“These ideas of connecting cars to an infrastructure are not new. We’ve been talking about this for decades,” says Anupam Malhotra, director of connected vehicles and data at Audi of America in Herndon, VA. “When telematics first started in the 1990s, even then there was this idea that cars could talk to traffic lights.” It was 20 years ago that ITS America first proposed that cellular spectrum be set aside for “active safety applications” including V2V and vehicle-to-infrastructure (V2I), Malhotra recalls. But at the time, cellular networks were largely analog and Wi-Fi needed faster data transfer speeds. Moreover, while cellular required all data to pass through a network operator’s base station, Wi-Fi forged a direct device-to-device connection. So, he says, the Institute of Electrical and Electronics Engineers developed DSRC, a version of Wi-Fi dubbed 802.11p, which allowed a direct and speedy car-to-car communications link.
Even with the introductions of 2G and 3G networks, cellular latency (the time span between when data is sent and when it’s received) remained too large for vehicle safety applications, Malhotra adds. Thus, until as recently as 2014, he says the division for automakers remained clear: DSRC underpinned active safety and cellular enabled connected infotainment.
Still, making DSRC commercially viable is challenging, and many of the ways to do that now rely on integrating some cellular connectivity, Malhotra says, citing features integrating vehicle data and data marketplaces.
With the debut of 4G LTE in 2012, cellular bandwidth expanded sevenfold, and latency fell by two-thirds, making possible new safety-related V2I services. These include Audi’s Traffic Light Information service, which was launched at CES in 2016. Via an LTE connection, it lets specially-equipped Audi vehicles receive the phase and timing of signal changes (from red to green and vice-versa) from smart traffic lights through a cloud server, and provides warnings to the drivers. Right now, Audi is collaborating with 20 cities nationwide to harvest the traffic light data, and by 2019 half of all Audi customers in the U.S. will be able to use the service. “The same could probably not be said about DSRC in the near term,” he says. “This is an example of the kinds of things that used to be lumped into the DSRC bucket, that have slowly bled into the cellular bucket in terms of what is possible.”
Now, proposed 5G cellular vehicle-to-everything (V2X) technology is expected to supply one-tenth the latency of LTE, or 10 times faster performance, and could turn the tide against DSRC. “When you look at latencies at that level, you end up taking those final few use cases that are in the DSRC bucket and saying you could also do it with 5G,” Malhotra states.
Technically, 5G matches all of DSRC’s capabilities and goes further, says Dominque Bonte, managing director and vice president at ABI Research in Brussels, Belgium. Both work with two vehicles traveling at speeds up to 250 kilometers per hour in opposite directions (for a relative velocity of 500 km/hr), and latency of about 1 millisecond. Plus, 5G offers greater range — up to about a mile, versus one-half mile with DSRC — although this is not relevant as regards the short-range communications needs of V2V and V2I, Bonte declares.
Also, because 5G operates in the 60GHz radio spectrum, its 10 gigabits per second (or higher) bandwidth far exceeds that of DSRC, which uses 5.9MHz radio spectrum, he says. So, “when 5G comes we can open it up to more use cases,” such as sending one vehicle’s sensor or camera data to another for better perception of the environment, streaming 4K or 8K videos to rear seat entertainment systems, or downloading big data files — including HD Map updates for self-driving cars — from the cloud in real-time, Bonte says.
The future of cellular in vehicles is assured, too. Every new vehicle in the next five years will come with a cellular modem embedded, and 80 percent of all cars on the road will have cellular onboard in 10 years, Bonte says.
“There’s no real reason to still need DSRC” after 5G is available, Bonte declares. To be sure, DSRC is a mature technology and 5G is not. But, the former serves only one purpose — safety-critical V2V or V2I communications — and has an uncertain future, he says. A federal government mandate proposed by the U.S. Department of Transportation last year calls for DSRC to be installed in all cars starting in 2019. It may be revised or repealed, however, following complaints from automakers and other commenters.
Currently in the U.S., DSRC is integrated into fewer than 200 traffic signals to communicate their phase and timing with cars, says Roger Lanctot, director of automotive connected mobility in the global automotive practice at Strategy Analytics, in a commentary titled DSRC: The Road to Ridiculous, published in June. Further, Lanctot notes, the only commercially available vehicle able to communicate with these signals — the sole U.S.-sold car with DSRC built in — is the 2017 Cadillac CTS.
By contrast, thousands of traffic signals now connect via cellular technology (LTE) to Audi’s feature and to a similar one from BMW, which includes the ConnectedSignals EnLighten app in the BMW Apps infotainment platform. So, DSRC is unnecessary to pursue, Lanctot concludes. “The creation of an expensive, dedicated network unsupported by any consumer device technology is a road to ridiculous and a waste of taxpayer dollars.” Cellular V2X (C-V2X) technologies such as LTE and 5G are a wiser path to follow in developing automotive active safety systems, he advises.
“We’re trying to pursue the government mandate,” says Gaurav Bansal, senior researcher in the network division at the Toyota InfoTechnology Center, U.S.A. Inc. in Mountain View, CA. And if the mandate takes effect, Toyota believes as much as three percent of cars on the road here in 2020 will be equipped with DSRC. By 2025, Bansal says, Toyota is expecting 42 percent of U.S. vehicles will be equipped with some sort of “cooperative automated driving” technology tied to either DSRC or 5G. And by 2030, he says, the automaker forecasts a jump to 68 percent.
“In 2025, when you go on the road, there’s a good probability that you’ll find another connected vehicle” using either DSRC or 5G, Bansal says. And the resulting “cooperative automotive driving” will facilitate maneuvers such as automated merging of cars as well as active safety features that don’t require sensors to maintain a “line of sight.” By 2030, Bansal predicts, it’s likely that 5G will be prevalent and that cooperative automotive driving might be a key aspect of self-driving cars.
Indeed, DSRC is already established in Japan, where it has been deployed since 2012, and by Toyota since late 2015. “But we see a great promise” for 5G, Bansal adds, especially regarding V2V sharing of sensor data.
In fact, Bansal says, Toyota expects that future self-driving cars will emerge equipped with both DSRC and 5G wireless technologies.
“There is a preconception that DSRC is outdated technology, which is not true,” says Ravi Puvvala, CEO of Savari Inc., a Santa Clara, CA-based V2X sensor supplier to automakers and municipalities (for “smart city” implementations). “If you think about it, both DSRC and C-V2X are extensions to specific radio platforms — either Wi-Fi or cellular. So as the Wi-Fi standards are improving to have more bandwidth, the extensions of DSRC are doing the same. These extensions can be carried over as Wi-Fi radios are getting better and better.” So, both DSRC and C-V2X can continue to be built in to vehicles, Puvvala says.
“The two technologies will coexist for at least a period of time until the transition happens,” says Manuela Papadopol, director of business development at Elektrobit, a Seattle-based subsidiary of Continental AG that supplies embedded and connected software solutions and services to automakers for autonomous driving, advanced driver assistance systems (ADAS), navigation, telematics and human machine interface features. But, “for autonomous driving, we at Elektrobit definitely believe that the 5G network combined with vehicle to everything — infrastructure, vehicle, pedestrian — will bring a safer, more efficient travel and better driving experience, mainly because of the low latency and enhanced reliability that 5G brings.”
Testing across networks, devices and vehicles must be completed before any of this is possible, though, Papadopol adds. Right now, “the only viable existing technology for direct V2V is DSRC,” and it does today what 5G might be able to do in five to seven years, contends Hagai Zyss, CEO of Autotalks, a Tier 2 provider of DSRC V2X communications chipsets, based in Kfar Netter, Israel, whose customers include Denso and Bosch. The former incorporates Autotalks’ chipsets in a V2X platform expected to be available in 2019. The latter is working with Autotalks to develop a motorcycle-to-car (bike-to-vehicle or B2V) communications platform. Zyss also contrasts DSRC’s 20-year history of technology stability with cellular’s recurring obsolescence as carriers move from one network technology to another.
In the near term, automakers will integrate both DSRC and cellular in vehicles, the former for V2V communications, says Siddhanth Kumaramanickavel, lead research analyst for connectivity and telematics at Frost & Sullivan in India. But the firm also anticipates 5G proliferation along with self-driving cars beginning in 2023.
“The solution is not one or the other, but it’s the two,” playing complementary roles like Wi-Fi and 4G in cell phones today, says Javier Gonzalvez, IEEE Standards Association representative on the IEEE 5G Steering Committee. “The issue will be, for safety, how they will be utilized. How they coexist will have to be addressed.”
Yet proponents of 5G insist it will replace DSRC in the long run, if only for economic reasons. “It’s not only a question of cost, but also a technology and product roadmap that can keep up with next generation automotive use cases,” explains Nakul Duggal, vice president of product management in the automotive business of Qualcomm Technologies Inc., based in San Diego, CA — a supplier of both DSRC and cellular technologies to automakers.
Given a choice between installing a new DSRC radio in a vehicle at added expense or extending the utility of a cellular modem that is already built-in, the answer for automakers is clearly in favor of cellular V2X, Duggal says. “We are talking to major automakers globally who are now reconsidering their previous positions on DSRC and thinking about doing trials on cellular based V2X. This is going to be a very interesting 12 to 24 months for the auto industry.”
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