Understanding the Cellular V2X ecosystem

The first of two articles from TMN on the Cellular-Vehicle-to-X (C-V2X) Ecosystem looks at global adoption, ecosystem sectors, potential applications and business drivers.

Adoption of Cellular-V2X (C-V2X) as the technology to enable connected vehicle use cases is growing. But the business models backing C-V2X’s complex ecosystem are still evolving. Despite that trials and pilots of C-V2X use cases continue to proliferate.

Introducing C-V2X

C-V2X technology allows vehicles to communicate directly with each other (V2V), with roadside infrastructure (V2I) and with pedestrians or other vulnerable road users (V2P).

There have been two main technologies proposed to enable these communications.

C-V2X is a technology for V2X that uses cellular standards and protocols to enable connectivity. A different technology, known as Direct Short Range Communications (DSRC), is applied in vehicles via a standard known as Wireless Access in Vehicular Environments (WAVE).

Standards for C-V2X are specified in releases from 3GPP, which defines cellular standards for the global industry. WAVE is defined in IEEE, which specifies Wi-Fi standards within its 802.11x family. (The radio link for WAVE is known as 802.11p.)

Backing for C-V2X

Both technologies operate in the 5.9 GHz band. Although DSRC dominated, especially in the USA, as the standard in the earlier years of Connected Vehicle development up to 2019, in recent years C-V2X has started to be adopted by more and more car makers and transport authorities.

China, in particular, has invested heavily in C-V2X. Its industry ministry decided in 2018 to dedicate spectrum in the 5.9 GHz band for use by C-V2X. In the same year China’s communications vendor, Huawei, launched its first C-V2X commercial product and first Road Side Unit (RSU) supporting both V2I and V2V mode of C-V2X communication.

In the USA, a 2021 proposal by the FCC named C-V2X as the technology standard for 5.9 GHz spectrum dedicated to Intelligent Transport System (ITS) services.

“While the Commission designated Dedicated Short-Range Communications (DSRC) services as the technology standard for ITS services over twenty years ago, DSRC has not been meaningfully deployed, and this critical mid-band spectrum has largely been unused for decades. Today’s action therefore begins the transition away from DSRC services—which are incompatible with C-V2X—to hasten the actual deployment of ITS services that will improve automotive safety,” the FCC said in its statement announcing the change.

While the final adoption of the rule was pending several US companies asked for a waiver to be allowed to start deploying C-V2X services, and in April 2023 the FCC agreed to the waiver, meaning we should shortly see C-V2X deployments in the USA.

Picture from: Rohde & Schwarz

European administrations have designated the 5.9 GHz band for use by road Intelligent Transport Systems (ITS). As is common practice in Europe, the spectrum is designated on a technology neutral basis, leaving C-V2X an open route to market.

European mobile network operators and car manufacturers use the Vehicle-to-Network (V2N) mode from C-V2X technology for services such as traffic information systems, in-vehicle entertainment, and to feed data back to automotive OEMs.  However there have been those, such as Volkswagen, who have deployed V2X based on IEEE802.11p.

C-V2X is also backed by the influential 5G Automotive Association (5GAA), which has 36 automotive members, including some of the largest European, US and Asian OEMs such as Audi, BMW, Ford, GM, Hyundai, Mercedes Benz, Mitsubishi, Nissan, Volkswagen, and Volvo. It also includes leading Chinese car makers such as FAW and SAIC.

Importantly, the 5GAA is not just an automotive industry body. It brings automotive companies together with telecoms companies, including some of the world’s largest mobile network operators, including Bell Canada, China Mobile, China Unicom, FarEasTone, NTT DOCOMO, TIM, Telus, Telstra, Rogers, Softbank and Vodafone.

The organisation brings the combined weight and investment power of its members behind C-V2X, creating a mutually supportive ecosystem to lobby for spectrum harmonisation, define service architecture, and engage in trials and pilots of C-V2X applications in live test beds and operational environments.

C-V2X architecture

C-V2X leverages cellular network infrastructure for V2N connectivity, using the standard air interface known as Uu to connect from the vehicle to a cell site. or. V2I to Roadside Units (RSU) and V2V connectivity between vehicles is enabled by another cellular standard interface called PC5 or sidelink.

