Abstract In the recent years, we are witnessing a growing interest into the design of smart vehicles and smart roads for Intelligent transportation systems. Vehicles as part of the Internet of Things should provide to the driver and passenger with a variety of services using efficient gateway discovery mechanism while maintaining a certain level of security and authentication to avoid potential malicious attacks. In this paper, we propose a secure hybrid adaptive gateway discovery and communication protocol for smart vehicular networks, which we refer to as SEGAL. Our proposed SEGAL protocol is based upon building a secure clustered vehicular network, and permits the exchange of gateway discovery messages through authenticated clusterheads and cluster members. We shall present the design of our protocol, and describe how it can overcome the possible malicious attacks that might harm the network. Then, we report its efficiency and scalability using an extensive set of simulation experiments using Ns‐2 simulator. Our results indicate that the proposed SEGAL protocol is scalable while achieving high success rate, low response time and dropping rate. Copyright © 2016 John Wiley & Sons, Ltd.

Abstract A great interest in vehicular ad‐hoc networks has been noticed by the research community. General goals of vehicular networks are to enhance safety on the road and to ensure the convenience of passengers by continuously providing them, in real time, with information and entertainment options such as routes to destinations, traffic conditions, facilities' information, and multimedia/Internet access. Indeed, time efficient systems that have high connectivity and low bandwidth usage are most needed to cope with realistic traffic mobility conditions. One foundation of such a system is the design of an efficient gateway discovery protocol that guarantees robust connectivity between vehicles, while assuring Internet access. Little work has been performed on how to concurrently integrate load balancing, quality of service (QoS), and fault tolerant mechanisms into these protocols. In this paper, we propose a reliable QoS‐aware and location aided gateway discovery protocol for vehicular networks by the name of fault tolerant location‐based gateway advertisement and discovery. One of the features of this protocol is its ability to tolerate gateway routers and/or road vehicle failure. Moreover, this protocol takes into consideration the aspects of the QoS requirements specified by the gateway requesters; furthermore, the protocol insures load balancing on the gateways as well as on the routes between gateways and gateway clients. We discuss its implementation and report on its performance in contrast with similar protocols through extensive simulation experiments using the ns‐2 simulator. Copyright © 2013 John Wiley & Sons, Ltd.

In recent years, we have witnessed a growing interest in Vehicular Networks from both the research community and industry. Several potential applications of Vehicular Networks are envisioned such as road safety and security, streaming services, traffic monitoring and driving comfort, just to mention a few. It is critical that the existence of convenience or driving comfort services do not negatively affect the performance of safety services. In essence, the dissemination of safety services or the discovery of convenience applications require the communication among service providers and service requesters through constrained bandwidth resources. Therefore, service discovery techniques for vehicular networks must efficiently use the available common resources. In this paper, we present a bandwidth-efficient and scalable hybrid adaptive service discovery protocol (VSDP) for Vehicular Networks. VSDP aims at providing high success ratio while guaranteeing low response time and good scalability when the number of requests increases. Our proposed protocol finds the service provider and its routing information simultaneously which results in overall bandwidth savings. It uses diverse channels to exchange discovery and routing packets, thereby decreasing the congestion on single channels and decreasing the delay of service discovery. Our proposed service discovery protocol adapts the advertisement zone size of service providers based on an efficient adaptation mechanism that takes into consideration network condition and application requirements. The adaptation process is based on an adjustment technique and a prediction technique. We discuss the implementation of our protocol, present its proof of correctness as well as the performance evaluation through an extensive set of simulation experiments and using different mobility models. Our results show the scalability of our protocol. They indicate that our techniques can achieve significant success rate (more than 90 percent), while guaranteeing low response time (in the order of milliseconds) and low bandwidth usage when compared to existing service discovery techniques.

ABSTRACT 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 © 2013 John Wiley & Sons, Ltd.

