case of an array four antennas system with respect to an array of two antennas system when secrecy threshold is 1 b i t / s / H z . Secrecy performance is measured in terms of secrecy outage probability (SOP). A closed-form expression of the SOP is derived to analyze the secrecy performance which is verified by the simulation results. [ABSTRACT FROM AUTHOR]

Currently, various machine learning (ML) techniques have been developed to solve geotechnical engineering problems. However, the lack of representative field samples limits the application of ML models. A shield jamming risk prediction method based on numerical samples and random forest (RF) classifier is proposed. The database with samples of different shield jamming risk levels is established by numerical simulation of the TBM construction process. By setting different values and combinations, seven influencing parameters, i.e., advance rate, overcut, elastic modulus, tensile strength, in situ stress, maximum thrust and friction coefficient are considered. The shield jamming risk level is determined according to the ratio of the total friction force to TBM residual thrust. Feature importance analysis indicates that elastic modulus, overcut and in-situ stress are the major influencing factors of shield jamming. Based on the labeled database, the RF model integrating multiple decision trees is established to capture the complex relationship between shield jamming risk and different influencing factors. The trained model has shown a good prediction performance on test set, and the prediction results of six field instances in DXL tunnel are in good agreement with the actual shield jamming situation. Compared with other conventional classifiers, i.e., support vector machine (SVM), k-nearest neighbors (KNN), decision tree (DT) and logistic regression (LR), the proposed FR classifier has stronger prediction accuracy and generalization ability. Additionally, the influence of sample numbers and sample imbalance is discussed. [ABSTRACT FROM AUTHOR]

In this paper, we consider the problem of multiple active and full-duplex (FD) attackers in physical-layer security of wireless communications. The attackers can eavesdrop the legitimate signal from a transmitter to a receiver and jam it at the same time with a high power. The channel realizations, pilot signals, and jamming signals of the attackers are not known at the legitimate nodes. This gives a difficulty because there are not enough degrees of freedom in the received signal space. However, we propose a novel scheme to opportunistically remove the jamming signals out of the received signals to reliably decode the legitimate signal. The numerical results show that there is a significant improvement in the secrecy rate (SR) compared to the conventional scheme. Especially, the higher the transmit power of the attackers, the better the performance of the proposed scheme. [ABSTRACT FROM AUTHOR]

Spectrum sharing (SS) and energy harvesting (EH) basically improve spectrum-and-energy efficiencies required by modern communications systems. Nonetheless, most publications have focused on the linear (L) EH model which did not characterize practically non-linearities of EH circuits. Moreover, SS induces secondary receivers to suffer primary interference (PI) and facilitates eavesdroppers to overhear legitimate data. To secure communications in energy harvesting spectrum sharing networks (EHSSNs), this paper proposes a full-duplex (FD) secondary destination which not only receives legitimate signal but also jams signal reception of the eavesdropper. Joint effects of non-linear (NL) EH, PI, and FD destination-assisted jamming on security-and-reliability performances of EHSSNs are first analyzed in terms of outage and intercept probabilities that are then endorsed by Monte-Carlo simulations. Next, the proposed analysis is exploited to achieve the asymptotic analysis and the security-and-reliability analysis for two baseline EHSSNs (half-duplex (HD) destination and L EH). Finally, numerous results demonstrate joint effects of NL EH, PI, and FD destination on data security and communication reliability by comparing three EHSSNs: (i) L EH and FD destination; (ii) NL EH and FD destination; (iii) NL EH and HD destination. Notably, the proposed communications scheme with the FD destination is more secure than the baseline scheme with the HD destination. In addition, the reliability of the communications scheme with the NL EH is inferior to that with the L EH but the data security of the former is better than the latter. Additionally, the security-reliability trade-off exists for all the considered communications schemes. Moreover, the PI enhances the security but degrades the reliability. Furthermore, the time fraction for EH can be optimized to attain the best security-reliability trade-off. [ABSTRACT FROM AUTHOR]

