# Evaluating V2X-Based Vehicle Control under Unreliable Network Conditions, Focusing on Safety Risk
## 1 Introduction  
In the near future, we will experience a new era in the vehicle and transportation industries as the development of new technologies gets to a new level. Autonomous driving has been a long-awaited improvement that could improve the safety and efficiency of our transport system. To enable autonomous features and vehicles, a new way of perception and communication had to be introduced to the industry in the form of Vehicle-to-Everything (V2X) communication. With this development, vehicles could send static and dynamic information about themselves to nearby system components. With the acquired data, vehicles will be able to create a local dynamic map (LDM) to improve ad hoc decision making and the safety of transportation. Moreover, with over-the-air communication between vehicles, previously unpredictable scenarios, like non-line-of-sight (NLOS) scenarios, can become safer, while line-of-sight (LOS) scenarios also benefit from the additional redundancy against sensor malfunction. To achieve this, two separate ways of communication are in development. One of them is Dedicated Short-Range Communication (DSRC), which is based on the IEEE 802.11p standard [1]. The alternative is Cellular-V2X (C-V2X), which was widely promoted by the 3 GPP organization. Cellular networks are expected to improve vehicular communications as simulation research shows that C-V2X outperforms DSRC in terms of communication range. DSRC is considered to operate up to a maximum of 1000 m, while C-V2X could have a coverage of up to several kilometers away [2; 3; 4]. A study performed by [PERSON] et al. [5] benchmarked DSRC and LTE-based C-V2X technologies. Based on their study, DSRC was able to achieve an average end-to-end latency of less than 100 milliseconds and an adequate packet delivery ratio (PDR) in all of the scenarios they investigated. In [6], the authors performed an exhaustive evaluation of available wireless technologies between vehicles in highway scenarios. Based on their evaluation, C-V2X, in general, has a higher operating range, but DSRC communication offers lower latency in low-density scenarios. In [7], the authors compared the performances of DSRC andLTE-V2X under urban scenarios. Meanwhile, DSRC is dedicated to Cooperative Intelligent Transportation Systems (C-ITSs), until LTE-V2X shares a network with other LTE applications (such as video streaming and VoIP). This aspect negatively influences LTE-V2X, and their results showed that DSRC outperforms LTE-V2X. Despite the intensive evolution of these new technologies, there are still a few gaps that need to be filled before they could be used in safety-critical automotive applications. One issue is the availability of the necessary information in specific high-risk situations. In safety-related applications, such as accident prevention or platooning, the timely arrival of messages from other vehicles or roadside units (RSUs) is crucial [8]. In degraded networks, where the quality of service (QoS) parameters are not adequate, the industry will have to focus on developing different control solutions to handle these conditions safely. Aiming for this research gap, we started to review relevant studies related to V2X technologies. [PERSON] et al. [9] studied Vehicle-to-Vehicle (V2V) communication performance and its impact on safety distance. They were able to prove the importance of a reliable communication in achieving a shorter stopping distance and reducing reaction time. [PERSON] et al. [10] studied the degradation of a vehicular ad hoc network (VANET) and found that the reliability of the network is a key requirement for V2V communication. Their simulation highlighted that transmission distance can be severely reduced. Their work was evaluated based on a traffic jam scenario where the vehicle density was high and the network degradation was caused by the other vehicles' interference. Consequently, their work showed that, in degraded network conditions, the available reaction time is shortened due to a lack of information. A study conducted by [PERSON] et al.