Malicious User Attack in Cognitive Radio Networks

Signal detection in cognitive radio network (CRN) is influenced by several factors. One of them is malicious user that emulate primary user (PU) signal. Emulation of PU signal causes detection error. This paper investigates the impact of malicious user attack to PU signal detection. A number of malicious users are randomly deployed around secondary user (SU) at a certain distance. They attempt to attack primary signal detection that is transmitted from 100 km to SU receiver. Then, the received signal power at secondary receiver and the performance of probability of false alarm and probability of miss detection under two hypothesis of Neyman Pearson criterion are studied. The derived results show that a number of malicious users has a significant impact to the performance of received power at SU and detection error rate

AN INVESTIGATION OF SECURITY CHALLENGES IN COGNITIVE RADIO NETWORKS

The recent advances in wireless communication have led to the problem of growing spectrum scarcity. The available wireless spectrum has become scarcer due to increasing spectrum demand for new wireless applications. The large portion of the allocated spectrum is sporadically used leading to underutilization of significant amount of spectrum. To improve the spectrum efficiency, the idea of cognitive radio technology was introduced. This concept of cognitive radio provides a promising solution for the spectrum scarcity issues in wireless networks. Meanwhile, the security issues of cognitive radio have received more attentions recently since the inherent properties of CR networks would pose new challenges to wireless communications. In this MS thesis, general concepts of security threats to the cognitive radio networks are briefly reviewed. Performances for primary user emulation attacks are studied from Neyman-Pearson criterion point of view. A novel system model with different configurations of the primary users has been proposed and studied. Our experimental results demonstrate the statistical characteristics of the probability of false alarm and miss detection in the proposed system. I will make performance comparison with others’ research in the future. Adviser: Yaoqing Yan

AN INVESTIGATION OF SECURITY CHALLENGES IN COGNITIVE RADIO NETWORKS

The recent advances in wireless communication have led to the problem of growing spectrum scarcity. The available wireless spectrum has become scarcer due to increasing spectrum demand for new wireless applications. The large portion of the allocated spectrum is sporadically used leading to underutilization of significant amount of spectrum. To improve the spectrum efficiency, the idea of cognitive radio technology was introduced. This concept of cognitive radio provides a promising solution for the spectrum scarcity issues in wireless networks. Meanwhile, the security issues of cognitive radio have received more attentions recently since the inherent properties of CR networks would pose new challenges to wireless communications. In this MS thesis, general concepts of security threats to the cognitive radio networks are briefly reviewed. Performances for primary user emulation attacks are studied from Neyman-Pearson criterion point of view. A novel system model with different configurations of the primary users has been proposed and studied. Our experimental results demonstrate the statistical characteristics of the probability of false alarm and miss detection in the proposed system. I will make performance comparison with others’ research in the future. Adviser: Yaoqing Yan

Physical Layer Defenses Against Primary User Emulation Attacks

Cognitive Radio (CR) is a promising technology that works by detecting unused parts of the spectrum and automatically reconfiguring the communication system\u27s parameters in order to operate in the available communication channels while minimizing interference. CR enables efficient use of the Radio Frequency (RF) spectrum by generating waveforms that can coexist with existing users in licensed spectrum bands. Spectrum sensing is one of the most important components of CR systems because it provides awareness of its operating environment, as well as detecting the presence of primary (licensed) users of the spectrum

Primary user emulation attack mitigation in cognitive radio networks.

