# Effects of Vehicular Communication on Risk Assessment in Automated Driving Vehicles
## 2 Sensor Characteristics and Information Fusion
### Vehicular Communication  
Connected vehicle technologies evolved from the 1980s with the widely known project called the California Partners for Advanced Transit and Highways (PATH) project. Multi vehicles made by Ford Motor Company are platooned together with the longitudinal control using wireless LAN communication systems as well as radar, throttle, brake actuators. In 1992, the it was remembered that the first ever platooning experiments and demonstrations on the highway were performed successfully. Volvo demonstrated vehicular wireless communication technology for the project named Safe Road Trains for the Environment (SARTRE) in 2012. In this demonstration, a Volvo FH truck drove around the test track, followed by other Volvo cars with quite close inter-distance. Although the inter-distance between the vehicles was smaller than when a human drives, it is much safer since the computer responds to even trivial or small change is detected. For the demonstration, V2V communication with 802.11 p is used for the main communication channel. In 2013, Hyundai Mobis and Seoul National University demonstrated V2X communication enabled autonomous driving technologies in Korea, at the ITS test site in Hwaseong. Two Hyundai Sonatas from Mobis and one Hyudai Azera are used to perform several scenarios with Cohda MK5 wireless communication device. The scenarios include Intersection Management Assist (IMA), Electronic Emergency Brake Light and Blind Spot Warning. Dedicated Short Range Communications (DSRC) is one of the researching hotspots, and it has already the become V2X communication standard in some areas, such as America and the Europe. Meanwhile, the performance of DSRC in non Line-of-Sight scenarios is quite terrible and the performance declines rapidly when the number of vehicles increases to some threshold. These shortcomings of DSRC are \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Host Vehicle** & **Remote Vehicle** \\ \hline
**Initial Speed** & 30/35/40/45/50/55/60/65/70/75/80 kph & 20 kph \\
**Initial Range** & 70 m & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Initial setting condition for sensor data acquisition. Figure 1: Range Error vs. Range of Radar and Camera (Vision sensor). widely admitted by researchers. Thus, LTE-V is one of the Cellular Vehicle-to-Everything (C-V2X) direct communication technologies, and which might take place of DSRC. To validate the performance of LTE-V, [PERSON] et al. [14] conducted an experiment with two cars at an intersection. During the experiment, messages were sent 10 Hz and two conclusions are derived: PDR (Package Deliver Rate) and latency, which are shown in Figure 2.  
Since safety related applications for V2V communication are susceptible to even a bit longer latencies, this could cause fatal accidents when an emergency braking situation. To guarantee traffic safety, when a control command, braking for example, is sent to a car, the car must receive the command within 1 ms. The latency of a 4 th Generation (4G) network, which is a sort of LTE-V, cannot meet this requirement. With the latency of a 4G network, a car driving at 100 km/h still moves 1.4 m from the time it finds an obstacle to the time when the braking command is executed. Under the same condition, with the latency on a 5G network, the car will move just 2.8 cm, and this performance is comparable with the standard of an anti-lock braking system (ABS) [15]. A 5G-based C-V2X communication is introduced by Huawei, LG and Qualcomm. Since 5G-enabled communication has ultra-low latency of 1 ms with the average communication speeds of 3.6G bit/s using 100 MHz bandwidth, safety related vehicle control applications can be considered. As the size of the data are getting bigger, infrastructure-based remote computing is needed and the 5G communication is applicable for the transmission and receipt of big data. Infrastructure-based computation means using a cloud or edge computing. Two computing methods have their own advantages and disadvantages.