Road accidents represent a serious social problem and are one of the leading causes of human death and disability on a global scale. To reduce the risk and severity of a road accident, a variety of new safety applications can be realized through wireless communications among vehicles driving nearby each other, or among vehicles and especially deployed road side units (RSUs), a technology known as a vehicular ad hoc network (VANET). Most of the VANET-enabled safety applications are based on broadcasting of safety messages by vehicles or RSUs, either periodically or in case of an unexpected event, such as a hard brake or dangerous road condition detection. Each broadcast safety message should be successfully delivered to the surrounding vehicles and RSUs without any excess delay, which is one of the main functions of a medium access control (MAC) protocol proposed for VANETs. This thesis presents VeMAC, a new multichannel time division multiple access (TDMA) protocol specifically designed to support the high priority safety applications in a VANET scenario. The ability of the VeMAC protocol to deliver periodic and event-driven safety messages in VANETs is demonstrated by a detailed delivery delay analysis, including queueing and service delays, for both types of safety messages. As well, computer simulations are conducted by using MATLAB, the network simulator ns-2, and the microscopic vehicle traffic simulator VISSIM, in order to evaluate the performance of the VeMAC protocol, in comparison with the IEEE 802.11p standard and the ADHOC MAC protocol (another TDMA protocol proposed for ad hoc networks). A real city scenario is simulated and different performance metrics are evaluated, including the network goodput, protocol overhead, channel utilization, protocol fairness, probability of a transmission collision, and safety message delivery delay. It is shown that the VeMAC protocol considerably outperforms the existing MAC schemes, which have significant limitations in supporting VANET safety applications. In addition to enhancing road safety, in-vehicle Internet access is one of the main applications of VANETs, which aims at providing the vehicle passengers with a low-cost access to the Internet via on-road gateways. This thesis presents a new strategy for deploying Internet gateways on the roads, in order to minimize the total cost of gateway deployment, while ensuring that a vehicle can connect to an Internet gateway (using multihop communications) with a probability greater than a specified threshold. This cost minimization problem is formulated by using binary integer programming, and applied for optimal gateway placement in a real city scenario. To the best of our knowledge, no previous strategy for gateway deployment has considered the probability of multihop connectivity among the vehicles and the deployed gateways. In order to allow a vehicle to discover the existence of an Internet gateway and to communicate with the gateway via multihops, a novel data packet routing scheme is proposed based on the VeMAC protocol. The performance of this cross-layer design is evaluated for a multichannel VANET in a highway scenario, mainly in terms of the end-to-end packet delivery delay. The packet queueing at each relay vehicle is considered in the end-to-end delay analysis, and numerical results are presented to study the effect of various parameters, such as the vehicle density and the packet arrival rate, on the performance metrics. The proposed VeMAC protocol is a promising candidate for MAC in VANETs, which can realize many advanced safety applications to enhance the public safety standards and improve the safety level of drivers/passengers and pedestrians on roads. On the other hand, the proposed gateway placement strategy and packet routing scheme represent a strong step toward providing reliable and ubiquitous in-vehicle Internet connectivity.

Vehicular networking is envisioned to be a key technology area for significant growth in the coming years. Although the expectations for this emerging technology are set very high, many practical aspects remain still unsolved for a vast deployment of vehicular networks. This dissertation addresses the enabling physical layer techniques to meet the challenges in vehicular networks operating in mobile wireless environments. Considering the infrastructure-less nature of vehicular networks, we envision cooperative diversity well positioned to meet the demanding requirements of vehicular networks with their underlying distributed structure. Cooperative diversity has been proposed as a powerful means to enhance the performance of high-rate communications over wireless fading channels. It realizes spatial diversity advantages in a distributed manner where a node uses others antennas to relay its message creating a virtual antenna array. Although cooperative diversity has garnered much attention recently, it has not yet been fully explored in the context of vehicular networks considering the unique characteristics of vehicular networks, this dissertation provides an error performance analysis study of cooperative transmission schemes for various deployment and traffic scenarios. In the first part of this dissertation, we investigate the performance of a cooperative vehicle-to-vehicle (V2V) system with amplify-and-forward relaying for typical traffic scenarios under city/urban settings and a highway area. We derive pairwise error probability (PEP) expressions and demonstrate the achievable diversity gains. The effect of imperfect channel state information (CSI) is also studied through an asymptotical PEP analysis. We present Monte-Carlo simulations to confirm the analytical derivations and present the error rate performance of the vehicular scheme with perfect and imperfect-CSI. In the second part, we consider road-to-vehicle (R2V) communications in which roadside access points use cooperating vehicles as relaying terminals. Under the assumption of decode-and-forward relaying, we derive PEP expressions for single-relay and multi-relay scenarios. In the third part, we consider a cooperative multi-hop V2V system in which direct transmission is not possible and investigate its performance through the PEP derivation and diversity gain analysis. Monte-Carlo simulations are further provided to con firm the analytical derivations and provide insight into the error rate performance improvement.

