Written by Jordan Schilbach | January 16, 2025
C-V2X
C-V2X technology makes intelligent traffic systems (ITS) and a safer driving experience possible.
For years, vehicle manufacturers and governments have sought to improve road safety, efficiently manage traffic and make driving more comfortable, convenient and safe. Vehicle-to-everything (V2X) is a new generation of information and communications technology for connecting vehicles to everything, with V2X offering low-latency vehicle-to-vehicle (V2V), vehicle-to-roadside infrastructure (V2I) and vehicle-to-pedestrian (V2P) communications and adds new dimensions for future driver assistance systems.
3GPP defines the C-V2X communications standard in Release 14 that uses LTE technology as the physical interface for communications.
Figure 1: Examples of C-V2X applications / emergency vehicle warning via V2I
Vehicle-to-roadside infrastructure resembles small cells
In vehicle-to-roadside infrastructure (V2I) communications, roadside units (RSU) broadcast traffic signal information via the C-V2X PC5 air interface in a vehicle. The RSU is connected to the traffic signal controller and broadcasts information about lanes at an intersection (straight, turning) and their status (green, red, for how long). The vehicle receives this information and can use it to inform the driver visually (traffic light turns green in 20 seconds) or actively improve road safety (active breaking on red light).
Figure 2: LTE C-V2X Release 14 features
Since RSUs are basically small cells, they are deployed with a similar planning, acceptance, regular verification and troubleshooting processes to ensure that RSU signals can reliably be received in the target coverage areas in all weather conditions for better road-safety. C-V2X operates in the 5.9 GHz spectrum (as with Wi-Fi 5) and faces inherent high frequency propagation challenges.
Field measurements
During the RSU deployment the R&S®TSMX drive test scanner with ROMES can execute for the necessary coverage measurements. Measuring RSU reference signal received power (RSRP) shows how far the RSU signal can reach and compare it with the intended coverage area. Measuring the signal to interference and noise ratio (SINR) for the RSU signal can be used to assess, whether a receiver can decode a signal, or if interference has degraded the signal quality.
Figure 3: Sample coverage map for two RSUs in a field trial in Munich
Field trial in Munich
The city of Munich performed field trials with C-V2X RSUs in selected parts of the city. The project team needed to be sure, that all the RSUs were up and running.
ROMES and a R&S®TSME6 drive test scanner helped the team quickly determine that all RSUs were active, and the signal level and quality were as expected in a test drive.
Figure 4: Field trial in Munich
To find out more about C-V2X technology and measuring it in the field, see our educational note How network scanners verify C-V2X communication or our webinar Safer roads by verifying critical C-V2X infrastructure and communications.
