The connected car

The connected car is coming

Reaching your destination safely, efficiently and comfortably

The connected car is coming. At first, mainly in Chinese megacities. But parallel to the introduction of 5G mobile communications, the C-V2X standard for vehicle connectivity derived from it will soon establish itself in Europe and the USA too. The major players rely on Rohde & Schwarz T&M solutions to safely and efficiently get autonomous vehicles on the road.

Shanghai at rush hour. Zipper merging? Here, the motto is: honk and step on the gas! If you have to brake, honk back, done. Putting the car in reverse in the middle of an intersection to change direction after all? That happens. And not crashing into one of the countless e-scooter riders who silently curve through all the gaps is purely down to luck. Electric scooter drivers, even drivers of e-drive vans shamelessly use the sidewalks. "The streets," says Munich based management consultant and Shanghai University of Finance and Economics graduate Julian Schneider, "are simply too unsafe for them." A particularly treacherous situation: if pedestrians want to cross an intersection with cars honking at them continuously, they're not even safe when the crosswalk light is green, he says. That's because right-turners are allowed to cross even when the light is red (as it is, by the way, in Canada, Australia and the US). The consequences? More traffic fatalities than anywhere else in the world. This can be seen in the latest available data from the World Health Organization (WHO) from 2018.

China's megacities – bubbling laboratories of the automotive revolution

But the Chinese government has declared war on these conditions. In its quest, it is especially welcoming to those measures that strengthen the country's technological competence. The smart city, for example, which in Western countries only exists on the drawing board, is gaining ground here. Already mentioned in 2011 in the 12th Chinese Five-Year Plan, the concept was substantively enhanced in the subsequent planning period under the term New Smart City. The "Made in China 2025" doctrine has been in force since 2015, with which the country is striving for global leadership in the innovation areas of robotics, artificial intelligence and electromobility.

And connected autonomous traffic fits seamlessly into these plans. Chinese start-ups are among the pioneers for the car traffic of the future. The chaotic conditions in their major cities are actually playing into their hands. James Peng, CEO of, a robotaxi company founded in 2016 but already a major player in the industry, believes the challenges in China are particularly high. Experience with unpredictable local conditions is more valuable and data more meaningful than in the US, the pioneer in autonomous driving, he says. is already running a large-scale field trial of self-driving cars on public roads in southern China. Other local players, such as Baidu, AutoX and DiDi Xungking, are doing the same. Insiders expect a breakthrough to a mass business between 2023 to 2025. By 2030, there should already be an army of millions of robotaxis on the road in the world's largest market. The development is favored by the fact that only around one in four Chinese have a driver's license, and most won't be able to afford their own car for the foreseeable future.

Automotive test solutions in China's megacities

An autonomous car that can survive here can survive anywhere. China's megacities are being used by local robotaxi pioneers as test labs for V2X worst-case scenarios. To ensure these pioneers' business idea can be realized everywhere and, most importantly, safely, they need automotive test solutions such as those from Rohde & Schwarz.

The USA is the pioneer

Of course, the automotive revolution began in the USA. Starting in 2014, the cuddly autonomous Google "eggs" showed where the journey was headed. In 2015, this resulted in the first driverless ride on public roads. Google, or its sister company Waymo, founded in 2017, is still considered the benchmark for autonomous driving, with the most test miles and the most sophisticated software. But more than a dozen other US companies, as well as several Chinese ones, are taking advantage of the favorable regulatory conditions – especially in California – for their own field tests. Not only is the commercial use of robotaxis already regulated there, but some operators have even had their operations approved without safety drivers. Any problems on the road are corrected via remote control from a control center.


Google's sister company Waymo is one of numerous companies in the U.S. and China that already have autonomous vehicles on public roads. The first commercial robotaxi fleets are expected in the next few years.

