• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.526-535
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• 2008

Recently, several MAC protocols using the directional antennas have been proposed for wireless mobile ad hoc networks. In the theory, it can improve spatial reuse and communication throughput in the Mobile Ad-hoc networks. But, or However even though direction transmissions using the Directional MAC protocol(D-MAC) are expected to provide significant improvements, they causes other problems such as deafness problem and fairness problem. In this paper, we analyze the D-MAC protocol in Mobile Ad-hoc network for Vehicle to vehicle(V2V) communication. Through the results of the analysis, We the fundamental problem of D-MAC protocol and finally we suggest new D-MAC protocol for V2V networks.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.12
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• pp.449-454
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• 2014

While the era of driverless car has come, Vehicular Ad hoc NETwork(VANET) is getting important. Original VANET has a limit that cannot use computation power, storage space of On Board Unit(OBU) installed in a vehicle efficiently. VANET cloud computing(VCC) solves the limit to focus on using abilities of each vehicle. This article proposes VCC architecture for supplementing user addition and initial cloud creation that have been researched insufficiently.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.207-213
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• 2021

Networks in Mobile ad hoc contain distribution and do not have a predefined structure which practically means that network modes can play the role of being clients or servers. The routing protocols used in mobile Ad-hoc networks (MANETs) are characterized by limited bandwidth, mobility, limited power supply, and routing protocols. Hybrid routing protocols solve the delay problem of reactive routing protocols and the routing overhead of proactive routing protocols. The Ant Colony Optimization (ACO) algorithm is used to solve other real-life problems such as the travelling salesman problem, capacity planning, and the vehicle routing challenge. Bio-inspired methods have probed lethal in helping to solve the problem domains in these networks. Hybrid routing protocols combine the distance vector routing protocol (DVRP) and the link-state routing protocol (LSRP) to solve the routing problem.

• Journal of Communications and Networks
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• v.6 no.4
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• pp.295-306
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• 2004

In this paper, a novel air-interface is presented for Fleet-Net1, a self-organizing network for inter-vehicle and vehicle-toroadsidecommunication. The air-interface is based upon the lowchip-rate version of UMTS/TDD. To adapt the cellular UMTS standard to an air-interface for ad hoc networks, changes of the physical layer, medium access control sub-layer and radio resource management are required. An overview of the required modifications is given here. Particularly, a decentralized synchronization mechanism is presented and analyzed by means of simulations. Furthermore, changes for the medium access control are explained in detail, which allow for an efficient operation in partly meshed networks and prioritization. Performance results of the overall system considering throughput and delay are derived by means of analytical evaluations and event-driven simulations. Based on realistic mobility models, it is shown that the presented solution provides a robust communication platform even in vehicular environments. The proposed air-interface is a cost-effective solution not only for inter-vehicle communication, but also for ad hoc networking in general, benefiting from the mass-market of UMTS.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.2
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• pp.80-87
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• 2013

This paper proposes a CW (Contention window) allocation scheme for real-time data transmission of emergency data on VANET (Vehicle to vehicle Ad hoc Network, V2V) protocol. The proposed scheme reduces the probability of packet collisions on V2V protocol and provides bandwidth efficiency with short delay of emergency sporadic data. In the case of high density traffic, the proposed scheme provides a decrease of recollision probability using dynamic CW adjustments. For the performance analysis, a throughput, end-to-end delays, and network loads were investigated on highway traffic. Simulation results show the performance enhancements in terms of the throughput, end-to-end delays, and network loads.

• The KIPS Transactions:PartC
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• v.18C no.6
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• pp.445-450
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• 2011

In the vehicular ad hoc network environment, the clustering mechanism is one of the efficient mechanisms to deliver broadcast messages. Most clustering mechanisms require message exchanges between vehicles to build stable clusters, which causes overhead. In order to reduce this overhead, CF-IVC [1] proposes the mechanism to construct clusters based on the vehicle speed. However, since CF-IVC does not consider the road traffic condition and the driver's behavior, it may result in inefficient clusters. Therefore, in this paper, we propose a mechanism to establish efficient clusters based on the vehicle local information with considering the road maximum speed limit and the road traffic condition. The performance of the proposed mechanism is validated by comparing with those of the simple flooding and CF-IVC through NS-2 simulations.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.423-434
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• 2007