We analyze the coherence degree of the radar signals reflected from the passive-interference sources with different spectral characteristics determined by different wind velocities. The entropy of the distribution of eigenvalues of the interference correlation matrix is used as a quantitative measure of the coherence degree of interference. It is shown that the entropy value can be used for estimating the maximum coefficient of the passive-interference suppression. The dependences of the coefficient of the passive-interference suppression on the rms width of the interference spectrum for various values of the process sampling length and the wavelength are given. The coherence of an additive mixture of the signals, which are reflected from the interference and the target, is estimated. It is shown that the coherence measure of radar signals in the form of the entropy of the distribution of the signal over eigensubspaces of its correlation matrix allows one to estimate the maximum subinterference visibility. [ABSTRACT FROM AUTHOR]

Communication in the wireless sensor networks could be disturbed by the jammer and this jamming attacks could be identified as a distinctive type of Denial of Service attacks. This might result in the degradation of the network which could be recognized. Due to the jamming signals, the packet transmission might not be proper. These kinds of attacks are destructive in low power and lossy wireless network due to the attributes such as disruption in communication and rapid trench in the batteries. To detect the attack and to perform the secure data transmission, the illegitimate nodes have to be eradicated. Machine learning and deep learning methods are used for network analysis of intrusion detection and security. Hence, the deep learning model is proposed to identify the attacks which result in secured data transmission. Also, the logistic regression is applied to classify the behaviour of the node so that the deviation could be determined. Deep learning is applied so it can adaptively learn the attacks and classify with higher accuracy. It is efficient as it is adaptive in learning and has improved precision. The performance of the model could be proved with simulations by varying the nodes. The secured data transmission could be proved by analysing several metrics such as packet drop rate, normalized routing overhead, and jitter. The packet drop is decreased to 50%, jitter is decreased to 6% and throughput shows a significant increase by 6% when compared with the Dodge-Jam, a lightweight Mitigating Stealthy Jamming Attacks (MJSA) technique. [ABSTRACT FROM AUTHOR]

Automatic Link Establishment (ALE) is crucial to channel assignment and data exchange in HF radio networks. The link establishment interval and quality are two main concerns in this context. In jamming environments, the jammer signals seriously influence the channel quality. The Frequency Hopping (FH) approach supports communication links to overcome the jamming impairments, so using the FH technique in the traditional ALE algorithm can make it more stable. This paper develops the ALE algorithms to handle different jamming scenarios and establish robust connections to exchange data using the proposed Frequency Hopping Based Automatic Link Establishment (FH-ALE) system. Besides, in the proposed algorithm, we consider the link establishment interval almost identical to the traditional ALE scenario. To evaluate the performance of the proposed system, we simulate the FH-ALE system and the Traditional ALE system in MATLAB software. Also, we calculate the link Establishment Probability and the throughput value for both systems in different channel conditions, including the AWGN channel without a jammer and in presence of Partial-band, Follower, and Multi-tone jammers. Hence, the throughput value is approximately identical in the proposed and traditional cases in the normal channel condition. The simulation results represent the superiority of the proposed FH-ALE approach in jamming environments. Thus, depending on the jammer type and the desired conditions for link establishment, including the channel noise status, the proposed system has about 1 to 5dB performance improvement in comparison to the traditional ALE systems. [ABSTRACT FROM AUTHOR]

IoT network-connected devices are increasing day by day. It is impossible to allocate a spectrum for all IoT devices. This spectrum scarcity can be solved by cognitive radio-based dynamic spectrum sharing, which is referred to as Cognitive Radio Internet of Things (CRIoT). The jamming physical layer attack in CRIoT resulting in a denial of cognitive radio services and make spectrum underutilization. Continuous jamming can be detected quickly based on time delay on spectrum access, but discrete random jamming detection is challenging. This article proposes an autoencoder-based jamming attack detection in cognitive radio. The jamming detection problem is modeled as anomaly detection. The autoencoder is used to detect the anomaly signal component and the jammer. The simulation of random jamming attack detecting with time instant of attack is carried out to mitigate it. The proposed mechanism able to detect the jammer with 89% of accuracy. [ABSTRACT FROM AUTHOR]

