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Mostafa, Ahmad APacket Delivery Delay and Throughput Optimization for Vehicular Networks
PhD, University of Cincinnati, 2013, Engineering and Applied Science: Computer Science and Engineering
Vehicular networking is a new emerging wireless technology that supports the communication amongst vehicles and enables vehicles to connect with the Internet. This networking technology provides vehicles with endless possibility of applications, including safety, convenience, and entertainment applications. Examples for these applications are safety messaging, real-time traffic, route updates, and general purpose Internet access. The goal of vehicular networks is to provide an efficient, safe, and convenient environment for the vehicles. In vehicular networking technology, vehicles connect either through other vehicles in an ad-hoc multi-hop fashion or through road side units (infrastructure) which connects them to the Internet. Each approach has its own advantages and disadvantages. However, one of the main objectives of vehicular networking is to achieve a minimal delay for message delivery, and encourage a continuous connectivity for vehicles. This dissertation introduces a novel hybrid communication paradigm for achieving seamless connectivity in Vehicular Ad-hoc NETworks (VANET), wherein the connectivity is often affected by changes in the dynamic topology, vehicles' speed, as well as traffic density. Our proposed technique ---named QoS-oriented Hybrid Vehicular Communications Protocol (QoSHVCP)--- exploits both existing network infrastructure through a Vehicle-to-Infrastructure (V2I) protocol, as well as a traditional Vehicle-to-Vehicle (V2V), that satisfies Quality-of-Service requirements. We analyze time delay as a performance metric, and determine delay propagation rates when vehicles are transmitting high priority messages via QoSHVCP. Focusing on V2V communication, we propose a novel reliable and low-collision packet-forwarding scheme, based on a probabilistic rebroadcasting. Our proposed scheme, called Collision-Aware REliable FORwarding (CAREFOR), works in a distributed fashion where each vehicle receiving a packet, rebroadcasts it based on a predefined probability. The success of rebroadcast is determined based on allowing the message to travel the furthest possible distance with the least amount of packet rebroadcast collision. Moreover, we present a QoS-Aware node Selection Algorithm (QASA) for VANET routing protocols. Our algorithm is focused on selecting the vehicle to communicate with, and is achieved by exploiting the bridging approach for message forwarding i.e., vehicles on the east (west) select from west (east). The QoS metrics that are being optimized are the throughput in the network, as well as end-to-end delay for packets. Finally, we exploit the use of autonomous vehicles in order to optimize the end-to-end packet delivery delay. Our protocol introduces a dynamic metric that depends on the vehicular density on the highway in order to control the inter-vehicle distance. Our results show a great promise for their future use in vehicular technology.

Committee:

Dharma Agrawal, D.Sc. (Committee Chair); Raj Bhatnagar, Ph.D. (Committee Member); Yizong Cheng, Ph.D. (Committee Member); John Franco, Ph.D. (Committee Member); Chia Han, Ph.D. (Committee Member); Yiming Hu, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

Vehicular Networks;Ad Hoc Networks;QoS;Autonomous Vehicles;

