Our researchers associated with this research area are listed below.
About the research area Active traffic safety and driver support technologies
The European Road Safety Observatory estimates that road traffic accidents within the European Union cause 43,000 fatalities and 1.8 million injuries each year. Passive safety systems have been successful in decreasing the injury risk in case of an accident, but with the use of modern sensing, signal processing and control technologies the focus is shifting towards helping drivers to avoid collisions in the first place.
Active safety systems usually contain sensors like radars, cameras and lasers that scan the area around the vehicle. Additionally in-vehicle sensors and communication links between vehicles, or between vehicles and the infrastructure, provide data that can be fused into a local dynamic map that represents the traffic environment, vehicle and driver state.
This local dynamic map is used to predict whether a collision is about to happen and to propose a countermeasure that can avoid an impeding collision. This can be a warning, such that the driver can take care of the situation, or an automatic braking and steering intervention to e.g. keep the vehicle on the road or avoid an intersection accident.
Additionally, the local dynamic map can be used to take over part of the driving task. E.g. Adaptive Cruise Control helps the driver to maintain speed and keep a safe distance to the car in front, through automatic control of brakes and powertrain.
As an ultimate consequence of these trends, future vehicles are expected that can drive completely automatically.
The research within Active safety and driver support technologies has its focus on the areas Vehicular communications, Sensor fusion, Collision Avoidance and Automated Driving.
Vehicular communications enables a host of applications, ranging from infotainment and web browsing to cooperative driving for enhanced traffic safety and efficiency. The latter two application areas are high on the global political agendas. This for good reasons: About 1.3 million people die and 20-40 million are injured in road accidents every year. Moreover, the global vehicle fleet, reported to 800 million in 2008 and predicted to reach 2 billion in 2050 , burns enormous amounts of fuel with the corresponding negative impact on the environment. The aim of our research is to reduce these frightening numbers and contribute to a future safe and sustainable road transport system.
To reach these end goals requires a multidisciplinary and global approach, and we therefore work with academia, industry and the public sector in many different contexts. Our technical contribution is focused on theory, methods, and algorithms for reliable wireless communications between vehicles (V2V) and vehicles and road infrastructure (V2I).
Communication for Traffic Safety and Efficiency
Vehicular communications enables many new and exciting traffic safety and traffic efficiency applications in which multiple vehicles share information and cooperate to avoid accidents, increase traffic flows, and reduce emissions and fuel consumption—crucial tasks for a future safe and sustainable road transport system. The communication system must be reliable (no errors in the received information), support real-time applications (bounded and predictable communication delays), and be scalable (support many vehicles in a limited geographical area). These requirements, coupled with harsh radio propagation conditions, limited spectrum allocation, and vehicular constraints on cost, antenna placement, etc., poses a challenging design problem, especially for the physical and medium access layers of the communication system.
Vehicular communications is here defined as vehicle-to-cellular (V2C), vehicle-to-satellite (V2S), vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications, collectively referred to as V2X communications. With infrastructure in V2I, we mean road infrastructure, such as traffic lights, street signs, road toll gantries, etc., which is not to be confused with communications infrastructure, such as access points or base stations. We distinguish between two types of communications: direct and indirect. With direct communications, the end-node transmitter and receiver communicate directly without using communication infrastructure. Indirect communications, on the other hand, use communication infrastructure. According to these definitions, two vehicles communicating over LTE with each other would be an example of indirect V2V communications, and a vehicle communicating with a toll booth over 802.11p would be an example of direct V2I communications.
At Chalmers, we are currently involved in research on key problems for direct V2V and V2I communications, and are planning to expand the research to cover also indirect communications.
PHY layer and MAC layer problems
V2X communication should be reliable (no errors in the received information), support real-time applications (bounded and predictable communication delays), and be scalable (support many vehicles in a limited geographical area). The physical (PHY) and medium access control (MAC) layers are the critical components of a communication system that control these requirements.
The technology that is currently under standardization for direct V2V and V2I communications is based on IEEE 802.11p, which is essentially a modified WLAN system. As such, its PHY and MAC layers are designed to be efficient for stationary channels and unicast, best effort data traffic. V2X communication is, however, characterized by highly time-varying channels and the dominating data traffic for safety and efficiency applications is broadcast, real-time data traffic. Hence, there is great potential for improvement of both the PHY and MAC layers.