To prevent detection of communication between legitimate users by warden and guarantee a strong security in wireless networks, covert communication technique is recommended. The covert communication is based on hiding the main message in the background of noise which poses challenges such as low transmission rate. On the other hand, the transmit power in the conventional networks is supplied by separate built-in batteries, which are sometimes hard to be recharged or replaced especially in the military applications. In this work, to tackle the low transmission rate, we employ three dimensions beamforming in which we can focus the main beam on the legitimate user and minimize the leakage information at the warden. Moreover, in the proposed network, we intend to employ cooperative jamming (CJ) to increase covert rat in which the jammer is equipped to multiple antennas. Furthermore, to tackle the recharging or replacing batteries in the proposed network, we employ the energy harvesting (EH) technique. The simulation results reveal that the energy harvesting from the jammer's signal reduce the total power consumption. Moreover, the simulation results show that the optimality gap is about 50% according to energy harvesting technique, and the 3D beamforming increases covert rate about 70% compared to two-dimensional beamforming method. [ABSTRACT FROM AUTHOR]

Adaptive beamforming (ABF) is considered the best suitable technique for beamforming in Radars as most systems are digital in recent times. Adaptive beamforming is an emerging research area, especially for Electronic Warfare (EW) applications such as jamming and Radar clutter suppression. Maintaining the necessary main lobe in the desired direction with reduced sidelobe levels is an essential feature of the Radar radiation pattern. To suppress the peak sidelobes, many algorithms and optimization techniques have been developed. These algorithms/techniques come with a cost of high computational complexity, which results in increased response time and additional hardware requirements. This criterion makes them non-suitable in real-time EW scenarios. The focus of the research work is to implement a novel weighted method for reducing sidelobe levels without deviating from the adaptive beamforming capabilities. The proposed weighted hybrid window method shows an excellent improvement in sidelobe suppression by 75% compared to the conventional ABF with a reduced convergence rate. The proposed method is compared to the conventional beamformers and other sidelobe reduction techniques. Further investigation is conducted, by varying the inter-element spacing in the antenna array. It was observed that there are no deviations in the main beam, placement of nulls, and also additional grating lobes. This feature provides additional flexibility to the designers, especially in Radar applications. This work proceeds to propose a novel weighted method for use in complex real-world scenarios. [ABSTRACT FROM AUTHOR]

We propose a system model for energy harvesting-based underlay relaying networks with transmit antenna selection and jamming where a multi-antenna unlicensed relay performs multiple tasks [received signal combining, transmit antenna selection (TAS), energy harvesting] to save energy consumption, ensure continuous connection of an unlicensed source to an unlicensed destination, and secure transmission against a wire-tapper. Moreover, to guarantee security for source-to-relay transmission, we propose embedding jamming signal into secret information at the source to reduce the wire-tapper's capability of decoding source message. To swiftly illustrate security-and-reliability trade-off of the proposed system model as well as compare with its counterparts so as to highlight our contributions, we propose closed forms of intercept and outage probabilities at the wire-tapper and the destination, correspondingly, under licensed interference and restraints of peak transmit/interference powers. We found from various results that (1) the proposed TAS scheme achieved the best reliability-and-security trade-off in comparison with previous schemes; (2) reliability saturation occurs at high peak transmit/interference power; (3) licensed interference and time for energy harvesting drastically enhance security yet mitigate reliability; (4) distributing power properly to secret and jamming signals at the source brings better security; (5) increasing the number of antennas at the relay dramatically improves both security and reliability for the proposed TAS scheme. [ABSTRACT FROM AUTHOR]

In the environment of electronic warfare, the countermeasure between radar and jammer has become a hot issue. Finding the solution to optimal waveforms between them is very great significance. Aiming at the problem of multi-target detection in clutter environment, the authors propose the waveform optimization method based on signal-to-interference-plus-noise ratio (SINR) criterion for radar and jammer, respectively. When radar is the dominant player, the maxmin strategy is used to establish the optimization model to optimize the radar transmission waveform. When jammer is the dominant player, the minmax strategy is used to establish the optimization model to optimize the jammer waveform. When dealing with random multi-target, the authors also propose an adaptive weight method to solve the problem of summation of weighted multiple targets. Then, an improved method combined with Jensen's inequality for radar and jammer is proposed, respectively, which could improve the detection performance of the radar system and reduce the computational complexity of maximum SINR-based method. The simulation results show that the proposed maximum SINR-based methods could adaptively allocate the transmission energy to improve the performance of the radar. The energy allocation of radar and jammer is slightly different under maxmin strategy and minmax strategy. The proposed improved methods could output the higher SINR than the maximum SINR-based methods. Both of the proposed methods could improve the performance of radar detecting targets. [ABSTRACT FROM AUTHOR]