Gungor, OnurINFORMATION THEORY ENABLED SECURE WIRELESS COMMUNICATION, KEY GENERATION AND AUTHENTICATION
Doctor of Philosophy, The Ohio State University, 2014, Electrical and Computer Engineering
The rapid growth in wireless communication systems has provided a flexibility of communication and content that has had a transformative impact to all aspects of society. However, the broadcast nature of the wireless medium makes these systems vulnerable to passive attacks in which the adversary attempts to eavesdrop on the transmitted messages, and to active attacks in which the adversary can intelligently manipulate legitimate transmissions, both of which can jeopardize a myriad of critical wireless services. Hence, it is imperative to design wireless networks with safeguards in place to ensure their resilience to attacks. To that end, this dissertation provides various perspectives in the domain of information theoretic secrecy and authentication, which provably guarantees security, regardless of the computational capabilities of the adversary. We strive to bridge the gap between the information theory of security and the practically implementable protocols within this paradigm. We first consider point to point secure communication over flat fading wireless channels under delay constraint. We extend the definition of outage capacity to account for the secrecy constraint and obtain sharp characterizations of the corresponding fundamental limits under different assumptions on the transmitter channel state information (CSI). The capacity achieving scheme relies on opportunistically exchanging private keys between the legitimate nodes. These keys are stored in a key buffer and used to secure delay sensitive data. We also characterize the optimal power control policies and analyze the effect of key buffer overflow on the overall outage probability. Next, we focus on investigating additional sources for generating secret key bits in mobile wireless networks. We propose an algorithm for secret key generation based on the observations of the relative locations between a pair of nodes. We test our algorithm in a vehicular setting based on observations made using wireless beacon exchange between the legitimate nodes. We also characterize theoretical bounds on achievable secret key bit rates under the presence of a possibly mobile eavesdropper, and illustrate, that relative localization information provides a significant additional resource for secret key generation in mobile networks. Finally, we focus on authentication based on the unique imperfections in the RF chain of radios, called the RF-Fingerprints. We develop a novel channel model for RF fingerprinting, and address the authentication problem in the presence of an adversary, where both the legitimate transmitter and the adversary are equipped with unique RF-fingerprints, in addition to a possible secret key available at the legitimate nodes. We provide bounds for the error exponents for reliable communication of the legitimate nodes, and the success exponent for impersonation and substitution attacks of the adversary. We illustrate that keyless authentication is possible via RF fingerprints if and only if the legitimate channel is not simulatable. In summary, this dissertation provides significant insights on practical implementation of information theory enabled secrecy and authentication protocols in wireless networks.

Committee:

Can Emre Koksal (Advisor); Hesham El Gamal (Advisor); Ness Shroff (Committee Member)

Subjects:

Electrical Engineering

Keywords:

information theory, information theoretic secrecy, key generation, delay constraints, secrecy outage, rf-fingerprints, error exponents, opportunistic, vehicular networks

Han, YouSpectrum Expansion to Solve the Spectrum Scarcity Problem in Vehicular Networks
Doctor of Philosophy, The Ohio State University, 2017, Electrical and Computer Engineering
Many studies show that the 5.9 GHz Dedicated Short Range Communication (DSRC) band with 75 MHz bandwidth is not sufficient to ensure reliable transmission of safety messages for the upcoming intelligent transportation systems. Moreover, the so-called vehicular spectrum scarcity problem is becoming severer in the DSRC band due to the rapid growth of wireless traffic demands in vehicular networks. Meanwhile, many frequency bands allocated to existing RF systems are largely underutilized. Since few new spectrum resources are available for vehicular communications, a potential solution to the spectrum scarcity problem in the DSRC band is to unload portion of the wireless traffic from the DSRC band to the other underutilized bands through spectrum sharing. The most fundamental requirement of the spectrum sharing approach is the protection of legacy users of the underutilized bands. In addition, a novel design of medium access control (MAC) protocols is required because few existing wireless MAC protocols support spectrum sharing functionality. This dissertation is focused on the resource allocation algorithm development and MAC protocol design to enable spectrum sharing between vehicular networks and other RF systems. Firstly, we study the sharing of the 54 MHz - 698 MHz TV White Space (TVWS) band between vehicular networks and licensed users of the band. The TVWS band has been officially released by FCC for cognitive access, and all existing wireless systems are allowed to access the band on condition that they must conform to FCC regulations on protection of legacy TVWS users. In this work, the channel allocation problem in the cognitive vehicular network is formulated as a nonlinear integer programming problem, to which three efficient approximation algorithms are developed. Secondly, we study the coexistence of vehicular networks and other unlicensed wireless networks in the TVWS band. The motivation of this study is that, multiple heterogeneous wireless networks can operate in the TVWS band simultaneously, which creates a challenging coexistence environment among these networks. In this work, the coexistence issue is formulated as a resource allocation problem in the vehicular networks, to which three efficient approximation algorithms with performance guarantees are developed. In addition to the TVWS band, we have also studied the vehicular spectrum expansion to the 77 – 81 GHz millimeter wave bands. Firstly, we propose a joint automotive radar-communication system (JARC) where radar imaging and vehicular communications share the 77 - 81 GHz automotive radar band. In this work, we show the trade-off of incorporating vehicular communications in automotive radars. Secondly, a distributed JARC system is developed to enable the spectrum sharing between vehicular communications and radar imaging in the 77 - 81 GHz band. The developed JARC systems consists of three key components: neighbor discovery, link establishment and maintenance, and data delivery. Finally, data delivery performance of the JARC system is evaluated through network simulations. To sum up, our research demonstrates the feasibility of spectrum expansion technologies to solve the vehicular spectrum scarcity problem. Moreover, we study the most important MAC layer issues and propose both theoretical solutions and implementation details, which facilitates the spectrum expansions.

