Compromise-resilient anti-jamming communication in wireless sensor networks

Jamming is a kind of Denial-of-Service attack in which an adversary purposefully emits radio frequency signals to corrupt the wireless transmissions among normal nodes. Although some research has been conducted on countering jamming attacks, few works consider jamming attacks launched by insiders, where an attacker first compromises some legitimate sensor nodes to acquire the common cryptographic information of the sensor network and then jams the network through those compromised nodes. In this paper, we address the insider jamming problem in wireless sensor networks. In our proposed solutions, the physical communication channel of a sensor network is determined by the group key shared by all the sensor nodes. When insider jamming happens, the network will generate a new group key to be shared only by the non-compromised nodes. After that, the insider jammers are revoked and will not be able to predict the future communication channels used by the non-compromised nodes. Specifically, we propose two compromise-resilient anti-jamming schemes: the split-pairing scheme which deals with a single insider jammer, and the key-tree-based scheme which copes with multiple colluding insider jammers. We implement and evaluate the proposed solutions using Mica2 Motes. Experimental results show that our solutions have low recovery latency and low communication overhead, and hence they are suitable for resource constrained sensor networks.     

Performance of IEEE 802.11 under Jamming

We study the performance of the IEEE 802.11 MAC protocol under a range of jammers that covers both channel-oblivious and channel-aware jamming. We consider two channel-oblivious jammers: a periodic jammer that jams deterministically at a specified rate, and a memoryless jammer whose interfering signals arrive according to a Poisson process. We also develop new models for channel-aware jamming, including a reactive jammer that only jams non-colliding transmissions and an omniscient jammer that optimally adjusts its strategy according to current states of the participating nodes. Our study comprises of a theoretical analysis of the saturation throughput of 802.11 under jamming, an extensive simulation study, and a testbed to conduct real world experimentation of jamming IEEE 802.11 using a software defined radio (GNU Radio combined with USRP boards). In our theoretical analysis, we use a discrete-time Markov chain analysis to derive formula for the saturation throughput of 802.11 under memoryless, reactive and omniscient jamming. One of our key results is a characterization of optimal omniscient jamming that establishes a lower bound on the saturation throughput of 802.11 under arbitrary jammer attacks. We validate the theoretical analysis by means of Qualnet simulations. Finally, we measure the real-world performance of periodic, memoryless and reactive jammers using our GNURadio/ USRP aided experimentation testbed.     

Multi-hop wireless network oriented multiple jammers localization algorithm

A multiple jammer localization algorithm in multi-hop wireless networks was proposed. The proposed algo-rithm contained three steps, packet delivery ratio (PDR) valley point determination based on gradient descent algorithm, received jamming signal strength (RJSS) peak point determination based on gradient ascent algorithm and cluster analysis. Firstly, the algorithm started from a few initial nodes and moved along the gradient descent direction of PDR to approach the jammers until reaches the PDR valley point. Then, the algorithm moved toward the jammers using power adaptation technique based on RJSS gradient ascent process until it reached the RJSS peak point. Finally, through applying cluster analysis on the neighbour nodes which fail to communicate with RJSS peak points, the number and positions of the jam-mers can be estimated. Experimental results have verified that the proposed algorithm can improve the accuracy of local-ization compared with existed localization algorithms. Furthermore, the performance of the proposed algorithm is promi-nent when the distance of jammers accords with constraint condition.     

Maximum number of independent paths and radio connectivity

Methods for determining the network reliability of a multihop packet radio network in the presence of hostile jammers are discussed. A new connectivity parameter called radio connectivity is defined as the maximum number of disjoint communication paths that are still usable between given nodes s and d after the jammer is on or, more generally, the minimum number of jammers needed to disconnect s and d. A lower bound on the radio connectivity is computed by studying the number of jamming independent paths. The time complexity of obtaining the radio connectivity is analyzed and shown to be NP-hard except for some special cases. Greedy heuristics for developing approximate answers for general networks are described. Euclidean networks, in which the nodes and links correspond to points and line segments in the Euclidean geometry and satisfy Euclid's four fundamental axioms, are also discussed. It is found that the maximum number of independent paths between a pair of source and destination nodes that can possibly exist is five. An extension in which there is a protected zone of known size around the sender and receiver is studied     

