Kaouther Abrougui

Design and Evaluation of Context-Aware and Location-Based Service Discovery Protocols for Vehicular Networks

The increasing number of potential applications related to intelligent transportation systems (ITSs) have attracted researchers to the area of vehicular networks (VNs). Two main classes of applications have lately gained popularity, i.e., security and safety, and traffic information and service location applications. However, several open research challenges are delaying the efficient and widespread deployment and management of such applications in VNs. One of these challenges comprises how vehicles and service providers could discover each other in VNs, which are well known for their large scale and high mobility. Most service discovery strategies available present high overhead and poor performance in a VN environment. Existing context-aware and location-based service discovery protocols (LocVSDPs) are either designed without considering the particularities of VNs or are not scalable with the increase in network density and the number of requests. In this paper, we propose a new context-aware and LocVSDP (EB-LocVSDP) for VNs and its variant (Naive-LocVSDP). Our protocols offer a scalable framework for the discovery of time-sensitive and location-based services in VNs. They rely on a cluster-based infrastructure. Furthermore, LocVSDPs are integrated into the network layer and use channel diversity to improve service discovery efficiency. We discuss the implementation of our protocols and techniques, report on performance evaluation experiments, and offer a comparison against an existing location-based discovery protocol [the Vehicular Information Transfer Protocol (VITP)]. Our simulation results indicate that our proposed LocVSDPs show a gain of 20% in terms of success rate. LocVSDPs use at least 90% less bandwidth than VITP, and their average response time is at least 10% lower than VITP for successful query transactions.

An efficient leader election protocol for mobile networks

In this paper, we present a leader election protocol that works under frequent network changes and node mobility. Our proposed protocol, which operates well in ad hoc networks, is based on electing a unique node that outperforms all the other nodes in a cluster identified by our protocol. We discuss our protocol and present an illustrative example to show how our proposed scheme works in a mobile network. We also show how our algorithm succeeds in electing a unique leader in a mobile ad hoc network environment.

Location-Aided Gateway Advertisement and Discovery Protocol for VANets

Intelligent transportation systems (ITSs) are gaining momentum among researchers. ITS encompasses several technologies, including wireless communications, sensor networks, voice and data communication, real-time driving-assistant systems, etc. These state-of-the-art technologies are expected to pave the way for a plethora of vehicular network applications. However, ITS faces difficult issues when trying to widely deploy such networks and applications. The interconnection of different networks, even in the case of the Internet, is one of the main difficulties that is delaying the wide spread of vehicular networks. In this paper, we present a novel gateway discovery technique for vehicular ad hoc networks (VANets). Our protocol aims to provide an efficient hybrid adaptive Location-Aided Gateway Advertisement and Discovery (LAGAD) mechanism for VANets. First, it permits gateway clients to discover nearby gateways; then, gateways keep advertising themselves to their clients to permit client information about the route toward the discovered gateway without having to resort to reactive route discovery. We discuss the implementation of our algorithm and present its proof of correctness, in addition to the performance evaluation demonstrated through an extensive set of simulation experiments using a Manhattan mobility model. Our results indicate that our LAGAD scheme is scalable and that a significant success rate could be achieved using our algorithm while guaranteeing low response time (on the order of milliseconds) and low bandwidth usage when compared with other gateway discovery approaches. Moreover, our results indicate that LAGAD achieves a high delivery ratio of data packets, as well as a low end-to-end delay, and permits duplicate and ordered data packet reception at the destination gateway.

Context-aware and location-based service discovery protocol for vehicular networks

Recent advances in Intelligent Transportation Systems (ITS) and the growing number of applications in Vehicular Networks (VN) have attracted many researchers. Applications in Vehicular Networks comprise but are not limited to safety applications and convenience applications. Deploying Vehicular Networks widely cannot be accomplished without overcoming the existing research challenges in such networks. Service discovery is one of the main challenges in Vehicular Networks which are characterized by their large scale and high mobility. Existing service discovery techniques for ad hoc networks cannot be applied directly to Vehicular Networks scenarios due to their poor performance and decreased efficiency in Vehicular Networks. In this paper, we present our location-based service discovery protocol for Vehicular Networks (LocVSDP). Our protocol permits the discovery of location-aware and timesensitive services in Vehicular Networks. Moreover, our LocVSDP protocol improves service discovery efficiency by integrating service information into the network layer and using diverse channels. In our protocol, we present our efficient mechanism that permits to service requesters to find service providers and their routing information simultaneously, which results in overall bandwidth savings. We make use of diverse channels for the exchange of discovery and routing packets, which decreases the congestion on single channels and improves the delay of service discovery. Then, we present our efficient location-based request propagation and an efficient computation of the service reply, based on the specified location of the requested service in the drivers request. We discuss the implementation of our protocol and present its proof of correctness.

