Papers by Aguilar Igartua
In recent years, the general interest in routing for vehicular ad hoc networks (VANETs) has incre... more In recent years, the general interest in routing for vehicular ad hoc networks (VANETs) has increased notably. Many proposals have been presented to improve the behavior of the routing decisions in these very changeable networks. In this paper, we propose a new routing protocol for VANETs that uses four different metrics. which are the distance to destination, the vehicles' density, the vehicles' trajectory and the available bandwidth, making use of the information retrieved by the sensors of the vehicle, in order to make forwarding decisions, minimizing packet losses and packet delay. Through simulation, we compare our proposal to other protocols, such as AODV (Ad hoc On-Demand Distance Vector), GPSR (Greedy Perimeter Stateless Routing), I-GPSR (Improvement GPSR) and to our previous proposal, GBSR-B (Greedy Buffer Stateless Routing Building-aware). Besides, we present a performance evaluation of the individual importance of each metric to make forwarding decisions. Experimental results show that our proposed forwarding decision outperforms existing solutions in terms of packet delivery.
Abstract- In this work we propose a methodology to obtain analytical models for the traffic gener... more Abstract- In this work we propose a methodology to obtain analytical models for the traffic generated from a Video on Demand service (VoD) system that adapts their transmission rate to the network conditions. The model has a direct relation with the design and operation of the VoD system, which implies to easily incorporate system modifications. It is a simple analytic model, computationally evaluated that allows obtaining a priori measures of the system performance, as the PSNR, effective bandwidth and reserved bandwidth. To allow this, we have used well-known methods used in Performability analysis [1]: we have modelled the VoD system with a Markov-Rewards Chain; and to solve it, we have used the randomization technique (or uniformization). The model is flexible enough to compute a wide range of Service Level Agreements parameters. The numerical results have been compared with the ones obtained from the testbed of the laboratory platform SSADE
Primero que todo me gustaría agradecer a Mónica y Carolina por toda la ayuda, apoyo y tiempo dedi... more Primero que todo me gustaría agradecer a Mónica y Carolina por toda la ayuda, apoyo y tiempo dedicado a este proyecto, además de haberme dado la oportunidad de ser parte del mismo. También me gustaría agradecer al resto de proyectistas que formaron parte del grupo de trabajo durante el desarrollo de todos y cada uno de sus proyectos individuales, en especial a Pablo Regañas Soto, con el cual he compartido ideas, problemas y soluciones. Seguidamente me gustaría agradecer a mis padres, hermanas y familiares cercanos. A mis padres por haberme dado una buena educación y la posibilidad para desarrollar mis habilidades y mi potencial al máximo, siempre siendo un apoyo incondicional durante todo el proceso. A mis hermanas por haberme ayudado durante toda mi vida a ser la persona que soy, y a estar siempre centrado en el lugar que debería de estar. A mis familiares cercanos por haberme dado acogida durante este tiempo de estudios en el exterior, abriéndome las puertas de su hogar y haciéndo...
This is the urban scenario designed what we implemented to perform the simulations. However, as i... more This is the urban scenario designed what we implemented to perform the simulations. However, as it is mentioned on the introduction of the project the mobility pattern generator is carried out by Citymob. On next section it is introduced Citymob after that, it is returned to this scenario in order to established the simulation settings.
En primer lloc m'agradaria donar les gràcies a la Mónica, pel seu enorme interés i orientació dur... more En primer lloc m'agradaria donar les gràcies a la Mónica, pel seu enorme interés i orientació durant la realització d'aquest projecte. Es mereixen una especial menció el Diego, el Xavi, la Carolina i l'Ahmad, per la seva essencial col•laboració i aportació al llarg d'aquests darrers mesos. A tots quatre, us desitjo la millor de les sorts en el futur. Finalment, a la meva família per l'inestimable suport rebut al llarg de la meva etapa universitària que ara culmina. I sobretot a la Bea, pel seu recolzament i comprensió en tot moment.
Sensors, 2021
A mobile ad hoc network (MANET) is a set of autonomous mobile devices connected by wireless links... more A mobile ad hoc network (MANET) is a set of autonomous mobile devices connected by wireless links in a distributed manner and without a fixed infrastructure. Real-time multimedia services, such as video-streaming over MANETs, offers very promising applications, e.g., two members of a group of tourists who want to share a video transmitted through the MANET they form, a video-streaming service deployed over a MANET where users watch a film, among other examples. On the other hand, social web technologies, where people actively interact online with others through social networks, are leading to a socialization of networks. Information of interaction among users is being used to provide socially-enhanced software. To achieve this, we need to know the strength of the relationship between a given user and each user they interact with. This strength of the relationship can be measured through a concept called tie strength (TS), first introduced by Mark Granovetter in 1973. In this article...
