357 research outputs found

    Towards video streaming in IoT environments: vehicular communication perspective

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    Multimedia oriented Internet of Things (IoT) enables pervasive and real-time communication of video, audio and image data among devices in an immediate surroundings. Today's vehicles have the capability of supporting real time multimedia acquisition. Vehicles with high illuminating infrared cameras and customized sensors can communicate with other on-road devices using dedicated short-range communication (DSRC) and 5G enabled communication technologies. Real time incidence of both urban and highway vehicular traffic environment can be captured and transmitted using vehicle-to-vehicle and vehicle-to-infrastructure communication modes. Video streaming in vehicular IoT (VSV-IoT) environments is in growing stage with several challenges that need to be addressed ranging from limited resources in IoT devices, intermittent connection in vehicular networks, heterogeneous devices, dynamism and scalability in video encoding, bandwidth underutilization in video delivery, and attaining application-precise quality of service in video streaming. In this context, this paper presents a comprehensive review on video streaming in IoT environments focusing on vehicular communication perspective. Specifically, significance of video streaming in vehicular IoT environments is highlighted focusing on integration of vehicular communication with 5G enabled IoT technologies, and smart city oriented application areas for VSV-IoT. A taxonomy is presented for the classification of related literature on video streaming in vehicular network environments. Following the taxonomy, critical review of literature is performed focusing on major functional model, strengths and weaknesses. Metrics for video streaming in vehicular IoT environments are derived and comparatively analyzed in terms of their usage and evaluation capabilities. Open research challenges in VSV-IoT are identified as future directions of research in the area. The survey would benefit both IoT and vehicle industry practitioners and researchers, in terms of augmenting understanding of vehicular video streaming and its IoT related trends and issues

    Survey on Congestion Detection and Control in Connected Vehicles

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    The dynamic nature of vehicular ad hoc network (VANET) induced by frequent topology changes and node mobility, imposes critical challenges for vehicular communications. Aggravated by the high volume of information dissemination among vehicles over limited bandwidth, the topological dynamics of VANET causes congestion in the communication channel, which is the primary cause of problems such as message drop, delay, and degraded quality of service. To mitigate these problems, congestion detection, and control techniques are needed to be incorporated in a vehicular network. Congestion control approaches can be either open-loop or closed loop based on pre-congestion or post congestion strategies. We present a general architecture of vehicular communication in urban and highway environment as well as a state-of-the-art survey of recent congestion detection and control techniques. We also identify the drawbacks of existing approaches and classify them according to different hierarchical schemes. Through an extensive literature review, we recommend solution approaches and future directions for handling congestion in vehicular communications

    Recent Developments on Mobile Ad-Hoc Networks and Vehicular Ad-Hoc Networks

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    This book presents collective works published in the recent Special Issue (SI) entitled "Recent Developments on Mobile Ad-Hoc Networks and Vehicular Ad-Hoc Networks”. These works expose the readership to the latest solutions and techniques for MANETs and VANETs. They cover interesting topics such as power-aware optimization solutions for MANETs, data dissemination in VANETs, adaptive multi-hop broadcast schemes for VANETs, multi-metric routing protocols for VANETs, and incentive mechanisms to encourage the distribution of information in VANETs. The book demonstrates pioneering work in these fields, investigates novel solutions and methods, and discusses future trends in these field

    Video streaming in urban vehicular environments: Junction-aware multipath approach

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    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. In multipath video streaming transmission, the selection of the best vehicle for video packet forwarding considering the junction area is a challenging task due to the several diversions in the junction area. The vehicles in the junction area change direction based on the different diversions, which lead to video packet drop. In the existing works, the explicit consideration of different positions in the junction areas has not been considered for forwarding vehicle selection. To address the aforementioned challenges, a Junction-Aware vehicle selection for Multipath Video Streaming (JA-MVS) scheme has been proposed. The JA-MVS scheme considers three different cases in the junction area including the vehicle after the junction, before the junction and inside the junction area, with an evaluation of the vehicle signal strength based on the signal to interference plus noise ratio (SINR), which is based on the multipath data forwarding concept using greedy-based geographic routing. The performance of the proposed scheme is evaluated based on the Packet Loss Ratio (PLR), Structural Similarity Index (SSIM) and End-to-End Delay (E2ED) metrics. The JA-MVS is compared against two baseline schemes, Junction-Based Multipath Source Routing (JMSR) and the Adaptive Multipath geographic routing for Video Transmission (AMVT), in urban Vehicular Ad-Hoc Networks (VANETs)

    Contributions to provide a QoS-aware self-configured framework for video-streaming services over ad hoc networks

