Efficient real-time video delivery in vehicular networks

Tesis por compendio[EN] Vehicular Ad-hoc Networks (VANET) are a special type of networks where the nodes involved in the communication are vehicles. VANETs are created when several vehicles connect among themselves without the use of any infrastructure. In certain situations the absence of infrastructure is an advantage, but it also creates several challenges that should be overcome. One of the main problems related with the absence of infrastructure is the lack of a coordinator that can ensure a certain level of quality in order to enable the correct transmission of video and audio. Video transmission can be extremely useful in this type of networks as it can be used for videoconferencing of by traffic authorities to monitor the scene of an accident. In this thesis we focused on real time video transmission, providing solutions for both unicast and multicast environments. Specifically, we built a real-world testbed scenario and made a comparison with simulation results to validate the behavior of the simulation models. Using that testbed we implemented and improved DACME, an admission control module able to provide Quality of Service (QoS) to unicast video transmissions. DACME proved to be a valid solution to obtain a certain level of QoS in multi-hop environments. Concerning multicast video transmission, we developed and simulated several flooding schemes, focusing specifically on VANET environments. In this scope, the main contribution of this thesis is the Automatic Copies Distance Based (ACDB) flooding scheme. Thanks to the use of the perceived vehicular density, ACDB is a zeroconf scheme able to achieve good video quality in both urban and highway environments, being specially effective in highway environments.[ES] Las redes vehiculares ad-hoc (VANET) son un tipo especial de redes en las que los nodos que participan de la comunicación son vehículos. Las VANETs se crean cuando diversos vehículos se conectan entre ellos sin el uso de ninguna infraestructura. En determinadas situaciones, la ausencia de infraestructura es una ventaja, pero también crea una gran cantidad de desafíos que se deben superar. Uno de los principales problemas relacionados con la ausencia de infraestructura, es la ausencia de un coordinador que pueda asegurar un determinado nivel de calidad, para poder asegurar la correcta transmisión de audio y vídeo. La transmisión de vídeo puede ser de extrema utilidad en este tipo de redes ya que puede ser empleada para videoconferencias o por las autoridades de tráfico para monitorizar el estado de un accidente. En esta tesis nos centramos en la transmisión de vídeo en tiempo real, proveyendo soluciones tanto para entornos unicast como multicast. En particular construimos un banco de pruebas real y comparamos los resultados obtenidos con resultados obtenidos en un entorno simulado para comprobar la fiabilidad de estos modelos. Usando el mismo banco de pruebas, implementamos y mejoramos DACME, un módulo de control de admisión capaz de proveer de calidad de servicio a transmisiones de vídeo unicast. DACME probó ser una solución válida para obtener ciertos niveles de calidad de servicio en entornos multisalto. En lo referente a la transmisión de vídeo multicast, desarrollamos y simulamos diversos esquemas de difusión diseñados específicamente para entornos VANET. En este campo, la principal contribución de esta tesis es el esquema de difusión "Automatic Copies Distance Based" (ACDB). Gracias al uso de la densidad vehicular percibida, ACDB es un esquema, que sin necesidad de configuración, permite alcanzar una buena calidad de vídeo tanto en entornos urbanos como en autopistas, siendo especialmente efectivo en este último entorno.[CA] Les xarxes vehiculars ad-hoc (VANET) son un tipus de xarxes especials a les que els diferents nodes que formen part d'una comunicació son vehicles. Les VANETs es formen quan diversos vehicles es connecten sense fer ús de cap infraestructura. A certes situacions l'absència d'una infraestructura suposa un avantatge, encara que també genera una gran quantitat de desafiaments que s'han de superar. U dels principals problemes relacionats amb l'absència d'infraestructura, és la manca d'un coordinador que puga garantir una correcta transmissió tant de video com d'àudio. La transmissió de video pot ser d'extrema utilitat a aquest tipus de xarxes, ja que es por emprar tant per a videoconferències com per part de les autoritats de trànsit per monitoritzar l'estat d'un accident. A aquesta tesi ens centrem en transmissió de video en temps real, proporcionant solucions tant a entorns unicast como a entorns multicast. Particularment, vam construir un banc de proves i obtinguérem resultats que comparàrem amb resultats obtinguts mitjançant simulació. D'aquesta manera validarem la fiabilitat dels resultats simulats. Fent ús del mateix banc de proves, vàrem implementar i millorar DACME, un mòdul de control d'admissió, capaç de proveir de qualitat de servici a transmissions de video unicast. DACME va provar ser una bona solució per obtindré un bon nivell de qualitat de servici en entorns de xarxes ad-hoc amb diversos salts. Si ens centrem a la transmissió de video multicast, vàrem implementar i simular diferents esquemes de difusió, específicament dissenyats per al seu ús a entorns VANET. La principal contribució d'aquesta tesi es l'esquema de difusió ACDB (Automatic Copies Distance Based). Fent ús de la densitat vehicular, ACDB es capaç d'obtindre una bona qualitat de video tant a ciutats com a vies interurbanes, sent a especialment efectiu a aquestes últimes. A més a més no es necessària cap configuració per part de l'usuari.Torres Cortés, Á. (2016). Efficient real-time video delivery in vehicular networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62685TESISCompendi