The specifications for LTE-V2X are finalised in 3GPP Release 14/15. In some cases, C-V2X applications are enabled by being hosted in edge-based platforms that can be co-located with Roadside Units (RSUs), at cellular base stations or in edge data centres.

5G connectivity is included from Re-15 onwards for V2N and for direct PC5 communication from Rel-16 onwards, and also enables Ultra Low Latency (URLLC) applications, as well as higher throughputs and device (vehicle) densities. The convergence with 5G is referred to as 5G C-V2X.

The upper layers, consisting of different message types for the support of various use cases, are developed by standardisation bodies such as Europe’s ETSI, the USA’s SAE, China’s C-SAE and IEEE. These different profiles and protocols are then implemented as software stacks in end-to-end systems to enable ITS use cases.

High accuracy positioning is provided by GNSS, from a range of satellite systems, including GPS, Galileo, BeiDou, SBAS and QZSS. C-V2X  and other wireless technologies such as UWB (Ultra Wide Band) are also being proposed as a solution to enable accurate ranging for connected vehicle applications such a warning vehicles of approaching pedestrians, as it enables centimetre-accurate distance measurements. As a technology it is still in development and research.

Chipset developers combine a cellular modem and RFFE (RF Front End) connectivity with GNSS support into a module. Combined with ITS software and antennas, these are integrated into Telematics Control Units (TCUs), which are then installed by car manufacturers. The TCUs communicate with other vehicles, and with roadside or nearby cellular sites.

Platforms that host data management and information, as well as data calculation, are located above the network, in edge servers or at network infrastructure sites. These act as service engines for the applications.

C-V2X applications

V2X applications

Sample V2X applications. Picture from: Rohde & Schwarz

There are a host of applications that can be enabled by C-V2X systems. The C-V2X industry has largely focussed to date on what it terms Day 1 use cases, mainly to do with road safety, with the aim of reducing death and injury for all road users. A second class of use case is designed to improve traffic flows and efficiency, to reduce congestion and pollution. A third class is more related to providing information to drivers and other road users.

Examples of safety applications are:

  • Intersection Collision Warnings that alert vehicles to potential collisions at intersections, using both V2V and V2I communications
  • Vulnerable Road User Collision Warning, which uses V2I and V2P to warn a driver of the presence of a pedestrian or other vulnerable user, as well as warning the pedestrian of the approach of a vehicle
  • Emergency brake warning: when a car brakes suddenly, that information is relayed automatically to cars following the braking car

Efficiency applications include:

  • Cooperative merge – a proposed application that would enable vehicles to merge efficiently from two lanes to a single lane
  • Emergency vehicle warning – making drivers aware of the approach of an emergency vehicle that needs preferential access
  • Automated road tolling

Information and management applications include services such as guided parking and dynamic lane management.

Picture from: Rohde & Schwarz

C-V2X ecosystem

C-V2X ecosystem

TMN has produced a visual that explains the integration chains that exist in the C-V2X ecosystem. To download your copy of the visual, CLICK HERE.

Integrating C-V2X systems in vehicles, in roadside infrastructure, in devices and in cellular infrastructure requires an interconnected ecosystem.

Chip developers such as Huawei, Qualcomm and Samsung provide the core, underlying enabling technology. The onus is on them to integrate functionality into packages that operate as efficiently as possible with the performance required by the TCU suppliers and their customers, the vehicle OEMs.

In January 2023, Qualcomm launched its system-on-a-chip (SoC) as a platform that vehicle OEMs will be able to use to power advanced driver assistance systems and automated driving on the same hardware architecture.

Those tasks typically are run on separate chips. However, Qualcomm said that pulling them together into a single platform can mean lower costs and faster manufacturing times. The SoC is sampling now and is scheduled to start production in early 2024.

Nakul Duggal, Senior Vice President and General Manager, Automotive, Qualcomm Technologies, said, “We are making it easier and more cost effective for automakers and Tier-1s to embrace the transition to an integrated, open, and scalable architecture across all vehicle tiers with our pre-integrated suite of hardware, software, and ADAS/AD stack solutions while enabling the ecosystem to differentiate on our platforms with an accelerated time-to-market advantage.”

