A Distributed Token Passing Protocol for Time Constrained Data Gathering in VANETs

Vehicular Ad Hoc Networks is a class of special wireless ad hoc network with the characteristics of high node mobility and fast topology changes. The Vehicular Networks can provide wide variety of services, range from safety-related warning systems to improved navigation mechanisms as well as information and entertainment applications. So lot of research work is being conducted to study the problems related to the vehicular communications including network architecture, protocols, routing algorithms, as well as security issues. In order to stimulate the ‘beginners in research’, here we present a paper on an overview of Vehicular Ad Hoc Networks.

Vehicular ad hoc network (VANET) is a mobile ad hoc network with a dynamic property; the vehicles possess high mobility and undergo fast topology changes. This special type of mobile ad hoc network is a popular topic of research. Owing to the specific features of VANETs, unique routing protocols are required for short-range, high-speed communication among nearby vehicles. In this study, we propose a new opportunistic routing scheme based on the timed bargaining game. In order to dynamically adapt to the current VANET situation, the proposed scheme effectively formulates the opportunistic routing mechanism as an iterative bargaining model with a timed learning approach. Based on a simulation study, it is confirmed that the proposed scheme can achieve better performance than other existing schemes in diverse VANET environments.

Vehicular plays an important role in day-to-day world in the field of automobiles. VANETs are the subclass of mobile ad-hoc Networks which have no central infrastructure. Nodes are highly mobile in VANET. VANET is distinguished from MANET by their features, design and applications. A Vehicular Ad-Hoc Network or VANET is a sub form of Mobile Ad-Hoc Network or MANET that provides communication between vehicles and between vehicles and road-side base stations with an aim of providing efficient and safe transportation. A vehicle in VANET is considered to be an intelligent mobile node capable of communicating with its neighbors and other vehicles in the network. VANET introduces more challenges aspects as compare to MANET because of high mobility of nodes and fast topology changes in VANET. In this paper, VANET basics structure, its architecture, challenges, applications are discussed. Data dissemination is a challenging task because by utilizing limited bandwidth, maximum data has to disseminate over the vehicular network. Many researchers have provided several techniques to disseminate data so that the data can be accessed more efficiently. Major stress is given to this topic where data dissemination types and its protocols are compared.

QoS-aware routing in mobile ad hoc networks (MANETs) is a major challenge due to node mobility and scarcity of resources. QoS-aware routing based on ant colony optimization (ACO) algorithms is a promising approach to overcome these problems. However, as compared to MANETs, vehicular ad hoc networks (VANETs) face additional challenges due to rapid topology change, making the estimation or prediction of QoS parameters difficult or stale. VANETs require time-critical message delivery, as late delivery may result in endangering lives. Currently existing routing protocols usually require the exchange of additional control message between neighbor nodes to compute QoS parameters. This makes the routing protocol too slow to react to fast topology change and also does not consider network congestion when forwarding a data packet. To reduce the overhead introduced to collect information from neighbor nodes and to obtain an accurate estimate of QoS parameters, we use the simple network management protocol to estimate these values locally. This paper describes a new approach for calculating QoS parameter locally and avoiding congestion during data transmission. The simulations are implemented using the network simulator ns-3, and the results show that our approach is scalable and performs well in high mobility. QoS-aware routing in mobile ad hoc networks (MANETs) is a major challenge due to node mobility and scarcity of resources. QoS-aware routing based on ant colony optimization (ACO) algorithms is a promising approach to overcome these problems. However, as compared to MANETs, vehicular ad hoc networks (VANETs) face additional challenges due to rapid topology change, making the estimation or prediction of QoS parameters difficult or stale. VANETs require time-critical message delivery, as late delivery may result in endangering lives. Currently existing routing protocols usually require the exchange of additional control message between neighbor nodes to compute QoS parameters. This makes the routing protocol too slow to react to fast topology change and also does not consider network congestion when forwarding a data packet. To reduce the overhead introduced to collect information from neighbor nodes and to obtain an accurate estimate of QoS parameters, we use the simple network management protocol to estimate these values locally. This paper describes a new approach for calculating QoS parameter locally and avoiding congestion during data transmission. The simulations are implemented using the network simulator ns-3, and the results show that our approach is scalable and performs well in high mobility.

