Vehicular ad-hoc networks (VANETs) are envisioned to provide many road and safety applications that will improve drivers' awareness and enhance the driving experience. Many of proposed applications are location-based that depend on sharing the location information of vehicles and events among neighboring nodes. The location-based applications should provide vehicle operators with knowledge of the current surrounding conditions to help them make appropriate traveling decisions, such as avoiding traffic congestion. Drivers expect to receive accurate and reliable information from other vehicles. Therefore, securing localization service integrity is important to support a VANET's overall system reliability. In this thesis, we study the exchanged location information in VANETs and designed a framework to prevent potential security threats that will violate users' privacy and overcome limitations that can impact the exchanged data integrity and reliability. The solution developed a secure neighborhood awareness service and shared localization information management protocol in a VANET. The proposed framework is constructed through several components: (i) a location verification protocol that will secure location information by providing a non-line-of-sight (NLOS) verification protocol to overcome moving obstacle effects; (ii) privacy-preserving location information management to detect data inconsistency and provide a recovery process while preventing attackers from tracking individual vehicles; (iii) a trust model evaluation mechanism based on neighborhood awareness; (iv) an adaptive beacon protocol that will reduce the number of messages and provide quality of service(QoS) control for network managers and authorities. We also propose a security evaluation model that quantifies the security attributes for the localization service in a VANET. The model will help evaluate an integrated security measures that are provided by different components of the network services.

Vehicular ad-hoc networks (VANETs) are envisioned to provide many road and safety applications that will improve drivers' awareness and enhance the driving experience. Many of proposed applications are location-based that depend on sharing the location information of vehicles and events among neighboring nodes. The location-based applications should provide vehicle operators with knowledge of the current surrounding conditions to help them make appropriate traveling decisions, such as avoiding traffic congestion. Drivers expect to receive accurate and reliable information from other vehicles. Therefore, securing localization service integrity is important to support a VANET's overall system reliability. In this thesis, we study the exchanged location information in VANETs and designed a framework to prevent potential security threats that will violate users' privacy and overcome limitations that can impact the exchanged data integrity and reliability. The solution developed a secure neighborhood awareness service and shared localization information management protocol in a VANET. The proposed framework is constructed through several components: (i) a location verification protocol that will secure location information by providing a non-line-of-sight (NLOS) verification protocol to overcome moving obstacle effects; (ii) privacy-preserving location information management to detect data inconsistency and provide a recovery process while preventing attackers from tracking individual vehicles; (iii) a trust model evaluation mechanism based on neighborhood awareness; (iv) an adaptive beacon protocol that will reduce the number of messages and provide quality of service(QoS) control for network managers and authorities. We also propose a security evaluation model that quantifies the security attributes for the localization service in a VANET. The model will help evaluate an integrated security measures that are provided by different components of the network services.

Cognitive radios is one of the hot topics for emerging and future wireless commu- nication. It has been proposed as a suitable solution for the spectrum scarcity caused by the increase in frequency demand. The concept is based on allowing unlicensed users, called cognitive or secondary users, to share the unoccupied frequency bands with their owners, called the primary users, under constraints on the interference they cause to them. The objective of our work is to propose some enhancements to cognitive radio systems while taking into account practical constraints. Cogni- tive radios requires a capability to detect spectrum holes (spectrum sensing) and a scheduling flexibility to avoid the occupied spectrum and selectively use the empty spectrum (dynamic resource allocation). Thus, the work is composed of two main parts. The first part focuses on cooperative spectrum sensing. We compute in this part the analytical performance of cooperative spectrum sensing under non identical and imperfect channels. Different schemes are considered for the cooperation between users such as hard binary, censored information, quantized, and soft information. The second part focuses on the dynamic resource allocation. We first propose low-cost re- source allocation algorithms that use location information to estimate the interference to primary users to replace absence of instantaneous channel state information. We extend these algorithms to handle practical implementation constraints such as dis- 5 crete bit-loading and collocated subcarriers allocations. We then propose a reduced dimension approach based on the grouping of subcarriers into clusters and performing the resource allocation over clusters of subcarriers instead of single subcarriers. This approach is shown to reduce the computational complexity of the algorithm with lim- ited performance loss. In addition, it is valid for a generic set of resource allocation problems in presence of co-channel interference between users.

