Design and performance evaluation of smart dissemination of emergence messages in vehicular ad-hoc networks

The growing demand to improve road safety and optimize road traffic has generated great interest in vehicular ad-hoc network (VANETs). Serious traffic accidents can cause financial losses, physical disability, and even death. However, if drivers were informed about the danger in advance through a warning message, this would give drivers enough time to react appropriately to the situation. There are many approaches that can prevent car accidents, and VANETs have been conceived as an excellent solution to improve road safety, through the use of a variety of applications enabled by vehicle communications. The key objective of this research is to achieve information dissemination from a vehicle to other vehicles around that migth be interested in receiving the content. We focus on the network layer and application layer protocols, which are discussed and developed as a protocol over the respective access technologies. We primarily present the research results of our proposals, and also provide a comprehensive review of existing challenges and solutions in data dissemination in VANETs. Our proposals include the design of three dissemination protocols compatible with the IEEE 802.11p standards for road safety applications. These dissemination protocols can be differentiated by their application trigger condition and the broadcast scheme. All three dissemination protocols have been implemented in the simulator VEINS to perform several large-scale experiments. The results of the experiments have shown that all three dissemination protocols are able to cope with an increasing number of vehicles in large scale scenarios without sufering a noticeable loss in performance. Finally, we have investigated solutions to increase the driver's privacy because VANETs can also introduce some location privacy risk by periodically broadcast beacon messages that include the vehicle's position. We evaluate the performance of the privacy schemes, described the experiments and discussed the results.La creixent demanda per millorar la seguretat viària i optimitzar el trànsit viari ha generat gran interès en les xarxes vehiculars ad-hoc (VANETs). Els accidents de trànsit greus poden causar pèrdues financeres, discapacitat física i fins i tot la mort. No obstant això, si els conductors van ser informats per endavant sobre el perill a través d’un missatge d’advertència, això donaria als conductors el temps suficient per reaccionar de manera apropiada a la situació. Hi ha molts enfocaments que poden prevenir accidents automobilístics, i les VANETs s’han concebut com una excel·lent solució per millorar la seguretat viària, a través de l’ús d’una varietat d’aplicacions habilitades per les comunicacions vehiculars. L’objectiu principal d’aquesta investigació és aconseguir la disseminació de la informació des d’un vehicle a altres vehicles que estiguin interessats en rebre el contingut. Ens enfoquem en la capa de xarxa i els protocols de capa d’aplicació, que es discuteixen i desenvolupen com un protocol sobre les respectives tecnologies d'accés. Principalment vam presentar els resultats d’investigació de les nostres propostes, i també provem una revisió exhaustiva dels desafiaments i solucions existents en la disseminació de dades en les VANETs. Les nostres propostes inclouen el disseny de tres protocols de disseminació compatibles amb els estàndards IEEE 802.11p per a aplicacions de seguretat viària. Aquests protocols de disseminació es poden diferenciar per la condició d’activació de l’aplicació i l’esquema de difusió. Els tres protocols de disseminació s’han implementat en el simulador VEINS per a realitzar diversos experiments a gran escala. Els resultats dels experiments han demostrat que els tres protocols de disseminació són capaços de fer front a un nombre creixent de vehicles en escenaris de gran escala sense patir una pèrdua notable en el rendiment. Finalment, hem investigat solucions per augmentar la privacitat del conductor perquè les VANETs també poden introduir algun risc de privacitat de la ubicació mitjanant missatges beacon emesos periòdicament que inclouen la posició dels vehicles. Avaluem l’acompliment dels esquemes de privacitat, descrivim els experiments i discutim els resultats.Postprint (published version

Design and performance evaluation of smart dissemination of emergence messages in vehicular ad-hoc networks

