Showing papers by "Alexandros Fragkiadakis published in 2013"

A Survey on Security Threats and Detection Techniques in Cognitive Radio Networks

Abstract: With the rapid proliferation of new technologies and services in the wireless domain, spectrum scarcity has become a major concern. The allocation of the Industrial, Medical and Scientific (ISM) band has enabled the explosion of new technologies (e.g. Wi-Fi) due to its licence-exempt characteristic. The widespread adoption of Wi-Fi technology, combined with the rapid penetration of smart phones running popular user services (e.g. social online networks) has overcrowded substantially the ISM band. On the other hand, according to a number of recent reports, several parts of the static allocated licensed bands are under-utilized. This has brought up the idea of the opportunistic use of these bands through the, so-called, cognitive radios and cognitive radio networks. Cognitive radios have enabled the opportunity to transmit in several licensed bands without causing harmful interference to licensed users. Along with the realization of cognitive radios, new security threats have been raised. Adversaries can exploit several vulnerabilities of this new technology and cause severe performance degradation. Security threats are mainly related to two fundamental characteristics of cognitive radios: cognitive capability, and reconfigurability. Threats related to the cognitive capability include attacks launched by adversaries that mimic primary transmitters, and transmission of false observations related to spectrum sensing. Reconfiguration can be exploited by attackers through the use of malicious code installed in cognitive radios. Furthermore, as cognitive radio networks are wireless in nature, they face all classic threats present in the conventional wireless networks. The scope of this work is to give an overview of the security threats and challenges that cognitive radios and cognitive radio networks face, along with the current state-of-the-art to detect the corresponding attacks. In addition, future challenges are addressed.

Spectrum Assignment in Cognitive Radio Networks: A Comprehensive Survey

Abstract: Cognitive radio (CR) has emerged as a promising technology to exploit the unused portions of spectrum in an opportunistic manner. The fixed spectrum allocation of governmental agencies results in unused portions of spectrum, which are called "spectrum holes" or "white spaces". CR technology overcomes this issue, allowing devices to sense the spectrum for unused portions and use the most suitable ones, according to some pre-defined criteria. Spectrum assignment is a key mechanism that limits the interference between CR devices and licensed users, enabling a more efficient usage of the wireless spectrum. Interference is a key factor that limits the performance in wireless networks. The scope of this work is to give an overview of the problem of spectrum assignment in cognitive radio networks, presenting the state-of-the-art proposals that have appeared in the literature, analyzing the criteria for selecting the most suitable portion of the spectrum and showing the most common approaches and techniques used to solve the spectrum assignment problem. Finally, an analysis of the techniques and approaches is presented, discussing also the open issues for future research in this area.

Joint compressed-sensing and matrix-completion for efficient data collection in WSNs

Abstract: Wireless sensor networks have gained considerable interest in the last few years, serving a large number of applications. Data collection efficiency is of paramount importance as sensors are severe resource-constrained devices, and current protocol inefficiencies lead to significant packet loss. In this work, we minimize the necessary information sensors transmit by applying the compressed sensing principles. Moreover, missing information due to packet loss is efficiently recovered using the matrix completion theory. The performance evaluation shows that when these advanced signal processing techniques are jointly used, the reconstruction error is small for high compression ratios, and fairly high packet loss. At the same time, the total energy consumption of the network substantially decreases.

Secure and Energy-Efficient Life-Logging in Wireless Pervasive Environments

Abstract: The current proliferation of ubiquitous networking (e.g. WiFi, bluetooth) along with the high penetration of the pervasive devices (smart phones, tablets) have provided a substantial boost to life-logging; a framework for the every-day recording of sensitive and personal data of individuals. Life-logging systems usually consist of resource-constrained devices (sensors). Moreover, as for every emerging technology, life-logging is susceptible to a number of security threats. In this paper, we implement and evaluate a joint encryption and compression scheme using the current advances in compressed sensing theory. The evaluation shows that the reconstruction error is kept low even for high compression ratios, and the power consumption of the life-logging system significantly reduces.

Malicious traffic analysis in wireless sensor networks using advanced signal processing techniques

Abstract: The recent advances in micro-sensor hardware technologies, along with the invention of energy-efficient protocols, have enabled a world-wide spread in wireless sensor networks deployment. These networks are used for a large number of purposes, while having small maintenance and deployment costs. However, as these are usually unattended networks, several security threats have emerged. In this work, we show how an adversary can overhear the encrypted wireless transmissions, and detect the periodic components of the wireless traffic that can further reveal the application used in the sensor network. Traffic analysis is performed in a very energy-efficient way using the compressed sensing principles. Furthermore, the periodic components are detected using the Lomb-Scargle periodogram technique.

Experience from testbeds and management platforms towards mesh networking with heterogeneous wireless access

Abstract: The MESH-WISE project is aiming to address key fundamental issues in wireless mesh networking that span from fundamental performance characterization to prototyping heterogeneous-access mesh networking solutions for emergency response scenarios. In this paper we present the infrastructures that will be leveraged in this project and the latest results that have been acquired from the ones that are deployed. We further discuss the state of the art in academic and industrial resource and network management platforms and discuss how we will use existing know-how towards a centralized solution.