LTE-V2X: Automobile direct communication on trial

 In the past, the main methods for this - DSRC (Dedicated Short Range Communication) in the U.S. and C-IST (Cooperative Intelligent Transport Systems) in Europe - were based on WLAN standards.

However, the 20 year old technology is now facing competition from mobile communications, which is not really surprising given the eagerly awaited all-round miracle standard G5. This is why the 3rd Generation Partnership Project (3GPP) changed the name LTE-V2X to C-V2X (Cellular V2X). Upgrades now don’t need any more name changes.

LTE-V2X via LTE
But presently, tests are still being carried out with LTE. And lately also on the digital test bed in Berlin, Germany. For this purpose, the Fraunhofer FOKUS integrated the first commercial LTE-V2X products from Huawei into the base stations at the side of the road and in the vehicles.

The extensions allow direct sharing of data in traffic - without the diversion over a central backend. This speeds up transfer and saves network capacity. Since last year, Huawai has been involved in similar tests for the V2X hardware on the A9 highway near Allershausen in Bavaria, Germany. Bosch and Vodafone are also involved.

LTE-V2X for clean air
Vehicles that are networked in this way communicate information, such as position, speed, or obstacles faster and more robustly to all other networked vehicles that are in the vicinity. The list of test scenarios includes danger warnings, electronic emergency braking, and speed recommendations from traffic lights.

In the future, junctions and other accident black spots - equipped with radar sensors - could considerably increase the detection accuracy of pedestrians and cyclists. In combination with weather and air data, it would also be possible to implement environmentally friendly traffic scenarios for individual roads or complete cities.

Competition or co-existence
It is not yet clear which of the competing communication technologies will ultimately take the lead. Demands on the technologies, such as latency, range, and reliability play a role in addition to cost-benefit considerations and plausible introduction scenarios. What is more, although the competitors are not compatible due to different structures in the physical layer, it is possible that both technologies could co-exist. For example, according to Huawei, it can guarantee a problem-free co-existence of WLAN-based V2X and Cellular V2X.

With regard to support, telecommunication companies are on the side of C-V2X as is to be expected, while the German Association of the Automotive Industry (VDA) prefers the WLAN-V2X standard. Recently, within the scope of a test environment in Wolfsburg, Germany, ten signal systems started transmitting the traffic light phases via WLANp to inform future V2X vehicles about green phases.