Internet access from vehicular networks is a very promising subject that needs to be investigated from the research community. Vehicles should be able to connect to the Internet, and provide drivers and passengers with a high number of services that need communication through gateways. Existing discovery protocols in VANets did not focus on secure gateway discovery in particular, but they considered the discovery of secure services in general. In this paper, we propose a secure hybrid adaptive gateway discovery and communication system for VANets that we call SEGAL. Our proposed SEGAL protocol aims to provide an efficient and secure gateway advertisement and discovery process for VANets. It is hybrid because it combines both proactive and reactive discovery approaches. Besides, it is adaptive because it shrinks or extends the advertisement zone of the gateway for scalability purposes. Our proposed protocol builds a secure clustered VANet and permits the exchange of gateway discovery messages through authenticated clusterheads and cluster members. We discuss the design of our protocol, and how it can overcome the possible attacks that can occur. Then we prove its efficiency and scalability in our performance evaluation. We show that our proposed SEGAL achieves high success rate, low response time and dropping rate, while maintaining the scalability in the VANet.

The number of applications in Intelligent Transportation Systems (ITS) is growing rapidly. Vehicular systems have been widely seen as a promising technique for ITS-based applications. Two main types of applications are considered in vehicular systems: safety and infotainment applications. While the first type of applications provides drivers with warning or alert messages to prevent them from an accident or a disaster, the second type of applications allows drivers and passengers to localize services, get information, and even perform transactions with the surrounding services. Thus, it is very important to have secure discovery and communication with these services, while not affecting drastically the communication delay and the network scalability. In this paper, we discuss the importance of secure service discovery and communication in vehicular systems. Then, we propose a secure service discovery protocol for vehicular systems dedicated mainly to the infotainment type of application. We discuss the security requirements achieved by the proposed protocol and we report on its performance evaluation.

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.

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.

A considerable number of Vehicular Network (VN) applications have been developed recently. These applications range from security and safety to traffic information and service location. However, several research challenges remain open concerning efficient service discovery in large scale VNs. Most of the existing service discovery strategies present high overhead and poor performance when applied to VNs. Furthermore, existing context-aware and location-based service discovery protocols are either designed without considering the particularities of VNs or are not scalable with the increase of network density and number of requests. In this paper, we present novel context-aware and location-based service discovery protocols (Election-Based LocVSDP and Naive LocVSDP) that offer a scalable framework for the discovery of time-sensitive and location based services in large scale VNs. We conduct a concrete set of simulation experiments to evaluate the performance of our techniques and compare the results with an existing location-based discovery protocol (VITP). Simulation results indicate that our techniques outperform the VITP protocol in terms of success rate, average response time and bandwidth usage. In essence, both LocVSDP protocols show a gain of 20 percent in terms of success rate, use at least 90 percent less bandwidth than VITP and their average response time is at least 10 percent lower than VITP for successful query transactions.

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 time-sensitive 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.

Recently, we have witnessed a growing interest in the study of service discovery in vehicular networks that guarantee QoS to service requesters. To the best of our knowledge, none of the existing service discovery protocols in Vehicular Networks have been provided in the literature that guarantee QoS to service requesters nd to the Vehicular Network. For efficient service discovery in vehicular networks, it is very important to provide users with services that suit better to their requests while balancing the load on service providers. Moreover, for service discovery protocol integrated with routing protocols, it is important to guarantee load balancing on routing paths between service providers and service requesters. In this paper, we present a QoS aware location based service discovery protocol for Vehicular Networks. Our protocol guarantees load balancing on service providers, and routing paths between service providers and service requesters. It permits also to choose service providers and routing paths between service providers and service requesters that satisfy some performance attributes specified by service requesters. We present our QoS aware protocol, report on its performance evaluation, and discuss our experimental results we have obtained using realistic scenarios.1

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.

Recently, vehicle networks are gaining great deal of attention from the research community. In order to provide efficient and pervasive road communication, Next Generation Vehicular Networks (NVN) are considered a promising solution. NVNs have unique characteristics and face challenging problems. Consequently, it is hard to use the traditional mechanisms and protocols in this type of network. Service discovery is a very challenging problem for NVN-based applications. Furthermore, to the best of our knowledge, very little work has been done to deal with the service discovery problem in NVNs. Due to the high mobility and density of vehicles, traditional discovery techniques do not perform well. To solve this problem, we propose a novel class of service discovery protocol that would allow vehicles to discover services through the vehicular 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, thus enabling efficient discovery characterized by low overhead and a high success rate. In this paper, we present the proof of correctness and the message and time complexities computation of our protocol.