Desarrollo de mecanismos distribuidos para soporte a calidad de servicio en redes inalámbricas ad-hoc

En esta tesina se desarrolla un entorno MANET de pruebas (testbed) pionero que ofrece QoS (calidad de servicio) activa. Tras su desarrollo y las pruebas de rendimiento pertinentes, se desarrolla una un módulo de control de admisión para mejorar el soporte que estas redes pueden brindar a comunicaciones con requerimientos de QoS.Torres Cortés, Á. (2010). Desarrollo de mecanismos distribuidos para soporte a calidad de servicio en redes inalámbricas ad-hoc. http://hdl.handle.net/10251/14191Archivo delegad

Breaking persistent working group partnerships: a social experiment

Facing multidisciplinary projects is becoming quite common in companies worldwide, meaning that experts from a specific area must team up with experts from other areas in a dynamic, ad hoc manner. For a professional to meet such requirements successfully, it is important that teamwork skills are developed during college. However, such issue is usually not addressed thoroughly, and most students end up teaming with the same partners over and over again, thereby failing to achieve the critical adaptability skills expected from them. To address this drawback, in this paper we present the results of a study where students were forced to team up with other partners based on the results of a computer networking skills-ranking exam. Experimental results confirm the repeating pattern in terms of past partnerships, and student resistance to partner changes. On the positive side, results show that having new partners indeed help at achieving a more even task distribution, and that students are moderately aware of the upcoming challenges in their future professional activity, recognizing the benefits of teaming up with new people.This work was partially supported by the School of Informatics (ETSINF) and the Department of Computer Engineering (DISCA) at the Universitat Politècnica de València.Tavares De Araujo Cesariny Calafate, CM.; Arlandis, J.; Torres Cortes, A. (2015). Breaking persistent working group partnerships: a social experiment. En INTED2015 Proceedings. IATED. 1329-1337. http://hdl.handle.net/10251/70447S1329133

V2X solutions for real-time video collection

© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] Quickly identifying the severity of highway acci-dents, as well as the resources required to assist the people involved in those accidents, is a basic requirement for future intelligent transportation systems. In this context, vehicular communication technologies currently being standardized are able to provide novel solutions to address this problem. In this work we study the feasibility of combining vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications to deliver a video stream from the place of the accident to the traffic authorities. Our approach relies on vehicles as data relays, thus having the additional advantage of providing drivers with a clear view about the accident, thereby helping to reduce stress and improving traffic flow. An experimental analysis comparing different traffic flooding mechanisms for wireless networks show that the proposed system is viable for highways with moderate/high amounts of traffic, although highlighting the need for more efficient mechanisms specifically addressing broadcast propagation in highway envi-ronments.This work was partially supported by the Ministerio de Economía y Competitividad, Spain, under Grant TIN2011- 27543-C03-01, by the Ministerio de Educación, Spain, under the FPU program, AP2009-2415, and by the National Institute of Informatics International Internship Program.Torres Cortes, A.; Ji, Y.; Tavares De Araujo Cesariny Calafate, CM.; Cano Escribá, JC.; Manzoni, P. (2014). V2X solutions for real-time video collection. En Wireless On-demand Network Systems and Services (WONS), 2014 11th Annual Conference on. IEEE. 116-121. doi:10.1109/WONS.2014.6814731S11612