Committee:

Eylem Ekici (Advisor); Ness Shroff (Committee Member); Emre Koksal (Committee Member); Yuejie Chi (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Spectrum Expansion; Spectrum Scarcity Problem in Vehicular Networks

Al-Shareeda, Sarah Yaseen AbdulrazzaqEnhancing Security, Privacy, and Efficiency of Vehicular Networks
Doctor of Philosophy, The Ohio State University, 2017, Electrical and Computer Engineering
Vehicular Adhoc Networks (VANETs) promises to empower the future autonomous vehicles with a cooperative awareness facility that will help in avoiding accidents and alleviating traffic congestion. The foreseen collective awareness requires the vehicles to communicate with their neighbors and with the infrastructure; such communication will need the fulfillment of many requirements such as security, privacy, and efficiency. The Dedicated Short-Range Communication (DSRC) standard has been formulated to afford these requisites. On one hand, when focusing on the application layer, DSRC adopts the successful Internet-based Public Key Infrastructure (PKI) framework to safeguard the vehicles. However, PKI alone cannot comprehensively meet all of the security and privacy requirements. On the other hand, the DSRC 's Medium Access Control (MAC) layer adopts the IEEE 802.11p access mode, which also needs augmentation to fulfill the efficiency of communication when collisions arise for safety beacons. Since many issues have not been well addressed in DSRC, academic, industrial, and governmental research has flourished over the last two decades to complement the standard. As being part of such large research community, we also have been incentivized to contribute with our own solutions. Our contributions have been ranging between two limits: either finding solutions to acclimate with the available DSRC shortcomings or disregarding the bias that DSRC has towards using only specific standards by bringing other alternative frameworks into scene. With the first direction in mind, our efforts are a mixture of high-level re-arrangement protocols such as grouping and overhead omissions to minimize the PKI and Carrier Sense Multiple Access - Collision Avoidance (CSMA/CA) privacy and efficiency shortcomings. For the other direction, we especially address the application layer level. Since some frameworks have small communication overhead while others have high anonymous traits, we have attempted low-level alternatives to PKI and Elliptic Curve Integrated Encryption Scheme (ECIES) and to overcome their confidentiality, privacy, and efficiency limitations. First, to augment the security of sensitive non-safety applications in PKI, our first research track concerns itself with finding alternatives for the used low-level encryption primitive such as ECIES and Advanced Encryption Standard (AES). The reason behind such effort is the authentication-dependability of ECIES/AES and key management of AES; therefore, we investigate the suitability of using a state-of-the-art low-level partial homomorphic encryption scheme to generate encrypted identities and keys to secure the sensitive non-safety data transfer. Our second research track concerns itself with preserving location privacy of vehicles since PKI does not afford privacy. To avoid the available privacy preservation solutions' covering-encryption overhead and silent-periods' lack of communication, we propose the idea of making vehicles create dynamic mix zones using an alternative super anonymous authentication scheme to hide their pseudonym change. Our third contribution falls within the augmentation of efficiency of communication when safety beacons collisions arise due to limited medium, CSMA/CA access mode, and PKI beaconed overhead. In this regard, we use the concept of grouping and overhead reduction to lower the vehicles' competition for the channel. Rather than having many individual vehicles communicate their information to the infrastructure, group leaders become main figures of communication. Our fourth work focuses on building an efficient identity based alternative authentication for VANETs other than PKI with the goal of having less communication overhead. Our built framework has fast computations, no elliptic curves pairings, smaller communication overhead, and more anonymous usage of pseudo identities to achieve the needed privacy. Focusing on the efficiency aspect of vehicular communication, in the fifth exerted effort, rather than using only PKI to authenticate users, we introduce a context aware authentication interchange protocol to match the situational neighborhood conditions of vehicles. If it is a dense network, our scheme switches to use a lower overhead authentication scheme; if it is a sparse network, the vehicle automatically switches to a more anonymous authentication. In a nutshell, the domain of VANETs offers a unique set of challenges; yet they present immense opportunities for research. We address three major challenges and suggested five research directions that may help in overcoming these limitations. We hope through these tracks of research to cast a light on the suitability of new concepts in affording the security, privacy, and availability of VANETs communications while achieving a comparable performance to the already adopted schemes.