This licentiate thesis work investigates two medium access control (MAC) methods, when used in traffic safety applications over vehicular ad hoc networks (VANETs). The MAC methods are carrier sense multiple access (CSMA), as specified by the leading standard for VANETs IEEE 802.11p, and self-organizing time-division multiple access (STDMA) as used by the leading standard for transponders on ships. All vehicles in traffic safety applications periodically broadcast cooperative awareness messages (CAMs). The CAM based data traffic implies requirements on a predictable, fair and scalable medium access mechanism. The investigated performance measures are channel access delay, number of consecutive packet drops and the distance between concurrently transmitting nodes. Performance is evaluated by computer simulations of a highway scenario in which all vehicles broadcast CAMs with different update rates and packet lengths. The obtained results show that nodes in a CSMA system can experience unbounded channel access delays and further that there is a significant difference between the best case and worst case channel access delay that a node could experience. In addition, with CSMA there is a very high probability that several concurrently transmitting nodes are located close to each other. This occurs when nodes start their listening periods at the same time or when nodes choose the same backoff value, which results in nodes starting to transmit at the same time instant. The CSMA algorithm is therefore both unpredictable and unfair besides the fact that it scales badly for broadcasted CAMs. STDMA, on the other hand, will always grant channel access for all packets before a predetermined time, regardless of the number of competing nodes. Therefore, the STDMA algorithm is predictable and fair. STDMA, using parameter settings that have been adapted to the vehicular environment, is shown to outperform CSMA when considering the performance measure distance between concurrently transmitting nodes. In CSMA the distance between concurrent transmissions is random, whereas STDMA uses the side information from the CAMs to properly schedule concurrent transmissions in space. The price paid for the superior performance of STDMA is the required network synchronization through a global navigation satellite system, e.g., GPS. That aside since STDMA was shown to be scalable, predictable and fair; it is an excellent candidate for use in VANETs when complex communication requirements from traffic safety applications should be met.

La popularisation des véhicules a engendré des problèmes de sécurité et d’environnement. Desprojets ont été lancés à travers le monde pour améliorer la sécurité sur la route, réduire l’encombrementdu trafic et apporter plus de confort aux conducteurs. L’environnement des réseaux devéhicules est complexe et dynamique, les sources sont souvent hétérogènes, de ce fait les informationséchangées peuvent souvent être imparfaites. La théorie des fonctions de croyance modélisesouplement les connaissances et fournit des outils riches pour gérer les différents types d’imperfection.Elle est utilisée pour représenter l’incertitude, gérer les différentes informations acquises etles fusionner. Nous nous intéressons à la gestion des informations imparfaites échangées entre lesvéhicules concernant les événements sur la route. Les événements locaux et les événements étendusn’ayant pas les mêmes caractéristiques, les travaux réalisés les distinguent. Dans un environnementsans infrastructure où chaque véhicule a son propre module de fusion, l’objectif est de fournir auxconducteurs la synthèse la plus proche possible de la réalité. Différents modèles fondés sur desfonctions de croyance sont proposés et différentes stratégies sont étudiées : affaiblir ou renforcervers l’absence de l’événement pour prendre en compte le vieillissement des messages, garder lesmessages initiaux ou seulement le résultat de la fusion dans la base des véhicules, considérer la miseà jour du monde, prendre en compte l’influence du voisinage pour gérer la spatialité des embouteillages.Les perspectives restent nombreuses, certaines sont développées dans ce manuscrit commela généralisation des méthodes proposées à tous les événements étendus tels que les brouillards. / The popularization of vehicles has created safety and environmental problems. Projects havebeen launched worldwide to improve road safety, reduce traffic congestion and bring more comfortto drivers. The vehicle network environment is dynamic and complex, sources are often heterogeneous,and therefore the exchanged information may be imperfect. The theory of belief functionsoffers flexibility in uncertainty modeling and provides rich tools for managing different types of imperfection.It is used to represent uncertainty, manage and fuse the various acquired information.We focus on the management of imperfect information exchanged between vehicles concerningevents on the road. The carried work distinguishes local events and spatial events, which do nothave the same characteristics. In an environment without infrastructure where each vehicle is afusion center and creates its own vision, the goal is to provide to each driver the synthesis of thesituation on the road as close as possible to the reality. Different models using belief functionsare proposed. Different strategies are considered: discount or reinforce towards the absence of theevent to take into account messages ageing, keep the original messages or just the fusion result invehicle database, consider the world update, manage the spatiality of traffic jam events by takinginto account neighborhood. Perspectives remain numerous; some are developed in the manuscriptas the generalization of proposed methods to all spatial events such as fog blankets.

