In this article, I will examine some of the latest efforts in V2X technology. This system can’t come fast enough for my liking—we desperately need this technology to save lives. V2X must have a robust and isolated cybersecurity protocol. Ideally, a global platform should be developed, but probably regional areas will start the deployment with cross-region communications in mind for later interconnection globally.
Some company highlights
Ford jumps ahead of competitors committing to C-V2X cellular radio-based systems. See my EDN article on Autonomous vehicles: The electronics road to making them safe
I really like ST Microelectronics’ V2X solution. Their solution is a very complete solution and is also a Wi-Fi derivative specifically defined for fast-moving objects and enabling the establishment of a reliable radio link, even in non-line-of-sight conditions. ST is in a long-term partnership with Autotalks, a V2X chipset maker. Autotalks has a really nice scheme, their solution does not depend upon cellular networks---check it out on their website for the many benefits of this system.
ST’s V2X solution with Autotalks’ chipset
For now, I will just introduce some new development ideas in V2X. You can expect a great deal more from EDN and Planet Analog on this topic as it matures in future articles as well:
Speed with safety on the highways1
Reference 1 discusses Platoon-based driving, especially on highways. In this scenario, multi-vehicles will use some sort of car-following model via Vehicle-to-vehicle (V2V) or Vehicle-to-everything (V2X) communication protocol environment. The goal is to drive to your destination in a shorter time with enhanced safety with a harmonized velocity which will allow for close following with smaller gaps and decreased aerodynamic drag.
The goal of the experiment is to treat each vehicle in the platoon as an individual agent and then design control algorithms involving the inter-vehicle gap and velocity to reach a consensus state. Interaction between vehicles will be essential for the system to work using a practical control strategy for Connected Vehicles (CVs).
There are N vehicles that will travel on a straight road with Vehicle 0 being the ‘leader’ with N-1 followers. This experiment uses a Bi-Directional Leader Following (BDLF) communications protocol. This means that every follower has access to real-time information of position and velocity of the leader, but the leader has access to information from each of the followers through V2X communication.
Beacon Transmission Analysis
The beacon gives position, velocity, and direction periodically. Only one beacon is transmitted in the channel in this experiment. The beacon can have three states: Idle with no transmission, only one transmitted beacon was successfully transmitted, or more than one vehicle will try to send beacons in the channel---this causes collisions. Reference 1 does a probability study of a successful beacon delivery for the vehicles.
The study captures car-following behavior of the CVs in the same lane without a lane change and formulates a new car-following model.
Reference 1 also does a Stability Analysis using the small perturbation model and then does a Platoon Control design using longitudinal and lateral platoon control algorithms. These were followed by experiments using four equipped devices. IEEE 802.11p was used as the communication links. The On Board Unit (OBU) included a Differential Global Positioning System (DGPS), a master chip, and a Dedicated Short Range Communication (DSRC) module and a Digital Global Positioning System (DGPS). The RoadSide Unit (RSU), containing the control box, DSRC module, and DGPS, received traffic flow information from the vehicles. The test involved platoon forming, vehicle merging, and vehicle diverging. See Figure 3 below:
Test vehicle equipped devices (Image courtesy of Reference 1)
The control algorithm which was designed in this study was limited by the need to consider
communication delays and communication packet drops, which will be the focus of the group’s ongoing work.