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.

The characteristics of wireless mesh networks (WMNs) have motivated us in the design of an efficient service discovery protocol that considers the capabilities of such networks. In this paper we propose a novel service discovery technique for WMNs. Our approach reduces the discovery overhead by integrating the discovery information in the routing layer. Based on an adaptively adjusted advertisement zone of service providers, we have combined proactive and reactive service discovery strategies to come up with an efficient hybrid adaptive service discovery protocol for WMNs. Our protocol optimizes the network overhead. We will show that our proposed protocol is scalable and that it outperforms existing service discovery protocols in terms of message overhead.

Abstract Recent demand for mobile telephone services has been growing rapidly while the electromagnetic spectrum of frequencies allocated for this purpose remains limited. Any solution to the channel assignment problem is subject to this limitation, as well as the interference constraint between adjacent channels in the spectrum. The early research focused on the fixed channel allocation and centralized schemes. Recently, distributed channel allocation schemes have received much attention because of their high reliability and scalability. In these schemes, a base station (BS) has to consult with its neighboring BSs in order to assign a channel to a call. If it cannot communicate with its neighbors, it fails in allocating a channel. However, it is a common phenomenon that a BS fails in communicating with its neighboring BSs due to some reasons, such as heavy traffic load. In this paper, we propose a distributed fault‐tolerant channel allocation schemes which can work well under the mobile host (MH) failures, BS failures, and communication link failures. This algorithm is based upon the mutual exclusion model where the channels are grouped into three equal sized groups and each group of channels cannot be shared concurrently within the same cluster. We prove its correctness. We also report our algorithm's performance with several channel systems using different types of call arrival pattern through comparing with a popular generic distributed algorithm for channel allocation DDRA. Copyright © 2008 John Wiley & Sons, Ltd.

In this paper, a leader election algorithm for wireless quasi-static mesh network is provided. Our mesh network consists of fixed mesh routers and mobile mesh clients. Our protocol performs well under a high mobility of mesh clients. The main particularity of our protocol is that it takes advantages of the wireless mesh network topology in order to elect a unique leader. It is based on the construction of a spanning tree that includes all static wireless mesh routers. Our protocol elects the node with the highest remaining battery life. It requires less time and messages for the election of a leader than the execution of a Kurose et al. algorithm in a mesh topology (3 timeshunits of time andO(3 timeschitimesnR) messages for our algorithm, versusT= 3 timeschitimeshunits of time andO(4 timeschi2timesnR) messages in Kurose et al. algorithm).

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.

Earlier studies on dynamic channel allocation protocols based upon the mutual exclusion paradigms have shown promising results. Though, very little data have been reported on how to integrate the quality of service (QoS) and fault tolerant components within these schemes. These two components are vital to the success of the deployment of future generation of wireless networks. Mobile users are not expected to have their connections cut off because of a base station or a link failure and require QoS guarantees on their connections. In this paper, we present an efficient QoS and fault tolerant based protocol for dynamic channel allocation using the mutual exclusion paradigm. Its main feature is its ability to tolerate the base station failure, mobile host failure and communication link failure, as well as reducing the connection dropping rate. QoS provisions are guaranteed in our protocol. We present our QoS and fault-tolerant protocol, and report on its performance evaluation using an extensive set of simulation experiments.

In recent years, we have witnessed a growing interest in the study of channel allocation and hand-off strategies for wireless networks to ensure continuous services that guarantee QoS to mobile users. To the best of our knowledge, most of the proposed channel allocation schemes do not take the QoS provisioning into account In this paper, we propose a distributed algorithm for dynamic channel allocation with an efficient adaptive channel reservation schema providing continuous QoS support. To acquire the low dropping rate, a proper number of channels in the congested cells is reserved for the handoff calls. This number of reserved channels is related to the wireless data traffic network. Our presented channel allocation protocol is based upon the mutual exclusion paradigm where all the channels are grouped into three groups and any cell in a cluster can not hold a channel group as long as another cell in the same cluster is holding the same group. We present our QoS-Based dynamic channel allocation protocol, and its performance evaluation, and discuss our experimental results we have obtained using realistic scenarios.