New wireless IoT technology provides smart pseudo intelligent solutions that will have a big impact on the infrastructures and the society in the future to come. In the last decade, many new low power longrange wireless technologies have emerged to support these wireless IoT based solutions. One of the most promising and commonly accepted technologies is LoRaWAN. Unfortunately, the introduction and deployment of a new wireless technology provides new risks and new security challenges. Some of these challenges can be categorized as "critical", which means that if they fail, this will have major consequences for the society's critical infrastructure and the society as a hole. In this paper one of these critical challenges is analyzed in terms of wireless jamming attacks that cause fatale denial-of-services on the LoRaWAN wireless infrastructure and connectivity. This analysis is based on a mathematical simulation model which is described and elaborated. By using this model on a selected societal critical service example, a sensitivity analysis in terms of jamming and DoS attacks is performed, provided, and elaborated. Finally, some selected prevention strategies to avoid and counter-fight these attacks are presented, discussed, and elaborated. [ABSTRACT FROM AUTHOR]

The Indian Regional Navigation Satellite System provides accurate positioning service to the users within and around India, extending up to 1500 km. However, when a receiver encounters a Continuous Wave Interference, its positioning accuracy degrades, or sometimes it even fails to work. Wavelet Packet Transform (WPT) is the most widely used technique for anti-jamming in Global Navigation Satellite System receivers. But the conventional method suffers from threshold drifting and employs inflexible thresholding functions. So, to address these issues, an efficient approach using Improved Particle Swarm Optimization based Parametric Wavelet Packet Thresholding (IPSO-PWPT) is proposed. Firstly, a new parameter adaptive thresholding function is constructed. Then, a new form of inertia weight is presented to enhance the performance of PSO. Later, IPSO is used to optimize the key parameters of WPT. Finally, the implementation of the IPSO-PWPT anti-jamming algorithm is discussed. The performance of the proposed technique is evaluated for various performance metrics in four jamming environments. The evaluation results manifest the proposed method's efficacy compared to the conventional WPT in terms of anti-jamming capability. Also, the results show the ability of the new thresholding function to process various signals effectively. Furthermore, the findings reveal that the improved PSO outperforms the variants of PSO. [ABSTRACT FROM AUTHOR]

This document is a retraction note for an article titled "Periodic multimedia spectrum sensing method based on high-order anti-jamming mechanism in cognitive wireless networks." The article has been retracted by the publisher due to concerns about compromised editorial handling and peer review process, inappropriate references, and being out of scope for the journal or guest-edited issue. The authors of the article, Yanli Ji, Weidong Wang, and Yinghai Zhang, have not responded to correspondence regarding the retraction. Springer Nature, the publisher, remains neutral regarding jurisdictional claims and institutional affiliations. [Extracted from the article]

This paper presents a new optimization algorithm that efficiently can optimize the beamforming of the linear and planar antenna arrays. The new algorithm is called the corrosion diffusion optimization algorithm (CDOA) because its concept is concluded from the behavior of the corrosion distribution on the metal surfaces. The general performance of the new algorithm is compared with some other important algorithms via some standard benchmark functions. This comparison results in about 100% success rate for the proposed algorithm with high execution speed and low complexity compared to the other algorithms. Subsequently, CDOA is applied to solve some of the antenna array beamforming problems by optimizing the amplitude of the antenna weights vector and/or the inter-element spacing between the elements of the array. The algorithm results in a side lobe ratio larger than 22 dB in solving the problem of enhancing the side lobe ratio. Besides, CDOA operates efficiently in generating a flat top and triangular beam shaping with enhanced side lobe ratio. Furthermore, all the jamming signals are perfectly eliminated in the anti-jamming antenna array system when optimizing the weights vector of the array using the proposed algorithm. For each beamforming problem, the outcomes of CDOA are compared with other optimization algorithms to highlight its superiority in solving these kinds of problems. [ABSTRACT FROM AUTHOR]

