# V2X-Based Highly Reliable Warning System for Emergency Vehicles
## 2 Literature Survey  
In [24], unmanned aerial vehicles (UAV) and deep-learning-based vehicle detecting, tracking, and counting systems showed more accuracy in traffic density calculations. The vehicle was detected with type identification based on deep learning and the number of vehicles counted. Using these data, their deep vehicle counting framework (DVCF) calculated the traffic density over that region. Dynamically flying UAV can record from the reverse side, which leads to a total collapse in traffic density estimation and to a drawback of this method. In [2], V2X communication with an energy-efficient relay-assisted transmission scheme in the uplink cellular networks for delay-insensitive applications was proposed. It maximizes the energy efficiency of the uplink considering both the circuit power and transmit power consumption. The optimal resource allocation policy satisfied the delay constraint and minimized energy consumption. The proposed system can achieve significant energy saving with less delay compared to the traditional direct scheme, the decoding-and-forward based transmission scheme, and the opportunistic store-carry and forward-based transmission scheme, especially when the cell radius is large. In [25], using roadside units (RSU) and onboard units (OBU), V2I was established and then was able to find the nearby hospital and shortest route using GPS. A microcontroller inside the EV sends the information to the RSU. The RSU then customizes the intelligent traffic system (ITS) and transfers the information to the nearby RSU via ethernet, and information is removed from the current RSU. This follows until the EV reaches the determined nearby hospital. When more than one EV approaches a junction, it will customize more than one signal to the green light, leading to traffic congestion and accidents. This is a major drawback of this work. As discussed in [7], dedicated short-range communication (DSRC) usually refers to the wireless technology for automotive and ITS applications through short-range information exchange between different DSRC devices, such as OBU equipped in vehicles, RSU deployed as infrastructure, or a handheld device carried by a pedestrian. DSRC supports interoperable services between vehicles and infrastructure as well as between vehicles. In [26], DSRC devices such as OBU and RSU provided wireless communication for ITS, and this wireless communication was achieved through reserved radio spectrum bands. Cellular technology uses a base station (BS) to broadcast the information to all vehicles in a wide range. The benefits of internetworking of both DSRC and cellular networks are that vehicular data can be backed up when the connection is broken while accessing the network and controlling message dissemination. DSRC and cellular technologies are subject to change; therefore, some limitations may vanish. This becomes a major disadvantage of this method. In [27], intelligent vehicle systems are designed for accident prevention, which include the collision warning system (CWS) and lane-keeping assistance (LKA). V2I communication is essential for reducing accidents by managing traffic situations. The AUTOPIA approach has been adapted for intelligent traffic management using V2I. An efficient algorithm that keeps each vehicle at a safe and comfortable distance and adjusts speed for avoiding collision and better traffic flow was developed. This proposed solution was obtained by an IEEE-802.11p-based communications study. In [28], cooperative-ITS (C-ITS) utilized vehicular ad hoc networks (VANET) for inter-vehicle wireless communication and networking. Real-time relative positioning (RRP) provides a lane-level positioning accuracy using GPS, DSRC, and real-time kinematics (RTK). RRP provides a warning on the basis of information communicated using DSRC, which includes vehicle position, speed, and distance about every vehicle in that lane. This majorly helps in avoiding major accidents occurring due to collisions.