In 2022, Qualcomm saw revenue for the automotive business grow 41% on its 2021 revenue to $1.4 billion. The company also says its order pipeline stands at about $30 billion, with companies like General Motors, Renault, Volkswagen, and BMW coming to the Snapdragon platform, with some moving away from Intel’s Mobileye unit.

TCU suppliers integrate the modules with software and other elements to create the onboard units that drive vehicular connectivity. Major players here include Bosch, Denso, (a Samsung company), Huawei and LG.

TCUs are integrated into vehicles by the ).  According to ABI Research, more than 10 million vehicles will be capable of short-range V2X communication by 2025, with available in 346 million vehicles by 2025. In China, C-V2X is currently found in low-volume premium vehicle models, but there are at least 25 OEMs in different stages of C-V2X production in the country. COVID-19 lockdowns and discussions about the GNSS positioning standard slowed down deployments in 2022. However, shipments of vehicles with C-V2X will grow exponentially in 2023, surpassing the one million mark as carmakers prepare for China NCAP 2025, ABI said.

Applications and services can be provided by the OEMs, as well as by external operators such as road operators, city authorities, and mobile network operators. Mobile operators are involved in the 5GAA as active participants, and see the potential to drive revenues both from connectivity, but also by providing platforms to provide safety and other applications. But the issue of who will invest in the enabling infrastructure remains open.

The ecosystem is also impacted and supported by a range of standardisation, regulatory and policy bodies. These bodies define the scope of the technology itself, harmonise and make spectrum available, and mandate safety standards.

“When comparing the various flavours of V2X standards in China, Europe and the US, there are differences in upper-layer protocols and security management solutions”, said 5GAA CTO Maxime Flament. “We believe more can be done to align these regions.”

Put simply, the question is: who is going to pay for the infrastructure required to develop connected vehicle services, and how are they going to see a return on their investment?

Business drivers

In describing the connected vehicle and C-V2X ecosystem, and the long chain of relationships between players in the ecosystem, one thing is still unclear. It is not straightforward to describe how the structural relationships in the ecosystem are aligned with participants’ business models.

What does this mean? Well, put simply, the question is: who is going to pay for the infrastructure required to develop connected vehicle services, and how are they going to see a return on their investment?

One clear driver for vehicle OEMs is to differentiate themselves by providing safer, more economical and efficient driving experiences for their customers. By integrating V2X functionality and enabling these assisted driving use cases, OEMs can increase the value of a car, increase margins and sell more units. The investment flow may seem fairly clear. The OEM purchases the TCU directly or indirectly, the TCU supplier sources the chip SoC and other hardware and software. However, with connected vehicle applications becoming increasingly data-centric, there have been suggestions that some OEMs have considered a role as service providers or even virtual network operators, rather than as traditional manufacturers.

But what of roadside and cellular infrastructure? Who will invest in Roadside Units (RSUs) that might sit at intersections, in urban environments to support traffic flow applications, and alongside busy highways and motorways?

One possible source of investment is for authorities and highway agencies to commit to such programmes as a public benefit, funded from Government spending. Private road operators might also invest, with a view to recouping their investment via tolls and charges from companies and private motorists that pay to drive in a safer and managed road environment.

A third source of investment could come from the owner-operators of RSUs and cellular infrastructure. Vodafone has created a platform known as Safer Transport for Europe Platform (STEP) that delivers safety and other messages to on-board units and also to cellular devices over the cellular network. The Platform acts almost like an OTT application, in that it is not embedded in Vodafone’s network. The operator also offers an SDK to developers to create third party applications on the platform. Via the platform it considers itself as a Tier One provider to vehicle OEM, and says it is also providing connectivity directly to a large number of OEMs.

Vodafone’s driver was to leverage its existing macro cellular network, rather than invest in new RSU infrastructure. It is not ruling out the role of RSUs, for example in places such as intersections where you need to be transacting a lot of information in real time, but it didn’t want to dedicate its solution on the presence of RSUs along every road on which it wants to provide services.

