C-V2X with 5G NR support: a new paradigm of data exchange between vehicles

The 5G technologies will allow more efficiently to collect telemetry data and discover completely new functions for vehicles that can improve road safety and develop the field of unmanned vehicles. In V2X systems (a system for exchanging data between vehicles, road infrastructure elements and other road users) there is a potential for the disclosure of which the 5G NR connection will be used. This will significantly improve safety for drivers, passengers and pedestrians, reduce fuel consumption and travel time.

In March of this year, 3GPP, which standardizes 5G networks, approved the introduction of the first C-V2X specifications with 5G NR support in the next version of the global standard 5G NR (Release 16). We believe that this version will be adopted in the first half of 2020. The combination of this technology and eMBB support (ultra-wideband mobile communication), the specifications of which were approved in 3GPP Release 15, will be the first step towards using 5G NR to create smart cars based on the Qualcomm Snapdragon Automotive Platform.

We are not waiting for the global deployment of 5G networks to launch direct data exchange between vehicles using cellular technology. In 3GPP Release 14, V2X technologies were described, which allow cars to exchange basic information with other road users and, for example, traffic lights, at regular intervals. Their capabilities were demonstrated during many tests using our C-V2X, Qualcomm 9150 chip. Direct data exchange using C-V2X technology allows the machine to “see” its surroundings even in situations when other objects are not visible, for example, on the blind intersections or in bad weather conditions. At the same time, new technologies complement and expand the possibilities introduced by other passive sensors, such as radar, LIDAR and camera systems, which have limitations in range and visibility.
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The 3GPP Release 16 document and the C-V2X standardization with 5G NR support will bring these capabilities to a whole new level and allow vehicles to receive and send much more information, for example, more detailed sensor data and information about the “intentions” of road users, road infrastructure and about pedestrian movements. Moreover, the exchange of data on the "intentions" will help more effectively plan the route of the car, which is important for the development of unmanned vehicles in the future. The C-V2X will evolve from technology, which in Release 14 served mainly as a means of increasing basic road safety, into a tool for direct interaction between road users, which will help improve traffic safety and awareness of the traffic situation, as well as reduce fuel and time costs. the road.

Take full advantage of the C-V2X and 5G NR

The C-V2X solutions based on 5G NR for their work use innovative features that have appeared along with 4G and 5G networks. The first version of 5G networks, which will begin to be implemented this spring and was standardized in 3GPP Release 15, introduced a scalable pitch of the frequency grid of channels, which is also used for C-V2X. One example of its application is the possibility of changing the density of the reference signal depending on the speed of the vehicle. According to our estimates, the spectral efficiency at high speeds in this case will increase by 3.5 times, which is extremely important for new scenarios of using C-V2X, for example, for interchange between cars and road infrastructure elements with large amounts of data from sensors.

C-V2X implementations with 5G NR support suggest several major radio level improvements unique to 5G NR. In Release 16, for the first time, a “side line” will be added to the 5G standard — a direct data exchange channel for V2X systems. This technology will serve as the basis for developing future solutions using 5G NR in smartphones and other areas, such as public safety. The basis for its creation was the development of Qualcomm Technologies for LTE Direct, which in fact led to the emergence of C-V2X technologies in 3GPP Release 14. Also, the technologies described in Release 14 will allow vehicles with support for the older C-V2X version to share data on the road even with the latest models that use both versions of the C-V2X (from Release 14 and Release 16 with 5G NR support).

New paradigm of data exchange between vehicles

In the modern paradigm of data exchange using mobile networks, devices change the signal transmission parameters, such as its modulation and coding, depending on the signal quality of base stations. With C-V2X, the task is complicated by the fact that we are talking about constantly moving vehicles, and not about stationary base stations. In this case, signal quality alone is not enough to understand which vehicles are suitable for data exchange in each specific case. Imagine a car at the intersection around the corner. The signal level is weak, but the car itself is close enough, that is, it is part of the environment that is important for our car. Therefore, both vehicles in this case should be able to receive full information from the sensors, regardless of whether they are in direct view of each other.

And this in turn means that a new paradigm is needed, which will take into account not only the signal level, but also the distance between the objects. The very approach to the development of 5G networks is different from the way the networks of previous generations were built. In particular, at the “lower” levels of 5G NR (physical and MAC levels), it becomes necessary to estimate the distance. For example, vehicles will send confirmations, such as automatic requests for retransmission of the ACK / NAK type, only if they are at a certain distance from the transmitter and only if the transmitted information is useful to this vehicle. This approach will help to cope with the problem of the "hidden node" in the form of the above-described car with a weak signal level, which is around the corner. In general, thanks to him, the reliability of information transfer for all vehicles is increased and a large system capacity is ensured, since network resources are no longer spent on transferring “useless” for a part of traffic participants.

C-V2X based on 5G NR - not only data transfer technology

The decision to include the C-V2X specifications with 5G NR support in the 3GPP Release 16 release will be an important step in the standardization of modern data transmission technologies that meet the automotive industry's requirements for new vehicles, including unmanned vehicles. In addition to data transmission methods, we also conduct research and standardize higher-level protocols and methods for transmitting messages in regional standards, such as SAE, ETSI ITS, and C-ITS. These standardized messages will allow cars from different manufacturers to take full advantage of the new C-V2X technologies. Like C-V2X, described in 3GPP Release 14, C-V2X solutions with 5G NR support will mainly use the 5.9 GHz band, which in many countries of the world, for example, in the USA, Europe and China, is dedicated to road transport. In this new version of the C-V2X will use other channels in this range.