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    Aplicat embargament des del dia 27 d'octubre de 2021 fins 31 de juliol de 2022Ad hoc networks have attracted much attention from the research community over the last years and important technical advances have risen as a consequence. These networks are foreseen as an important kind of next generation access networks, where multimedia services will be demanded by end users from their wireless devices everywhere. In this thesis, we specially focus our research work on mobile ad hoc networks (MANETs) and on vehicular ad hoc networks (VANETs), two kind of ad hoc networks over which interesting multimedia services can be provided. The special haracteristics of MANETs/VANETs, such as mobility, dynamic network topology (specially in VANETs), energy constraints (in case of MANETs), infrastructureless and variable link capacity, make the QoS (Quality of Service) provision over these networks an important challenge for the research community. Due to that, there is a need to develop new routing protocols specially designed for MANETs and VANETs able to provide multimedia services. The main objective of this thesis is to contribute in the development of the communication framework for MANETs and VANETs to improve decisions to select paths or next hops in the moment of forwarding video-reporting messages. In this way, it would be possible to have a quick answer to manage daily problems in the city and help the emergency units (e.g., police, ambulances, health care units) in case of incidents (e.g., traffic accidents). Furthermore, in case of VANETs, a real scenario must be created and thus we have analysed the presence of obstacles in real maps. Also, in case of an obstacle found between the current forwarding node and the candidate next forwarding node, the packet is stored in a buffer, for a maximum time, until a forwarding neighbour node is found; otherwise, the packet is dropped. To improve the communication framework for MANETs, we propose a new routing protocol based on a game-theoretical scheme for N users specially designed to transmit video-reporting messages. Our proposal makes the network more efficient and provides a higher degree of satisfaction of the users by receiving much more packets with a lower average end-to-end delay, lower jitter and higher PSNR (Peak Signal-to-Noise Ratio). In addition, we propose a geographical routing protocol for VANETs that considers multiple metrics named 3MRP (Multimedia Multimetric Map-Aware Routing Protocol) [1]. 3MRP is a geographical protocol based on hop-by-hop forwarding. The metrics considered in 3MRP are the distance, the density of vehicles in transmission range, the available bandwidth, the future trajectory of the neighbouring nodes and the MAC layer losses. Those metrics are weighted to obtain a multimetric score. Thus, a node selects another node among its neighbours as the best forwarding node to increase the percentage of successful packet delivery, minimizing the average packet delay and offering a certain level of quality and service. Furthermore, a new algorithm named DSW (Dynamic Self-configured Weights) computes for each metric its corresponding weight depending on the current network conditions. As a consequence, nodes are classiffied in a better way.Les xarxes sense fils ad hoc han captat molt l'atenció per part de la comunitat científica en els últims anys, a més dels importants avenços tècnics que han sorgit. Aquestes xarxes es preveuen com un tipus important de xarxes d'accés de nova generació, a on els serveis multimèdia seran requerits pels usuaris a través dels seus dispositius sense fils desde tot arreu. En aquesta tesi, centrem el nostre treball especialment en les xarxes mòbils ad hoc (MANET, Mobile Ad hoc Network) i en les xarxes vehiculars ad hoc (VANET, Vehicular Ad hoc Network). Les característiques especials de les MANETs i les VANETs, com la mobilitat, la topologia dinàmica de la xarxa (especialment en VANETs), les restriccions de bateria (en cas de MANETs), l'absència d'infrastructura i la capacitat variable de l'enllaç sense fil fa que la provisió de la qualitat de servei en aquestes xarxes sigui un repte important per a la comunitat científica. A causa d'això, hi ha la necessitat de desenvolupar nous protocols d'encaminament especialment dissenyats per a MANETs i VANETs capaços de proporcionar els serveis de multimèdia requerits. L'objectiu principal d'aquesta tesi és proveir millores en la comunicació per a les xarxes ad hoc MANET i VANET per millorar les decisions a l'hora de seleccionar els propers camins o nodes, respectivament, en el moment de l'enviament de les trames del video. D'aquesta manera serà possible tenir una resposta ràpida per resoldre els problema diaris a la ciutat i ajudar a les unitats d'emergència (per exemple, policia, ambulàncies, unitats de salut) en cas d'incidents, com ara els accidents de trànsit. Per analitzar adequadament les nostres propostes sobre VANETs hem dissenyat un entorn de simulació realista que incorpora la presència d'edificis en mapes reals i en el cas que hi hagi un obstacle entre el node actual i el candidat per a ser el pròxim salt el paquet s'emmagatzema en un buffer, per un temps màxim, fins a trobar un nou candidat; en cas contrari, es descarta el paquet. Per millorar les comunicacions en les MANETs, proposem un nou protocol d'encaminament basat en teoria de jocs per a N usuaris especialment dissenyat per a enviar missatges de vídeo. Això fa que la xarxa sigui més eficient, i així s'aconsegueix un major grau de satisfacció dels usuaris en rebre molts més paquets amb