战术跳频系统智能抗干扰决策

作为一种有效的抗干扰方法,跳频（Frequency hopping, FH）技术已被广泛应用于战术通信系统来提高在强对抗环境下军事通信网络的可靠性。跳频通信网络面临的主要威胁是具有灵敏的频谱侦察和频率捷变能力的跟踪干扰机。为提高战术跳频通信系统在跟踪干扰攻击环境中的抗脆性和吞吐量,本文提出了一种基于双深度Q网络（Double deep Q-network, DDQN）的功率和跳速联合抗干扰决策方法。该算法将战术电台发射机与跟踪干扰机之间的对抗建模为马尔可夫决策过程（Markov decision process, MDP）,其中干扰器通过调整频谱扫描速率提高干扰效能,战术电台终端则将接收状态反馈信息作为算法输入,根据决策网络的输出调整数据传输的发射功率和跳频速率。该算法模型在未知环境状态和干扰参数的情况下,通过与环境的交互学习更新网络参数,逐渐收敛于最佳功率和跳速联合控制策略,以使跳频通信系统的平均吞吐量最大化。仿真结果表明,相比传统的无模型抗干扰方法,本文所提算法在跟踪干扰环境下能够更有效改善跳频系统的抗干扰性能。     

Topology control in the presence of jammers for wireless sensor networks

In this paper, the problem of ensuring packet delivery ratio and high network lifetime in wireless sensor networks in the presence of single or multiple jammers is studied using single‐leader‐multiple‐followers Stackelberg game theory. A topology control scheme is proposed, in which the sink node, which acts as the leader, identifies the set of jamming affected nodes. On the other hand, the sensor nodes, which act as followers, need to decide an optimum transmission power level, while ensuring an optimal set of neighbor nodes covered. A scheme, named TC‐JAM, for ensuring packet delivery ratio, while avoiding jammers and increasing network lifetime in wireless sensor networks, is proposed. In existing literatures, the sensor nodes are envisioned to be equipped with multiple interfaces, while having access for multiple channels. However, in TC‐JAM, the sensor nodes have simple hardware with single interface for communication, ie, the sensor nodes have single channel for communication. Additionally, in the proposed scheme, TC‐JAM, each sensor node has a provision to vary its transmission power according to the chosen strategies. Using TC‐JAM, the energy consumption of the overall network reduces by up to 62%, and the network lifetime increases by 56% to 73%.     

Jamming sensor networks: attack and defense strategies

Wireless sensor networks are built upon a shared medium that makes it easy for adversaries to conduct radio interference, or jamming, attacks that effectively cause a denial of service of either transmission or reception functionalities. These attacks can easily be accomplished by an adversary by either bypassing MAC-layer protocols or emitting a radio signal targeted at jamming a particular channel. In this article we survey different jamming attacks that may be employed against a sensor network. In order to cope with the problem of jamming, we discuss a two-phase strategy involving the diagnosis of the attack, followed by a suitable defense strategy. We highlight the challenges associated with detecting jamming. To cope with jamming, we propose two different but complementary approaches. One approach is to simply retreat from the interferer which may be accomplished by either spectral evasion (channel surfing) or spatial evasion (spatial retreats). The second approach aims to compete more actively with the interferer by adjusting resources, such as power levels and communication coding, to achieve communication in the presence of the jammer.     

A New Relay and Jammer Selection Schemes for Secure One-Way Cooperative Networks

This paper presents different relay and jammer selection schemes for one-way cooperative networks to increase the security against malicious eavesdroppers. We consider a single source-destination cooperative network with multiple intermediate nodes and one or more eavesdroppers. The selection in the proposed schemes is made with the presence of direct links and the assumption that the broadcast phase is unsecured. The proposed schemes select three intermediate nodes. The first selected node operates in the conventional relay mode and assists the source to deliver its data to the corresponding destination via a Decode-and-Forward strategy. The second and third selected nodes are used in different communication phases as jammers to create intentional interference at the eavesdroppers’ nodes. Moreover, a hybrid scheme which switches between jamming and non-jamming modes is introduced in this paper. The proposed schemes are analyzed in terms of ergodic secrecy capacity and secrecy outage probability. Extensive analysis and a set of simulation results are presented to demonstrate the effectiveness of the different schemes presented in this work. The obtained results show that the proposed schemes with jamming outperform the conventional non-jamming schemes and the hybrid switching scheme further improves the secrecy capacity. The impact of changing both the eavesdroppers and the relays location on ergodic secrecy capacity and secrecy outage probability is also discussed. Finally, the impact of the presence of multiple eavesdroppers is studied in this paper.     

Jamming in slotted ALOHA multihop packet radio networks

The properties of a packet radio network in the presence of active interference are discussed. Both the jammer and the network nodes are subject to an average power constraint. The network uses slotted ALOHA multiple access schemes and some simple fixed routing strategies with constant transmitter power. By using a game-theoretic approach the situation is considered as a two-person constant-sum game. The author defines network performance as the values of the game in terms of the expected forward progress of a packet. Both the performance and the optimum strategies for access and jamming are investigated     

一种多干扰机幅-频协同调制的SAR-GMTI欺骗干扰方法

针对单干扰机生成的虚假目标经三天线合成孔径雷达-地面动目标显示(Synthetic Aperture Radar-Ground Moving Target Indication,SAR-GMTI)处理后,其重定位结果不可控,始终回归于干扰机处的问题,本文提出了一种多干扰机幅-频协同调制的欺骗干扰方法.文中首先建立了以噪...     

