Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
A Survey of MAC Protocols in Vehicular Ad Hoc Networks

汤恒亮, 吴昊, 孟嘉
Hans Journal of Wireless Communications (HJWC) , 2012, DOI: 10.12677/hjwc.2012.24014
Abstract: 近年来,随着车载通信系统的不断发展和自组织网络技术的日益成熟,将二者有机结合成一体的车载自组织网络(VANET, Vehicular Ad Hoc Networks)已引起学术界和工业界的极大关注。媒介接入控制(MAC, Medium Access Control)协议是保证移动终端能够公平有效地共享无线信道的必要手段,是车载自组织网络的关键技术之一。由于VANET自身的特点及不断增长的业务不同,现有自组织网络的MAC协议并不能直接用于车载自组织网络中。本文在简要介绍车载自组织网络特点和MAC协议基本原理的基础上,对车载自组织网络MAC协议的最新研究进展进行了综述,探讨了几种具有代表性的车载自组织网络MAC协议方案,分析了目前研究中存在的主要问题和挑战,并指出了该领域未来发展趋势。
In recent years, with the rapid development of vehicular communication systems and advanced ad hoc network technologies, Vehicular Ad Hoc Networks (VANET) which combines both of them has greatly attracted those people’s attention in academic and industry fields. As one of the key technologies in vehicular ad hoc networks, MAC (Medium Access Control) protocol is indispensable to ensure the mobile nodes share the wireless medium fairly and efficiently. Since the specific characteristics and the increased variety of services in VANET, MAC protocols which are designed for Mobile Ad Hoc Networks
Non DTN Geographic Routing Protocols for Vehicular Ad Hoc Networks  [PDF]
Ramin Karimi,Norafida Ithnin,Shukor Abd Razak,Sara Najafzadeh
International Journal of Computer Science Issues , 2011,
Abstract: Vehicular Ad Hoc Networks are highly mobile wireless ad hoc networks. Routing of data in VANETs is a challenging task due to rapidly changing topology and high speed mobility of vehicles. Geographic routing protocols are becoming popular due to advancement and availability of GPS devices. In this paper, we review the existing non DTN Geographic Routing Protocols for VANETs and also provide a qualitative comparison of them.
Mac Protocols in Mobile Ad Hoc Networks  [cached]
Nermin Makhlouf,Pavel Vajsar
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems , 2012, DOI: 10.11601/ijates.v1i1.4
Abstract: Mobile Ad hoc NETwork (MANET) is a wireless net- work of mobile nodes connected by wireless link without a central control. The Medium Access Control (MAC) protocol is one of the important issues in such network, thereby the presented paper will discuss the MAC protocol used in MANET depending on IEEE 802.11 standard which known as Distributed Coordination Function (DCF).However, the limitation of MANET is that, the collision increases with the rise of nodes number. Therefore paper study the MAC protocol using directional antennas to reduce the collisions, increase the range of transmission and largely reduce the interference between the directions. However, the main problem of using directional antennas is caused by frequent node mobility. So the movement plays a vital role in wireless Ad hoc networks to predict the location of MNs.
Collision Free MAC Protocols for Wireless Ad Hoc Networks based on BIBD Architecture  [cached]
Pietro Camarda,Orazio Fiume
Journal of Communications , 2007, DOI: 10.4304/jcm.2.7.1-8
Abstract: Wireless Ad hoc networks represent a powerful telecommunication infrastructure that is being exploited for enabling general wireless networking connectivity for a variety of significant applications, e.g., military applications, industrial automation, sensor networks, vehicular networks, applications in case of disaster, etc.The distributed and flexible architecture of wireless ad hoc networks is a key factor, however, their wide deployment relies on protocols able to provide energetic optimization, high channel utilization, support for real time traffic, etc. In such a context, recently a Collision Free MAC protocol (CFMAC), based on the theory of Balanced Incomplete Block Design (BIBD), has been proposed. Its effectiveness has been already investigated showing significant improvements compared to the Standard IEEE 802.11, in terms of throughput, one -way packet delay, energy consumption and support of real time traffic.In this paper enhanced versions of CF-MAC have been considered with significant novelties regarding the introduction of variable time slot dimension, different management of Power Saving (PS) mechanisms, more efficient utilization of channel bandwidth, etc. The performance of these variants have been investigated by simple analytical models, in terms of energy saving, channel utilization, average access delay, etc., highlighting their improvements over basic CF-MAC protocol. In addition, computer simulations have been exploited to study the suitability of the proposed schemes to support VoIp applications.
Comparative Study of MAC Protocols for Mobile Ad Hoc Networks
Sanjeev Sharma,R.C. Jain,Sarita Bhadauria,Ramesh Cherukuru
International Journal of Soft Computing , 2012,
Abstract: Studies of ad hoc wireless networks are a relatively new field gaining more popularity for various new applications. In these networks, the Medium Access Control (MAC) protocols are responsible for coordinating the access from active nodes. These protocols are of significant importance since the wireless communication channel is inherently prone to errors and unique problems such as the hidden-terminal problem, the exposed-terminal problem, and signal fading effects. Although a lot of research has been conducted on MAC protocols, the various issues involved have mostly been presented in isolation of each other. We therefore make an attempt to present a comparative study of major schemes, integrating various related issues and challenges. We present a classification of MAC protocols and their brief description based on their operating principles and underlying features.
Research in security problems of vehicular Ad hoc networks MAC layer

