Augmenting Vehicle-to-Roadside connectivity in multi-channel vehicular Ad Hoc Networks C. Campolo a,n , H.A. Cozzetti b , A. Molinaro a , R. Scopigno b a Universita’ Mediterranea di Reggio Calabria, DIMET (Dipartimento di Informatica, Matematica, Elettronica e Trasporti), Italy b BWA Lab (Broadband Wireless Access), Istituto Superiore Mario Boella, Turin, Italy article info Article history: Received 14 July 2011 Received in revised form 20 December 2011 Accepted 3 April 2012 Keywords: Connectivity IEEE 802.11p Multichannel organization Urban environment Network advertisements Vehicular networks WAVE abstract Vehicle-to-Roadside (V2R) wireless communication is a cornerstone for providing a wide plethora of intelligent transportation system (ITS) applications in the near future. Initial investment costs could discourage the deployment of a ubiquitous roadside infrastructure to support on-the-road networks; this would imply discontinuous coverage and short-lived connectivity. The purpose of this paper is to design techniques that make the best of sparse road-side unit (RSU) placement by supporting the spreading of network initialization advertisements from RSUs, when considering the multichannel features of the recently published IEEE 802.11p/IEEE 1609.4 standards for wireless access in vehicular environment (WAVE). The proposed techniques leverage time, space and channel diversity to improve efficiency and robustness of the network advertisement procedure in a urban scenario where obstructions to signal propagation due to buildings and traffic jam could hinder successful message spreading. Simulation under different RSU density, vehicular networking technol- ogy penetration rate, data rate, and packet size, aims at assessing effectiveness and efficiency of the proposed solutions. & 2012 Elsevier Ltd. All rights reserved. 1. Introduction Several ongoing research projects supported by car manufac- turers, electronic industries, governments and academia have been underway to accelerate the deployment of short-range wireless networks that exploit Vehicle-to-Vehicle (V2V) and Vehicle-to-Roadside infrastructure (V2R) communications. These networks, named Vehicular Ad Hoc Networks (VANETs), are characterized by rapidly changing topologies and short connec- tion lifetime. Drivers and passengers on VANET-equipped vehicles may benefit of safety-critical, transport efficiency and information/ entertainment (infotainment) services (Hossain et al., 2010). The latter two classes, referred to as non-safety services, aim at offering traffic information and augmenting comfort/entertain- ment for travelers on the road. So they have great potential as a driver for VANET market penetration. Beside multimedia interactive Internet-based applications (e.g., media streaming, voice over IP, Internet gaming, web browsing), new applications, not necessarily IP-based, are expected to be specifically tailored to the vehicular environment (Gerla and Kleinrock, 2011). For instance, vehicles could collect data about traffic density and average car speed, or pollution measurements retrieved through on-the-road sensors; additionally, media-rich streaming (e.g., videos recorded by on board cameras) could be uploaded for monitoring purposes to remote Intelligent Trans- portation Systems (ITS); moreover, identifications of detected malicious vehicles could be uploaded to a Certification Authority responsible for certificate revocation. On the other hand, Roadside Units (RSUs) could broadcast location-based information, e.g., news items, proximity advertisements about nearby petrol sta- tions, museums, theaters, points-of-interests, and traffic-related information. We can say that almost the totality of non-safety applications targeted for the vehicular environment requires reliable connec- tions between On-board Units (OBUs) on vehicles and the road- side communication infrastructure made up of Road-side Units (RSUs) located at the strategic places, e.g., at city crossroads or at gas stations along highways. High costs required for the deployment of a ubiquitous road- side communication infrastructure would result in only a few RSU installations in the early stage of vehicular network develop- ments, thus providing discontinuous connectivity along the road. The RSU limited coverage plus OBU mobility (especially fast in highways) would lead to short RSU-OBU connection lifetimes. V2R connectivity is further challenged in urban scenarios, because of obstructions due to buildings which limit the network radio Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/jnca Journal of Network and Computer Applications 1084-8045/$ - see front matter & 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jnca.2012.04.001 n Corresponding author. Tel.: þ393491775654. E-mail addresses: claudia.campolo@unirc.it (C. Campolo), cozzetti@ismb.it (H.A. Cozzetti), antonella.molinaro@unirc.it (A. Molinaro), scopigno@ismb.it (R. Scopigno). Please cite this article as: Campolo C, et al. Augmenting Vehicle-to-Roadside connectivity in multi-channel vehicular Ad Hoc Networks. Journal of Network and Computer Applications (2012), http://dx.doi.org/10.1016/j.jnca.2012.04.001 Journal of Network and Computer Applications ] (]]]]) ]]]–]]]