By Lou Frenzel, Contributing Editor
Communications is the key feature of forthcoming self-driving cars or autonomous vehicles (AV). It will first complement the already effective advanced driver assistance systems (ADAS), then go on to play an even more important role in full AVs of the future. The communications is wireless that allows vehicles to not only speak to one another directly, but also talk to various nearby road side units, networks, or other infrastructure facilities (Fig. 1). This capability will greatly improve safety and convenience for conventional vehicles, as well as various levels of AVs. However, there are five significant issues that still must be dealt with. These are being addressed now by multiple organizations but final conclusions have not been fully resolved.
Radio standards have already been developed to facilitate the vehicle-to-vehicle (V2V) and vehicle-to-infrastructure or other resource (V2X) communications. One of these is the Dedicated Short Range Communications (DSRC) standard, a specialized form of Wi-Fi called 802.11p. It is a variant of 802.11a and operates in the 5.9 GHz unlicensed band using OFDM. It has a data rate in the 3 to 27 Mb/s range and can cover a distance of 300 meters to one kilometer. This standard transmits a Basic Safety Message (BSM) 10 times a second that contains vehicle statistics like exact GPS location, speed, direction, turn, and braking status, among other factors. Other vehicles receive the data and can determine their relationships to avoid conflict. Figure 2 shows the DSRC system.
Another wireless technology vying for this role is Cellular V2X. It too uses the 5 GHz band, but employs a form of LTE that is compatible with existing cellular networks. C-V2X permits direct vehicle-to-vehicle links so that BSMs can be exchanged. Its advantage over DSRC is that its latency is less and no separate V2X networks need to be developed since the system uses existing LTE cell networks. Furthermore, future versions will follow the designated path to 5G cellular technology.
The issue here is which technology will prevail? And when? Complicating this issue is the recent decision by the Trump administration to drop the V2V mandate saying that it would be a regulation that would cost the auto manufacturers millions to implement, an unwanted burden. Yet most auto companies like the idea of V2V. Furthermore, it would take a decade or more to make V2V useful as it requires all or most cars to have it first. So in the meantime, we wait to see what happens. One problem is that other services would love to acquire the 75 MHz of bandwidth about 5.9 GHz for Wi-Fi or cellular. And the C-V2X folks could eventually find a way to kill off DSRC. We shall see.
Choosing the standard is important since it will be used for a long time. Automobile development is a long-term process and companies work many years in advance. It is critical to maintain compatibility with new and older vehicles over a long period of time. After all, this V2V and V2X will not really be effective or useful until many (if not most) vehicles have this feature. Vehicles will gradually incorporate it once a standard is decided upon, but the phase-in will take some years. It is to be mandated by 2023, so look out a decade or more before we see the real benefits of this communications.
Yes, hacking an ADAS or AV is a potential problem. The communications technology chosen will have security features that will help prevent that. DSRC uses the IEEE 1609.2 standard for security. C-V2X incorporates another form of security. Already it has been demonstrated that hacking is possible. A few years back, some engineers hacked into a Jeep Cherokee and took control. The entry was via the Jeep’s built-in cellular connection. That is still a potential entry point, as is any DSRC link, or even through Bluetooth or the OBD II port. A clear-cut solution is needed. Perhaps individual automakers should be working together to come up with a common cybersecurity standard.
Driver distraction is already a major problem and a leading cause of accidents as drivers eat, smoke, text, talk on the phone, and engage other non-driving activities. Even setting the radio or looking at and setting up the GPS nav system is major attention diverter. The more technology we add to a vehicle, the more distractions we add. Incorporating V2V and V2X will undoubtedly add some display, warnings, or other driver information that must be acted upon. Some steering or braking actions may be automated by activating them directly with the ADAS system. Nevertheless, some attention needs to be paid to this increasing distraction problem that could negate any safety gains otherwise achieved.
Let’s face it, drivers are going to have to adapt to the new systems. It has taken some time and multiple experiences to fully adjust to my own new vehicle’s ADAS. I must admit that it works well and it does help the driving experience. But it has taken time to get educated about what the systems are, how they work, and the kinds of warnings and actions to expect. I learned from the vehicle’s owner’s manual and actual experience. Still, as systems get more sophisticated—especially with the addition of V2V and V2X—more formal driver training will be necessary. Videos, dealer classes, or other sources of instruction are clearly necessary. Is anyone addressing this?
Cars are already connected by way of their AM, FM, satellite radios, GPS nav systems, and cellular Wi-Fi hot spots. With the addition of V2X in the coming years all drivers, with full AVs or conventional vehicles, will be relearning how to drive. The increased safety and convenience will be worth the added cost.