As a special subset of ad hoc networks, airborne networks aim to provide efficient network access for airborne and ground assets in a tactical environment. Conventional ad hoc routing protocols face some difficulties in such networks. First, significant overhead may be generated due to the high node mobility and dramatic topology changes. Second, temporary link failure may abort the delivery of a packet in some intermediate router. In this thesis, we propose a cluster-based reactive routing protocol to alleviate these problems. Our solution takes advantage of mesh routers installed in unmanned aerial vehicles or aircraft capable of hovering, when such airborne assets are available. As those mesh points usually have relatively stable connections among themselves, they play the role of cluster heads, forming a hierarchical routing structure. A simple self-organizing rule is introduced in cluster management to limit the cluster control overhead and route discovery flooding. In addition, a disruption tolerant mechanism (DTM) is deployed in the routing protocol to increase resilience to temporary link or node failure. The DTM utilizes the location, bearing and speed information provided by each node and intelligently maintains a buffer of packets that cannot be immediately delivered. If a temporary link failure occurs in the intermediate router during delivery, the packet is then buffered in that router up to a maximum time-to-live. The DTM also keeps track of link changes and tries to deliver the message as soon as a new path toward the destination is found. If the buffered messages are about to time out and the destination is still unreachable, the DTM still makes an effort to deliver the packet to another router with higher probability of eventually reaching the destination. This thesis also presents an implementation of the proposed solution in the ns-2 network simulator. The conventional Ad hoc On-Demand Distance Vector (AODV) routing protocol is adopted as the base model in the implementation. A mesh router model is programmed with two wireless interfaces. One of the interfaces is utilized to exchange routing information and packets with cluster members; the other is used to communicate with other mesh routers. This model is then installed on top of the AODV routing protocol and forms the hierarchical routing structure. The traditional AODV messages, including RREQ, RREP and HELLO, and routing tables are modified to support additional location information. Finally, the DTM is programmed and added to the AODV buffer management. The objective of this research is to use a mesh structure and DTM to improve the reliability and performance of airborne networks. The metrics of throughput and routing overhead are taken into consideration. The simulation results demonstrate that the proposed solution satisfies our research objectives. It achieves better performance than the conventional AODV, but introduces little overhead. The mesh structure can effectively adapt to high mobility, dynamic topology and different routing capabilities. The DTM provides a sophisticated way to maintain the buffer and mitigates the impact of intermittent links. / Master of Science

Adoption of location-based services (LBS) was for a long time below expectations, and most of the studies attribute it to privacy concerns of users. However, many new LBS applications are currently among the most downloaded application for smartphones, particularly entertainment applications. Therefore, this research aims to find out whether privacy concerns still matter to users and to explore the role of the privacy in the adoption of LBS entertaining applications. The adopted methodology is qualitative research and data are collected through interviews and additional information from the smartphones ofparticipants. Ten individuals among university students at Linnaeus University in Sweden are selected for this research, and this sample choice is per their experience with two selected LBS entertaining applications, Pokémon Go and Tinder. As a result, six themes have been recognized to answer the research questions. Low privacy concerns about location information, especially in entertainment applications with negligible effect on adoption have been identified. However, author of this research suggests, that developers of LBS entertaining applications should care for retaining their credibility because it can have an impact on the adoption of their LBS services.

It is a challenge to collect data on visitors' movement patterns via a mobile app for an alpine ski resort. Because gathering of location information is based on voluntariness. One way to motivate more people to share their location information is to offer the features that users expects or want in such a mobile app. This study aims to investigate what features a mobile app should include in order for users to share their location information. The research strategy used is case study and the data collection method is interviews. 22 alpine skiers were interviewed and in addition, an expert on the topic of mobile solutions with experience of leading development of location-based mobile apps has been interviewed. The interviews generated qualitative data that was analyzed thematically. The results presented by the study show that users are positive about sharing their location information if they receive something significant in return. The results are presented in two parts, one with general needs that the overwhelming majority desired, and one with interest-driven needs. / Det är en utmaning att samla in data om besökarnas rörelsemönster via en mobilapp för en alpin skidanläggning eftersom insamlingen av platsinformation baseras på frivillighet. Ett sätt att motivera fler att dela sin platsinformation är att erbjuda de funktioner användarna förväntar sig eller önskar i en sådan mobilapp. Denna studie syftar till att undersöka vilka funktioner en mobilapp bör innehålla för att användare ska dela med sig av sin platsinformation. Forskningsstrategin som tillämpas är fallstudie. Fallstudien baseras på intervjuer som datainsamlingsmetod. Intervjuer har genomförts med 22 alpinåkare samt en expert med erfarenhet inom att leda utveckling av platsbaserade mobila lösningar. Intervjuerna har genererat kvalitativ data som analyserats tematiskt. Resultaten som studien presenterar visar att användarna är positivt inställda till att dela sin platsinformation om de får något signifikant i gengäld. Resultaten presenteras i två delar. En del med allmänna behov vilka en övervägande majoritet önskade samt en del med intressestyrda behov.

