Performance evaluation of realistic scenarios for vehicular ad hoc networks with VanetMobiSim and NS2

Català: En els darrers anys, el considerable creixement del sector dels serveis mòbils arreu del món es certament el major fenòmen al camp de les telecomunicaciones. Les tecnologies inalàmbriques han conduït al desenvolupament de nous sistemes de comunicació y serveis multimèdia. Degut al constant creixement del mercat automobilístic juntament amb la creixent demanda de la seguretat viària ha nascut un nou concepte al camp de les comunicaciones: les xarxes entre vehicles (VANETs). A les VANETs, cada vehicle pot actuar com a router o node, establint connexions entre vehicles propers o amb infraestructura a la carretera. Les VANET estan rebent més atenció del govern i de la indústria automobilística degut a l'àmplia varietat d'aplicacions y serveis que poden oferir, tal com sistemes de seguretet viària assistència a la carretera i accès a Internet. No obstant, el disseny i l'implementació de VANETs és una àrea d'investigació àmplia i complexa tal i com podem percebre, sabent que durant els darrers anys la comunitat investigadora s'ha centrat en l'estudi d'aquestes xarxes. Bàsicament, el nostre projecte està dividit en dues parts principals: Primerament, hem dut a terme una recerca relacionada amb l'estat actual de les VANET avui en dia, amb l'objectiu d'identificar els generadors de moviment i els simuladors de xarxes més apropiats i recomenats a la literatura. En segon lloc, hem decidit utilitzar el VanetMobiSim [80], com a generador de moviment degut a la seva varietat de models de movilitat que es poden testejar, i el NS2 [63] com a simulador de xarxes per ser un dels més utilitzats per molts autors a més de la seva compatibilitat amb el VanetMobiSim. Amb l'ús d'aquestes eines, VanetMobiSim i NS2, hem dut a terme una avaluació profunda de les prestacions de les VANET en diversos escenaris reals, assignant valors diferents a paràmetres tals com el nombre de nodes, la velocitat i el model de propagació.Castellano: En los últimos años, el considerable crecimiento del sector de los servicios móviles alrededor del mundo es con certeza el mayor fenómeno en el campo de las telecomunicaciones. Las tecnologías inalámbricas han conducido al desarrollo de nuevos sistemas de comunicación y servicios multimedia. Debido al constante crecimiento del mercado automovilístico y la creciente demanda en seguridad vial ha nacido un nuevo concepto en el campo de las comunicaciones: las redes entre vehículos (VANETs). En ellas, cada vehículo actúa como router, estableciendo conexiones entre vehículos cercanos o con infraestructura en la carretera. Las VANET estan recibiendo más atención del gobierno y de la industria automovilística debido a la amplia variedad de aplicaciones y servicios que puede ofrecer, tales como sistemas de seguridad vial, asistencia en carretera y acceso a Internet. Sin embargo, el diseño e implementación de las VANET es un area de investigación amplia y compleja, tal y como podemos percibir, sabiendo que durante los últimos años la comunidad investigadora se ha centrado en el estudio de estas redes. Básicamente, nuestro proyecto está dividido en dos partes principales: Primeramente, hemos llevado a cabo una búsqueda relacionada con el estado de arte de las VANET hoy en día, con el objetivo de identificar los generadores de movimiento i los simuladores de redes más apropiados i recomendados en la literatura. En segundo lugar, hemos decidido utilizar el VanetMobiSim [80], como generador de movimiento debido a la alta variedad de modelos de mobilidad que que se pueden testear, y el NS2 [63] como simulador de redes por ser uno de los más utilizados per muchos autores además de su compatibilidad con el VanetMobiSim. Con el uso de estas herramientas, hemos llevado a cabo una evaluación profunda de las prestaciones de las VANET en varios escenarios reales, asignando valores diferentes a parámetros tales como el número de nodos, la velocidad y el modelo de propagación.English: Over recent years, the considerable mobile services sector growth around the world was certainly the major phenomenon in the telecommunications field. Wireless technology has led to the development of new communications systems and multimedia services. Due to the continued growth of the vehicular industry and the increasing demand of road safety, a new concept in the communications field was born: vehicular networks (VANETs). In VANETs, each vehicle could act as router or node, establishing connections among nearby vehicles or with roadside infrastructure. VANETs are receiving more attention from governments and car manufacturers due to the wide variety of applications and services they can provide such as road safety systems, car assistance and Internet acces. However, designing and implementing VANETs is a complex and wide area of research as we can notice, knowing that in the last years the research and development community has focused on the study of such networks. Basically, our project is divided in two main parts: Firstly, we made a state of art related to the actual state of VANETs nowadays in order to find the most appropiate and recommended mobility generator and network simulator reported in the literature. Secondly, we decided to use VanetMobiSim [80], as a mobility generator due to its variety mobility models that could be tested, and NS2 [63] as a network simulator for being one of the most used by many authors and also due to its compatibilty with VanetMobiSim. Using these tools, VanetMobiSim and NS2, we carried out a deep performance evaluation of VANETs in several realistic scenarios, giving different values to parameters such as the number of nodes, speed and the propagation model