This paper presents an empirical analysis of the mutual interference between the IEEE 802.11ad communication link and the Texas Instruments (TI) millimeter wave (mmWave) radar in 60 GHz bands. We study the impact of IEEE 802.11ad communication link on the mmWave radar coverage and precision, and we model the impact of mmWave radar interference on the IEEE 802.11ad wireless communication packet loss rate. The paper investigates interference based on the angle between the interfering multiple input multiple output (MIMO) beamforming antennas of the two devices. We benefit from the Cramer-Rao Lower Bound for the analysis of precision degradations of the mmWave radar due to interference from the IEEE 802.11ad, and we benefit from empirical path-loss models to analyze the impact of the interference on coverage of the radar. We measure the empirical packet loss rate of the IEEE 802.11ad due to the interference from the mmWave radar in a laboratory testbed. [ABSTRACT FROM AUTHOR]

Friendly spectrum jamming is a flexible scheme to establish secure communications among heterogeneous wireless devices without the need of encryption. Previous works have indicated that this scheme however has weak security strength against multiple antenna eavesdropper in today's wireless communication systems, which limits its wide applicability. To tackle this challenge, we propose a novel modulation method, called energy modulation. The basic idea of our method is to keep the secrecy of the channel state information in modulation, so as to bring high uncertainty to the MIMO's separation and the eavesdropper's decoding. As a result, the security strength of friendly jamming notably increases facing multiple antenna eavesdropper. To demonstrate the effectiveness of our method, we perform independent component analysis to decouple the components of the measured signals with maximum likelihood separation. We find that our solution dramatically decreases the eavesdropper's partial information and has much less bits being compromised comparing with common amplitude and phase modulation. [ABSTRACT FROM AUTHOR]

This is the fourth paper in a series of articles devoted to modern methods of protection of coherent-pulse radars against the combined interference (i.e., an additive mixture of internal noise, masking noise jamming and clutter). It proposes the structures of an adaptive system of cooperative space-time signal processing (STSP) against the background of masking combined interference based on a two-dimensional adaptive lattice filter with matrix elementary lattice filters. These structures eliminate significant energy losses of adaptive systems of separate STSP caused by the non-classified nature of training samples of noise jamming and clutter in estimating the weight vectors of spatial and inter-period signal processing and the need to store the spatial weight vector during the time of inter-period compensation of clutter. The results of mathematical simulation of the developed parallel-sequential adaptive system of cooperative STSP with reduced number of complex multiplication operations as compared with direct inversion of interference correlation matrix are presented that confirm its high efficiency. [ABSTRACT FROM AUTHOR]

We analyze the coherence degree of active noise interference in radar systems. The entropy of the distribution of eigenvalues of the interference correlation matrix is used as a quantitative measure of the coherence degree of interference. The main factors influencing the coherence of active noise interference are analyzed, namely, the interference spectrum width and the interferenceenvironment nonstationarity due to variation in the angular relations between the antenna-array beam and the interference source in the process of the radar observation. It is shown that the analysis of coherence of an active noise interference allows one to quantitatively estimate the notions of wideband and narrowband interference. [ABSTRACT FROM AUTHOR]

To enhance the consistency verification ability of data transmission in Petri net, a consistency verification method based on fuzzy c-means and spectral feature extraction was proposed. The invention adopts a fuzzy neural network clustering Petri net data transmission channel model design, test method of Petri nets jamming signal to extract the training data set of attributes in reduction and extraction to influence the decision attribute set classification of condition attribute values, form a Petri net jamming signal extraction and selection model, and to filter the interference of symbol sequence. The matching filter and fuzzy information clustering detection method are combined to realize the Petri net data transmission channel equalization. The false alarm rate of the proposed method is 30%, and the reconstruction accuracy is above 80%. The proposed method has strong channel balance and adaptability, which can improve the accuracy comparison of redundant data reorganization and enhance the data output quality of Petri net. [ABSTRACT FROM AUTHOR]