Channel Assignment Strategies for Multiradio Wireless Mesh Networks: Issues and Solutions

Next-generation wireless mobile communications will be driven by converged networks that integrate disparate technologies and services. The wireless mesh network is envisaged to be one of the key components in the converged networks of the future, providing flexible high- bandwidth wireless backhaul over large geographical areas. While single radio mesh nodes operating on a single channel suffer from capacity constraints, equipping mesh routers with multiple radios using multiple nonoverlap- ping channels can significantly alleviate the capacity problem and increase the aggregate bandwidth available to the network. However, the assignment of channels to the radio interfaces poses significant challenges. The goal of channel assignment algorithms in multiradio mesh networks is to minimize interference while improving the aggregate network capacity and maintaining the connectivity of the network. In this article we examine the unique constraints of channel assignment in wireless mesh networks and identify the key factors governing assignment schemes, with particular reference to interference, traffic patterns, and multipath connectivity. After presenting a taxonomy of existing channel assignment algorithms for WMNs, we describe a new channel assignment scheme called MesTiC, which incorporates the mesh traffic pattern together with connectivity issues in order to minimize interference in multi- radio mesh networks.     

基于弹道仿真的激光高重频干扰技术探讨

为了确定高重频干扰激光制导武器时激光干扰机所需要的重复频率,在已研制的激光制导武器弹道仿真系统的基础上进行了软件的二次开发,建立了激光导引头信号处理的数学模型,研制出了高重频干扰下的激光制导武器弹道仿真系统。以比例导引的激光制导炸弹为研究对象,进行了激光制导武器高重频干扰作战效果的仿真研究。研究表明为了得到最佳的干扰效果,要求高重频激光干扰机的重复频率不能与制导信号的重复频率成倍数关系。研究结果还表明使用一台高重频激光干扰机时,对于不同的波门宽度其最佳干扰频率是不一样的,因此一台高重频激光干扰机不能满足实战需要。为此研究了使用二台高重频激光干扰机干扰激光制导武器的作战效果。当重频频率达到某个值后,干扰成功概率和杀伤激光干扰机的概率都可以满足战术要求。     

多部干扰机支援干扰压制区建模与效果仿真

支援干扰是掩护重要空中目标的电子防护手段,在海上编队作战中起到举足轻重的作用。支援干扰的核心问题在于怎样合理分配编队干扰资源以及如何确定干扰机与被掩护目标的最佳空间位置关系并达到最佳干扰效果。通过雷达干扰的空间能量方程,在分析单部干扰机进行支援干扰时压制区域模型的基础上,推导出多部干扰机的压制区域模型。用MATLAB语言对模型进行仿真,研究了在单部以及多部干扰机条件下的干扰效果并绘制了压制区域图形。     

LIP: an efficient lightweight iterative positioning algorithm for wireless sensor networks

Wireless sensor networks (WSNs) are increasingly being used in remote environment monitoring, security surveillance, military applications, and health monitoring systems among many other applications. Designing efficient localization techniques have been a major obstacle towards the deployment of WSN for these applications. In this paper, we present a novel lightweight iterative positioning (LIP) algorithm for next generation of wireless sensor networks, where we propose to resolve the localization problem through the following two phases: (1) initial position estimation and (2) iterative refinement. In the initial position estimation phase, instead of flooding the network with beacon messages, we propose to limit the propagation of the messages by using a random time-to-live for the majority of the beacon nodes. In the second phase of the algorithm, the nodes select random waiting periods for correcting their position estimates based on the information received from neighbouring nodes. We propose the use of Weighted Moving Average when the nodes have received multiple position corrections from a neighbouring node in order to emphasize the corrections with a high confidence. In addition, in the refinement phase, the algorithm employs low duty-cycling for the nodes that have low confidence in their position estimates, with the goal of reducing their impact on localization of neighbouring nodes and preserving their energy. Our simulation results indicate that LIP is not only scalable, but it is also capable of providing localization accuracy comparable to the Robust Positioning Algorithm, while significantly reducing the number of messages exchanged, and achieving energy savings.     