We have suggested improvements to the MAC layers in a series of papers by Katrin Sjöberg et al. She propose to use a time-slotted MAC layer called Self-organizing Time-Division Multiple Access (STDMA) which has much better delay and scaling properties compared to the IEEE 802.11p MAC.
The V2X PHY layer research at Chalmers is still in build-up phase. Currently, we are working on network synchronization (with the aim to support time-slotted MAC layers), and are planning research on conformal (i.e., hidden) antenna systems for V2X communications. Moreover, we are planning research on channel estimation, coding and modulation for the V2V channel (which is the most challenging V2X channel).
Together with Decentralized Systems and Network Services research group at Karlsruhe Institute of Technology, we have developed open source simulation tools for vehicular communication networks, which are described in a 2011 paper of the Proceedings of the IEEE
and are available for download at Karlsruhe Institute of Technology
A global, multidisciplinary research effort
To fulfill the vision of a safe and sustainable transport system, we need to interact with many other research fields, standardization bodies, and vehicular industry.
At Chalmers, we take part in research and leadership of the Area of Advance Transport’s profile Traffic Safety. The area of advance is closely related to the competence center SAFER, in which we meet people from some 20 different partner organizations: vehicular manufactures, consulting companies, institutes, and public sector organizations. Erik Ström is leading SAFER’s competence area Sensors and Communication and take part in the center’s extended management group. We interact with the Mechatronics, Signal Processing, and Biomedical research groups on issues that require a multidisciplinary approach, e.g., we worked together in the 2011 Grand Cooperative Driving Challenge competition, in which the Chalmers team claimed third prize.
To ensure that we are using the latest findings from the channel modeling community, we participate in the COST action IC1004, which is the unofficial continuation of COST 2100. The COST action gathers the cream of channel measurement and modeling expertise in Europe and elsewhere. Erik Ström participated the COST 2100 Special Interest Group C on Mobile-to-Mobile Channels (read vehicular channels), which proved to be a very fruitful experience, and will co-chair the Topical Working Group on Vehicular Environments in IC1004. The other co-chair is Dr. Alex Paier from Kapsch TrafficCom AG, Austria.
Standardization of communication protocols is crucial for taking MAC and PHY layer research into practical use. To this end, Katrin Sjöberg is participating in the European Telecommunications Standards Institute’s (ETSI) technical committee on Intelligent Transport Systems (TC ITS).
We also enjoy working and writing papers with colleagues at other academic institutions such as Karlsruhe Inst. of Technology (Hannes Hartenstein, Jens Mittag), Vienna University of Technology (Christoph Mecklenbräuker, Arrate Alfonso), Lund University (Fredrik Tufvesson), Halmstad University (Elisabeth Uhlemann) , and University of Southern California (Urbashi Mitra).
The Chalmers vehicle simulator is a moving base simulator. The driving simulator can be divided into seven main sections; a simulation kernel, vehicle dynamics , motion cueing algorithm, graphical environment generation, a sound generating system, a steering wheel force feedback system, and a vehicle cabin...
The aim of the project is to develop a tactical framework for decision-making regarding how to interact with surrounding traffic...
The project is focusing on jointly developing technologies to reduce accident risks for both passenger cars and commercial vehicles and particularly addressing the situations at which today’s active safety systems are not yet sufficient...
Cooperative systems are essential in order to reach vision zero. Few passive or active safety systems are available for unprotected road users...
The main research objective for this project is to address key problems in the physical layer and MAC layer of vehicular communications, including channel modeling, channel estimation and interference management...
Nowadays vehicles offer an increasing number of In-Vehicle Information Systems (IVIS) and Advanced Driver Assistance Systems (ADAS). Cruise control and route guidance are examples of systems already in frequent use, and lane departure warning, night vision and collision warning are examples of systems now coming into commercial use...
Volvo Car Corporation develops vehicles with world-class safety systems. The long term vision is to design cars that do not crash. Developing active safety systems that assist the driver in mitigating or avoiding accidents will be essential for achieving the short term aim: by 2020 no one should be killed or injured in a Volvo...