Committee:

Fusun Ozguner, Professor (Advisor); Can Emre Koksal, Professor (Committee Member); Xiaorui Wang, Professor (Committee Member)

Subjects:

Computer Engineering; Computer Science; Electrical Engineering; Transportation

Keywords:

Vehicular Networks; Public Key Infrastructure; Security; Privacy; Cryptography; Elliptic Curves Cryptography; Pairings; Group Signatures; Trust; Authentication; Grouping; Dedicated Short Range Communication; Beaconing Rate

Prakash, AbhinavRendering Secured Connectivity in a Wireless IoT Mesh Network with WPAN's and VANET's
PhD, University of Cincinnati, 2017, Engineering and Applied Science: Computer Science and Engineering
A ubiquitous pervasive network incorporates today’s Internet of Things/Internet of Everything Paradigm: Everything becomes smart with at least one microprocessor and a network interface. All these are under an umbrella of IoT/IoE paradigm where everything is network capable and connected. In most of the cases, these devices have multiple microprocessors and network interfaces at their disposal. In such a scenario, bringing every application to specific network on the same platform is critical, specifically for Sensor Networks, Cloud, WPANs and VANETs. While, enforcing and satisfying the requirements of CIA triad with non-repudiation universally is critical as this can solve multiple existing problems of ISM band exhaustion, leading to excessive collisions and contentions. Cooperative Interoperability also enables universal availability of data across all platforms which can be reliable and fully synchronized. Plug and play universal usability can be delivered. Such a network necessitates robust security and privacy protocols, spanning uniformly across all platforms. Once, reliable data access is made available, it leads to an accurate situation aware decision modeling. Simultaneous multiple channel usage can be exploited to maximize bandwidth otherwise unused. Optimizing Content delivery in hybrid mode which will be the major chunk of network traffic as predicted for near future of IoE. Now, such a proposed hybrid network does sound very complicated and hard to establish and maintain. However, this is the future of networks with huge leaps of technological advancement and ever dropping prices of hardware coupled with immensely improved capabilities, such a hybrid ubiquitous network can be designed and deployed in a realistic scenario. In this work, we go through not only looking into the issues of the large scale hybrid WMN, but also minutely discovering every possible scenario of direct mesh clients or sub-nets (VANET, Cloud or BAN) associated to it. Further, we propose to design and implement a robust all around security and privacy for each and every possible unit of such a large network. Special focus is provided to the application of a BAN in medical usage with intricate details is provided in form of our recent endeavor, along with an ongoing work for a wearable device patent, Smart Shoe (Patent Pending). The concepts explained with this example are equally applicable to any such Wireless Personal Area Networks (WPAN’s).

Committee:

Dharma Agrawal, D.Sc. (Committee Chair); Richard Beck, Ph.D. (Committee Member); Yizong Cheng, Ph.D. (Committee Member); Rashmi Jha, Ph.D. (Committee Member); Wen-Ben Jone, Ph.D. (Committee Member); Marepalli Rao, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

IoT;Mesh Networks;Security;Ubiquitous Networks;Vehicular Networks;Cryptography