Les réseaux ad hoc véhiculaires (VANETs) permettent le partage de différents types de données entre les véhicules, de manière collaborative. Dans cette thèse, nous nous sommes tout particulièrement intéressés aux applications de sûreté et de sécurité routière, dédiées à l'échange des informations sur l'état de l'environnement routier. Les contraintes de ces applications en termes de qualité de services sont des plus rigoureuses, car l'acheminent de leurs données doit être exhaustif et ne souffrir d'aucun retard pour assurer une information utile et en temps opportun au profit de tous les usagers concernés. Cet acheminement doit faire face aux difficultés induites par la dispersion et la forte mobilité des véhicules, l'absence ou l'insuffisance d'infrastructure, la densité variable du réseau, la surcharge en informations à envoyer et l'étendue des zones géographiques à couvrir. En effet, la problématique de diffusion des données dans les VANETs s'avère non-triviale et de nombreux verrous scientifiques doivent être levés pour permettre un support efficace, collaboratif et fiable pour les applications de sûreté et de sécurité routière.Plus précisément, nous aborderons la problématique de la dissémination collaborative en se posant trois questions : “comment disséminer les données ? À quel moment le faire ? Mais aussi quoi disséminer et comment inciter à le faire ? ” Nous avons apporté des réponses à travers les trois contributions de cette thèse. La première consiste à proposer une stratégie de dissémination efficace, qui soit adaptée à l'importance de l'information échangée et à sa durée de vie, permettant ainsi d'éviter un processus de diffusion intensif. Celui-ci est inapproprié dans ce cas de figure, car il génère de la congestion et beaucoup de redondance. Une étude de performances par simulation est réalisée, laquelle montre une diminution de 90% du taux de messages redondants par rapport au cas de la diffusion par inondation. Afin d'améliorer plus encore les performances du processus de diffusion des messages de sûreté, nous proposons, dans un second temps, un ordonnanceur pour l'accès au canal de communication qui a pour objectif de réduire le nombre de collisions dues aux synchronisations afférentes à l'utilisation du multi-canal dans le standard IEEE 802.11p/1609.4 et donc élever le taux de réception des données. Nous basons notre proposition sur la théorie de l'arrêt optimal, qui décide du moment opportun pour l'envoi d'une information en conciliant occupation du canal, efficacité de l'envoi et délai d'ajournement toléré par une information. Dans notre cas, la théorie de l'arrêt optimal est formulée par un processus de décision Markovien (MDP). Nous montrons ainsi par simulation une amélioration substantielle du taux de réception (de 25%) et une diminution importante des pertes (de 47%).Après s'être intéressé à l'aspect quantitatif des performances du réseau, nous nous intéresserons ensuite à l'amélioration de la fiabilité du processus de diffusion. Cette fiabilité est obtenue grâce à l'incitation des véhicules à la coopération et à l'exclusion des véhicules malicieux de celui-ci. Ceci est réalisé au travers de la proposition d'un modèle de confiance, inspiré des jeux de signaux. Le modèle crée une situation d'équilibre, tel que les différentes parties le composant ne soient pas tentées de le contourner, ainsi découle une auto-sélection des véhicules, laquelle est rapide et peu coûteuse. À notre connaissance, notre modèle est le seul à s'attaquer aux effets néfastes des deux types de véhicules, malicieux et égoïstes, en même temps. Comme précédemment, nous évaluons les performances de notre solution au travers d'une modélisation par une chaîne de Markov et divers jeux de simulation. Ceci a permis de montrer que 100% des véhicules malicieux sont exclus, avec le maintien d'un taux de coopération élevé dans le réseau, soit une amélioration de 42% / Vehicular Ad Hoc Networks (VANETs) allow sharing different kinds of data between vehicles in a collaborative way. In this thesis, we are particularly interested in road safety applications, designed for the exchange of information on road traffic and conditions. This kind of applications have strict Quality of Service (QoS) requirements, as data must be routed