The growing demand to improve road safety and optimize road traffic has generated great interest in vehicular ad-hoc network (VANETs). Serious traffic accidents can cause financial losses, physical disability, and even death. However, if drivers were informed about the danger in advance through a warning message, this would give drivers enough time to react appropriately to the situation. There are many approaches that can prevent car accidents, and VANETs have been conceived as an excellent solution to improve road safety, through the use of a variety of applications enabled by vehicle communications. The key objective of this research is to achieve information dissemination from a vehicle to other vehicles around that migth be interested in receiving the content. We focus on the network layer and application layer protocols, which are discussed and developed as a protocol over the respective access technologies. We primarily present the research results of our proposals, and also provide a comprehensive review of existing challenges and solutions in data dissemination in VANETs. Our proposals include the design of three dissemination protocols compatible with the IEEE 802.11p standards for road safety applications. These dissemination protocols can be differentiated by their application trigger condition and the broadcast scheme. All three dissemination protocols have been implemented in the simulator VEINS to perform several large-scale experiments. The results of the experiments have shown that all three dissemination protocols are able to cope with an increasing number of vehicles in large scale scenarios without sufering a noticeable loss in performance. Finally, we have investigated solutions to increase the driver's privacy because VANETs can also introduce some location privacy risk by periodically broadcast beacon messages that include the vehicle's position. We evaluate the performance of the privacy schemes, described the experiments and discussed the results.La creixent demanda per millorar la seguretat viària i optimitzar el trànsit viari ha generat gran interès en les xarxes vehiculars ad-hoc (VANETs). Els accidents de trànsit greus poden causar pèrdues financeres, discapacitat física i fins i tot la mort. No obstant això, si els conductors van ser informats per endavant sobre el perill a través d’un missatge d’advertència, això donaria als conductors el temps suficient per reaccionar de manera apropiada a la situació. Hi ha molts enfocaments que poden prevenir accidents automobilístics, i les VANETs s’han concebut com una excel·lent solució per millorar la seguretat viària, a través de l’ús d’una varietat d’aplicacions habilitades per les comunicacions vehiculars. L’objectiu principal d’aquesta investigació és aconseguir la disseminació de la informació des d’un vehicle a altres vehicles que estiguin interessats en rebre el contingut. Ens enfoquem en la capa de xarxa i els protocols de capa d’aplicació, que es discuteixen i desenvolupen com un protocol sobre les respectives tecnologies d'accés. Principalment vam presentar els resultats d’investigació de les nostres propostes, i també provem una revisió exhaustiva dels desafiaments i solucions existents en la disseminació de dades en les VANETs. Les nostres propostes inclouen el disseny de tres protocols de disseminació compatibles amb els estàndards IEEE 802.11p per a aplicacions de seguretat viària. Aquests protocols de disseminació es poden diferenciar per la condició d’activació de l’aplicació i l’esquema de difusió. Els tres protocols de disseminació s’han implementat en el simulador VEINS per a realitzar diversos experiments a gran escala. Els resultats dels experiments han demostrat que els tres protocols de disseminació són capaços de fer front a un nombre creixent de vehicles en escenaris de gran escala sense patir una pèrdua notable en el rendiment. Finalment, hem investigat solucions per augmentar la privacitat del conductor perquè les VANETs també poden introduir algun risc de privacitat de la ubicació mitjanant missatges beacon emesos periòdicament que inclouen la posició dels vehicles. Avaluem l’acompliment dels esquemes de privacitat, descrivim els experiments i discutim els resultats

Game-theoretical design of an adaptive distributed dissemination protocol for VANETs

Road safety applications envisaged for Vehicular Ad Hoc Networks (VANETs) depend largely on the dissemination of warning messages to deliver information to concerned vehicles. The intended applications, as well as some inherent VANET characteristics, make data dissemination an essential service and a challenging task in this kind of networks. This work lays out a decentralized stochastic solution for the data dissemination problem through two game-theoretical mechanisms. Given the non-stationarity induced by a highly dynamic topology, diverse network densities, and intermittent connectivity, a solution for the formulated game requires an adaptive procedure able to exploit the environment changes. Extensive simulations reveal that our proposal excels in terms of number of transmissions, lower end-to-end delay and reduced overhead while maintaining high delivery ratio, compared to other proposalsPeer ReviewedPostprint (published version

