On the Experimental Evaluation of Vehicular Networks: Issues, Requirements and Methodology Applied to a Real Use Case

One of the most challenging fields in vehicular communications has been the experimental assessment of protocols and novel technologies. Researchers usually tend to simulate vehicular scenarios and/or partially validate new contributions in the area by using constrained testbeds and carrying out minor tests. In this line, the present work reviews the issues that pioneers in the area of vehicular communications and, in general, in telematics, have to deal with if they want to perform a good evaluation campaign by real testing. The key needs for a good experimental evaluation is the use of proper software tools for gathering testing data, post-processing and generating relevant figures of merit and, finally, properly showing the most important results. For this reason, a key contribution of this paper is the presentation of an evaluation environment called AnaVANET, which covers the previous needs. By using this tool and presenting a reference case of study, a generic testing methodology is described and applied. This way, the usage of the IPv6 protocol over a vehicle-to-vehicle routing protocol, and supporting IETF-based network mobility, is tested at the same time the main features of the AnaVANET system are presented. This work contributes in laying the foundations for a proper experimental evaluation of vehicular networks and will be useful for many researchers in the area.Comment: in EAI Endorsed Transactions on Industrial Networks and Intelligent Systems, 201

Extended interface ID for virtual link selection in GeoNetworking to IPv6 Adaptation Sub-layer (GN6ASL)

Proposition to ETSI TC ITS WP3 about Draft EN 302 636-6-1 V0.1.2 (2012-11).We describe the limitation of Draft EN 302 636-6-1 V0.1.2 (2012-11). Note that this study is based on year December 2012 versions of the ETSI Standards and that the standards constantly evolve. As a result, parameters, primitives and virtual links on GN6ASL may have changed at the time of reading. We propose a solution to allocate different IPv6 address on each virtual interface in order to distinguish them without changing the addressing scheme in MAC address and GeoNetworking address. The proposition complies also with Dynamic Geographical Virtual Link (DVL)

Proposition of Dynamic Virtual Link for IPv6 GeoNetworking (GN6) in ETSI

A proposition to ETSI ITS WP3.First, we describe the limitation of Draft EN 302 636-6-1 V0.1.2 (2012-11). Note that this study is based on year November 2012 versions of the ETSI Standards and that the standards constantly evolve. As a result, parameters, primitives and virtual links on GN6ASL may have changed at the time of reading. To overcome the limitation, we propose Dynamic Virtual Link (DVL)

Clothoid Curve-based Emergency-Stopping Path Planning with Adaptive Potential Field for Autonomous Vehicles

The Potential Field (PF)-based path planning method is widely adopted for autonomous vehicles (AVs) due to its real-time efficiency and simplicity. PF often creates a rigid road boundary, and while this ensures that the ego vehicle consistently operates within the confines of the road, it also brings a lurking peril in emergency scenarios. If nearby vehicles suddenly switch lanes, the AV has to veer off and brake to evade a collision, leading to the "blind alley" effect. In such a situation, the vehicle can become trapped or confused by the conflicting forces from the obstacle vehicle PF and road boundary PF, often resulting in indecision or erratic behavior, even crashes. To address the above-mentioned challenges, this research introduces an Emergency-Stopping Path Planning (ESPP) that incorporates an adaptive PF (APF) and a clothoid curve for urgent evasion. First, we design an emergency triggering estimation to detect the "blind alley" problem by analyzing the PF distribution. Second, we regionalize the driving scene to search the optimal breach point on the road PF and the final stopping point for the vehicle by considering the possible motion range of the obstacle. Finally, we use the optimized clothoid curve to fit these calculated points under vehicle dynamics constraints to generate a smooth emergency avoidance path. The proposed ESPP-based APF method was evaluated by conducting the co-simulation between MATLAB/Simulink and CarSim Simulator in a freeway scene. The simulation results reveal that the proposed method shows increased performance in emergency collision avoidance and renders the vehicle safer, in which the duration of wheel slip is 61.9% shorter, and the maximum steering angle amplitude is 76.9% lower than other potential field-based methods.Comment: 14 pages, 20 figures, journal paper in submissio

Experimental evaluation of an open source implementation of IPv6 GeoNetworking in VANETs