Unmanned aerial vehicles (UAVs) for wireless communication and networks : potentials and design challenges

Unmanned aerial vehicles (UAVs) are mostly considered by the military for surveillance and reconnaissance operations, and by hobbyists for aerial photography. However, in recent years, the UAV operations have been extended for civilian and commercial purposes due to their agile and cost-effective deployment. UAVs appear to be more prolific platforms to enable wireless communication due to their better line-of-sight (LOS) channel conditions as compared with the fixed base stations (BSs) in terrestrial communication which suffer from severe path loss, shadowing, and multipath fading in more challenging propagation environments. In UAV-enabled wireless communications, the UAV can either act as a complementary aerial BS to provide on-demand communication or as an aerial user equipment (UE) which is operated by the existing cellular network. Several challenges exist in the design of UAV communications which include but not limited to channel modeling, optimal deployment, interference generation, performance analysis, limited on-board battery lifetime, trajectory optimization, and unavailability of regulations and standards which are specific for UAV communication and networking. This thesis particularly investigates some important design challenges for safe and reliable functionalities of UAV for wireless communication and networking. UAV communication has its own distinctive channel characteristics compared to the widely used cellular or satellite systems. However, several challenges exist in UAV channel modeling. For example, the propagation characteristics of UAV channels are under explored for spatial and temporal variations in non-stationary channels. Therefore, first and foremost, this thesis provides an extensive review of the measurement methods proposed for UAV channel modeling and discusses channel modeling efforts for air-to-ground and air-to-air channels. Furthermore, knowledge-gaps are identified to realize accurate UAV channel models. The efficient deployment strategy is imperative to compensate the adverse impact of interference on the coverage area performance of multiple UAVs. As a result, this thesis proposes an optimal deployment strategy for multiple UAVs in presence of downlink co-channel interference in the worst-case scenario. In particular, this work presents coordinated multi-UAV strategy in two schemes. In the first scheme, symmetric placement of UAVs is assumed at a common optimal altitude and transmit power. In the second scheme, asymmetric deployment of UAVs with different altitudes and transmit powers is assumed. The impact of various system parameters, such as signal-to interference-plus-noise ratio (SINR) threshold, separation distance between UAVs, and the number of UAVs and their formations are carefully studied to achieve the maximum coverage area inside and to reduce the unnecessary coverage expansion outside the target area. Fundamental analysis is required to obtain the optimal trade-off between the design parameters and performance metrics of any communication systems. This thesis particularly considers two emerging scenarios for evaluating performance of UAV communication systems. In the first scenario, the uplink UAV communication system is considered where the ground user follows the random waypoint (RWP) model for user mobility, the small-scale channel fading follows the Nakagami-m model, and the uplink interference is modeled by Gamma approximation. Specifically, the closed-form expressions for the probability density function (PDF), the cumulative distribution function (CDF), the outage probability, and the average bit error rate (BER) of the considered UAV system are derived as performance metrics. In the second scenario, the downlink hybrid caching system is considered where UAVs and ground small-cell BSs (SBSs) are distributed according to two independent homogeneous Poisson point processes (PPPs), and downlink interference is modeled by the Laplace transforms. Specifically, the analytical expressions of the successful content delivery probability and energy efficiency of the considered network are derived as performance metrics. In both scenarios, results are presented to demonstrate the interplay between the communication performance and the design parameters

