In field trials at the Japan Automotive Research Institute last month, the trailblazing Japanese mobile operator says it achieved several firsts in communicating with a car going well over 100mph. The car was meant to simulate the velocity of a high-speed train, but 5G broadband links to motor vehicles also are expected to play a big role in road-safety and self-driving cars. (And what better excuse to drive a Nissan GT-R race car at triple-digit speeds?)
NTT DoCoMo connected with a car going 305 kilometers per hour (189mph) using 5G equipment on both ends and transmitting on a 28GHz frequency. This is important because 28GHz is one of the new cellular bands designated for 5G in many countries and requires new radio techniques because it has a shorter range than the bands cellular networks use now.
The trade-off with 28GHz, as well as other bands above the current 6GHz ceiling, is that they can provide more capacity. In the US, the Federal Communications Commission has proposed an auction of 28GHz licenses beginning in November.
Some developers of autonomous vehicle technology are looking to 5G for high bandwidth and low latency in cars.
C-V2X, which lets cars communicate with the cloud, other vehicles, and roadside infrastructure like connected signs, is expected to become part of the 5G standard as it evolves. One automotive application of 5G may be to send large amounts of data between cars and the cloud for detailed 3D maps that will need to be kept up to date.
High-bandwidth connections to moving vehicles are also expected to help cars keep up with streaming-media demand as entertainment and messaging services use ever-higher resolution and richer content. Those needs will emerge in both autonomous and human-driven cars on the mixed-technology roads of the future.
Also in the Tsukuba trials, NTT DoCoMo sent a live relay of 4K, 120-frames-per-second video from a 5G radio in a car moving at 200kph. And it achieved a 1.1Gbit/s transmission from a 5G basestation to a 5G-equipped car traveling at 293kph.
One of the challenges of providing cell service to moving vehicles is handing off the connection to a car as it moves in and out of each cell station's range. DoCoMo said it achieved a fast handover connecting to a car moving at 290kph.
Because wavelengths are shorter in 28GHz and other high-frequency bands, it's harder to cover a wide area like a stretch of highway. To deal with this, NTT DoCoMo concentrated the radio signal in one direction using a technique called beam-forming. Then it used beam-tracking to change the direction of the signal as the car moved along the road -- in this case, a closed track.
The results of the tests, which took place in early April, weren't announced until May 9. Equipment maker NEC and telecommunications carrier NTT participated in the trials.
5G is coming soon, though not necessarily to your local street yet.
Some smartphone makers plan to release 5G phones in some markets before the end of this year, and most of the planned 5G devices will offer top speeds of 2 Gbit/s to 4Gbit/s, depending on which frequencies they can use, a Qualcomm executive said last week.
In the US, AT&T and Verizon have said they will turn on 5G networks in some areas this year, though broad availability will take much longer. Early 5G handsets will use LTE as a fallback where the new networks are not available.
— Stephen Lawson is a freelance writer based in San Francisco. Follow him on Twitter @sdlawsonmedia.