Conventional phased array radar can direct the high-gain beam, resulting in high visibility under the reconnaissance system and even direct exposure to the enemy. As an amplitude-based direction-finding system, the amplitude monopulse system can recognize the traditional radar signals. However, there are still some issues with the countermeasures of the monopulse system, so it is necessary to find better styles of jamming. Since the beam of the frequency diverse array (FDA) signal at a certain angle varies with the range, we studied the deception effect of the FDA against the amplitude-comparison monopulse direction-finding system. By analyzing the established FDA-based direction-of-arrival location deception model against the amplitude-comparison monopulse system, we found that the introduction of the frequency increment might cause the FDA signals to deceit the monopulse system in principle. Then, to indicate the superiority of our deception method, we obtain the instantaneous signal-to-noise ratio, Cramér–Rao lower bound, root-means-square error, and variation. Numerical simulation results demonstrate that the FDA can generate deceptive signals to counteract the amplitude-comparison monopulse direction-finding system. [ABSTRACT FROM AUTHOR]

How to utilize the limited power budget to accurately track more targets plays a critical role for the radar system in air defense applications, especially in the weapon guidance application. In this paper, we propose a robust power allocation (RPA) strategy in the collocated multiple-input and multiple-output (C-MIMO) radar system for multiple target guidance (MTG) under blanket jamming. The optimization model is established with the aim of increasing the number of effective tracking targets (ETTs) and improving the overall tracking accuracy among those targets. Since the mutual information (MI) quantifies the parameter estimation performance and can be predicted, the MI under blanket jamming is derived and utilized as the optimization criterion. We then propose a two-step optimization algorithm based on benefit–cost ratio (BCR) to solve the non-convex problem. Finally, numerical results are provided to demonstrate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Compressive sensing has attracted considerable attention in automotive radar interference mitigation. However, these algorithms usually cannot be applied directly to commercial automotive radar as most of them are computationally intense. In this paper, we therefore introduce a computationally efficient two-dimensional masked residual updates (2D MRU) compressive sensing framework. By utilizing the sparsity of the beat signal in the frequency domain, the range-Doppler (RD) spectrum can be reconstructed with the help of undistorted samples in the beat signal. Unlike the other schemes, where a 2D signal measurement is vectorized into a 1D signal, the proposed 2D MRU can directly take a 2D signal measurement and reconstruct the corresponding RD spectrum. Furthermore, the 2D MRU framework can be easily integrated into well-known optimization schemes such as basis pursuit, iterative hard thresholding, iterative soft thresholding, orthogonal matching pursuit, and approximate message-passing algorithm. In addition to the standard iterative thresholding algorithms, we propose a novel prior-model-based iterative thresholding method to further reduce the computation time and reconstruction error. Theoretical analysis shows that the proposed framework can successfully reconstruct the RD spectrum with high probability. Moreover, numerical experiments demonstrate the superiority of the proposed framework in terms of computational complexity. [ABSTRACT FROM AUTHOR]

We propose and study a method of defense against intelligent simulating signal-like active interference on the basis of an assessment of the coherent properties of radar signals. The signalcoherence measure, which is defined as the entropy of the signal-energy distribution over the eigensubspaces of the signal correlation matrix, is proposed as a selection criterion. The main factors, which influence the coherence degree of radar signals, are analyzed. The computation cost during the implementation of the proposed method for estimating the quantitative measure of the signal coherence is estimated. The results of the full-scale experimental studies, which employ various types of aircraft (with a propeller engine and turbojets) and the special equipment, i.e., a repeater of simulating signal-like interference, are presented. The estimated degree of coherence of the signals from real airborne objects and the simulating signal-like interference, which has been obtained during the experimental studies, confirms the possibility of selecting the simulating signal-like interference by the proposed method. [ABSTRACT FROM AUTHOR]

Highlights: A novel BAS-DNN model for prediction of TBM advance rate is developed. A database involving geotechnical and operating risks (RMR, TWCR, and RI) is set up. Quadratic relationships exist between RMR, TWCR, and AR. AR decreases while the descending rate gradually increases with RI increasing. The BAS-DNN model shows good performance in the tunnel section with a jamming event. [ABSTRACT FROM AUTHOR]

The article is devoted to a comparative analysis of the results of experimental studies of an adaptive MTI system (moving target indication) based on adaptive lattice filter (ALF) and standard non-adaptive MTI systems of working pulse radars of various applications and wave ranges. This analysis is performed using the seminatural experiment method based on digital recordings of real clutter. Adaptive antijamming systems promptly extract the necessary information about the parameters and characteristics of the interference directly from the input signals, track changes in these characteristics and promptly change their parameters (and, if necessary, the structure) based on the results of the corresponding processing of samples of the received interference of finite volume. It has been shown that the adaptive ALF-based MTI system provides significant gains in the effectiveness of radar protection from clutter as compared with non-adaptive standard systems of working radars and the stable tracking of air targets in the area of intense clutter, while target drop-outs are observed at the output of standard non-adaptive MTI systems. [ABSTRACT FROM AUTHOR]

