Ademar Takeo Akabane

An adaptive solution for data dissemination under diverse road traffic conditions in urban scenarios

Vehicular Ad hoc Networks (VANETs) are an emerging technology that allows vehicles to form self-organized networks without the requirement of permanent infrastructure. VANETs have opened up a myriad of on the road applications and increased their potential by providing intelligent transport systems. The envisaged applications, as well as some inherent VANET characteristics (i.e., highly dynamic topology, diverse network densities, and intermittent connectivity) make data dissemination an essential service and a challenging task in these networks. Many data dissemination protocols have been proposed in the literature. However, most of these protocols were designed to operate exclusively under dense or sparse networks. In addition, the existing solutions for data dissemination do not effectively address broadcast storm and network partition problems simultaneously. To tackle these problems, we propose a suitable multi-hop broadcast protocol named as TURBO that relies exclusively on local one-hop neighbor information to deliver messages under dense and sparse networks. We compared our protocol with other protocols from literature - AID, DBRS, GEDDAI, and simple Flooding. Simulation results show that TURBO performs data dissemination with better efficiency than other protocols, outperforming them in different scenarios in all the evaluations carried out.

GTO: A Broadcast Protocol for Highway Environments over Diverse Traffic Conditions

Several data dissemination protocols in VANETs have been proposed in the literature, however, most of these protocols do not efficiently address broadcast storm and network partition problems simultaneously. This work attempts to fill this gap by proposing a suitable broadcast protocol in vehicular networks, designated GTO, that addresses both the broadcast storm and network partition problems in highway environment. In GTO protocol, all vehicles send beacon packets notifying whether there is or not the information, besides we employ the technique of zone of preference to rebroadcast messages to further vehicles. We compared the proposed protocol with the other five protocols - ATENA, DV-CAST, SRD, AID and Flooding - The results of evaluation show that our proposed protocol was more efficient to disseminate the information, within area of interest, than other five protocols in different traffic conditions.

Data dissemination in highway scenarios using car-to-car communication

Vehicular Ad Hoc Networks (VANETs) are a specific type of mobile networks in which the nodes are vehicles with capability of processing, storing, and wireless communication. VANETs face a number of challenges in terms of data dissemination due to volatile vehicle density and the frequent network topology changes induced by high mobility of vehicles and short-range communications. The envisaged applications, as well as some inherent VANET characteristics make data dissemination an essential service and a challenging task in these networks. Many data dissemination protocols have been proposed in the literature. However, most of these protocols do not effectively address broadcast storm and network partition problems simultaneously. To tackle these problems, we propose a novel data dissemination protocol in vehicular networks (ATENA) to operate in highway environment. ATENA selects vehicles inside a sweet spot to rebroadcast messages to further vehicles. Moreover, the protocol employs implicit acknowledgements to guarantee robustness in message delivery under sparse scenarios. ATENA eliminates the broadcast storm problem and maximizes data dissemination capabilities across network partitions with short delays and low overhead. When compared to five well-known solutions - DBRS, DV-CAST, SRD, Flooding and AID - we show that our proposal performs data dissemination with better efficiency than other algorithms, outperforming them in different scenarios in all the evaluations carried out.

Efficient Encounter-based Event Dissemination Protocol (E-BED) for urban and highway Vehicular Ad Hoc Networks

Efficient and reliable data dissemination is crucial to most of the vehicular network applications. However, the inherent vehicular network characteristics make data dissemination a challenging task. Typically, the existing algorithms generate too many redundant packets that saturate the network, thus causing frequent channel contention and packet collisions. To tackle these problems we propose an Efficient Encounter-based Event Dissemination Protocol. By exploiting the distance and the encountering probability of the vehicles to the event, the proposed protocol is capable of performing an efficient data dissemination in both urban and highway scenarios. An extensive set of simulation experiments was conducted to evaluate the performance of the proposed algorithms. Results showed that the proposed protocol outperforms the selected approaches in terms of retransmission packets and delivery ratio.