Europe is another story

Europe lacks start-up initiatives comparable to those in the USA and China. Here, people rely on the development services of the automotive industry itself, on cooperative ventures with the major IT players, or even, in Germany, for example, on local projects with automated shuttles or people movers that are used on the first or last mile of public transportation. After all, Germany was the first country to pass a countrywide law on autonomous driving up to level 4 in July 2021. This will allow automated taxi fleets to operate on German roads as well. The car rental company Sixt promptly announced its intention to launch robotaxis in Munich as early as 2022, which will navigate using technology from Intel subsidiary Mobileye. However, a safety driver will still need to be on board.

Jürgen Meyer

"The idea of connected, autonomous driving is picking up speed worldwide. Our cars are increasingly becoming smartphones on wheels. The goal is for road traffic to become even safer for everyone. But we have to be able to trust the technology contained in a very small space within a connected vehicle. At all times and everywhere. Innovative T&M solutions make this possible. Everything is rigorously tested before the vehicles are deployed."

Jürgen Meyer, Vice President Market Segment Automotive, Rohde & Schwarz

Complete autonomy is suboptimal

In all the reporting about the car traffic of the future days, you hear the buzzwords electromobility and autonomous driving. But while these major technology building blocks happen to be on the agenda at the same time, they're actually quite independent of each other. The automotive industry is faced with the mammoth task of tackling both at the same time, which is also a major challenge for the largest manufacturers.

While newcomers from outside the industry, such as Waymo, Argo AI or Baidu, are putting pressure on the classic car OEMs with their navigation systems, the latter have to counteract this to avoid becoming dependent, while at the same time managing the switch to electric platforms. In addition, electronics are taking a rapidly growing share of vehicle development. Increasingly sophisticated driver assistance systems are enhancing safety and increasing the level of autonomy. At the same time, complete autonomy (level 5) – while possible at some point – is not the actual goal at all. Instead, the big picture is unfolding under the heading C-ITS: cooperative intelligent transportation systems.

This vision looks at traffic from a higher vantage point, with the intention of maximizing both traffic safety ("Vision Zero": hardly any traffic fatalities in 2050) and traffic efficiency by technical means. But this will only become possible if the vehicles communicate with each other as well as with the surrounding infrastructure and a traffic control center. 5G mobile communications will form the basis for this.

The car as a cell in a mobile ecosystem

As is typical with technology topics, talk about the communicating car is awash with catchy phrases. V2X for "vehicle to everything" forms the conceptual superstructure, under which V2V (... to vehicle), V2I (... to infrastructure), V2N (... to network), and V2P (... to pedestrian) fall. The car of the future will engage in lively communications with these counterparts to get it from A to B as safely, quickly and comfortably as possible. Until this is up and running, there's still some development, coordination and investment work to be done. But with 5G, the most important prerequisite – a suitable wireless system – is already in place. Now the technology has to be installed in the car.

V2X animation


An integral part of the smart city: the wirelessly networked car communicates with the infrastructure and other road users. In autonomous driving mode, all signals are processed automatically. Rohde & Schwarz mobile radio network simulators can be used to confront vehicles with such V2X scenarios in the test field long before they are encountered in the real world.

The better driver

Humans are pretty good drivers, considering how complex and unpredictable traffic can be. But technology is now doing some things better. In future models, it has its eyes everywhere via cameras, radar and lidar sensors, knows the route, is more responsive, always alert and never gets tired. If wireless communications also come into play, then information about remote situations can be incorporated into the vehicle's guidance, which is not accessible to the driver without assistance.

When everything works: a model drive

Overnight, our car has been updated to the latest software status via mobile communications and is ready for its next excursion, now with new features. Our automated model drive begins with the destination being entered into the on-board computer, which first fetches up-to-the-minute map and traffic information from the network. Beethoven Street is blocked because of an accident that has just occurred, which the vehicles involved have automatically reported, and is bypassed. Traffic through the city center flows without any major gridlock because the control center has an overview of the entire traffic situation and optimizes the traffic light phases. The cars' restarting when a red light turns green is remotely orchestrated. The traffic light ("roadside unit") wirelessly signals the jump to green.