Proceedings XIII Jornadas de Ingenieria Telematica - JITEL2017, Sep 27, 2017
IEEE Transactions on Vehicular Technology, 2018
The development of analytical models to analyze the behavior of vehicular ad hoc networks (VANETs... more The development of analytical models to analyze the behavior of vehicular ad hoc networks (VANETs) is a challenging aim. Adaptive methods are suitable for many algorithms (e.g., choice of forwarding paths, dynamic resource allocation, channel control congestion) and services (e.g., provision of multimedia services, message dissemination). These adaptive algorithms help the network to maintain a desired performance level. However, this is a difficult goal to achieve, especially in VANETs due to fast position changes of the VANET nodes. Adaptive decisions should be taken according to the current conditions of the VANET. Therefore, evaluation of transient measures is required for the characterization of VANETs. In the literature, different works address the characterization and measurement of the idle (or busy) time to be used in different proposals to attain a more efficient usage of wireless network. This paper focuses on the idle time of the link between two VANET nodes, which we denote as T idle. Specifically, we have developed an analytical model based on a straightforward Markov reward chain to obtain transient measurements of T idle. Numerical results from the analytical model fit well with simulation results. Index Terms-Analytical model, channel idle time, vehicular ad hoc networks (VANETs), Markov reward chain (MRC), Markovian model, performability.
Revista de Investigación en Tecnologías de la Investigaión, 2013
Resumen En la actualidad las redes inalámbricas están protagonizando un gran auge y suponen un ár... more Resumen En la actualidad las redes inalámbricas están protagonizando un gran auge y suponen un área de investigación que ha despertado un gran interés en la comunidad científica. Muchas aportaciones se han presentado en los últimos años, principalmente sobre redes Ad Hoc sin infraestructura fija, como son las WSN (Wireless Sensor Networks) y las VANET (Vehicular Ad Hoc Networks). La gran cantidad de vehículos en las carreteras ha propiciado incluir en las nuevas tecnologías de comunicaciones el compromiso de hacer el transporte en vehículos más seguro y confortable. Esta es una de las principales aplicaciones de las redes vehiculares, que con ayuda de las redes de sensores será más capaz y confiable. Una muestra de esto se presenta en este trabajo de investigación, donde se presentan dos propuestas sobre cómo hacer más seguro el transportarse en vehículo.
Journal of Communications Software and Systems, 2007
In this paper we present ViStA-XL, a Cross-Layer (XL) design aiming to optimize the overall perfo... more In this paper we present ViStA-XL, a Cross-Layer (XL) design aiming to optimize the overall performance of videostreaming services over Mobile Ad Hoc Networks (MANETs). The idea relies on applying optimization strategies to different network layers in a holistic way. In ViStA-XL, a real-time Optimizer (XLO) periodically gathers information of the state of node and network from different layers of the stack of protocols, takes optimization decisions, and then modifies some parameters of the protocols accordingly. In addition, our proposal exploits path diversity through MM-DSR (Multipath MultimediaDynamic Source Routing) protocol as a means to reinforce the Quality of Service (QoS) provision to multi-layer encoded videostreaming applications, by protecting the most important video information packets, balancing the load and decreasing the endto-end delay. To show the advantages of our approach, we have developed and tested an algorithm based on ViStA-XL. Simulation results show that ...
Proceedings of the 13th ACM Symposium on Performance Evaluation of Wireless Ad Hoc, Sensor, & Ubiquitous Networks, 2016
The dissemination of video information contents migth enhance the performances of safety-related ... more The dissemination of video information contents migth enhance the performances of safety-related applications in vehicular ah-hoc networks (VANETs). A major problem concerns the high sensitivity of the compressed video streams to the severe channel conditions in wireless ad-hoc networks. The reliable dissemination of video contents in mobile environments is recognized as one of the main challenges for the developing and deploying of VANETs. To improve the robustness of dissemination, we propose RCP+ (Road-Casting Protocol) scheme for distributing high-definition video contents in VANETs. RCP+ is a cross layer dissemination mechanism for video safety messages that specifically addresses highway scenarios with zero infrastructure support. Also, a comparison of one of the most popular and widely spread video encoder H.264/AVC with respect to the recently released video coding scheme H.265/HEVC is presented. The comparison is performed by means of simulations showing differences between encoding algorithms in terms of perceived quality. The results indicate a better performance of HEVC based encoding algorithm in comparison to AVC in VANET environments.