un menor retard mig extrem a extrem, menor variació del retard (jitter ) i major PSNR (Relació Senyal Soroll de Pic) . A més, es proposa un protocol d'encaminament geogràfic basat en el reenviament hop-by-hop per a VANETs anomenat 3MRP (Multimedia Multimetric Map-Aware Routing Protocol ) [1] que prèn en consideració múltiples mètriques. Les mètriques considerades en 3MRP són la distància a destinació, la densitat de vehicles en el rang de transmissió, l'ample de banda disponible, la trajectòria futura dels nodes veíns i la perdua de paquets a la capa MAC. Aquestes mètriques es ponderen per a obtenir una puntuació multimètrica. Així, un node pot seleccionar el millor node de reenviament entre tots els seus veíns per augmentar la probabilitat d' èxit de lliurament de paquets, minimitzant el retard mitjà dels paquets i oferint un cert nivell de qualitat de servei.Las redes ad hoc han llamado mucho la atención por parte de la comunidad científica en los últimos años, además de los importantes avances técnicos que han surgido. Estas redes se prevén como un tipo importante de redes de acceso de nueva generación, donde los servicios multimedia sean requeridos por los usuarios a través de sus dispositivos inalámbricos desde todas partes. En esta tesis, centramos nuestro trabajo de investigación especialmente en las redes móviles ad hoc (MANET, Mobile Ad hoc Network) y las redes vehiculares ad hoc (VANET, Vehicular Ad hoc Network). Las características especiales de las MANETs y las VANETs, como la movilidad, la topología dinámica de la red (especialmente en VANETs), las restricciones de batería (en caso de MANETs), la ausencia de infraestructura y la capacidad variable del enlace inalámbrico hace que la provisión de la calidad de servicio en estas redes sea un reto importante para la comunidad científica. Debido a esto, existe la necesidad de desarrollar nuevos protocolos de encaminamiento especialmente diseñados para MANETs y VANETs capaces de proporcionar los servicios de multimedia requeridos. El objetivo principal de esta tesis es proveer mejoras en la comunicación para las redes ad hoc MANET y VANET para mejorar las decisiones a la hora de seleccionar los próximos caminos o nodos, respectivamente, en el momento del envío de las tramas del video y de esta manera sería posible tener una respuesta rápida para resolver los problema diarios en la ciudad y ayudar a las unidades de emergencia (por ejemplo, policía, ambulancias, unidades de salud) en caso de incidentes, como accidentes de tráfico. Para analizar adecuadamente nuestras propuestas sobre VANETs hemos diseñado un entorno de simulación realista que incorpora la presencia de edificios en mapas reales. En el caso de que haya un obstáculo entre el nodo actual y el candidato para ser el próximo salto el paquete se almacena en un buer, durante un tiempo máximo, hasta encontrar un nuevo candidato; en caso contrario, se descarta el paquete. Para mejorar las comunicaciones en las MANETs, proponemos un nuevo protocolo de encaminamiento basado en teoría de juegos para N usuarios especialmente diseñados para enviar mensajes de video. Esto hace que la red sea más eficiente, y así se consigue un mayor grado de satisfacción de los usuarios al recibir muchos más paquetes con un menor promedio de retardo de extremo a extremo, variación de retardo (jitter) y mayor PSNR (Relación Señal a Ruido de Pico). Además, se propone un protocolo de encaminamiento geográfico basado en el reenvío de salto-a-salto para VANETs llamado 3MRP (Multimedia multimetric Map-Aware Routing Protocol) [1] que incluye diversas métricas. Las métricas consideradas en 3MRP son la distancia al destino, la densidad de vehículos en el rango de transmisión, el ancho de banda disponible, la trayectoria futura de los nodos vecinos y la pérdida de paquetes en la capa MAC. Estas métricas se ponderan para obtener una puntuación multimetricanal. Así, un nodo puede seleccionar el mejor nodo de reenvío entre todos sus vecinos para aumentar la probabilidad de éxito de entrega de paquetes, minimizando el retardo medio de los paquetes y ofreciendo un cierto nivel de calidad de servicio. Por otra parte, se ha diseñado un nuevo algoritmo capaz de dar a cada métrica su correspondiente peso en función de las condiciones actuales de la red. De esta forma, los nodos se pueden clasificar de una mejor manera. Por último, se propone un nuevo protocolo de encaminamiento para VANETs llamado G-3MRP (Game Theoretical Multimedia Multimetric Map-aware Routing Protocol) [2] para enviar mensajes de video basado en teoría de juegos para N usuarios en escenarios urbanos. G-3MRP se basa en el protocolo de encaminamiento 3MRP. G-3MRP utiliza hasta tres nodos a través de los cuales los tres tipos de cuadros de video I, P y B serán enviados. Las métricas utilizadas son las mismas que en 3MRP. G-3MRP logra una mayor grado de satisfacción de los usuarios mediante la recepción de muchos más paquetes de video y con un mayor nivel de PSNR, que la anterior propuesta 3MRP+DSW. También hemos analizado el problema de detección de obstáculos en mapas reales para VANETs en escenarios urbanos. Para este propósito, hemos desarrollado nuestra herramienta REVsim [3] de tal forma que puede estar fácilmente integrada en nuestra propuesta de protocolo de encaminamiento para que las simulaciones sean más realistas.Postprint (published version

    Exploiting the power of multiplicity: a holistic survey of network-layer multipath

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    The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work
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