thoroughly and without any delays so for assuring the timely delivery of useful information to the drivers. In this context, data routing must face several issues raised by the high mobility and dispersion of vehicles, inadequate or completely lacking infrastructure, a variable network density, network saturation due to the large of information to deliver, and the size of the geographical areas to cover. Indeed, the problem of data dissemination in VANETs is non-trivial, and several research challenges must be solved in order to provide an efficient, collaborative, and reliable support for road safety applications. Specifically, we will address the problem of collaborative data dissemination through the following three questions: “How to perform data dissemination?”, “When should we do it?”, and “What must be disseminated?” We have provided answers to these questions through the three contributions of this thesis. Our first contribution is an efficient dissemination strategy, specifically tailored to the importance of the exchanged information as well as its lifespan, which is able to avoid the intensive dissemination process that generates network congestion and data redundancy. We confirm our statements and validate the performance of our solution by modeling it using a discrete-time Markov chain, which demonstrates the number of necessary retransmissions for all concerned vehicles to receive information. Moreover, we performed extensive simulations that show a reduction of up to 90% of redundant messages with respect to message flooding dissemination strategies. Next, in order to further improve the road safety message dissemination process, we propose a communications channel access scheduler, which aims at reducing the number of collisions caused by IEEE 802.11p/1609.4 multi-channel synchronizations, and thus improving the data reception rate. We base our solution on the optimal stopping theory, which chooses the right moment to send information by balancing the channel occupancy rate, the data delivery efficiency, and the maximum deferment delay tolerated by the information. To this end, we formulate the optimal stopping theory through a Markov decision process (MDP). We show through simulation-based evaluations an improvement of the reception rate of up to 25% and a reduction of up to 47% of message losses. Finally, after being interested in the quantitative aspect of network performance, we centered our efforts on improving the reliability of the dissemination process, which is obtained by motivating vehicles to cooperate and evicting malicious vehicles from the process. To this end, we propose a trust model inspired on signaling games, which are a type of dynamic Bayesian games. Through the use of our model, equilibrium is achieved, thus resulting in a fast and low-cost vehicle self-selection process. We define the parameters of our trust model through a discrete-time Markov chain model. To the best of our knowledge, our solution is the only existing solution that tackles the negative effects introduced by the presence of both malicious and selfish vehicles in a VANET. We evaluated the performance of our solution by modeling it using a Markov chain, and a set of simulations. Our results show that up to 100% of malicious vehicles are evicted while keeping a high cooperation rate, thus achieving an improvement of 42% when compared to other similar solutions

Indiana University-Purdue University Indianapolis (IUPUI) / With the rapid growth in wireless mobile communication technology, Vehicular Ad-hoc Network (VANET) has emerged as a promising method to effectively solve transportation-related issues. So far, most of researches on VANETs have been conducted with simulations as the real-world experiment is expensive. A core problem affecting the fidelity of simulation is the mobility model employed. In this thesis, a sophisticated traffic simulator capable of generating realistic vehicle traces is introduced. Combined with network simulator NS-2, we used this tool to evaluate the general performance of several routing protocols and studied the impact of intersections on simulation results. We show that static nodes near the intersection tend to become more active in packet delivery with higher transferred throughput.