Conference is technically co-sponsored by IEEE Communications Society and co-organized by the Technical Sub-Committee on Vehicular Networks and Telematics (VNAT)International audienceISO TC204 and ETSI TC ITS are developing a set of standards for Cooperative ITS (Cooperative Intelligent transportation Systems) which will allow ITS stations i.e. vehicles, the road infrastructure and other peers reachable through the Internet to cooperate and exchange information with one another in order to enhance road safety, traffic efficiency and comfort for all road users. In situations where the exchange of information has to transit through the Internet, the use of IP, more specifically IPv6, is crucial and meets ITS needs for reliable and scalable communication capabilities in vehicular networks. An implementation of Cooperative ITS communication protocols is necessary to validate extensively the ETSI and ISO Coop- erative ITS standards. In this paper, we describe CarGeo6, an ongoing open-source implementation of the IPv6 GeoNetworking capabilities of the ITS station reference architecture based on the output of the GeoNet European Project. CarGeo6 combines IPv6 and GeoNetworking capabilities into a common protocol stack for the transmission of IPv6 packets into a given geographical area. This paper reports the validation process and the network performance evaluation of CarGeo6 as well as a comparison of these results with GeoNet results

Experimentation Towards IPv6 over IEEE 802.11p with ITS Station Architecture

International audienceThe goal of Cooperative Intelligent Transportation Systems (ITS) is to enhance road safety, traffic efficiency, and comfort of road users based on Vehicle-to-Vehicle, Vehicle-to- Roadside, and Vehicle-to-Central communications over diverse media such as DSRC, Wi-Fi, 3G, WiMAX, and LTE. IPv6 is the most promising technology that enables a convergence of such different communications over diverse media. This paper is about investigating the issues regarding IP-communications over DSRC band. The investigation is made through field test experiments using communication devices equipped with hardware interfaces for different media as well as an IPv6 stack. Based on our field test results, we discuss the issues and some potential solutions towards achieving sufficient perfomance of IPv6 communications over DSRC band

Experimental Analysis of Multi-hop Routing in Vehicular Ad-hoc Networks

International audienceEvaluation of vehicular ad-hoc networks (VANETs) over real environments is still a remaining issue for most re- searchers. There are some works dealing with common 802.11 anal- ysis over real vehicular environments, which carry out performance tests to measure the quality of the communication channel and justify results according to physical and MAC conditions. There are only a few works regarding multi-hop experimentation in this field, and even less (if not none) testing multi-hop protocols. In this paper an integral VANET testbed is evaluated, using 802.11b and a multi-hop network managed by the Optimized Link State Routing protocol (OLSR). Up to four vehicles are used over urban and highway environments to study the VANET performance, and different metrics are used to analyse the results in terms of delay, bandwidth, packet loss and distance between nodes. Furthermore, a deeper analysis is carried out to study the route followed by packets end to end, which enables us to count the number of hops and detect the links where packets are lost. Because a routing protocol is used, results differ from traditional two-hop and static- route tests, presenting a more realistic study. OLSR is considered as a good reference point for the research community, although it is not the most suitable protocol for vehicular environments, as results show

Location-aware service discovery on IPv6 GeoNetworking for VANET

Conference is technically co-sponsored by IEEE Communications Society and co-organized by the Technical Sub-Committee on Vehicular Networks and Telematics (VNAT)International audienceService discovery is an essential component for applications in vehicular communication systems. While there have been numerous service discovery protocols dedicated to a local network, mobile ad-hoc networks and the Internet, in vehicular communication systems, applications pose additional requirements; They need to discover services according to geo- graphical position. In this paper, we propose a location-aware service discovery mechanism for Vehicular Ad-hoc NETwork (VANET). The proposed mechanism exploits IPv6 multicast on top of IPv6 GeoNetworking specified by the GeoNet project. Thanks to the GeoBroadcast mechanism, it efficiently propagates service discovery messages to a subset of nodes inside a relevant geographical area with encapsulating IPv6 multicast packets. We implemented the mechanism using CarGeo6, an open source implementation of IPv6 GeoNetworking. Our real field evaluation shows the system can discover services with low latency and low bandwidth usage in VANETs

AnaVANET: an experiment and visualization tool for vehicular networks

International audienceThe experimental evaluation of wireless and mobile networks is a challenge that rarely substitutes simulation in research works. This statement is even more evident in vehicular communications, due to the equipment and effort needed to obtain significant and realistic results. In this paper, key issues in vehicular experimental evaluation are analyzed by an evaluation tool called AnaVANET, especially designed for assessing the performance of vehicular networks. This software processes the output of well-known testing tools such as ping or iperf, together with navigation information, to generate geo-aware performance figures of merit both in numeric and graphical forms. Its main analysis capabilities are used to validate the good performance in terms of delay, packet delivery ratio and throughput of NEMO, when using a road-side segment based on IPv6 GeoNetworking