Past few decades have witnessed large increase in number of vehicles on roads due to which the traffic safety needs have also become complex and hence necessary to be taken care of. Vehicular ad hoc networks (VANETs) are becoming an asset for achieving all these goals. VANETs provide applications like driver assistance, passenger comfort and vehicle safety. Apart from its general characteristics due to the dynamic nature of road environments and traffic patterns, communication linkage among vehicles in VANETs suffers breakage problem hence requires a very reliable routing protocol. To manage the communication efficiently many routing protocols are already available for MANETs which can be further used for routing and communication among vehicles in VANETs, but characteristics of these two networks (VANET and MANET) are very different, so there is requirement to enhance these MANET routing protocols so that those can be used in VANETs. When we use some existing routing protocols in VANET then number of link breakage are surprisingly high because mobility is higher in VANETs as compared to MANETs. So this paper presents advanced version of an existing MANET routing protocol for better performance in VANET environment. The new routing protocol has removed problem of large number of routing error messages which was existing in AODV routing protocol. Protocol proposed in this paper has better results as compared to AODV and paper has also shown results of simulation and also elaborated the findings.

Vehicular Ad-hoc NETwork (VANET) is a subcategory of Mobile Ad-hoc NETwork (MANET) which is one of the popular emerging research areas. On one side increase in the number of vehicles, and on the other side due to the presence of communication unit i.e. On Board Unit (OBU) in vehicles helped in the creation of a new network called as VANET. VANET is becoming so popular that it is widely used for different applications that may be safety or non-safety applications. An effective routing protocol is required for the efficient use of VANET for different applications which can optimize different generic parameters of VANET like end-to-end delay, number of hops, etc. Altough multiple paths exist between a source and a destination but the routing protocols evaluate a single path for the transmission of information packets based on parameters like shortest distance towards the destination, density of vehicles, number of hops, etc. Different swarm intelligence techniques like Ant Colony Optimization (ACO), Particle Swarm Optimization (PSO), etc. can be used in VANET to optimize the parameters used in the routing protocol. In this chapter, Ant Colony Optimization (ACO) is used to establish multiple routes between nodes which is vital in the network where network connectivity is random and is frequently changing. This also helps in the parallel transmission of packets in multi-path which reduces end-to-end delay. For this proposed work, a variation of end-to-end delay with respect to transmission distance and a number of vehicles is compared with the existing VANET routing protocol i.e. Geographic Source Routing (GSR), Anchor based Street Traffic Aware Routing (A-STAR). The comparison shows that the proposed work performs better as compared to GSR and A-STAR. To implement multi-path routes MongoDB—an open source distributed database is used and the corresponding operation on the database is implemented using node-red. Selection of effective route and intermediate hop for the transmission of emergency information is essential. The optimized route in VANET not only saves the overall transmission time but also reduces the end-to-end delay. For the optimization of route and number of hops in VANET, another swarm intelligence technique i.e. Particle Swarm Intelligence (PSO) can be used through which the transmission of emergency information with optimum delay is proposed.

A new concept such as smart city was introduced in the last years where the Intelligent Transportation system (ITS ) plays a critical role to provide road safety and manage Vehicular Ad Hoc Networks (VANETs) traffic. Nevertheless, VANETs have significant constraints like nodes high mobility, intermittent connectivity, variable network density and heterogeneity. However, the different types of traffic, the different Quality of Service requirements, the need to exchange mobile data, multi-services and data diversity leads mainly to load and time constraints in this specific and stringent type of networks. The main characteristic of this kind of networks is the very changing topology that poses supplementary constraints and makes achieving QoS constraints a very challenging task. In VANET network the vehicle generated traffic will be transferred to the data center from road side unit to the base station by using Long Term Evolution (LTE) in an urban area. Despite LTE has a larger system capacity and it provides a higher transmission speed, the network performance is affected by the implemented scheduling algorithm. In this context, we study the efficiency of LTE scheduler algorithms such as Proportional Fairness, Round Robin, Priority Set Scheduler, Maximum Throughput Scheduler and Throughput to Average Scheduler and Blind Equal Throughput mainly at the road side unit using Network Simulator 3(NS3) to determinate the most suitable scheduler for VANET traffic. Results demonstrate that the round robin algorithm is more effective for volumetric VANET traffic in terms of throughput, delay, packet loss rate and fairness.

Vehicular Networking is of immense importance and continuous research is going on in this field for building the Intelligent Transportation System (ITS). Vehicular ad hoc networks (VANET) are distributed, self-organizing communication networks which progressed from traveling vehicles. Therefore VANET's are characterized by very high speed of vehicles and limited degree of freedom in vehicles movement pattern. VANETs are infrastructure less which allows communication between vehicles without any type of configuration and any worthy cellular networks. Mobility Management for VANET is a challenging task because of the fast mobility of the vehicles. The main goal of VANET is to improve road traffic safety and to efficiently achieve intelligent intervehicle communications. In this paper, the scalability and efficiency of mobility management protocol MMIP6 has been further enhanced to accommodate more number of vehicles with reduction in total cost of the entire network. Numerical analysis has been carried out for comparing the total communication cost of enhanced MMIP6 with Network Mobility protocol (NEMO) of VANET.