Relaying in the Internet of Things (IoT): A Survey

The deployment of relays between Internet of Things (IoT) end devices and gateways can improve link quality. In cellular-based IoT, relays have the potential to reduce base station overload. The energy expended in single-hop long-range communication can be reduced if relays listen to transmissions of end devices and forward these observations to gateways. However, incorporating relays into IoT networks faces some challenges. IoT end devices are designed primarily for uplink communication of small-sized observations toward the network; hence, opportunistically using end devices as relays needs a redesign of both the medium access control (MAC) layer protocol of such end devices and possible addition of new communication interfaces. Additionally, the wake-up time of IoT end devices needs to be synchronized with that of the relays. For cellular-based IoT, the possibility of using infrastructure relays exists, and noncellular IoT networks can leverage the presence of mobile devices for relaying, for example, in remote healthcare. However, the latter presents problems of incentivizing relay participation and managing the mobility of relays. Furthermore, although relays can increase the lifetime of IoT networks, deploying relays implies the need for additional batteries to power them. This can erode the energy efficiency gain that relays offer. Therefore, designing relay-assisted IoT networks that provide acceptable trade-offs is key, and this goes beyond adding an extra transmit RF chain to a relay-enabled IoT end device. There has been increasing research interest in IoT relaying, as demonstrated in the available literature. Works that consider these issues are surveyed in this paper to provide insight into the state of the art, provide design insights for network designers and motivate future research directions

Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

Satellite Communications

This study is motivated by the need to give the reader a broad view of the developments, key concepts, and technologies related to information society evolution, with a focus on the wireless communications and geoinformation technologies and their role in the environment. Giving perspective, it aims at assisting people active in the industry, the public sector, and Earth science fields as well, by providing a base for their continued work and thinking

Unmanned Aircraft Systems in the Cyber Domain

Unmanned Aircraft Systems are an integral part of the US national critical infrastructure. The authors have endeavored to bring a breadth and quality of information to the reader that is unparalleled in the unclassified sphere. This textbook will fully immerse and engage the reader / student in the cyber-security considerations of this rapidly emerging technology that we know as unmanned aircraft systems (UAS). The first edition topics covered National Airspace (NAS) policy issues, information security (INFOSEC), UAS vulnerabilities in key systems (Sense and Avoid / SCADA), navigation and collision avoidance systems, stealth design, intelligence, surveillance and reconnaissance (ISR) platforms; weapons systems security; electronic warfare considerations; data-links, jamming, operational vulnerabilities and still-emerging political scenarios that affect US military / commercial decisions. This second edition discusses state-of-the-art technology issues facing US UAS designers. It focuses on counter unmanned aircraft systems (C-UAS) – especially research designed to mitigate and terminate threats by SWARMS. Topics include high-altitude platforms (HAPS) for wireless communications; C-UAS and large scale threats; acoustic countermeasures against SWARMS and building an Identify Friend or Foe (IFF) acoustic library; updates to the legal / regulatory landscape; UAS proliferation along the Chinese New Silk Road Sea / Land routes; and ethics in this new age of autonomous systems and artificial intelligence (AI).https://newprairiepress.org/ebooks/1027/thumbnail.jp

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion