Vehicle-to-vehicle/infrastructure (V2X) hasn’t lived up to expectations, but many feel it will soon become an important factor for improving safety and autonomous driving systems. To make it successful, engineers will need to create strategies that fuse V2X data with input from the vehicle’s sensors while also paying close attention to security and signal reliability.

V2X has been in development for decades, but it hasn’t gained traction in part because connectivity wasn’t widespread. As modem usage becomes more common, it’s expected to grow, driven by increasing focus on safety and autonomy. Safety planners like V2X because it can “see” around corners and obstructions, augmenting sensors like cameras, radar and lidar that are limited to line of sight (LOS) data collection.

“V2X provides more information than LOS sensors, such as steering wheel angle and self-reported vehicle speed of the other vehicles,” said Robert Gee, senior manager portfolio development, connected vehicle solutions & V2X at Continental. “But this is not to say that V2X does more than LOS sensors in every situation. It is important to recognize that V2X can help to confirm, enhance, and extend the data from the LOS sensors, providing both additional information and corroboration of LOS sensor information to enable the vehicle to make the best decision.”

That can help improve safety margins by identifying vehicles that are not detected by on-vehicle sensors. The benefits go beyond spotting vehicles in blind spots. Information can include warnings for nearby emergency vehicles as well as speed data for unseen vehicles.

“V2X could extend the range of the vehicle environment,” said Michael Burkhart, system engineering connected car manager at ZF. “For example, with on-board sensors, it's not easy to identify an emergency vehicle. Additionally, V2X provides position, speed and lane information. Information gathered by the on-vehicle sensors, for example traffic jam/accident after the curve, could be forwarded to other vehicles.”

The commercial rollout of V2X will likely be slow. Many OEMs and infrastructure planners are reluctant to spend money on V2X until there are some vehicles that can communicate. This chicken-or-egg issue has bene a long-term stumbling block for deployment.

The reluctance to move ahead with V2X on mainstream production vehicles is also driven by questions over communication protocols. Cellular V2X (C-V2X) has been gaining momentum in the U.S. and China. The seasoned WiFi-like standard, dedicated short range communications (DSRC), is showing signs of strength in Europe. While different regions may settle on different standards, the issue brings some uncertainty and doubt for product planners.

Caveat emptor
While V2X is considered a powerful tool in the efforts to improve safety and advance autonomy, even proponents note that it’s like all sensors: They have strengths and weaknesses that work best when multiple inputs are fused together to create a single image. Wireless links are generally considered to be limited to augmenting on-vehicle systems, unlike some on-vehicle sensors that can temporarily guide vehicles single handedly.

V2X connections can operate in snow and other harsh conditions that blind most sensors, but they may fail in other situations. Though wireless protocols have improved dramatically, they are still prone to dropouts. Even a brief disconnection could cause serious problems for vehicles dependent on those connections.

“While some experts claim V2X is essential in the large-scale deployment of AVs, in reality, a self-driving car cannot be reliant on anything external through connectivity, either to other vehicles, infrastructure, or the cloud,” said Danny Shapiro, senior director of automotive, NVIDIA. “Driving decisions must happen at lightning-fast speed, requiring all sensor processing, perception and planning to happen in-vehicle.”

Who are you?
Security is another huge issue. Signals sent by cars and roadside stations must be reliable, or they’re worthless. That means signal generators must be vetted and controlled, while communication channels must be immune to hackers. In the vehicle, hardware must protect the encryption keys. Software must use a layered, defense-in-depth approach. A vehicle’s network gateways and vehicle buses must be protected, with security techniques that separate and protect critical driving and safety functions from non-critical functions like infotainment.

Over the air updates will be critical so vehicle systems can be updated as new threats emerge. Staying current will be a complex issue, since vehicle lifetimes are long. Hack attacks on vehicles will be compounded by attacks on corporate servers that communicate with cars.

“The vehicle is never alone: A secure server system is the vehicle’s overwatch,” Gee said. “While an attack on one vehicle might be able to expose that one vehicle’s protected data, a successful attack on a server system could expose the data for many vehicles. Because such back-end systems are monitored 24/7 and have constant patches and upgrades, the vehicle’s overwatch can filter and block new attacks from compromised third party servers.”

Future needs
As autonomy comes into play, communications will grow in importance. Satellite navigation data is likely to be used to help advanced vehicles navigate better, conserving fuel or battery life by adjusting speed before entering curves or hilly areas. GPS data will further supplement V2X links by providing very precise positioning data. Combining V2X and GPS data can provide important information, such as telling the vehicle it will need to adjust lanes in construction zones.

“Unlike GPS navigation for human-driven vehicles, which operate within a few meters of accuracy to provide turn-by-turn directions, maps for AVs have greater requirements to ensure safety,” Shapiro said. “They must operate with centimeter-level precision for accurate localization, the ability of an AV to locate itself in space. Proper localization also requires maps that are constantly updated and reflect current road conditions, such as a work zone or a lane closure.”

Communication can also help system designers continue to make ongoing improvements. Data collected from vehicles helps engineers and programmers enhance systems and software. “Data collection, data quality and data management are of vital importance,” said Arnaud Lagandré, ADAS business unit VP, Continental North America. “Therefore, we collect daily more than 100 terabytes with our global fleets that entail hundreds of vehicles.”

Standards security foundation
Gaining the benefits of V2X requires a heavy focus on security, since quick life-and-death decisions will be made based in part on data from vehicles and roadside infrastructure. Internationally, industry stakeholders are working together to ensure data integrity, creating standards and developing ways to share data as new security challenges arise.

V2X promises to enhance vehicle safety systems by providing input that on-board sensors can’t detect. Given the importance of making sure that data is not hacked or otherwise corrupted is a major challenge, one that’s compounded by the long life of vehicles. Creating system strategies that provide acceptable security risks at levels that society can support requires broad long-term strategies.

“Maintaining security over 15-20 years is an extremely difficult task and might require hardware changes after several years,” said Achim Fahrner, head of Automotive Security, Autonomous Mobility Systems at ZF. “Also, the security activities – security process, implementation of security measures, lifetime security support, and so on – can cause significant efforts and costs. In the end, all road users will be protected by cybersecurity, but it potentially results in significantly higher product costs.”

Several standards have been created to help system designers achieve adequate cybersecurity levels. Highlighting the international focus on vehicle security, SAE and the International Standards Organization have developed ISO/SAE FDIS 21434. Additionally, the United Nations Economic Commission for Europe created UN R155, which is based on ISO/SAE FDIS 21434. It makes cybersecurity a pre-requisite for final approvals. Japan and China have started similar security standard developments.

Standards create a base for companies to build on, as well as processes that can be followed to ensure the integrity of solutions. Though the goal is to eliminate vulnerabilities, quick responses to breaches are an important element in all automakers’ protective schemes.

“A robust security monitoring system and the fast ability to respond to security incidents in the field is critical,” Shapiro said. “Zero-day issues and the value of targets in the automotive industry dictate the ability to rapidly respond, within hours or days, to security incidents that occur in the field. Having a robust product security incident response team program is a must going forward.”

Those response teams will work to create patches that will generally be downloaded to vehicles over the air. Their efforts will be supported by groups like the AutoISAC, a U.S. organization that gathers security-related information and shares it with members. AutoISAC members, which number nearly 50, can also work together to address security breaches as they arise.

These efforts dovetail the strategies built into V2X schemes. The teams that developed C-V2X and DSRC started with an emphasis on security. For example, they require that devices have a valid certificate issued by a certificate authority. Otherwise, its transmissions will be simply ignored.

“V2X security was developed by industry experts and scrutinized by national security authorities,” said Onn Haran, Autotalks CTO. “Every vehicle must use a certified V2X solution by an accredited lab. The security strength is far beyond the security needed for the next decades. Having said that, security can be upgraded over lifetime, if needed. Some chipsets, like Autotalks’ V2X chipset manufactured by ST, are crypto-agile, and can support longer security keys. Over-the-air updates can be used to fix vulnerabilities, if detected during vehicle lifetime.”