# Analysis of Low Cost Communication Technologies for V2I Applications
## 1 Introduction  
In terms of mobility, the two worst problems are accidents on the road and CO\({}_{2}\) emissions. There were 1.5 million injured in Europe alone between 2007 and 2016 [1]. Meanwhile, CO\({}_{2}\) emissions were quantified in Europe alone in 2015 with 1100 tonnes of CO\({}_{2}\), based on a well-to-wheel analysis, which was made by the European Federation for Transport and Environment [2]. The solution to those problems is the development of a Cooperative, Connected, and Automated Mobility, which was named CCAM [3] by Europe. Thanks to the exchange of information in real time, CCAM will be able to increase road safety and choose the best route for the cars so that they maintain speed and reduce fuel consumption (decreasing CO\({}_{2}\) emissions), cutting down the two main problems which were mentioned above. This mobility will be real when the automated vehicle will be completely developed. But the ability to communicate with the environment is still more important and it must be available before the automated car arrival, because it will base their decisions on the data exchanged. CCAM is already working in this communication tool, which was named communication Vehicle to Everything (V2X). This idea is made up by different subconcepts: Vehicle to Infrastructure (V2I), Vehicle to Vehicle (V2V), Vehicle to Pedestrians (V2P), and Vehicle to Network (V2N), among others. Without doubt, the backbone of the CCAM will be the communication V2V and V2I, because they enable the cooperation between the car and the environment everywhere and in real time. The European Community has boosted their development with the implementation of the Cooperative and Intelligent Transport Systems platform (C-ITS). The aim of the platform is to promote real-life pilot projects which will create new ITS services and improve the connectivity for all European road users. A full list with the applications (split up in applications of day 1, 1.5, and 2) is available in the annex A of the study carried out for the European Commission [4]. To put these ideas into effect, the right communication technology is required, which must have the adequate performance for this type of applications (in terms of latency and network capacity). Currently, there are two main tendencies [4; 5; 6]:  
* Technology based on Wi-Fi: It is based on the standard IEEE802.11p for vehicular communication. It is also known as ITS-G5 (Wireless short range to Intelligent Transport System) or DSRC (Dedicated Short-Range Communications) (American or European protocol, respectively). It is a short/middle range technology for V2V and V2I communications. In contrast with the other ones, this standard lets an ad hoc or direct network between the road nodes. It works in the frequency band of 5.9 GHz, which is reserved for vehicular communication. The last evolution of this technology was the standard 802.11 bd in 2018. * Technology based on mobile telephony: It is known as C-V2X(Cellular-V2X). Currently, it uses the standard LTE (Long Term Evolution), but it will evolve into 5G in the next years. Its performance is more adequate thanks to the higher transmission rate and bigger network capacity, achieving smaller latencies in the message delivery. This technology has a solution for short/middle range and another for long range. * 4G LTE (long-term evolution) LTE-Uu: It has been used for long range, particularly for V2N communication. It works in the frequency band of cellular network, so it depends on the availability and right operation of the cellular network. * 4G LTE LTE-PC5 (LTE-V2X): It has been used for short/middle range. It allows the direct communication between the different nodes on the road. It works in the frequency band for the automotive industry, 5.9 GHz, and thus it is able to work independently of the cellular networks. Recently, the European Community selected 5G instead of 802.11p [7]. The main reason is the integration of the technology without cost. It will use the infrastructure of the mobile telephony, which has already been built.