Performance evaluation of an efficient fault tolerant service discovery protocol for vehicular networks

Recently, vehicular networks and inter-vehicle communication have received attention from the research community and the automotive industry. In this context, many services are deployed in vehicular networks that are beneficial to drivers and passengers. Service discovery in vehicular networks is vital to make such services useful. However, due to the lack of communication reliability in vehicular ad hoc networks, it is necessary to implement fault-tolerant techniques during the discovery of service providers in vehicular networks. Very few service discovery protocols for vehicular networks have considered fault tolerant techniques, which are very important for the efficiency of service discovery. Fault tolerant techniques improve service request satisfaction and reduce dropped connections due to faulty components between the service provider and the service requester. In this paper, we propose a fault tolerant location based service discovery protocol for vehicular networks which can work well under service provider failures, communication link failures and roadside router failures. Our protocol permits the discovery of location based services where the requester specifies the region of interest within the request. Our protocol uses an infrastructure support consisting of clusters of roadside routers formed in specific regions in the vehicular network. In addition, service discovery messages are integrated into the network layer and use channel diversity in order to improve service discovery efficiency. We describe our fault tolerant location based vehicular service discovery protocol (FTLocVSDP) and discuss its proof of correctness and performance evaluation. We prove that the success rate is improved in the roadside router failure and in the communication link failure scenarios by 50% and 30%, respectively, compared to the location based service discovery protocol for vehicular networks (LocVSDP) which does not consider fault tolerant techniques.

An Efficient Hybrid Adaptive Location-Aided Gateway Advertisement and Discovery Protocol for Heterogeneous Wireless and Mobile Networks

Recent advances in wireless communications and the availability of Heterogeneous Wireless and Mobile Networks (HWMNs) have enabled the development of interesting applications. The main objective of HWMNs is the delivery of wireless services to potential applications in personal, local, campus, and metropolitan areas. However, in these networks, there is a need of gateway discovery mechanisms that will support several of these HWMN applications. It is essential that the deployment of a gateway discovery protocol in HWMNs does not degrade the performance of existing applications in terms of bandwidth usage. Any gateway discovery approach in HWMNs is highly susceptible to this issue, due to the limited bandwidth. In this paper, we present a novel gateway discovery technique for HWMNs. Our protocol aims at providing an efficient hybrid adaptive location-aided gateway advertisement and discovery mechanism for HWMNs. Essentially, the originality of ou technique lies in its unique and novel characteristics: (i) it is built on top of the network layer; (ii) it uses channel diversity; (iii) and it is based upon a location-aided adaptation of the advertisement zone of the gateway. Our proposed approach benefits from the routing information to find the gateway service and the routing information to the gateway at the same time, thereby saving the overall bandwidth. It uses diverse channels to exchange discovery and routing packets that decreases the congestion on single channels and also the delay of gateway discovery. Our proposed gateway discovery protocol adapts the advertisement zone of gateways based on the location information and the speed of requesting wireless and mobile nodes. We discuss the implementation of our technique, and report on its performance evaluation through an extensive set of simulation experiments. Our results indicate that significant success rate can be achieved by our technique in the worst case (more than 90 percent), while guaranteeing low response time and low message complexity when compared to the selected gateway discovery approaches.

