The following LTE V2X Technology White Paper describes Long-Term Evolution (LTE) Vehicle-to-Everything (V2X) and is part one of a 5-part Summary of our 3GPP Core Technologies series. You can also download and print them by clicking below.
Long-term Evolution (LTE) and Vehicle-to-Everything (V2X)
1. Introduction
2. Vehicle to Everything (V2X)
Vehicle to everything (V2X) refers to communications initiated by an entity such as vehicle, pedestrian, infrastructure, or network to pass information to one or a group of users. The communicated typically carries information such as traffic warning for collision, lane change, emergency vehicle approaching, upcoming intersection, or upcoming road works. V2X may also be employed for car platooning to reduce the gas consumption, or for autonomous vehicles to sense the environment and to navigate and self-drive.
The standardization work for V2X was initiated by American Society for Testing and Materials (ASTM) in the early 2000s. Later, IEEE approved 802.11p as an amendment to 802.11 for wireless access in vehicular environments (WAVE) for exchange of the data among vehicular and roadside infrastructure without establishing any basic service set and the associated procedures such as authentication. IEEE 802.11p is a Wireless Local Area Network (WLAN) standard and employs the frequency band 5.850 GHz to 5.925 GHz, which has been allocated by the United States Federal Communications Commission (FCC) for intelligent transport systems.
The standards organizations of Japanese Association of Radio Industries and Businesses (ARIB), Republic of Korea Telecommunication Technology Association (TTA), and European Telecoms Standards Institute (ETSI) also specified V2X based on IEEE 802.11.
In 3rd Generation Partnership Project (3GPP), the V2X work item started in release 14. V2X is in 3GPP defined as a Proximity Service (ProSe) and utilizes direct communication or communications via Long-Term Evolution (LTE) network. V2X services transport short bursts of data typically 300 to 1200 Bytes and uses the LTE network for high efficiency real time communications, high reliability, and low latency.
V2X services are categorized into
V2X services are for the purposes such as:
3GPP release 14 of V2X technology does not require ProSe discovery and is solely employed to pass the information to other V2X entities. However, the use of discovery is left as an option if new use cases for V2X may require employing this mechanism.
Figure 1
Figure 1 illustrates a scenario where V2V, V2P, V2I, and V2N can all be employed for communication. In this scenario, a vehicle can have a direct communication with another vehicle, pedestrian, or a roadside unit (RSU). A vehicle may also have communication with the LTE network comprising the V2X application server. The figure also shows that a vehicle or an RSU may be a UE- to-Network relay UE which conveys the data and signaling between the LTE network and an out-of-coverage vehicle or pedestrian.
Figure 2
V2X services are Group Communication Services (GCS). These services may be unicast or broadcast depending on the use case. Figure 2 illustrates a high-level architecture. The V2X services employ LTE network and are implemented by connecting the V2X Application Server (AS) to the Packet Data Network (PDN) gateway i.e. P-GW and connecting the V2X-AS to the Policy and Charging Rules Function (PCRF). The PCRF adjusts the Quality of Service (QoS) due to the provided V2X service and the V2X UE’s subscription profile. The V2X AS determines whether Multimedia Broadcast Multicast Service (MBMS) or unicast service should be employed for a given V2X UE. The MBMS bearer services are implemented by the connection between the V2X-AS and the Broadcast Multicast Service Center (BM-SC).
Note that, in Figure 2, V2X UE 2 does not communicate via the LTE network but communicates directly with V2X UE 1 via PC5 reference point. V2X UE 1 may also function as UE-to-Network relay UE for data and signaling transmission between the network and V2X UE 2. In order to communicate over PC5, V2X UE 1 registers its capability for communication over PC5 to the network.
For more information on our whitepaper topics including LTE EPC Technology, LTE Mission Critical Technology, LTE ProSe Technology, LTE IMS Technology, and LTE GCS Technology, please visit our Technology White Paper section.