Vehicular ad-hoc network (VANET), a kind of mobile ad-hoc network (MANET), is a key technology for building intelligent transportation system (ITS). VANET is automatically and temporarily established through vehicle-to-vehicle communication without network infrastructure. It has the characteristics that frequent changes of network topology and node density are occurred and messages are disseminated through several relay nodes in the network. Due to frequent change of network topology and node density, however, VANET requires an effective relay node selection scheme to disseminate messages through the multi-hop broadcast. In this paper, we propose a contention window based multi-hop broadcast scheme for VANET. Each node has an optimized contention window and competes with each other for a relay node. The experimental results show that the proposed scheme has a better performance than the distance-based deterministic broadcast scheme in terms of message propagation delay and network traffic.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.12-20
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• 2008

Recent wireless communication technologies are envisioned as an innovative alternative to solve transportation problems. On ad hoc networks, as a wireless communication technology, nodes can communicate data without any infrastructure. In particular, vehicular ad hoc networks (VANETs), a specific ad hoc network applied to vehicles, enable vehicles equipped with a communication device to form decentralized traffic information systems in which vehicles share traffic information they experienced. This study investigated traffic information dissemination in a VANET-based traffic information system. For this study, an integrated transportation and communications simulation framework was developed, and experiments were conducted with real highway networks and traffic demands. The results showed that it took 3 minutes in the low traffic density situations (10 vehicle/lane.km) and 43 seconds in the high traffic density condition (40 vehicle/lane.km) to deliver traffic information of 5km away with 10% market penetration rate. In uncongested traffic conditions, information seems to be disseminated via equipped vehicles in the opposite direction. In congested traffic conditions, the sufficient availability of equipped vehicles traveling in the same direction reduces the chance to use vehicles in the opposing direction even though it is still possible.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.167-174
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• 2022

Vehicular Ad hoc Networks are considered as special kind of Mobile Ad Hoc Networks. VANETs are a new emerging recently developed, advanced technology that allows a wide set of applications related to providing more safety on roads, more convenience for passengers, self-driven vehicles, and intelligent transportation systems (ITS). Delay Tolerant Networks (DTN) are networks that allow communication in the event of connection problems, such as delays, intermittent connections, high error rates, and so on. Moreover, these are used in areas that may not have end-to-end connectivity. The expansion from DTN to VANET resulted in Vehicle Delay Tolerant Networks (VDTN). In this approach, a vehicle stores and carries a message in its buffer, and when the opportunity arises, it forwards the message to another node. Carry-store-forward mechanisms, packets in VDTNs can be delivered to the destination without clear connection between the transmitter and the receiver. The primary goals of routing protocols in VDTNs is to maximize the probability of delivery ratio to the destination node, while minimizing the total end-to-end delay. DTNs are used in a variety of operating environments, including those that are subject to failures and interruptions, and those with high delay, such as vehicle ad hoc networks (VANETs). This paper discusses DTN routing protocols belonging to unicast delay tolerant position based. The comparison was implemented using the NS2 simulator. Simulation of the three DTN routing protocols GeOpps, GeoSpray, and MaxProp is recorded, and the results are presented.

• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.105-110
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• 2021

Contact between Vehicle-to-vehicle and vehicle-to-infrastructural is becoming increasingly popular in recent years due to their crucial role in the field of intelligent transportation. Vehicular Ad-hoc networks (VANETs) security and privacy are of the highest value since a transparent wireless communication tool allows an intruder to intercept, tamper, reply and erase messages in plain text. The security of a VANET based intelligent transport system may therefore be compromised. There is a strong likelihood. Securing and maintaining message exchange in VANETs is currently the focal point of several security testing teams, as it is reflected in the number of authentication schemes. However, these systems have not fulfilled all aspects of security and privacy criteria. This study is an attempt to provide a detailed history of VANETs and their components; different kinds of attacks and all protection and privacy criteria for VANETs. This paper contributed to the existing literature by systematically analyzes and compares existing authentication and confidentiality systems based on all security needs, the cost of information and communication as well as the level of resistance to different types of attacks. This paper may be used as a guide and reference for any new VANET protection and privacy technologies in the design and development.