Danda B. Rawat

Enhancing VANET Performance by Joint Adaptation of Transmission Power and Contention Window Size

In this paper, we present a new scheme for dynamic adaptation of transmission power and contention window (CW) size to enhance performance of information dissemination in Vehicular Ad-hoc Networks (VANETs). The proposed scheme incorporates the Enhanced Distributed Channel Access (EDCA) mechanism of 802.11e and uses a joint approach to adapt transmission power at the physical (PHY) layer and quality-of-service (QoS) parameters at the medium access control (MAC) layer. In our scheme, transmission power is adapted based on the estimated local vehicle density to change the transmission range dynamically, while the CW size is adapted according to the instantaneous collision rate to enable service differentiation. In the interest of promoting timely propagation of information, VANET advisories are prioritized according to their urgency and the EDCA mechanism is employed for their dissemination. The performance of the proposed joint adaptation scheme was evaluated using the ns-2 simulator with added EDCA support. Extensive simulations have demonstrated that our scheme features significantly better throughput and lower average end-to-end delay compared with a similar scheme with static parameters.

Advances on Security Threats and Countermeasures for Cognitive Radio Networks: A Survey

Cognitive radio (CR) is regarded as an emerging technology, which equips wireless devices with the capability to adapt their operating parameters on the fly based on the radio environment, to utilize the scarce radio frequency spectrum in an efficient and opportunistic manner. However, due to the increasingly pervasive existence of smart wireless devices in cognitive radio networks (CRNs), CR systems are vulnerable to numerous security threats that affect the overall performance. There have been many significant advances on security threats and countermeasures in CRNs in the past few years. Our main goal in this paper is to present the state-of-the-art research results and approaches proposed for CRN security to protect both unlicensed secondary users and licensed primary users. Specifically, we present the recent advances on security threats/attacks and countermeasures in CRNs focusing more on the physical layer by categorizing them in terms of their types, their existence in the CR cycle, network protocol layers (exploited during their activities and defense strategies), and game theoretic approaches. The recent important attacks and countermeasures in CRNs are also summarized in the form of tables. We also present recommendations that can be followed while implementing countermeasures to enhance CRN security. With this paper, readers can have a more thorough understanding of CRN security attacks and countermeasures, as well as research trends in this area.

Towards Secure Vehicular Clouds

The past decade has witnessed a growing interest in vehicular networking and its panoply of potential applications among vehicles. Olariu and his co-workers [1, 2, 3] have put forth the vision of a new type of cloud, Vehicular Cloud Computing (VCC). It is clear that the VCC concept raise exceptional security and privacy challenges. It is also clear that if the VCC concept is to see a wide adoption and to have a significant societal impact, security and privacy issues need to be addressed. In this paper we are interested to analyze the security challenges and potential privacy threats in VCC. We address some major design issues that will affect the future implementation of VCC and provide a set of security and privacy-protecting protocols. To the best of our knowledge, this is the first paper that deals with security problems in VCC. But we state that few VCC security issues are fundamentally new. Many of the security challenges have received attentions in related fields such as cloud computing and VANETs. On the other hand, we address relatively unique security challenges resulted by features of VCC, e.g. the challenges of authentication of high-mobility vehicles and the complexity of trust relationships among multi-players caused by intermittent short-range communication.

Dynamic Adaptation of Joint Transmission Power and Contention Window in VANET

In this paper, we propose an algorithm for joint adaptation of transmission power and contention window to improve the performance of vehicular network in a cross layer approach. The high mobility of vehicles in vehicular communica- tion results in the change in topology of the Vehicular Ad-hoc Network (VANET) dynamically, and the communication link between two vehicles might remain active only for short duration of time. In order for VANET to make a connection for long time and to mitigate adverse effects due to high and fixed transmission power, the proposed algorithm adapts transmission power dynamically based on estimated local traffic density. In addition to that, the prioritization of messages according to their urgency is performed for timely propagation of high priority messages to the destination region. In this paper, we incorporate the contention based MAC protocol 802.11e enhanced distributed channel access (EDCA) mechanism to implement a priority- based vehicle-to-vehicle (V2V) communication. Simulation results show that the proposed algorithm is successful in getting better throughput with lower average end-to-end delay than the algorithm with static/default parameters.

Software Defined Networking Architecture, Security and Energy Efficiency: A Survey

Software-defined networking (SDN) is an emerging paradigm, which breaks the vertical integration in traditional networks to provide the flexibility to program the network through (logical) centralized network control. SDN has the capability to adapt its network parameters on the fly based on its operating environment. The decoupled structure of SDN serves as a solution for managing the network with more flexibility and ease. In SDN, the centralized cost effective architecture provides network visibility which helps to achieve efficient resource utilization and high performance. Due to the increasingly pervasive existence of smart programmable devices in the network, SDN provides security, energy efficiency, and network virtualization for enhancing the overall network performance. We present various security threats that are resolved by SDN and new threats that arise as a result of SDN implementation. The recent security attacks and countermeasures in SDN are also summarized in the form of tables. We also provide a survey on the different strategies that are implemented to achieve energy efficiency and network security through SDN implementation. In an effort to anticipate the future evolution of this new paradigm, we discuss the main ongoing research efforts, challenges, and research trends in this area. With this paper, readers can have a more thorough understanding of SDN architecture, different security attacks and countermeasures, and energy efficiency.