Vehicles on the road today are complex multi-node computer networks. Security has always been a critical issue in the automotive computing industry. It is becoming even more crucial with the advent of autonomous vehicles and driver assistant technology. There is potential for attackers to control vehicles maliciously. Traditionally Original Equipment Manufacturers have relied on physical security and a firewall to secure vehicles but with network connected and autonomous capable vehicles this is not enough. The concept of defence in depth is required. This means not trusting that internal traffic inside the firewall is benign. Each node in the vehicles network should be able to verify the authenticity and validity of communications it receives from other nodes. Implementation of the crypto-graphic systems for doing this is error prone. Therefore a key issue in the thesis is reducing the attack surface by developing these checks in the autonomous vehicle stack in a scalable way so the programmer does not have to be aware of this security layer on a day-to-day basis nor re-implement it for each node in these heterogeneous systems. Although message integrity and authenticity verification have been studied and implemented in many fields, the area of heterogeneous autonomous systems present unique research challenges. There are tight performance constraints due to the real time requirements for vehicle control systems and data publishing rates. It is an open question if this approach can achieve performance within the bounds required for a reliable autonomous vehicle. Additionally the security benefit of scalably automatically generating the message integrity verification code across all of the nodes in a heterogeneous system would help the field quantify the defect reduction and security benefit of this kind of code generation on complex software systems. / Dagens fordon på vägarna är komplexa datanät med flera noder. Säkerheten har alltid varit en viktig fråga inom bilindustrin. Det blir ännu viktigare i och med tillkomsten av autonoma fordon och förarassistentteknik. Det finns en potential för angripare att styra fordon på ett illvilligt sätt. Traditionellt har tillverkare av originalutrustning förlitat sig på fysisk säkerhet och en brandvägg för att säkra fordonen, men med nätverksanslutna och autonoma fordon räcker detta inte längre. Begreppet försvar på djupet är nödvändigt. Detta innebär att man inte kan lita på att den interna trafiken innanför brandväggen är godartad. Varje nod i fordonets nätverk bör kunna kontrollera äktheten och giltigheten hos den kommunikation som den tar emot från andra noder. Genomförandet av kryptografiska system för att göra detta är felkänsligt. En viktig fråga i avhandlingen är därför att minska angreppsytan genom att utveckla dessa kontroller i det autonoma fordonet på ett skalbart sätt så att programmeraren inte behöver vara medveten om detta säkerhetslager dagligen eller implementera det på nytt för varje nod i dessa heterogena system. Även om meddelandeintegritet och äkthetskontroll har studerats och genomförts inom många områden, innebär området heterogena autonoma system unika forskningsutmaningar. Det finns snäva prestandabegränsningar på grund av realtidskraven för fordonskontrollsystem och datapubliceringshastigheter. Det är en öppen fråga om detta tillvägagångssätt kan uppnå prestanda inom de gränser som krävs för ett tillförlitligt autonomt fordon. Dessutom skulle säkerhetsfördelarna med en skalbar automatisk generering av koden för verifiering av meddelandets integritet över alla noder i ett heterogent system hjälpa fältet att kvantifiera felminskningen och säkerhetsfördelarna med denna typ av kodgenerering i komplexa programvarusystem.

The Vehicular Ad Hoc Network (VANET) is a promising approach for future Intelligent Transportation Systems (ITS) implementation. The data transmission is wireless primarily in the VANET system. The secure data transmission in VANET attracts research attention without any doubt. The Ciphertext-Policy Attribute-Based Encryption (CP-ABE) provides an encrypted access control mechanism for broadcasting messages in VANET. The user’s attributes stand for its current property. However, if we apply vehicle location as the attribute, this attribute has to keep up-to-date with the vehicle’s movement. It is not easy for current CP-ABE algorithms because whenever one attribute changes, the entire private key, which is based on all the attributes, must be changed. In this thesis, we apply fading function to realize the “dynamic attribute” feature in CP-ABE. The dynamic attribute allows the user to update each attribute separately, and fading function gives each attribute a valid period. We introduce the dynamic attribute feature to three different CP-ABE algorithms. Then we design a VANET system that applies the CP-ABE with dynamic attribute feature. We evaluate the processing time of three different CP-ABE algorithms. We apply two different pairing curves for different security requirements. Our results show that the introduction of fading function does not cause significant extra time cost to current CP-ABE algorithms. The fading function causes extra 0.2ms on average for each attribute that participates in encryption and decryption. The sum-up time for encryption and decryption is between 100ms to 200ms when there are ten attributes participating in encryption and decryption. / VANET är ett lovande tillvägagångssätt för framtida genomförande av ITS. Dataöverföringen är i första hand trådlös i VANET-systemet. Den säkra dataöverföringen i VANET är utan tvekan föremål för forskningens uppmärksamhet. CP-ABE ger en krypterad åtkomstkontrollmekanism för sändning av meddelanden i VANET. Användarens attribut står för dennes aktuella egenskaper. Men om vi använder fordonets position som attribut måste detta attribut hålla sig uppdaterat med fordonets rörelse. Det är inte lätt för de nuvarande CP-ABE-algoritmerna eftersom hela den privata nyckeln, som är baserad på alla attribut, måste ändras när ett attribut ändras. I den här avhandlingen tillämpar vi fading-funktionen för att realisera funktionen ”dynamiskt attribut” i CP-ABE. Det dynamiska attributet gör det möjligt för användaren att uppdatera varje attribut separat, och fading-funktionen ger varje attribut en giltighetstid. Vi inför den dynamiska attributfunktionen i tre olika CP-ABE-algoritmer. Därefter utformar vi ett VANET-system som tillämpar CP-ABE med dynamisk attributfunktion. Vi utvärderar tidsåtgången för tre olika CP-ABE-algoritmer. Vi tillämpar två olika parningskurvor för olika säkerhetskrav. Våra resultat visar att införandet av fading-funktionen inte orsakar någon betydande tidsåtgång för de nuvarande CP-ABE-algoritmerna. Fading-funktionen orsakar i genomsnitt 0,2 ms extra för varje attribut som deltar i kryptering och dekryptering. Den sammanlagda tiden för kryptering och dekryptering är mellan 100 och 200 ms när tio attribut deltar i kryptering och dekryptering.

Vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communication enable the sharing, in real time, of vehicular locations and speeds with other vehicles, traffic signals, and traffic control centers. This shared information can help traffic to better traverse intersections, road segments, and congested neighborhoods, thereby reducing travel times, increasing driver safety, generating data for traffic planning, and reducing vehicular pollution. This study, which focuses on vehicular pollution, used an analysis of data from NREL, BTS, and the EPA to determine that the widespread use of V2V-based truck platooning—the convoying of trucks in close proximity to one another so as to reduce air drag across the convoy—could eliminate 37.9 million metric tons of CO2 emissions between 2022 and 2026.

La convergencia de las telecomunicaciones, la informática, la tecnología inalámbrica y los sistemas de transporte, va a facilitar que nuestras carreteras y autopistas nos sirvan tanto como plataforma de transporte, como de comunicaciones. Estos cambios van a revolucionar completamente cómo y cuándo vamos a acceder a determinados servicios, comunicarnos, viajar, entretenernos, y navegar, en un futuro muy cercano. Las redes vehiculares ad hoc (vehicular ad hoc networks VANETs) son redes de comunicación inalámbricas que no requieren de ningún tipo de infraestructura, y que permiten la comunicación y conducción cooperativa entre los vehículos en la carretera. Los vehículos actúan como nodos de comunicación y transmisores, formando redes dinámicas junto a otros vehículos cercanos en entornos urbanos y autopistas. Las características especiales de las redes vehiculares favorecen el desarrollo de servicios y aplicaciones atractivas y desafiantes. En esta tesis nos centramos en las aplicaciones relacionadas con la seguridad. Específicamente, desarrollamos y evaluamos un novedoso protocol que mejora la seguridad en las carreteras. Nuestra propuesta combina el uso de información de la localización de los vehículos y las características del mapa del escenario, para mejorar la diseminación de los mensajes de alerta. En las aplicaciones de seguridad para redes vehiculares, nuestra propuesta permite reducir el problema de las tormentas de difusión, mientras que se mantiene una alta efectividad en la diseminación de los mensajes hacia los vehículos cercanos. Debido a que desplegar y evaluar redes VANET supone un gran coste y una tarea dura, la metodología basada en la simulación se muestra como una metodología alternativa a la implementación real. A diferencia de otros trabajos previos, con el fin de evaluar nuestra propuesta en un entorno realista, en nuestras simulaciones tenemos muy en cuenta tanto la movilidad de los vehículos, como la transmisión de radio en entornos urbanos, especialmente cuando los edificios interfieren en la propagación de la señal de radio. Con este propósito, desarrollamos herramientas para la simulación de VANETs más precisas y realistas, mejorando tanto la modelización de la propagación de radio, como la movilidad de los vehículos, obteniendo una solución que permite integrar mapas reales en el entorno de simulación. Finalmente, evaluamos las prestaciones de nuestro protocolo propuesto haciendo uso de nuestra plataforma de simulación mejorada, evidenciando la importancia del uso de un entorno de simulación adecuado para conseguir resultados más realistas y poder obtener conclusiones más significativas. / Martínez Domínguez, FJ. (2010). Improving Vehicular ad hoc Network Protocols to Support Safety Applications in Realistic Scenarios [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/9195