Nor did it want to wait for the adoption of PC5 connectivity, which it says has been slow. It says that by using its cellular network for V2V and V2I connectivity, siting the platform in AWS edge zones, it can meet the latency required – a few hundred milliseconds – for the applications it is providing, such as dynamic speed advisory alerts to drivers, and alerting drivers to the presence of vulnerable road users.

Another motivation for Vodafone has been to overcome what it sees as a fragmented ecosystem. It wanted to do something that demonstrated, from a best practice perspective,  how it could make roads safer by allowing vehicles from different brands to exchange sector related messages. It hopes that the standards-based telco model can overcome the challenge of enabling interoperability in the automotive space.

Trials, pilots and activity

However the business drivers play out, there are an increasing number of trials globally investigating C-V2X use cases and applications.

China is committed to equipping cars with C-V2X technology. It has had C-V2X pilot areas across the country since 2018, and began to roll out the technology commercially from 2019. Now more than 90 cities have partnered with local wireless network operators, deploying tens of thousands of roadside units to demonstrate intelligent highways and urban intelligent networked roads.

It also continues to develop pilots to test new applications and the capabilities of intelligent road infrastructure. The Beijing High-level Autonomous Driving Demonstration Zone 2.0 has more than 300 road intersections, two-way 750-kilometre urban roads and 10-kilometer expressways with full coverage of intelligent-network roads and smart city private networks.

As of the end of 2022, OEMs had launched over 20 C-V2X-equiped cars in the country, reaching about 46,000 units.

Working with Navinfo, Ford has C-V2X technology installed and offers V2I applications at over 100 intersections in Xi-an. Drivers receive information including green light optimised speed advisory (GLOSA), traffic light information, red light violation warnings, and relevant road infrastructure details. The vehicle’s gauge cluster can remind drivers to maintain a certain speed range so that they can avoid waiting at traffic lights, which saves fuel consumption and improves overall traffic efficiency.

Ford claims to be the first automaker in China that has implemented C-V2X technology in its production models. The upcoming Audi A7 L and A6 L made in China will be equipped with 5G communication modules that support C-V2X.

In February 2021, MG a SAIC brand officially launched MARVEL R, the world’s first “5G smart electric SUV” with the SRRC certificate and being the first model that passed the automotive-grade 5G /C-V2X terminal certification.

NIO ET7 uses the 3rd-Gen Qualcomm SnapdragonT automotive digital cockpit platform and Qualcomm SnapdragonT 5G automotive platform. It is possessed of 5G, C-V2X, Bluetooth 5.0, WiFi-6, UWB, among others.

ARCFOX ?-T, the first production SUV of BAIC BJEV ARCFOX, officially called “the 5G smart electric vehicle”, is equipped with the MH5000 T-BOX based on Huawei’s next-generation 5G chips.

A series of plugfests have been held over recent years to test and demonstrate interoperability and performance of different components, services and applications. The most recent event was held in China in mid-2022, bringing together more than 40 companies including automakers, manufacturers, autonomous driving systems providers and information security vendors to test applications within the Beijing High-level Autonomous Driving Demonstration Zone 2.0.

During the interoperability demonstrations and tests, several V2I and V2V use cases were showcased, including speed limit warning, vehicle malfunction warning, road works warning, green wave speed guidance, and V2X misbehavior detection function.


The 5G-PPP programme, which directs public and private funding into research projects for 5G use cases, has a number of trials and pilots for connected vehicles, such as 5G Mobix, 5g MED, 5GCroCo and 5G-ROUTES.

Sixteen 5GAA members gathered in Malaga in late 2022 to showcase ready-to-deploy C-V2X technology.

Using both direct and mobile network communications, the open-road demonstrations C-V2X applications including:

  • Protecting vulnerable road users and increasing the safety of cyclists on the road by alerting them of a possible collision
  • Enabling smart intersections to enhance VRU safety by sending awareness messages to C-V2X-enabled cyclists
  • Warning road users of traffic incidents between connected vehicles

The demonstrations were held at the Dekra Test Track, a private field-testing area that reproduces multiple traffic situations using different V2X communications systems and networks, as well as traffic elements like traffic signs, traffic lights, road cones, pedestrians’ simulators that allow setting up various test cases.