With an identical number of physical sensors, a coprime array provides a greater number of degrees of freedom (DOFs) and virtually offers a larger array aperture compared with the conventional uniform linear array. A larger array aperture enables greater resolution and stronger interference suppression capabilities. Thus, a coprime array has appropriate uses in real-time applications with reduced computational complexity. On the other hand, the development of compressive sensing theory has effectively enabled solutions to an underdetermined system of linear equations. In this paper, the estimation of the direction of arrival (DOA) of signals impinging on a coprime array of sensors, incorporating the compressive sensing framework based on a single snapshot, is investigated. The received signals are compressed using the low-dimensional kernel generated using the coprime array model, consequently preserving the large array aperture of the coprime array. These compressed signals are then used to accomplish the high- resolution DOA estimation process by using a suitable reconstruction algorithm. Simulation results in terms of the mean square error (MSE) for signal reconstruction, root mean square error (RMSE) of the estimated DOA and failure rate with respect to the variation of signal-to-noise ratio (SNR) values validate the superiority of the proposed method. Also, reduced computational complexity and reconstruction time further confirms the advantages of the proposed method. The interference suppression ability is further exploited by localizing jammers and possible mitigating the effect by producing nulls in the jammer directions. [ABSTRACT FROM AUTHOR]

This study focuses on the issue of H ∞ filtering for discrete-time semi-Markov jump systems encountering denial-ofservice jamming attacks. The semi-Markov kernel, which describes the switching of the system, is determined by the sojourn-time probability density functions and the transition probability. A Bernoulli distribution white sequence is introduced to describe the phenomenon while accounting for the DoS jamming attacks and channel inherent factors on packet dropout. Considering that the DoS jammer has limited energy, it adopts a random attack strategy, and each work cycle and attack period are different. Based on the mean-square stability criterion, a sufficient condition is provided, and the filter is designed to ensure that the filtering error system is stable with the H ∞ performance index. Two examples, including a cognitive radio system, are provided to demonstrate the effectiveness of the proposed filtering method. [ABSTRACT FROM AUTHOR]

Advanced metering infrastructure (AMI) is the core component of the smart grid. As the wireless connection between smart meters in AMI is featured with high packet loss and low transmission rate, AMI is considered as a representative of the low power and lossy networks (LLNs). In such communication environment, the routing protocol in AMI network is essential to ensure the reliability and real-time of data transmission. The IPv6 routing protocol for low-power and lossy networks (RPL), proposed by IETF ROLL working group, is considered to be the best routing solution for the AMI communication environment. However, the performance of RPL can be seriously degraded due to jamming attack. In this paper, we analyze the performance degradation problem of RPL protocol under jamming attack. We propose a backup node selection mechanism based on the standard RPL protocol. The proposed mechanism chooses a predefined number of backup nodes that maximize the probability of successful transmission. We evaluation the proposed mechanism through MATLAB simulations, results show the proposed mechanism improves the performance of RPL under jamming attack prominently. [ABSTRACT FROM AUTHOR]

Aiming at problems of low probability of interception and poor anti-jamming performance of the multi-output radar, the numerical simulation based on a chaos optimization algorithm is proposed. Firstly, chaotic frequency coding is applied to the multi-output radar signal, and different frequency modulation methods are applied to different subpulses. At the same time, in view of the low efficiency of the numerical simulation algorithm in large space and high dimensional optimization, the GASA algorithm is used to increase the diversity of chaotic optimization algorithm search process. According to the specific working mode, the initial phase of each cycle of the multi-output radar orthogonal waveform is obtained, and the number of numerical simulations of multi-output radar orthogonal waveforms is established by the Model. Experimental results show that the proposed method can improve the radar energy utilization and signal-to-noise ratio, allocate reasonably the transmitting energy, and keep the structural stability of the LFM signal frequency changing continuously with time. [ABSTRACT FROM AUTHOR]