Mobile computing is becoming increasingly important, due to the rise in the number of portable computers and the desire to have continuous network connectivity to the Internet, irrespective of the physical location of the node. We have also seen a steady growth of the market for wireless communication devices. Such devices can only have the effect of increasing the options for making connections to the global Internet. The Internet infrastructure is built on top of a collection of protocols called the TCP/IP protocol suite. Transmission Control Protocol (TCP) and Internet Protocol (IP) are the core protocols in this suite. There are currently two standards: one to support the current IPv4 and one for the upcoming IPv6 [1]. IP requires the location of any node connected to the Internet to be uniquely identified by an assigned IP address. This raises one of the most important issues in mobility because, when a node moves to another physical location, it has to change its IP address. However, the higher-level protocols require the IP address of a node to be fixed for identifying connections. The Mobile Internet Protocol (Mobile IP) is an extension to the Internet Protocol proposed by the Internet Engineering Task Force (IETF) that addresses this issue. It enables mobile devices to stay connected to the Internet regardless of their locations, without changing their IP addresses and, therefore, an ongoing IP session will not be interrupted [2, 3, 4]. More precisely, Mobile IP is a standard protocol that builds on the Internet Protocol by making mobility transparent to applications and higher-level protocols like TCP. However, before Mobile IP can be broadly deployed, there are still several technical barriers, such as long handover periods and packet loss that have to be overcome, in addition to other technical obstacles, including handover performance, security issues and routing efficiency [7]. This study presents an investigation into developing new handover mechanisms based on link layer information in Mobile IP and fast handover in Mobile IPv6 environments. The main goal of the developed mechanisms is to improve the overall IP mobility performance by reducing packet loss, minimizing signalling overheads and reducing the handover processing time. These models include the development of a cross-layer handover scheme using link layer information and Mobile Node (MN) location information to improve the performance of the communication system by reducing transmission delay, packet loss and registration signalling overheads. Finally, the new schemes are developed, tested and validated through a set of experiments to demonstrate the relative merits and capabilities of these schemes.

Mobile computing is becoming increasingly important, due to the rise in the number of portable computers and the desire to have continuous network connectivity to the Internet, irrespective of the physical location of the node. We have also seen a steady growth of the market for wireless communication devices. Such devices can only have the effect of increasing the options for making connections to the global Internet. The Internet infrastructure is built on top of a collection of protocols called the TCP/IP protocol suite. Transmission Control Protocol (TCP) and Internet Protocol (IP) are the core protocols in this suite. There are currently two standards: one to support the current IPv4 and one for the upcoming IPv6 [1]. IP requires the location of any node connected to the Internet to be uniquely identified by an assigned IP address. This raises one of the most important issues in mobility because, when a node moves to another physical location, it has to change its IP address. However, the higher-level protocols require the IP address of a node to be fixed for identifying connections. The Mobile Internet Protocol (Mobile IP) is an extension to the Internet Protocol proposed by the Internet Engineering Task Force (IETF) that addresses this issue. It enables mobile devices to stay connected to the Internet regardless of their locations, without changing their IP addresses and, therefore, an ongoing IP session will not be interrupted [2, 3, 4]. More precisely, Mobile IP is a standard protocol that builds on the Internet Protocol by making mobility transparent to applications and higher-level protocols like TCP. However, before Mobile IP can be broadly deployed, there are still several technical barriers, such as long handover periods and packet loss that have to be overcome, in addition to other technical obstacles, including handover performance, security issues and routing efficiency [7]. This study presents an investigation into developing new handover mechanisms based on link layer information in Mobile IP and fast handover in Mobile IPv6 environments. The main goal of the developed mechanisms is to improve the overall IP mobility performance by reducing packet loss, minimizing signalling overheads and reducing the handover processing time. These models include the development of a cross-layer handover scheme using link layer information and Mobile Node (MN) location information to improve the performance of the communication system by reducing transmission delay, packet loss and registration signalling overheads. Finally, the new schemes are developed, tested and validated through a set of experiments to demonstrate the relative merits and capabilities of these schemes.