In Italy, the 5G-CARMEN project demonstrated the outcomes of an autonomous driving pilot that connected low latency, autonomous and assisted driving vehicle functions using a 5G mobile network. 5G connectivity and the Edge Computing infrastructure was deployed by the project’s network operators TIM, Magenta and Deutsche Telekom, as well as by technology participants such as Nokia, Qualcomm, NEC and INWIT, with the road operator A22 Autostrada del Brennero. Automated functions were developed leveraging 5G as a sensor of the traffic environment to extend the capabilities of vehicle automation from SAE Level 2 up to 4. Tests have been conducted not only within each country, but particularly across the borders from Italy to Austria and Austria to Germany. Moreover, 5G service continuity for cars driving along the corridor has also been coordinated by Edge Computing platforms.

Transport for West Midlands (TfWM), which is part of the West Midlands Combined Authority, is leading the way in the UK with the adoption of ‘vehicle-to-everything’ technology, starting with the region’s city centres and key transport hubs including Birmingham, Coventry, and Wolverhampton.

Using Vodafone’s 4G and 5G network and multi-access edge computing (MEC) technology built into the platform, it allows real time road information from Highways England to be displayed initially on users’ smartphones, and in the future, on in-car infotainment systems.

The platform works with Convex, Chordant’s Mobility Data Exchange facility, to enable dynamic data to be exchanged with road operators and their traffic systems and is the UK’s first live implementation of Cellular Vehicle-to-Everything (C-V2X) technology. C-V2X combines the latest mobile technologies with in-vehicle computer systems to create new mobility services for improved safety and reliability as well as allowing road operators to build ‘greener’ and more sustainable transport networks.

There have been a number of trials and pilots for C-V2X in the USA already. These will grow following the FCC’s decision to grant a waiver to companies looking to deploy C-V2X technology.

Qualcomm and Audi completed trials with the Virgina Department of Transportation testing two use cases: providing warning of roadworks; and providing information on the timing of traffic signals at major junctions.

The US Department of Transportation is making $1 billion a year available via its Safe Streets and Roads for All (SS4A) grants. The National Highway Traffic Safety Administration believes that safety applications supported by V2V and V2I could eliminate or mitigate the severity of up to 80 percent of crashes. It highlighted red-light violation warnings, intersection movement,  spot weather warnings, traffic signal pre-emption and school zone safety as use cases it thinks can reduce accidents and injury.

US operator AT&T moved its IoT and connected car products and functions into a new organisational structure, seeking to accelerate momentum in the sectors.

AT&T Connected Solutions is part of the operator’s corporate strategy and development organisation. It focuses on strategic growth opportunities, using the same model the company previously employed in an innovation push. Cameron Coursey will serve as the interim leader of AT&T Connected Solutions. He said, “As we deploy 5G ultra-reliable low-latency communication, we believe many V2X use cases can be served by AT&T’s 5G network.”

AT&T has said it will start equipping vehicles with 5G modems in 2024, but has not publicly committed to numbers or anything in the broader C-V2X realm.

The role of testing

As we have seen, the C-V2X ecosystem is complex and wide-ranging, requiring contributions from many different players to realise a functioning system. Thorough and consistent testing in the lab, on the proving ground and production line is therefore a key factor to ensure conformance, performance and interoperability.

Holger Rosier, Automotive Market Segment Manager at Rohde & Schwarz observes, “To develop an efficient C-V2X testing strategy, whether you are an OBU vendor, a car manufacturer or network operator, an overall perspective is required that considers the role of each player in the integration chain and gives close attention to conformance with relevant standards.”


With trials and pilots ongoing, and business models still in flux across the integration chain, one key enabler for C-V2X will be the ability to test and validate performance, certification and interoperability across the value chain.

Our next article in this series will look at how testing methodologies and solutions can enable faster adoption of C-V2X standards across the ecosystem.

*  This is a sponsored article produced in association with Rohde & Schwarz.