This paper proposes a novel network architecture based on content routing and dissemination techniques, expressly adapted for hybrid mobile and vehicular ad-hoc networks. Hybrid vehicular ad-hoc networks (VANETs) are a subclass of mobile ad-hoc networks (MANETs) where each node is a moving vehicle equipped with one or more communication devices, potentially having access to several different physical communication channels. This results in a partly decentralized, self-organizing mobile radio network with a fast changing topology. Applications designed for VANETs still require efficient mapping techniques to associate content to the host serving it, as well as centralized databases associating vehicles and mobile nodes to a persistent and unique identifier. They also assume that the content providers are located in the infrastructure, but nodes and vehicles can be equipped with sensors and as such produce information. This means that dissemination and retrieval algorithms have to take into account the distribution of the consumers, providers and forwarder all over the network.

Analysis and adaptive optimization of vehicular safety message communications at intersections

In vehicular ad hoc networks (VANETs), efficient data dissemination to a specified number of vehicles with minimum collisions and limited access delay is critical for accident prevention in road safety. However, packet collisions have a significant impact on access delay, and they may lead to unanticipated link failure when a range of diversified collisions are combined due to complex traffic conditions and rapid changes in network topology. In this paper, we propose a distributed contention-free cooperative medium access control (CFC-MAC) protocol to reduce heterogenous collisions and unintended access delay in stochastic traffic scenarios. Firstly, we develop a cooperative communication system model and cooperative forwarding mechanism to explore the optimum road path between the source and destination by identifying the potential cooperative vehicles. Secondly, we propose a vectorized trajectory estimation mechanism to suppress merging collisions by identifying the relative velocity of vehicles with different speeds in a specific time interval. Based on the case study, typical heterogeneous collisions and aggregated heterogeneous collisions at dissociated positions and associated positions are investigated. In both cases, we propose the corresponding collision-resolving mechanisms by methodically recapturing the colliding time slot or acquiring the available free time slots after identifying the access vehicles and comparing the received signal strengths. Performance analysis for collision probability and access delay is conducted. Finally, the simulation results show that the proposed protocol can achieve deterministic access delay and a minimal collision rate, substantially outperforming the existing solutions.

The vehicular ad hoc networks (VANETs) are characterized by high mobility of nodes, which resulting in frequent and fast changes in the network topologies. To make sure the messages are received efficiently and reliably, particularly for safety applications, broadcasting is the most natural and promising approach. Besides the efficiency, security is another important issue for VANETs. Because the open nature of VANETs make it simple for malicious users to disrupt the system or lead to accidents. In this paper, we propose a PKI-based Multihop Broadcasting Protocol (PMBP), which aims at providing authenticated, integrated, non-repudiated vehicular communication. The authentication scheme is based on the Elliptic Curve Digital Signature Algorithm (ECDSA) method. To provide an efficient trusted broadcasting scheme, two strategies are adopted: only the message originator signs the message, one message only be rebroadcasted once by each vehicle. Experimental results prove that this protocol is efficient enough to support safety related vehicular applications.

Vehicular communication ad hoc routing protocols: A survey

Vehicular Ad Hoc Network (VANET) is a multi-hop wireless network which involves vehicles acting as nodes to communicate with each other without infrastructural support. With the increase in Quality of Service (QoS) needs in evolving applications and the widespread use of wireless and mobile devices, it is desirable to support QoS in VANETs. The resource limitations and variability further add to the need for QoS support in such networks. However, the characteristics of these networks make QoS support a complex process due to rapid topology changes caused by high mobility of communicating nodes. Modulation scheme implemented in wireless network affect the data rate hence the throughput of the communicating nodes, this in turn affect QoS. The paper focuses on adaptive modulation to improve the data throughput and efficiency of channel spectrum in VANET. Through theoretical and simulation results, it was shown that adaptive modulation performs well and improves throughput than other modulations schemes when used singularly in dynamic changing network topology like VANET.

A significant increase in the popularity of autonomous vehicles (AVs) in the last few years is quite evident. At the same time, applications through Internet access in Ad Hoc Networks have evolved remarkably such as Video on Demand, VoIP, and Online Gaming. These applications will not be able to fulfill their potentials without high-speed wireless communication. For most of the cellular carriers across the globe, LTE is the de facto standard to share multimedia data in significantly less time. As LTE has already been tested as a promising candidate for high speed communication in networks like Vehicular Ad Hoc Networks (VANETs) [1], we have tried out the advanced version of LTE which is LTE-A in a simulated VANET environment. The notion of this paper is to evaluate the performance of multimedia transmission over LTE-A for a typical Vehicular Ad Hoc Network (VANET) using a popular simulation framework OMNET++. We use the VoIP application as a test-case for this evaluation. Results indicate that the performance of the network is impacted with respect to the number of vehicles as well as the speed of their mobility.