Industrial Internet of Things

This book develops the core system science needed to enable the development of a complex industrial internet of things/manufacturing cyber-physical systems (IIoT/M-CPS). Gathering contributions from leading experts in the field with years of experience in advancing manufacturing, it fosters a research community committed to advancing research and education in IIoT/M-CPS and to translating applicable science and technology into engineering practice. Presenting the current state of IIoT and the concept of cybermanufacturing, this book is at the nexus of research advances from the engineering and computer and information science domains. Readers will acquire the core system science needed to transform to cybermanufacturing that spans the full spectrum from ideation to physical realization.

Signal processing techniques for spectrum sensing in cognitive radio systems: Challenges and perspectives

Cognitive radio (CR) is regarded as an emerging technology to utilize the scarce RF (radio frequency) spectrum in opportunistic manner to increase the spectrum efficiency. However, major challenge to successful operation and realization of CR system is the identification and detection of primary user signals in the wide band regime to identify spectrum opportunities reliably and optimally. Several signal detection techniques for spectrum sensing have been proposed in the literature in order to identify idle spectrum so that the CR user can use those idle spectrum bands opportunistically without causing harmful interference to the licensed/primary users. In this article, we provide a comprehensive study of signal detection techniques for spectrum sensing in CR system. We also outline current state of the research and future perspectives. With this article, readers can have a more thorough understanding of signal processing techniques for spectrum sensing in CR system and the research trends in this area.

Stackelberg-Game-Based Dynamic Spectrum Access in Heterogeneous Wireless Systems

In this paper, we investigate a two-stage Stackelberg game for dynamic spectrum access (DSA) in cognitive radio networks using a leader [spectrum provider (SP)] subgame and a follower [secondary user (SU)] subgame. Our research distinguishes itself in a number of ways. First, a two-stage Stackelberg game has been proposed to provide a unique optimal solution that facilitates a tradeoff between quality of service (QoS) of unlicensed SUs and revenue of SPs. Second, comprehensive budget and QoS constraints imposed by the signal-to-interference-plus-noise ratio are defined to fully take into account QoS requirements. Third, a necessary condition and closed form for the existence of the Stackelberg equilibrium are presented for multiradio multichannel DSA. Analytical and simulation studies are carried out to assess the performance of the proposed game, and the numerical results verify that the proposed approach reaches the unique Stackelberg equilibrium.

Advances on localization techniques for wireless sensor networks

Localization in wireless sensor networks (WSNs) is regarded as an emerging technology for numerous cyber-physical system applications, which equips wireless sensors with the capability to report data that is geographically meaningful for location based services and applications. However, due to the increasingly pervasive existence of smart sensors in WSN, a single localization technique that affects the overall performance is not sufficient for all applications. Thus, there have been many significant advances on localization techniques in WSNs in the past few years. The main goal in this paper is to present the state-of-the-art research results and approaches proposed for localization in WSNs. Specifically, we present the recent advances on localization techniques in WSNs by considering a wide variety of factors and categorizing them in terms of data processing (centralized vs. distributed), transmission range (range free vs. range based), mobility (static vs. mobile), operating environments (indoor vs. outdoor), node density (sparse vs. dense), routing, algorithms, etc. The recent localization techniques in WSNs are also summarized in the form of tables. With this paper, readers can have a more thorough understanding of localization in sensor networks, as well as research trends and future research directions in this area.

Securing Vehicular Ad-hoc Networks Against Malicious Drivers: A Probabilistic Approach

Future development of Intelligent Transportation Systems (ITS) depends on Vehicular Ad-hoc Networks (VANETs) in which communications will help to improve traffic safety and efficiency through exchanging information among vehicles. As each vehicle cannot be a source of all messages in VANET, most communications depend on the information received from other vehicles. To protect VANET from malicious action, each vehicle must be able to evaluate, decide and react locally on information received from other vehicles. Message verification is more challenging in VANETs since the security and privacy of the participating vehicles, in general, and of the drivers and passengers specifically is of major concern. Each vehicle needs to verify the accuracy of the message and needs to verify that the received message is from a legitimate vehicle. In this paper, we propose a new algorithm to secure vehicular communication with the help of trust measured for the given period using a probabilistic approach. The proposed algorithm secures VANETs against the untrustworthy drivers. The proposed algorithm is illustrated through numerical results obtained from simulations.