M. Sc. Eng. University of KwaZulu-Natal, Durban 2014.The rapid progress in the number of users and applications in wireless communication have led to the problem of growing spectrum scarcity in recent years. This imminent spectrum scarcity problem is in part due to a rapidly increasing demand for wireless services and in part due to the inefficient usage of currently licensed spectrum bands. Cognitive radio (CR) is a new technology that is proposed to improve spectrum efficiency by allowing unlicensed secondary users to access the licensed frequency bands without interfering with the licensed primary users. A malicious secondary user can decide to exploit this spectrum access etiquette by mimicking the spectral characteristics of a primary user, and gain priority access to a wireless channel over other secondary users. This scenario is referred to in literature as Primary User Emulation Attack (PUEA). Though quite a lot of research efforts have been focused on the detection and defense strategy of PUEA in cognitive radio networks, less attention have been given to combating and mitigating PUEA in a cooperative spectrum sensing environment. This dissertation seeks to contribute to research in the field of cognitive radio networks through an investigation into the impacts of Primary User Emulation Attacks (PUEA) on cognitive radio networks, the problem of trust amongst users in the networks and also mitigating the activities of PUEA in the network. An analytical and system model for PUEA in cognitive radio networks is presented and its impacts are also studied using Neyman-Pearson Composite Hypothesis Test. The intention is to evict malicious users from the network and maximize spectrum utilization efficiency. To achieve this, techniques to verify that the source of spectrum occupancy information is from a genuine user are proposed. In a primary user emulation attack, malicious users tend to destruct the spectrum sensing process of a cognitive radio network by imitating the primary signal and deceive other secondary users from accessing vacant frequency bands. An energy detection cooperative spectrum sensing technique is proposed to mitigate this attack. This technique assists in the reduction of errors made by secondary users in detecting primary user signals in frequency bands considering the existence of PUEA in the network. The performance of our proposed method is compared to an existing energy detection spectrum sensing method that does not consider the existence of PUEA in the network. Simulated results show that the proposed method can effectively mitigate PUEA in a cognitive radio network

Contributions to the security of cognitive radio networks

The increasing emergence of wireless applications along with the static spectrum allocation followed by regulatory bodies has led to a high inefficiency in spectrum usage, and the lack of spectrum for new services. In this context, Cognitive Radio (CR) technology has been proposed as a possible solution to reuse the spectrum being underutilized by licensed services. CRs are intelligent devices capable of sensing the medium and identifying those portions of the spectrum being unused. Based on their current perception of the environment and on that learned from past experiences, they can optimally tune themselves with regard to parameters such as frequency, coding and modulation, among others. Due to such properties, Cognitive Radio Networks (CRNs) can act as secondary users of the spectrum left unused by their legal owners or primary users, under the requirement of not interfering primary communications. The successful deployment of these networks relies on the proper design of mechanisms in order to efficiently detect spectrum holes, adapt to changing environment conditions and manage the available spectrum. Furthermore, the need for addressing security issues is evidenced by two facts. First, as for any other type of wireless network, the air is used as communications medium and can easily be accessed by attackers. On the other hand, the particular attributes of CRNs offer new opportunities to malicious users, ranging from providing wrong information on the radio environment to disrupting the cognitive mechanisms, which could severely undermine the operation of these networks. In this Ph.D thesis we have approached the challenge of securing Cognitive Radio Networks. Because CR technology is still evolving, to achieve this goal involves not only providing countermeasures for existing attacks but also to identify new potential threats and evaluate their impact on CRNs performance. The main contributions of this thesis can be summarized as follows. First, a critical study on the State of the Art in this area is presented. A qualitative analysis of those threats to CRNs already identified in the literature is provided, and the efficacy of existing countermeasures is discussed. Based on this work, a set of guidelines are designed in order to design a detection system for the main threats to CRNs. Besides, a high level description of the components of this system is provided, being it the second contribution of this thesis. The third contribution is the proposal of a new cross-layer attack to the Transmission Control Protocol (TCP) in CRNs. An analytical model of the impact of this attack on the throughput of TCP connections is derived, and a set of countermeasures in order to detect and mitigate the effect of such attack are proposed. One of the main threats to CRNs is the Primary User Emulation (PUE) attack. This attack prevents CRNs from using available portions of the spectrum and can even lead to a Denial of Service (DoS). In the fourth contribution of this the method is proposed in order to deal with such attack. The method relies on a set of time measures provided by the members of the network and allows estimating the position of an emitter. This estimation is then used to determine the legitimacy of a given transmission and detect PUE attacks. Cooperative methods are prone to be disrupted by malicious nodes reporting false data. This problem is addressed, in the context of cooperative location, in the fifth and last contribution of this thesis. A method based on Least Median Squares (LMS) fitting is proposed in order to detect forged measures and make the location process robust to them. The efficiency and accuracy of the proposed methodologies are demonstrated by means of simulation