## 2 Related Work  
### Vehicular Communication and Driving Safety Applications Issue, Related Works and Methods  
#### 2.1.1 Current Stages in DSRC, V2V, V2I, and V2X Communications  
The current situation shows that most vehicles benefit from sensor-based equipment that can participate in crowdsourcing applications. They can implement ad hoc vehicle networks (VANET) based on DSRC-type technologies in data transport. There is also a multi-hop transmission for collection between road type units (RSU) in VANET, but in these conditions there is the possibility of a delayed and extremely difficult transmission [20]. In order to address these issues, academia is trying to build hybrid networks that incorporate these technologies by transforming them into new communication protocols dedicated to the timely transport of data between vehicles and infrastructure. The most intensively studied mechanisms approach clustering type centralization with a single hop in order to maximize the data supply. However, there is also a compromise that reduces the cost of cellular bandwidth but also the way in which the delay occurs. Thus, a supply of data is managed in the agreed system through multi-hop transmissions (V2V) or cellular networks. The lack of ideal protocols and technologies highlights the C-V2X (Cellular-Vehicle-to-Everything) based on autonomous and dedicated driving in intelligent transport systems. Its variety and volatility allow an evolution from LTE (Long Term Evolution) to V2X to NR (New Radio) and V2X. These elements indicate complementarity and a capacity to work together in order to obtain low latencies and ideal reliability. Features have highlighted the high efficiency of using such hybrid communications. At the heart of C-V2X communications are cells that have the ability to carry vital information that is periodically broadcast from vehicle to vehicle through cooperative awareness services (CAM) [21; 22]. We can say that the research highlights several levels and programming modes dedicated to semi-resistant iterations with utility in type detection (SB-SPS), where a vehicle detects the environment and interconnects resources in time and space through the frequencies available in the process of CAM transmission. Another aspect that the academic environment has in mind is the detection of the channels in real-time and the adjustment of transmission power in order to avoid interference in relation to other vehicles in the network. We can say that these aspects are the purpose of all research on systems dedicated to transport and road safety, regardless of the type of communication protocol used. The recent literature highlights that V2V and V2I communication systems are decisive and significant elements in traffic optimization and the development of road safety systems. Therefore, new standards have emerged in this direction, ITS-GS (IEEE 802.11p) and C-V2X (3 GPP), previously highlighted and presented [23; 24]. The performance of both standards in terms of physical layers and associated MAC layers is presented in [25], with the capacity of a link and of their use in obtaining notable performance in a loaded network. It also shows how the performance advantage offered by C-V2X for low-density levels in cases of congestion becomes high and automatically the performance difference is reduced until ITS-G5 reduces the gap and exceeds C-V2X. The study of latencies and reliability is also analyzed in [26] in conditions of the emergence of a new generation of communications that can raise the standard of requirements, decrease latency and increase reliability so that the delivery process is completed in a timely manner. Expectations from fifth-generation (5G) networks are extremely diverse in terms of the requirements they have to meet. Although the C-V2X has progressed in terms of LTE V2X to the 14 th version, this is only in the context of improving reliability and low latency performance to meet even the most demanding V2X applications.