Evaluating H.265 real-time video flooding quality in highway V2V environments

© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works[EN] Video transmission over VANETs is an extremely difficult task not only due to the high bandwidth requirements, but also due to typical VANET characteristics such as signal attenuation, packet losses, high relative speeds and fast topology changes. In future scenarios, vehicles will provide other vehicles with information about accidents or congestion on the road, and in these cases offering visual information can be a really valuable resource for both drivers and traffic authorities. Hence, achieving an efficient transmission is critical to maximize the user-perceived quality. In this paper we evaluate solutions that combine different flooding techniques, and different video codecs to assess the effectiveness of long-distance real-time video streaming. In particular, we will compare the most effective video coding standard available (H.264) with the upcoming H.265 codec in terms of both frame loss and PSNR.This work was partially supported by the Ministerio de Economía y Competitividad, Spain, under Grant TIN2011- 27543-C03-01, and by the Ministerio de Educación, Spain, under the FPU program, AP2009-2415.Torres Cortés, Á.; Piñol, P.; Tavares De Araujo Cesariny Calafate, CM.; Cano Escribá, JC.; Manzoni, P. (2014). Evaluating H.265 real-time video flooding quality in highway V2V environments. En 2014 IEEE Wireless Communications and Networking Conference (WCNC). IEEE. 2758-2763. https://doi.org/10.1109/WCNC.2014.6952858S2758276

Evaluation of flooding schemes for real-time video transmission in VANETs

This is the author’s version of a work that was accepted for publication in Ad Hoc Networks. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Ad Hoc Networks, vol. 24, (2015) DOI 10.1016/j.adhoc.2014.07.030Long-distance real-time video flooding over Vehicular Ad-hoc Networks (VANETs) is challenging due to the dynamic nature of vehicular networks. Real-time video transmission has high requirements in terms of bandwidth and delay, while VANETs are characterized by very limited radio resources and high mobility. Our objective is to compare ten different flooding schemes specially designed for this task and select the best in terms of packet arrival ratio and Peak Signal-to-Noise Ratio (PSNR). Additionally, we propose Automatic Copies Distance Based (ACDB), an improved flooding scheme, to cope with variable vehicle density situations. Furthermore, to ensure a good behavior under all types of circumstances, we also study the impact of Global Positioning System (GPS) drift on these schemes. Simulation results show that long-distance real-time video flooding transmission is feasible under certain vehicle density conditions and the quality achieved is enough to allow using such solutions in future applications.This work was partially supported by the Ministerio de Economia y Competitividad, Spain, under Grant TIN2011-27543-C03-01, by the Ministerio de Educacion, Spain, under the FPU program, AP2009-2415, and by the National Institute of Informatics International Internship Program.Torres Cortés, Á.; Tavares De Araujo Cesariny Calafate, CM.; Cano Escribá, JC.; Manzoni, P.; Ji, Y. (2015). Evaluation of flooding schemes for real-time video transmission in VANETs. Ad Hoc Networks. 24:3-20. https://doi.org/10.1016/j.adhoc.2014.07.030S3202