The first vehicle ("host vehicle") takes over and initiates a V2V wireless chain along the line of standing traffic, which picks up speed in a controlled manner. Two streets further on, a critical incident occurs: a pedestrian suddenly steps into the lane, forcing a car to make an automatic emergency stop. A V2V signal sent simultaneously by the car to the traffic behind it, including our vehicle, causes the same reaction everywhere within milliseconds, so the incident has no negative effect on traffic. We take the on-ramp to the busy city highway. Our on-board computer informs the next vehicles that we want to merge and uses the gap they then create. Shortly thereafter, a rescue lane is created as if by magic, because an emergency vehicle is approaching. This is because the traffic control center had alerted all the vehicles along the route via mobile communications.

At our destination, we need a space in the parking garage and leave the whole procedure to the garage management system, which directs our car to the next free space, where it parks itself. A call signal will later make it available again at the exit.

An under-the-hood look at the technology

The model drive makes it clear that a mobility system based on wireless networking and vehicle autonomy (C-ITS: cooperative intelligent transport system) requires automatic mechanisms for a variety of traffic situations (use cases). These need to be standardized in a manufacturer-independent way. Organizations such as the 5G Automotive Association (5GAA) are working on this. The 5GAA includes representatives from all the major players in the automotive and communications industry, including Rohde & Schwarz, and, as the name suggests, is focusing on 5G mobile communications.

The automotive industry took up the 5G standardization process early on to ensure that its concerns were taken into account. 5G's intrinsic characteristics of high transmission rate, availability, reliability and short signal propagation time (latency) made it an ideal candidate for traffic networking from the outset. However, cellular mobile communications – radio traffic via switching base stations – can only cover part of the communications tasks. In dead spots or ad hoc situations, vehicles must be able to talk to each other directly. A sidelink interface ("PC5") was already provided for this purpose in the 5G predecessor LTE, and it's been integrated again in 5G. Depending on the use case, communications will take place either via the network (Cellular-VTX, C-VTX, Uu) or the PC5 sidelink.

An alternative sidelink technology based on WLAN (variant 802.11p) has now been sidelined after the major markets of the USA and China, as well as practically all European manufacturers, have spoken out in favor of 5G-PC5.


To be able to implement these visionary plans, the coming vehicle generations need to be 5G ready. General mobile communications capability has already been standard for years due to the mandatory eCall emergency call system for all new vehicles. However, 5G is significantly more demanding than previous standards in terms of the central role it will play in future traffic scenarios. Connection failures are not an option in safety-critical real-time applications. Therefore, manufacturers of the telematics units responsible for vehicle communications, as well as the automakers themselves, need the support of mobile communications experts like Rohde & Schwarz.

A whole range of specialized test equipment provides developers and system integrators with the means to efficiently integrate every type of wireless system – not just mobile communications, but also Bluetooth, WLAN and GNSS. Mobile radio testers such as the R&S®CMW500 or R&S®CMX500 simulate a mobile communications network in all its functions, measure and assess the performance of connected devices and enable lab testing of any 5G applications, such as the use cases for autonomous driving. Special attention is also paid to the vehicles' air interfaces: the antennas. Turnkey measurement systems automate the necessary tests and relieve manufacturers of time-consuming and error-prone procedures that require special expertise (e.g., full vehicle antenna test, or FVAT).

In addition to (mobile) radio test equipment, Rohde & Schwarz provides automotive manufacturers and suppliers with all the test equipment they need to develop and test electrical and electronic vehicle components, be it eCall, multimedia equipment, vehicle data buses, radar sensors or electric drives. The portfolio also includes equipment for testing electromagnetic compatibility. Conclusion: The bottom line is that test and measurement equipment from Rohde & Schwarz is now getting the car of the future rolling.

Mobile radio testers such as the R&S®CMW500 and R&S®CMX500 simulate a complete mobile communications network. A connected device, such as an automotive telematics unit or an entire car, can be challenged under lab conditions with all conceivable scenarios that do not yet exist live on the road.

Antenna tests take place over the air and require large test facilities. After the car is driven onto the turntable, the test runs automatically. The coordinated movement of the turntable and the swivel arm allows the measurement antenna to be positioned at its end at any point on an imaginary hemisphere above the car. The measurement thus provides a seamless picture that includes all spatial directions.