CARRO: A context-awareness protocol for data dissemination in urban and highway scenarios

A distributed network of vehicles well-known as Vehicular Ad Hoc Networks (VANETs) has created a new communication paradigm, which enables us to exploit the mobility of vehicles for data dissemination process within a geographical area of interest. Several data dissemination protocols have focused on two main problems in VANETs: broadcast storm and disconnected network. Moreover, the most of data dissemination protocols were deployed to operate solely on the highway or urban scenarios. Therefore, in this paper, we take a step further by proposing the Context-Aware Routing pROtocol (CARRO), a data dissemination protocol designed to operate over both scenarios, highway and urban. Furthermore, the proposed protocol handles the broadcast storm and disconnect network problems. When compared to related protocols, simulation results report that CARRO guarantees higher delivery ratio and minimum delay without saturating the bandwidth.

ATENA: A Broadcast-Storm-Aware Solution for Highway Environments

The fast growth of ad hoc wireless communication, combined with advances of vehicular technology, has allowed the appearing of a new communication paradigm known as VANETs (Vehicular Ad Hoc Networks). This new communication paradigm is enabling to exploit the mobility of vehicles to disseminate information that can be: traffic jam, congested area, and eventual accident. We have focused on a broadcast protocol over VANETs to efficiently disseminate the information among the vehicles within an Area of Interest (AoI). The proposal of our broadcast protocol -ATENA- is to eliminate the broadcast storm problem and maximize data dissemination with short delays and low overhead. ATENA was compared with five well-known protocols from literature: DBRS, DV-CAST, SRD, Flooding, and AID. It shows, through the simulation, that our proposal has performed better than other five protocols, outperforming them in different scenarios in all the evaluations carried out.

Distributed Egocentric Betweenness Measure as a Vehicle Selection Mechanism in VANETs: A Performance Evaluation Study

In the traditional approach for centrality measures, also known as sociocentric, a network node usually requires global knowledge of the network topology in order to evaluate its importance. Therefore, it becomes difficult to deploy such an approach in large-scale or highly dynamic networks. For this reason, another concept known as egocentric has been introduced, which analyses the social environment surrounding individuals (through the ego-network). In other words, this type of network has the benefit of using only locally available knowledge of the topology to evaluate the importance of a node. It is worth emphasizing that in this approach, each network node will have a sub-optimal accuracy. However, such accuracy may be enough for a given purpose, for instance, the vehicle selection mechanism (VSM) that is applied to find, in a distributed fashion, the best-ranked vehicles in the network after each topology change. In order to confirm that egocentric measures can be a viable alternative for implementing a VSM, in particular, a case study was carried out to validate the effectiveness and viability of that mechanism for a distributed information management system. To this end, we used the egocentric betweenness measure as a selection mechanism of the most appropriate vehicle to carry out the tasks of information aggregation and knowledge generation. Based on the analysis of the performance results, it was confirmed that a VSM is extremely useful for VANET applications, and two major contributions of this mechanism can be highlighted: (i) reduction of bandwidth consumption; and (ii) overcoming the issue of highly dynamic topologies. Another contribution of this work is a thorough study by implementing and evaluating how well egocentric betweenness performs in comparison to the sociocentric measure in VANETs. Evaluation results show that the use of the egocentric betweenness measure in highly dynamic topologies has demonstrated a high degree of similarity compared to the sociocentric approach.

A Suitable Vehicular Broadcast Protocol under Different Traffic Patterns for Urban Scenario

VANETs have emerged as an exciting research and application area. Increasingly vehicles are being equipped with embedded sensors, processing and wireless communication capabilities. This has opened a myriad of possibilities for powerful and potential life-changing applications on safety, efficiency, comfort, public collaboration and participation, while they are on the road. Although, considered as a special case of a Mobile Ad Hoc Network, the high but constrained mobility of vehicles bring new challenges to data communication and application design in VANETs. This is due to their highly dynamic and intermittent connected topology and different applications QoS requirements.. In this work, we propose a new data dissemination protocol named as TURBO. The TURBO aims is to eliminate the broadcast storm problem in dense scenario and maximize the coverage in sparse scenario. TURBO protocol was compared with four well-known protocols from literature: AID, DBRS, Flooding, and GEDDAI. Simulation results show that our proposed protocol has performed better than other four protocols, outperforming them in different scenarios in all the evaluations carried out.