A Tool Offering Steady-State Simulations for VANETs

[EN] Without realistic vehicle mobility patterns, the evaluation of communication protocols in vehicular networks is compromised. Moreover, in order to ensure repeatability and fairness in vehicular simulations, researchers require simulation tools that allow them to have a complete control of simulations. In this paper we present VACaMobil, a Mobility Manager for the OMNeT++ simulator which offers a way to create complex scenarios with realistic vehicular mobility by allowing to define the desired average number of vehicles, along with its upper and lower bounds, which are maintained throughout the simulation. We compare VACaMobil against other commonly used methods which also generate and manage vehicular mobility. Results expose some flaws of those basic tools, and shows that VACaMobil behaves significantly better. The harmful impact on communication protocols when using common tools is also quantified, revealing VACaMobil as a necessity for current research.This work was partially supported by the Ministerio de Economía y Competitividad, Spain, under Grants TIN2011-27543- C03-01 and BES-2012-052673, by the Ministerio de Educación, Spain, under the FPU program, AP2010-4397, AP2009-2415, and by the Universitat Politècnica de València under project ABATIS (PAID-05-12).Báguena Albaladejo, M.; Martínez Tornell, S.; Torres Cortés, Á.; Calafate, CT.; Cano Escribá, JC.; Manzoni, P. (2013). A Tool Offering Steady-State Simulations for VANETs. Recent Patents on Telecommunications. 2(2):102-112. http://hdl.handle.net/10251/40658S1021122

VACaMobil: VANET Car Mobility Manager for OMNeT++

©2013 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The performance of communication protocols in vehicular networks highly depends on the mobility pattern. Therefore, one of the most important issues when simulating this kind of protocols is how to properly model vehicular mobility. In this paper we present VACaMobil, a VANET Car Mobility Manager for the OMNeT++ simulator which allows researchers to completely define vehicular mobility by setting the desired average number of vehicles along with its upper and lower bounds. We compare VACaMobil against other common methods employed to generate vehicular mobility. Results clearly show the advantages of the VACaMobil tool when distributing vehicles in a real scenario, becoming one of the best mobility generators to evaluate the performance of different communication protocols and algorithms in VANET environments.This work was partially supported by the Ministerio de Economía y Competitividad, Spain, under Grants TIN2011-27543-C03-01 and BES-2012-052673, and by the Ministerio de Educación, Spain, under the FPU program, AP2010-4397, AP2009-2415.Báguena Albaladejo, M.; Tornell, SM.; Torres Cortés, Á.; Tavares De Araujo Cesariny Calafate, CM.; Cano Escribá, JC.; Manzoni, P. (2013). VACaMobil: VANET Car Mobility Manager for OMNeT++. IEEE. https://doi.org/10.1109/ICCW.2013.6649393

Seamless MANET autoconfiguration through enhanced 802.11 beaconing

The deployment of mobile ad-hoc networks involves several configuration steps, which complicate research efforts and hinder user interest. This problem prompts for new approaches offering full autoconfiguration of terminals at the different network layers involved. In this paper we propose a novel solution for the autoconfiguration of IEEE 802.11 based MANETs that relies on SSID parameter embedding. Our solution allows users to join an existing MANET without resorting to any additional technology, and even in the presence of encrypted communications. Experimental testbed results using a real implementation of the proposed solution show that it introduces significant improvements compared to other existing solutions, allowing nearby stations to be configured in about two seconds, and also enabling multi-hop dissemination of configuration data to take place quickly and efficiently.This work was partially supported by the Ministerio de Educacion y Ciencia, Spain, under Grant TIN2011-27543-C03-01.Villanueva Del Pozo, MJ.; Tavares De Araujo Cesariny Calafate, CM.; Torres Cortes, A.; Cano Reyes, J.; Cano Escribá, JC.; Manzoni, P. (2013). Seamless MANET autoconfiguration through enhanced 802.11 beaconing. Mobile Information Systems. 9(1):19-35. doi:10.3233/MIS-2012-0145S19359

Programa de desarrollo de sistemas integrales de infraestructura y movilidad colectiva. Nuevas formas de movilidad para la vida

Las poblaciones urbanas padecen diversos problemas ambientales, de salud, segregación y pérdida de espacios públicos, derroche energético, ruido, así como altas inversiones de tiempo y dinero. Estas situaciones poseen un denominador común: una tecnología inadecuada llamada automóvil unipersonal. Buscamos intervenir tecnológicamente el contexto de las ciudades mediante un sistema de movilidad público, eficiente, no invasivo, silencioso, de bajo costo, saludable y ecológico. En este trabajo presentamos diferentes soluciones, con la intención de ir llevando esta tecnología hacia su transferencia tecnológica.ITESO, A.C.CoecytjalIngenieros Sin Frontera