Section: Research Program

V2V and V2I Communications for ITS

Participants : Thierry Ernst, Oyunchimeg Shagdar, Gérard Le Lann, Younes Bouchaala, Pierre Merdrignac, Ines Ben Jemaa, Mohammad Abu Alhoul, Fawzi Nashashibi, Arnaud de La Fortelle.

Wireless communications are expected to play an important role for road safety, road efficiency, and comfort of road users. Road safety applications often require highly responsive and reliable information exchange between neighboring vehicles in any road density condition. Because the performance of the existing radio communications technology largely degrades with the increase of the node density, the challenge of designing wireless communications for safety applications is enabling reliable communications in highly dense scenarios. Targeting this issue, RITS has been working on medium access control design and visible light communications, especially for highly dense scenarios. The works have been carried out considering the vehicle behavior such as vehicle merging and vehicle platooning.

Unlike many of the road safety applications, the applications regarding road efficiency and comfort of road users, on the other hand, often require connectivity to the Internet. Based on our expertise in both Internet-based communications in the mobility context and in ITS, we are now investigating the use of IPv6 (Internet Protocol version 6 which is going to replace the current version, IPv4, in a few years from now) for vehicular communications, in a combined architecture allowing both V2V and V2I.

The wireless channel and the topology dynamics need to be studied when understanding the dynamics and designing efficient communications mechanisms. Targeting this issue, we have been working on channel modeling for both radio and visible light communications, and design of communications mechanisms especially for security, service discovery, multicast and geocast message delivery, and access point selection.

Below follows a more detailed description of the related research issues.

Geographic multicast addressing and routing

Participants : Ines Ben Jemaa, Oyunchimeg Shagdar, Thierry Ernst, Arnaud de La Fortelle.

Many ITS applications such as fleet management require multicast data delivery. Existing work on this subject tackles mainly the problems of IP multicasting inside the Internet or geocasting in the VANETs. To enable Internet-based multicast services for VANETs, we introduced a framework that:

i) defines a distributed and efficient geographic multicast auto-addressing mechanism to ensure vehicular multicast group reachability through the infrastructure network,

ii) introduces a simplified approach that locally manages the group membership and distributes the packets among themto allow simple and efficient data delivery.

Platooning control using visible light communications

Participants : Mohammad Abu Alhoul, Oyunchimeg Shagdar, Fawzi Nashashibi.

The main purpose of our research is to propose and test new successful supportive communication technology, which can provide stable and reliable communication between vehicles, especially for the platooning scenario. Although VLC technology has a short history in comparison with other communication technologies, the infrastructure availability and the presence of the congestion in wireless communication channels lead to propose VLC technology as a reliable and supportive technology which can takeoff some loads of the wireless radio communication. The first objective of this work is to develop an analytical model of VLC to understand its characteristics and limitations. The second objective is to design vehicle platooning control using VLC. In platooning control, a cooperation between control and communication is strongly required in order to guarantee the platoon's stability (e.g. string stability problem). For this purpose we work on VLC model platooning scenario, to permit for each vehicle the trajectory tracking of the vehicle ahead, altogether with a prescribed inter-vehicle distance and considering all the VLC channel model limitations. The integrated channel model of the main Simulink platooning model will be responsible for deciding the availability of the Line-of-Sight for different trajectory's curvatures, which means the capability of using light communication between each couple of vehicles in the platooning queue. At the same time the model will compute all the required parameters acquired from each vehicle controller.

V2X radio communications for road safety applications

Participants : Mohammad Abu Alhoul, Pierre Merdrignac, Oyunchimeg Shagdar, Fawzi Nashashibi.

While 5.9 GHz radio frequency band is dedicated to ITS applications, the channel and network behaviors in mobile scenarios are not very well known. In this work we theoretically and experimentally study the radio channel characteristics in vehicular networks, especially the radio quality and bandwidth availability. Based on our study, we develop mechanisms for efficient and reliable V2X communications, channel allocation, congestion control, and access point selection, which are especially dedicated to road safety and autonomous driving applications.

Fully automated driving, intelligent vehicular networks, and safety

Participant : Gérard Le Lann.

In the future, which of the following approaches may dominate: the progressive approach (human-assisted driving) or the disruptive approach (fully automated/driverless driving)? Prior to opting for one approach, a number of clarifications are in order such as, e.g., defining targeted goals and conditions unambiguously. According to SAE standard J3016, full automation (level 5) means "the full-time performance by an automated driving system of all aspects of the dynamic driving task under all roadway and environmental conditions that can be managed by a human driver." From a strictly logical viewpoint, this definition is problematic. An obvious corollary is "Level 5 vehicles will be as safe as human-driven vehicles, but no more". Which appears to be antagonistic with one of the primary motivations behind the autonomous/automated driving revolution: a quasi-elimination of accidents caused by humans, who are major contributors according to acknowledged statistics. Choosing between human-assisted or fully automated driving is pointless unless fully automated driving is shown to be achievable. This question is at the core of the work reported here. We consider ad hoc/open intelligent vehicular networks (IVNs) comprised of fully automated vehicles circulating on highways and main roads, with minimal reliance on road-side infrastructures as regards the handling of safety-critical (SC) scenarios. For example, V2V communications only are considered. (IVNs in urban environments, where infrastructures are "naturally" available, will be studied later.) We proceed as follows:

• Identification of real challenging SC scenarios hardly manageable by humans,

• Identification and specification of cyber-physical problems that arise in such SC scenarios,

• Specification of cyber-physical solutions, along with analytical proofs, with a strong focus on time-bounded reliable communications and distributed algorithms.