Recently, the automotive industries have accelerated the deployment of Cellular V2X as a motivation to integrate vehicular communication with NewRadio-5G (NR-5G) technology. Nowadays, two critical technologies are concurrently supporting V2X communication: IEEE802.11p and cellular technologies. C-V2X is standardized and designed by the Third Generation Partnership Project (3GPP) for automotive services. C-V2X supports two communication modes through a single platform to provide Wifi-short-range and cellular-long-range communication. Wifi-short-range communication doesn't require network subscription or coverage while the cellular-long-range requires network subscription and coverage. LTE-V2X is the current standard of C-V2X which completed in March-2017 as the 3GPP-Release 14 and enhanced to support the upcoming 3GPP-Release 16 which support the NR-5G capabilities, enhancement, and services. In this chapter, the authors propose the Optimizing of 5G with V2X and analyzing the current V2X standards, introducing the evolution of 5G, challenges, features, requirements, design, and technologies.
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Intelligent Transportation Systems (ITS) recently depend on V2X communications with many industrial cooperative efforts. Vehicles, infrastructures, and pedestrians communicate wirelessly to gather and exchange information about the road environment within real time as shown in Figure 1. For that, a lot of dangerous and critical accidents can be avoided as the communicating vehicles are computers with extended onboard sensors. Dedicated Short Range Communications (DSRC) (Kenney et al., 2011) is designed as a standard for Wireless Access in Vehicular Environments (WAVE) which supports the V2X communications specially safety-applications. DSRC protocol stack and messages format are defined by the cooperation between European Telecommunications Standards Institute (ETSI) and IEEE, for ETSI, V2X has two types of messages: Cooperative Awareness Messages (CAMs) and Decentralized Environmental Notification Messages (DENMs) (Xu et al., 2004). CAMs messages are exchanged periodically every 100ms, to share the road status within a specific communication range while DENMs are only triggered by accident events to alert the road drivers.
Many industrial projects, research organizations, and too much regulatory efforts have been cooperated to enhance and deploy the V2X services in different countries, one of these projects are the Car 2 Car Communication Consortium (C2C-CC) (CAR2CAR et al., 2019) in Europe and Crash Avoidance Metrics Partnership (CAMP) in America (Shulman et al., 2007). DSRC protocol stack has a lot of disadvantages such as collisions due to the hidden node and asynchronous problems which degrade the total performance. One of the critical issues of DSRC is the cost-effectiveness of the Road Side Units’ (RSUs) deployment, as well as that, DSRC has no clear steps about evolution, latency, network coverage, and network security.
The mobile industry has made significant progress within the last years as the Long Term Evolution (LTE) technology has been introduced to support different communication types including unicast and broadcast modes which can enhance V2X applications (Sun et al., 2016). Moving from DSRC vehicular technology to LTE based V2X is defined in the Third Generation Partnership Project (3GPP) standardization. 3GPP is planned to enhance V2X performance satisfying the industrial market within its Release 14 in 2016 and 2017 to apply LTE technology in the automotive industry. LTE-V2X reuses application layer protocols of the DSRC standards while focusing on the development of the network and physical layers with an efficient radio air-interface.
China has officially allocated about 20MHz frequency for LTE-V project validation and deployment in six different areas. Many projects such as Next Generation Mobile Networks Alliance (NGMN) (Ngmn et al., 2019) and 5G Automotive Association (5GAA) cooperate with the automotive industry to evaluate the 5G New Radio (5G-NR) and LTE based V2X services. C -V2X is a complete traffic efficiency and road safety solution which allows different communication modes between vehicles to guarantee full coverage and service continuity. C-V2X communication is integrated with the existing vehicle technology to assist vehicles in automated or semi-automated driving-modes. C-V2X introduces two transmission modes of Vehicle-to-Vehicle (V2V) communication and Vehicle-to-Infrastructure (V2I) communications within the radio spectrum 5.9GHz frequency band, and Vehicle-to-Network (V2N) communication using the licensed mobile spectrum.
The former communication mode does not require the assistance of a mobile network, while the latter can use the existing cellular network infrastructure and the new 5G mobile networks. IEEE 802.11p is the current short-range wireless standard technology that has been developed over the past decade to support V2V and V2I communication, both IEEE 802.11p and C-V2X provide safety and efficiency benefits to the automotive industry.
Japan and America have followed China with 90 percent LTE penetration which supports evolution from LTE to 5G mobile standards, technology, trials, development, and demos. Many growing requirements and demands from a 5G perspective target higher data capacity, increasing throughputs and decreasing latency to support better multimedia broadband services. 3GPP actively continued focusing on the enhancements and deployments of LTE while at the same time has many trials of defining the 5G specifications and applications.