TransAID Deliverable 5.2: V2X-based cooperative sensing and driving in Transition Areas (second iteration)

Kurzfassung

The objective of the TransAID (Transition Areas for Infrastructure-Assisted Driving) project is to deal with situations that cooperative and automated vehicles (CAV) might face when they are approaching to traffic conditions or zones that their automated systems are not able to handle by themselves. In those cases, the driver will be required to take control of the vehicle; this is the so-called Transition of Control (ToC). TransAID develops and demonstrates traffic management procedures and protocols to increase the overall traffic safety and efficiency specially at transition areas (i.e. zones where ToCs should take place) considering the coexistence of CAVs,autonomous vehicles (AVs), cooperative vehicles (CVs) and legacy vehicles (LV). TransAID measures require the use of communications between vehicles (V2V), and between vehicles and the road infrastructure (V2I) which are mainly used to gather information about the traffic stream through cooperative sensing and to support in the coordination of the vehicles maneuvers through cooperative maneuvers. In this context, this document shows the sensor devices and techniques to fuse their data that are being developed in TransAID. This includes techniques implemented at camera-equipped infrastructures that are able to detect, create bounding boxes and uniquely track objects using optical flow, and at the vehicle employing a hybrid sensor fusion strategy which contains a low-level LIDAR fusion module, that transforms the sensor data of multiple laser scanners into a common coordinate system, and an object-level fusion module, that fuses in-vehicle sensor data with data coming from neighbouringvehicles. The document also shows the cooperative techniques that are being designed to enable the Collective Perception Service (CPS) in line with ETSI. The ETSI's CPS entails the continuous exchange of Collective Perception Messages (CPM) that include a logic representation of the objects detected by the sensors and which are useful to improve the vehicles' and the infrastructure's perception of the driving environment. A key aspect for the efficient execution of the CPS is the definition of appropriate generation rules for the transmission of the CPMs, i.e. how often they are transmittedand what information do they include. This document includes a comprehensive analysis of the effect on the communications performance and information awareness of different CPM generation rules that are being considered in ETSI. The conducted analysis has shown that there is a trade-off between perception capabilities and communications performance/scalability: vehicles detecting the same object(s) and including them in their CPMs create redundant detection which can help improve the perception capabilities but generate higher channel load levels and therefore impact the performance of V2X networks. In the framework of TransAID, advanced policies have been proposed to further optimize the CPM, both its content and transmission triggering conditions, in order to achieve the necessary levels of redundancy and minimize the impact of the implementation of CPM in the stability and scalability of future V2X networks. In particular, four different methods have been designed: a) the look ahead mechanism that reduces the number of CPM transmitted with a small number of objects by the prediction of objects that will need to be transmitted in a near future; b) the redundancy mitigation mechanism that reduces the size of the CPMs and thus increases reliability by limiting the transmission of objects that have been recently transmitted by a neighbour vehicle and c) two different proposals for the combination of previous methods that enhance the performance of collective perception. In addition, this document investigates existing cooperative driving mechanisms, and specially the ETSI approach on manoeuvre coordination. The ETSI's Manoeuvre Coordination Service (MCS) is defining new concepts and messages which can be used to coordinate manoeuvres between vehicles. TransAID is actively participating in this process, e.g., by means of the definition of the Manoeuvre Coordination Message (MCM) and extendingthe role of the infrastructure to support the vehicles' manoeuvres coordination under certain scenarios and conditions. In this context, this document presents the message flow for the set of services that are being consideredin TransAID. First, this documenthas analysed the traffic management measures defined by the different services of the TransAID project, and the required message flow for each service has been defined. Each message flow describes how, when, and where the vehicles communicate between them, and between them and the infrastructure, to execute the traffic management measures. Then, this document provides ananalysis of the MCM generation rules. As highlighted for the CPMs, MCM messages should be transmitted with a frequency high enough to guarantee that the vehicles' manoeuvre coordination is possible. However, a too frequent exchange of MCM messages can increase the channel load to the point that it can negatively impact the performance and scalability of the V2X network. The conducted analysis has shown the importance of considering the vehicular context for the generation of the MCM messages in order to achieve a good balance between channel load and reliability for a safe execution of the cooperative manoeuvres. In particular, two main MCM generation rules approaches have been developed: a) the riskapproach that measures the risk of vehicles with their neighbours and adaptsthe transmission rate based on the risk;b) the tracking trajectories approach that measures the variations between the trajectories transmitted by a vehicle and only sends a new message when the variation is significant. The analysis performed showed that the benefits of both approaches as the risk approach increases the possibilities of successful coordination while the tracking trajectories approach performs an efficient use of the communications channel while keeping neighbours updated about any change in the trajectory.