With the increasingly fierce competition for electromagnetic spectrum resources and the rapid development in artificial intelligence, frequency-hopping (FH) communication systems are facing serious intelligent jamming attacks. Under this background, game theory has become an effective tool to solve the optimal decision-making problem in communication countermeasures. In this paper, focusing on defending against sweep jamming attacks and considering the inevitable transmission delay of an actual communication system, we propose a multi-step prediction Markov decision process (MPMDP) and set up a multi-step prediction Bellman iterative equation (MPBIE). To solve the MPBIE, multi-step state transition probabilities are derived, and a simplified algorithm is designed. Combing the complete strategy we proposed, the MPMDP strategy to maximize the utility of the FH communication system is obtained. With the assumption that the jammer can learn the MPMDP strategy of the FH communication system, we furtherly study its optional sweep jamming attack strategy. The MPMDP strategy and the optional intelligent sweep jamming attack strategy as a Nash equilibrium of the communication system and the jammer are proved. Lastly, simulation results show that the property and theorems proposed in this paper are valid, and our MPMDP strategy outperforms similar algorithms in terms of the applicable range and performance. [ABSTRACT FROM AUTHOR]

This study proposes a novel approach to suppress noise jamming and smart jamming. The traditional method of using auxiliary channels to cancel interference requires pure interference samples to calculate weights, which is almost impossible for pulsed interference signals. In this work, to avoid the difficulty of choosing suitable interference samples, we construct the parameterized expected signal according to the time-delay relation between target reflecting echo and transmitted signal. The objective function is established in the form of the minimum mean square error between the recovered signal and the expected signal. The optimization problem is solved by an alternating iteration method. Simulation results demonstrate that the proposed method achieves excellent performance for suppressing noise jamming and smart jamming and is not sensitive to signal-to-noise ratio and jamming-to-noise ratio. The processing results of the measured data show that the method has a certain practical application value. [ABSTRACT FROM AUTHOR]

Internet of Things (IoT) makes possible diverse smart applications through incorporating information from various sensors and enabling interoperability among different control systems. Adopting IoT in smart building paradigm enables efficient design, control, and management of converged infrastructures. As one of the dominated wireless communication standards adopted in smart buildings-oriented IoT architecture, IEEE 802.11-series standards are expected to play an important role in the nascent IoT. Furthermore, heterogeneous sensors, devices, and controllers deployed for different smart 'silos' could connect and collaborate with each other via the converged wireless networks. To simultaneously support a large number of devices, it is critical to know the transmission capacity of the network in the design stage, especially when malicious jamming attacks exist. In this backdrop, stochastic geometry theory is adopted in this paper to investigate the throughput of IEEE 802.11 enabled IoT, where a ring model is put forward to capture the distribution of legitimate nodes and jammers. Afterwards, the collision probability of wireless transmission is derived from the perspective of both physical layer and MAC layer. Then, the throughput of each IoT node is calculated. To validate our models, numerical tests as well as simulation results derived on NS3 are provided with various parameter settings. Simulation results show that our models could accurately characterize the performance of IEEE 802.11-enabled wireless networks under jamming attacks. [ABSTRACT FROM AUTHOR]

This paper mainly investigates the multi-user coordinated anti-jamming problem in clustering communication networks. In such kinds of networks, there exist multiple clusters and multiple users who communicate with their receivers simultaneously. Besides, a malicious jammer persistently attacks channels with wide-band and dynamic changing jamming signals. To cope with these challenges brought by the large-scale clustering network and the dynamic wide-band jamming, a hierarchical coordinated anti-jamming approach is proposed, and a multi-leader multi-follower Stackelberg game is introduced to model the anti-jamming problem. In detail, cluster heads act as leaders, and select available frequency bands to avoid jamming attacks, while users in each cluster act as followers and select corresponding channels distributedly and independently. Moreover, it is proved that there exist multiple Stackelberg equilibriums (SEs) in the proposed game. To obtain SEs, a hierarchical coordinated anti-jamming channel access (HCACA) algorithm is designed. Simulation results illustrate that the proposed approach is effective to cope with the dynamic wide-band jamming attacks. Furthermore, it is also depicted that the proposed approach outperforms the distributed anti-jamming comparative approach in terms of convergence speed. [ABSTRACT FROM AUTHOR]