Available connectivity analysis under free flow state in VANETs

Chen Chen, Liu Lei, Du Xiaobo, Wei Xiaolu, Pei, Pei Changxing

Description

Emerging of inter-vehicle communication gives vehicles opportunities to exchange information within limited radio ranges and self-organize in Ad Hoc manner into Vehicular Ad Hoc Networks (VANETs). However, due to strong mobility, limited market penetration rate, and lack of roadside units, connectivity is obviously a scarce resource in VANETs. Further, only depending on direct connectivity, i.e. one-hop connected links between vehicles, is far from the continuous growing communication demands in VANETs, such as inter-vehicle amusement, cooperative collision avoidance, inter-vehicle emergency notification etc. Therefore, the indirect connectivity from multi-hop forwarding and store-carry-forward strategy is also a necessary and powerful complement especially to the case where direct connections are hardly obtained. In this article, we define a new metric named available connectivity which involves both direct and indirect connectivity. By deep analyzing the statistical properties of direct and indirect connectivity in free flow state, the proposed available connectivity is obtained and quantified to increase the information dissemination opportunities for vehicles especially in a relatively slow topology changing scenario. Numerical results show that the available connectivity could provide better references for different VANETs applications and has potential relationships with many network parameters.

Sujets

• Connection
• Mobility

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 5
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

Chenet al. EURASIP Journal on Wireless Communications and Networking2012,2012:270 http://jwcn.eurasipjournals.com/content/2012/1/270

R E S E A R C HOpen Access Available connectivity analysis under free flow state in VANETs * Chen Chen , Lei Liu, Xiaobo Du, Xiaolu Wei and Changxing Pei

Abstract Emerging of intervehicle communication gives vehicles opportunities to exchange information within limited radio ranges and selforganize in Ad Hoc manner into Vehicular Ad Hoc Networks (VANETs). However, due to strong mobility, limited market penetration rate, and lack of roadside units, connectivity is obviously a scarce resource in VANETs. Further, only depending on direct connectivity, i.e. onehop connected links between vehicles, is far from the continuous growing communication demands in VANETs, such as intervehicle amusement, cooperative collision avoidance, intervehicle emergency notification etc. Therefore, the indirect connectivity from multihop forwarding and storecarryforward strategy is also a necessary and powerful complement especially to the case where direct connections are hardly obtained. In this article, we define a new metric named available connectivity which involves both direct and indirect connectivity. By deep analyzing the statistical properties of direct and indirect connectivity in free flow state, the proposed available connectivity is obtained and quantified to increase the information dissemination opportunities for vehicles especially in a relatively slow topology changing scenario. Numerical results show that the available connectivity could provide better references for different VANETs applications and has potential relationships with many network parameters. Keywords:Vehicular Ad Hoc Networks, Connectivity, Mobility

Introduction multihop forwarding. Although connectivity can be Vehicular Ad hoc Networks [1] (VANETs) are distributed,obtained directly or indirectly, it is still a limited resource selforganizing communication networks built up byespecially during sparse communication environment moving vehicles, and are thus characterized by verysuch as on highway or with low market penetration ratio strong node mobility and limited degrees of freedom in[7], i.e. the number of equipped vehicles to the number of the mobility patterns. The discussed IEEE 1609 Wireless total vehicles. Limited connectivity directly affects the Access in Vehicular Environments [2] draft is beingpossible speed and range at which information can be developed for VANETs applications including mainly disseminated over a VANET, and hence limits the upto safetyrelated scenarios, such as Cooperative forwarddatedness of the shared information that can be achieved. Collision Warning [3] (CCW) system, traffic signal violaIn summary, connectivity in VANET is important for us tion warning [4], lane change warning [5] and some inforto analyze and evaluate the overall network performance. mation applications [6]. All these applications greatly relyMany schemes, such as stochastic process [8], Gaussian on the successful packets exchanging which is based onunitary ensemble of randommatrix theory [9] queuing reliable links or node connectivity on a road segment. theory [10] etc., have been proposed to calculate the Thereupon, network connectivity is fundamental andprobability of connectivity with different premises in crucial to any practical application in VANETs. Due toVANETs. Their works all discussed connectivity based on mobility, vehicles on a road segment can not only comthe famous 3state traffic theory in which the fundamen municate with each other directly, they can also delivertal relation of traffic parameters on a road is given by the the packets indirectly to the receiver by storecarry orfollowing equation: F¼SK;ð1Þ * Correspondence: [e-mail] where F, S, and K are the traffic flow, average speed, and State Key Laboratory of Integrated Services Networks, Xidian University, Xian 710071, China traffic density, respectively. The influence of above three © 2012 Chen et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.