Efficient group‐based authentication protocol for location‐based service discovery in intelligent transportation systems

Intelligent transportation systems have attracted many researchers. These latter have invested much effort to develop many applications and services mainly for vehicular systems. Services can be classified as safety or convenience services. A service discovery mechanism is needed to permit the discovery and the interaction with the existing services. However, so far security issues for service discovery in vehicular systems have not been widely considered, mainly for the convenience type of applications. Thus, a secure service discovery and communication protocol is necessary to prevent from many attacks and malicious processes in the vehicular system. In this paper, we investigate the possible attacks that can occur during the service discovery and communication processes. Then, we present our proposed group-based authentication scheme for secure service discovery and communication in vehicular systems. Our proposed scheme is mainly dedicated for the convenience type of applications. We discuss the security requirements achieved by our proposed protocol and we report on its performance evaluation. We prove through our extensive set of simulations that our proposed scheme achieves a high success rate for the secure discovery of services, while maintaining the scalability of the network and low discovery delays. Copyright

An Efficient Fault Tolerant Location Based Service Discovery Protocol for Vehicular Networks

Recent studies on service discovery protocols in vehicular networks have shown promising results. However, very little work has been reported on how to integrate the fault tolerance feature into these mechanisms. This feature is vital for the success of the deployment of service discovery protocols in vehicular networks. Drivers on their cars should not have their requests dissatisfied or their connections dropped because a service provider or some components between the service provider and the service requester have failed. In this paper, we present a fault tolerant location based service discovery protocol for Vehicular Networks. The main advantages of our protocol is its ability to tolerate service providers failure, communication links failure and roadside routers failure. We present our fault tolerant protocol, and report on its performance evaluation. Our simulation experiments show that our proposed fault tolerant LocVSDP algorithm improves the success rate significantly over the basic LocVSDP. In fact, the success rate is improved in the roadside routers failures scenario and in the links failures scenarios by 50 percent and 30 percent respectively.

Location-aided gateway advertisement and discovery protocol for VANets: Proof of correctness

The Internet access from vehicular networks is gaining great interest from the research community. In fact, vehicles should be able to connect to the Internet and communicate with different networks through gateways. Guaranteeing safety on the roads is the main objective of vehicular networks. Safety applications need to collaborate with other types of services for efficient safety assurance. Consequently, many services would coexist with safety applications, including the gateway discovery service, and share a limited bandwidth. Any solution to the gateway discovery problem in vehicular ad hoc networks (VANets) is subject to this limitation. In this work, we present a novel gateway discovery technique for VANets. Our protocol aims to provide an efficient hybrid adaptive location-aided gateway advertisement and discovery mechanism for VANets (LAGAD). It has the following unique and novel characteristics for gateway discovery in VANets: (i) it is built on top of the network layer; (ii) it uses channel diversity; (iii) and it is based upon a location-aided adaptation of the advertisement zone of the gateway. Our proposed protocol benefits from the routing information to find the gateway service and the routing information to the gateway at the same time saving the overall bandwidth. It uses diverse channels to exchange discovery and routing packets decreasing the congestion on single channels and decreasing the delay of gateway discovery. Our proposed gateway discovery protocol adapts the advertisement zone of gateways based on the location information and the velocity of requesting vehicles. We discuss the implementation of our algorithm, then present its proof of correctness and message and time complexities computations.

Performance evaluation of a hybrid adaptive service discovery protocol for next generation Heterogeneous Vehicular Networks (HVNs)

Recently, vehicle networks are gaining lots of interest from the research community. In order to provide efficient and pervasive road communication, Heterogeneous Vehicular Networks (HVN) are considered as a promising solution. HVNs have unique characteristics and face challenging problems. Consequently, it is hard to use the traditional mechanisms and protocols in this type of networks. service discovery is a very challenging problem for HVNs based applications. Furthermore, to the best of our knowledge, very little work has been done to deal with the service discovery problem in HVNs. Due to the heterogeneity of the vehicular network and the high mobility and density of vehicles, traditional discovery techniques do not perform well. To solve this problem, we first propose a new architecture for Next Generation Heterogeneous Vehicular Networks, then we propose a novel class of service discovery protocol that permits to vehicles to discover services through the heterogeneous wireless network. Our hybrid proposed technique combines both proactive and reactive discovery approaches. It is also adaptive because it adapts to the vehicular network conditions in order to permit efficient discovery in terms of low overhead, and high success rate. We present extensive simulation results to evaluate the performance of our scheme.