平流层飞艇对GPS接收机的干扰优势

为解决地面干扰衰减严重、干扰效果不理想的问题,提出了将干扰机置于平流层飞艇的思想。在对GPS伪距测量精度分析的基础上,推导了干扰位置与GPS接收机接收到的干扰功率之间的关系,得到了不同干扰位置下伪距测量方差的数学模型。在给定GPS伪距测量误差的前提下,仿真分析了干扰平台高度与干扰效果之间的关系,结果验证了平流层飞艇载干扰器的高度优势。     

Hierarchical game based spectrum access optimization for anti-jamming in UAV network

For the anti-jamming spectrum access optimization problem in unmanned aerial vehicle (UAV) communication networks,considering the complex and diverse malicious jamming from jammers,a Bayesian Stackelberg game was proposed to formulate the competitive relations between UAV users and jammers.Specifically,jammers acted as the leader,whereas users acted as followers of the proposed game.Based on their different utility functions,the jammer and users independently and selfishly selected their optimal strategies and obtained the optimal channels selection.Due to the NP-hard nature,it was challenging to obtain the Stackelberg Equilibrium of the proposed game.To this end,a hierarchical learning framework was formulated,and a hierarchical channel selection-learning algorithm was proposed.Simulations demonstrate that with the proposed hierarchical learning algorithm,UAV nodes can adjust their channel selection and obtain superior performance.     

基于相干两点源的虚假运动目标生成方法

针对传统的2维移频干扰生成的虚假运动目标对抗双通道合成孔径雷达地面运动目标指示(SAR-GMTI)时,存在方位位置固定、径向速度无法控制的问题,该文提出一种基于双干扰机协同的移频调制新型虚假运动目标生成方法.该方法通过2维移频调制控制虚假目标的位置,使用双干扰机协同控制虚假目标的径向速度,其中双干扰机通过幅相调制系数进...     

Tree‐based channel assignment schemes for multi‐channel wireless sensor networks

Many sensor node platforms used for establishing wireless sensor networks (WSNs) can support multiple radio channels for wireless communication. Therefore, rather than using a single radio channel for whole network, multiple channels can be utilized in a sensor network simultaneously to decrease overall network interference, which may help increase the aggregate network throughput and decrease packet collisions and delays. This method, however, requires appropriate schemes to be used for assigning channels to nodes for multi‐channel communication in the network. Because data generated by sensor nodes are usually delivered to the sink node using routing trees, a tree‐based channel assignment scheme is a natural approach for assigning channels in a WSN. We present two fast tree‐based channel assignment schemes (called bottom up channel assignment and neighbor count‐based channel assignment) for multi‐channel WSNs. We also propose a new interference metric that is used by our algorithms in making decisions. We validated and evaluated our proposed schemes via extensive simulation experiments. Our simulation results show that our algorithms can decrease interference in a network, thereby increasing performance, and that our algorithms are good alternatives for static channel assignment in WSNs. Copyright © 2015 John Wiley & Sons, Ltd.     

Evaluating the impact of network density,hidden nodes and capture effect for throughput guarantee in multi-hop wireless networks

To optimize the performance of wireless networks, one needs to consider the impact of key factors such as interference from hidden nodes, the capture effect, the network density and network conditions (saturated versus non-saturated). In this research, our goal is to quantify the impact of these factors and to propose effective mechanisms and algorithms for throughput guarantees in multi-hop wireless networks. For this purpose, we have developed a model that takes into account all these key factors, based on which an admission control algorithm and an end-to-end available bandwidth estimation algorithm are proposed. Given the necessary network information and traffic demands as inputs, these algorithms are able to provide predictive control via an iterative approach. Evaluations using analytical comparison with simulations as well as existing research show that the proposed model and algorithms are accurate and effective.     

Cross‐layer scheduling for multi‐users in cognitive multi‐radio mesh networks

A wireless mesh network has been popularly researched as a wireless backbone for Internet access. However, the deployment of wireless mesh networks in unlicensed bands of urban areas is challenging because of interference from external users such as residential access points. We have proposed Urban‐X, which is a first attempt towards multi‐radio cognitive mesh networks in industrial, scientific, and medical bands. Urban‐X first controls network topology with a distributed channel assignment to avoid interference in large timescale. In such a topology, we develop a new link‐layer transmission‐scheduling algorithm together with source rate control as a small‐timescale approach, which exploits receiver diversity when receivers of multi‐flows can have different channel conditions because of varying interference. For this purpose, mesh nodes probe the channel condition of received mesh nodes using group Request to Send and group Clear to Send. In this study, we establish a mathematical Urban‐X model in a cross‐layer architecture, adopting a well‐known network utility maximization framework. We demonstrate the feasibility of our idea using a simulation on the model. Simulation results show improved network throughput from exploiting receiver diversity and distributed channel assignment under varying external user interference. Copyright © 2012 John Wiley & Sons, Ltd.