Lecture Notes in Computer Science, 2015
This paper offers an empirical study of the impact of the way how the distance between two nodes ... more This paper offers an empirical study of the impact of the way how the distance between two nodes is measured by a geographical routing protocol for VANETs in order to take its forwarding decision. The distance equations used in this work are obtained by setting the order parameter of the Minkowski distance function. Simulation results from the topology of a real city indicate that the use of dominant distance can improve some classical performance metrics like the packet delivery ratio, average number of hops or end-to-end packet delay.
IFIP International Federation for Information Processing
The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networ... more The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system. ' This work has been financed by the Spanish investigation projects SECONNET (CICYT-TSI2005-07293-C02-01) and ARPA (CICYT-TIC2003-08184-C02-02)
2006 14th IEEE International Conference on Networks, 2006
Feasible video-streaming applications require end-to-end Quality of Service (QoS) from the underl... more Feasible video-streaming applications require end-to-end Quality of Service (QoS) from the underlying transmission networks. However, providing end-to-end QoS over Mobile Ad hoc Networks (MANETs) poses a specially challenging problem because of the inherent dynamic characteristics of these networks. In this paper we propose a cross-layer QoS-provisioning algorithm that uses information collected at different layers of the network's protocol stack. Besides, we develop a multipath routing scheme based on the Dynamic Source Routing (DSR) protocol to provide multiple source-to-destination loop-free paths. We have analysed the multipath design focusing on the load-balancing benefits and the video frame losses. The proposed algorithm shows to improve the performance of video-streaming applications over ad hoc networks.
Ad Hoc Networks, 2015
Modeling and Performance Evaluation of Wireless Ad-Hoc Networks" A primary aim of wireless ad-hoc... more Modeling and Performance Evaluation of Wireless Ad-Hoc Networks" A primary aim of wireless ad-hoc networks is to deliver data in areas where there is no pre-defined infrastructure. In these networks, the users, but also the network entities can be potentially mobile. Wireless ad-hoc networks have recently witnessed their fastest growth period ever in history. Real wireless ad-hoc networks are now implemented, deployed and tested, and this trend is likely to increase in the future. However, as such networks are increasingly complex, performance modeling and evaluation play a crucial part in their design process to ensure their successful deployment and exploitation in practice. This special issue on Modeling and Performance Evaluation of Wireless Ad-Hoc Networks aims to open a new critical debate on the evaluation of wireless ad-hoc networks. It includes original theoretical and/or practical contributions, from researchers and practitioners that identify and address issues in evaluating wireless ad-hoc networks. Special attention is devoted to challenging ad-hoc networking scenarios like the vehicular and the mesh-based ones, new applications of the ad-hoc networking paradigm like wireless communities and content centric approaches, and emerging applications like video streaming. Also, new networking approaches based on network coding and data compression have been considered.
Proceedings of the Fifth International ICST Conference on Heterogeneous Networking for Quality Reliability Security and Robustness, 2008
In recent years the growing proliferation of small wireless devices able to maintain wireless com... more In recent years the growing proliferation of small wireless devices able to maintain wireless communications using IEEE 802.11 technologies has enabled the deployment of MANETs (Mobile Ad Hoc Networks). This fact has stimulated the demand of multimedia services over this type of networks, such as video-streaming services. Providing QoS in this environment is a challenging task due to the inherent dynamic characteristics of these networks. In this paper we propose a-MMDSR (adaptable-Multipath Multimedia Dynamic Source Routing), a dynamic framework for video streaming services which improves the user perceived quality. We have perfected our previous approach s-MMDSR (static-MMDSR), a multipath routing protocol based on DSR which works simultaneously with a cross-layer algorithm. Through simulations, we demonstrate that the performance of our proposal framework outperforms DSR and s-MMDSR.
Proceedings. 2004 12th IEEE International Conference on Networks (ICON 2004) (IEEE Cat. No.04EX955)
In this work we propose to use a set of equations to calculate some user&... more In this work we propose to use a set of equations to calculate some user's level parameters expressed in the service level agreements (SLA). As example, we particularize these expressions for a video-on-demand service (VoD) that adapts its transmission rate to the network conditions. These equations are obtained from an analytical model, which allows obtaining a priori measures of the
IEEE Latin America Transactions, 2007
Abstract Nowadays, services over Mobile Ad hoc Networks (MANETs) are becoming more used, and mult... more Abstract Nowadays, services over Mobile Ad hoc Networks (MANETs) are becoming more used, and multimedia services such as video-streaming applications are more demanded. Hence, it is necessary to provide end-to-end QoS over MANETs, although it poses a ...
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Papers by Aguilar Igartua