Achieving Data Utility Fairness in Periodic Dissemination for VANETs

In addition to safety, Vehicular Ad-hoc Networks (VANETs) enable the development of new information-rich applications that disseminate relevant data to vehicles. One key challenge in such networks is to use the available bandwidth efficiently when there is: (i) a short connectivity time due to the rapidly changing road environment, and (ii) bandwidth congestion due to continuous collection and dissemination of data. Numerous solutions were proposed to alleviate bandwidth congestion by using transmission power and beaconing rate control. However, the reduction of data messages transmitted by using priority-based data selection mechanisms has not been fully explored. In this work, we propose a periodic data dissemination protocol for non-safety applications which distributes data utility fairly among vehicles with conflicting data interests. Furthermore, given a defined maximum network load allowed, only the least relevant data is suppressed. Fairness is achieved using the concept of Nash Bargaining from game theory. Simulation results show that our approach leads to an efficient bandwidth utilization in terms of utility per message received and higher fairness index compared with other approaches

Achieving Data Utility Fairness in Periodic Dissemination for VANETs

In addition to safety, Vehicular Ad-hoc Networks (VANETs) enable the development of new information-rich applications that disseminate relevant data to vehicles. One key challenge in such networks is to use the available bandwidth efficiently when there is: (i) a short connectivity time due to the rapidly changing road environment, and (ii) bandwidth congestion due to continuous collection and dissemination of data. Numerous solutions were proposed to alleviate bandwidth congestion by using transmission power and beaconing rate control. However, the reduction of data messages transmitted by using priority-based data selection mechanisms has not been fully explored. In this work, we propose a periodic data dissemination protocol for non-safety applications which distributes data utility fairly among vehicles with conflicting data interests. Furthermore, given a defined maximum network load allowed, only the least relevant data is suppressed. Fairness is achieved using the concept of Nash Bargaining from game theory. Simulation results show that our approach leads to an efficient bandwidth utilization in terms of utility per message received and higher fairness index compared with other approaches

Popular Content Distribution in Public Transportation Using Artificial Intelligence Techniques

Outdoor wireless networks suffer nowadays from an increasing data traffic demand which comes at the time where almost no vacant frequency spectrum has been left. A vast majority of this demand comes from popular content generated by video streaming and social media sites. In the future, other sources will generate even more demand with emerging applications such as virtual reality, connected cars and environmental sensing. While a significant progress has been made to address this network saturation in indoor environments, current outdoor solutions, based on fixed network deployments, are expensive to build and maintain. They tend to be immobile and therefore are inflexible in coping with the dynamics of outdoor data demand. On the other hand, Vehicular Ad-hoc NETworks (VANETs) are in nature more scalable, dynamic, flexible, and therefore more promising in terms of addressing such demand. This is especially feasible if we take advantage of public transportation vehicles and stops. These vehicles and stops are often owned and operated by the same administrative entity which overcomes the routing selfishness issue. Moreover, the mobility patterns of these vehicles are highly predictable given their regular schedules; their locations are publicly-sharable and their location distribution is uniform throughout space and time. Given these factors, a system that utilizes public transportation vehicles and stops to build a reliable, scalable and dynamic VANET for wireless network offloading in outdoor environments is proposed. This is done by exploiting the predictability demonstrated by such vehicles using an Artificial-Intelligence (AI) based system for wireless network offloading via popular content distribution. The AI techniques used are the Upper Popularity Bound (UPB) collaborative and group-based recommender based on multi-armed bandits for content recommendation and bayesian optimization based on batch-based Random Forest (RF) regression for content routing. They are used after analyzing the mobility data of public transportation vehicles and stops. This analysis includes both preprocessing and processing the data in order to select the optimal set of stops and clustering vehicles and stops based on cumulative contact duration thresholds. The final system has shown the promising networking potential of public transportation. It incorporates a recommender that has shown a versatile performance under different consumer interest and network capacity scenarios. It has also demonstrated a superior performance using a bayesian optimization technique that offloads as high as 95% of the wireless network load in an interference and collision free manner