AN Jian-wei,ZHOU Xian-wei,HUANG Huan,WU Xiao-bo,

计算机应用研究 , 2009,
Abstract: The paper first analyzed the security threats of VANET(vehicular Ad hoc networks) MAC layer and the principles of attacks.Secondly it illustrated and evaluated present solutions for the threats and attacks,and proposed the security architecture for VANET MAC layer.Finally it discussed the unresolved topics in the implementation process of security mechanism and showed the further directions.
Collision Resolution MAC Protocols for Wireless Ad Hoc Networks  [PDF]
Xinhua Yang, Tracy Camp
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.51003

In wireless ad hoc networks, nodes cooperatively form a network without any infrastructure such as a BS/AP (base station or access point). The widely-used contention-based MAC protocol, IEEE 802.11b, is inefficient in multi-hop networks due to the hidden and exposed terminal problems. The most popular schedule-based MAC protocol, TDMA (time division multiple access), is difficult to implement in an ad hoc network due to the lack of infrastructure. The contribution of this paper is to provide the community novel and efficient MAC (medium access control) protocols (i.e., a collision resolution protocol) for a wireless ad hoc network without a centralized infrastructure. We propose two new MAC protocols (one distributed algorithm and one cluster-based algorithm) that use a collision resolution scheme for a network with a single BS/AP. We first compare the performance of our distributed algorithm with our cluster-based algorithm. Then, we compare our algorithm that performs better (i.e., our cluster-based algorithm) to TDMA in a two-hop network. The simulation results illustrate that our cluster-based algorithm provides higher throughput and lower delay than TDMA in a two-hop network.

Survey of Routing Protocols in Vehicular Ad-Hoc Network
Karthikumar. P.,Dr. V. Krishnaveni
International Journal of Engineering Innovations and Research , 2012,
Abstract: Vehicular ad-hoc networks (VANETs) are a promising communication scenario. Several new applications are envisioned, which will improve traffic management and safety. In comparison to other communication networks, Vehicular Ad-hoc Networks (VANETs) have unique requirements with respect to applications, types of communication, self-organization and other issues. VANETspecific protocol layers, a staircase approach for interaction among layers and the use of an information connector for cross-layer information exchange using the publisher/subscriber pattern. The main goal of VANET is providing safety and comfort for passengers. Each vehicle equipped with VANET device will be a node in the Ad-hoc network and can receive
Clustering and OFDMA-based MAC protocol (COMAC) for vehicular ad hoc networks  [cached]
Abdel Hafeez Khalid,Zhao Lian,Liao Zaiyi,Ma Bobby
EURASIP Journal on Wireless Communications and Networking , 2011,
Abstract: The IEEE community is working on the wireless access in vehicular environments as a main technology for vehicular ad hoc networks. The medium access control (MAC) protocol of this system known as IEEE 802.11p is based on the distributed coordination function (DCF) of the IEEE 802.11 and enhanced DCF of the IEEE 802.11e that have low performance especially in high-density networks with nodes of high mobility. In this paper, we propose a novel MAC protocol where nodes dynamically organize themselves into clusters. Cluster heads are elected based on their stability on the road with minimal overhead since all clustering information is embedded in control channel's safety messages. The proposed MAC protocol is adaptable to drivers' behavior on the road and has learning mechanism for predicting the future speed and position of all cluster members using the fuzzy logic inference system. By using OFDMA, each cluster will use a set of subcarriers that are different from the neighboring clusters to eliminate the hidden terminal problem. Increasing the system reliability, reducing the time delay for vehicular safety applications and efficiently clustering vehicles in highly dynamic and dense networks in a distributed manner are the main contributions of our proposed MAC protocol.
Routing Protocols for Mobile and Vehicular Ad-Hoc Networks: A Comparative Analysis  [PDF]
Preetida Vinayakray-Jani,Sugata Sanyal
Computer Science , 2012,
Abstract: We present comparative analysis of MANET (Mobile Ad-Hoc Network) and VANET (Vehicular Ad-Hoc Network) routing protocols, in this paper. The analysis is based on various design factors. The traditional routing protocols of AODV (Ad hoc On-Demand Distance Vector), DSR (Dynamic Source Routing), and DSDV (Destination-Sequenced Distance-Vector) of MANET are utilizing node centric routing which leads to frequent breaking of routes, causing instability in routing. Usage of these protocols in high mobility environment like VANET may eventually cause many packets to drop. Route repairs and failures notification overheads increase significantly leading to low throughput and long delays. Such phenomenon is not suitable for Vehicular Ad hoc Networks (VANET) due to high mobility of nodes where network can be dense or sparse. Researchers have proposed various routing algorithms or mechanism for MANET and VANET. This paper describes the relevant protocols, associated algorithm and the strength and weakness of these routing protocols.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.