In dieser Arbeit werden P2P-Algorithmen in ressourcen-limitierten und irregulären Wireless-ad-hoc-Netzwerken (WAHN) betrachtet, die effizient, skalierbar und fehlertolerant in Situationen arbeiten sollen, in denen eine räumlich benachbarte Gruppe von Netzwerkknoten simultan ausfällt. Es wird ein fehlertolerantes Replikationsschema zur datenzentrischen Speicherung betrachtet, und eine selbstorganisierende, skalierbare Berechnung von Datenaggregaten zur Lösung des Konsensproblems. Existierende P2P-Algorithmen die Skalierbarkeit, Fehlertoleranz und Selbstorganisation in drahtgebundenen Netzen betrachten sind für die Klasse des WAHNs nicht geeignet weil sie Engpässe in WAHNs verursachen können und in Katastrophenmanagement-szenarien die Zuverlässigkeit der Daten nicht sicherstellen können. Die Verwendung von Informationen der geographischen Position von Knoten ist ein möglicher Weg, um die Effizienz und Skalierbarkeit von P2P-Anwendungen in drahtlosen Netzwerken zu verbessern. In dieser Arbeit wird ein neuer Ansatz vorgestellt, wie auf effiziente Weise 1) Gebiet des Netzwerks, das die geographische Ausbreitung seiner Knoten umfasst, und 2) Gruppenzugehörigkeit, wobei jeder Knoten zu genau einer Gruppe innerhalb eines einstellbaren Gebietes gehört, erzeugt werden kann. Dadurch können: existierenden, skalierbare P2P Datenspeicheralgorithmen für WAHNs genutzt werden, effiziente, fehlertolerante Replikation erstellt werden, die Effizienz von geographischen Routing und der Suche nach Replikaten verbessert werden sowie, Anwendungen auf einen bestimmten geographischen Bereich innerhalb des WAHN beschränkt werden (z.B. im Aggregationsprotokoll). Die entwickelten Protokolle sind tolerant gegenüber Nachrichtenverlust und verwenden ausschließlich lokale Broadcast-Nachrichten. Das Protokoll wurde mit Simulationen untersucht, die auf realistischen Netzwerktopologien mit Anteilen an sehr spärlichen und sehr dichten Knotenansammlungen basieren. / This dissertation addresses the challenge of reaching efficiency, scalability and fault-tolerance by P2P algorithms for resource-limited and irregular wireless ad-hoc networks (WAHNs) in disaster management (DM) scenarios where a spatially correlated group of nodes may crash simultaneously. In particular, we consider a fault-tolerant replication scheme for data-centric storage and a self-organized, scalable calculation of localized data aggregates for solving the consensus problem. Existing Peer-to-Peer algorithms that address issues of scalability, fault tolerance and self-organization in wired networks are inadequate for the addressed systems, they may cause bottlenecks in WAHNs and use replication that abstracts from geographical location of replicas and cannot therefore supply data survivability in DM scenarios in WAHNs. Incorporating information on geographical location of nodes is a recognized way to increase the efficiency and scalability of P2P applications in wireless networks. This dissertation proposes to efficiently construct new position information in a location-aware WAHN, where each node knows its own location and location of its direct neighbors. The new information are: network area, which expresses the geographical area covered by the network, and group membership, where each node belongs to exactly one group that is placed over the area of a maximum defined size. Together, they enable the use of the existing, scalable P2P data store in WAHNs (Geographical Hash Table), allow design of efficient fault-tolerant replication for the assumed fault model, increase efficiency of geographic routing and replica search, and allow to limit the geographical extent of activity of any distributed application, as we show using an example of data aggregation protocol. Proposed protocols tolerate message loss and use local broadcast only. They are evaluated by simulation over irregular topologies following the node placement of the existing, large WAHNs.