Awareness Messages for Vulnerable Road Users

The goal of this thesis work was to implement a communication standard enabling the so-called Vulnerable Road Users (VRUs) to communicate with one another as well as with vehicles. This protocol has been implemented first on a simulator and then on a physical device, i.e., an On-Board Unit (OBU). This allowed us to test the communication standard on the field, in a real world scenario. The first step, before the implementation of the communication protocol, was to create a scenario. A map containing both vehicles and VRUs, such as pedestrians, was created. Specifically, we took advantage of an online program, i.e., OpenStreetMap, to build the map for the simulated scenario and then, using Linux and Python APIs, I filled the map with vehicles and pedestrians, being them the most common type of VRUs we can find on the road. Once the map was complete and ready to be used, the following step was to implement the communication protocol on ms-van3t, an open source simulator and emulator for vehicular networks. First of all, we expanded the functionalities already available in the simulator and related to the management of road traffic. This has been done with the main aim of providing full support for VRUs. This involved, in particular, the update of the “TraCI client”, the ms-van3t module serving as a bridge between ns-3, the network simulator, and SUMO, the road traffic simulator, so that the VRUs present in the simulated scenario were correctly mapped into suitable ns-3 nodes, to be used to allow VRUs to exchange standardised packets during the simulation. Once the simulator had been extended to support VRUs, we implemented the Facilities Layer entity supporting the applications for the transmission and reception of VAMs, i.e., the VRU Basic Service (VBS). The VBS implements a number of functions which are designed not only to manage the reception and transmission of VAMs, but also to perform their encoding and decoding. It should be noted that the VBS was designed to support both the static and dynamic conditions related to the management of the transmission frequency of VAMs. Since one of the functions of the VBS is to fill and then encode the VAM message, a VRU data provider was implemented in order to make the acquisition of data from simulated entities as simple as possible. This data provider returns a number of custom type structures containing all the data which have to be included inside a VAM message, mandatory and optional. We developed a preliminary sample application, which was simulated and from which different metrics were collected to verify the effectiveness of this communication protocol. Since this first simulation gave us the expected results, we also implemented the full support for the dynamic frequency conditions managing the transmission of VAMs, as foreseen by ETSI. These dynamic conditions include a VAM variable frequency between 0.2 Hz and 10 Hz, computed on the basis of the state of motion of the VRU. When it comes to the Packet Reception Ratio (PRR) of VAMs, a metric showing the percentage of transmitted VAMs which are correctly received within a given baseline, we obtain very similar results to those of CAMs, showing the high effectiveness of this communication protocol. The second part of the thesis was aimed at implementing the communication standard for VAMs on a real OBU, in such a way that this protocol could be tested on the field, in a real world scenario.