Should Radar Be Improved Under 5G?
5G is the 5th generation of wireless technology. For context, 5G will deliver information up to 100 times faster than what is possible with 4G. 5G uses a higher range of frequency, the RF spectrum, thus enabling higher bandwidth waves that support faster speeds, but don't travel as far as current wireless frequencies since they are smaller waves. So, instead of relying on large cell towers spread far apart, like 4G does, 5G will rely on “small cell” sites that are much closer together.
“A 5G tower is different than a 4G tower both physically and functionally: more are needed to cover the same amount of space, they’re much smaller, and they transmit data on an entirely different part of the radio spectrum.” According to SDX Central.
Radar signals, essentially, carry no data or information. The way radar works is much like a bat used to “see” in the dark. The system sends a short pulse of the carrier frequency. Then, it starts a timer and starts listening for the pulse to be reflected off the target and be received. The timer is then stopped. The speed of the pulse is essentially the speed of light. So, the distance to the target is equal to one half of the time for the pulse to be received (since the signal has to traverse the distance both to the target and back). Subsequently, the distance is just 1/2 of the time divided by the speed of light. The frequency and pulse of the radar signal does have an effect on the resolution of measuring the distance to a target (which is called Range in radar terms). A narrow pulse, essentially, can make higher resolution measurements.
There are some similarities in Radar and 5G technology; the radar technology was a revolution, whereas 5G is more of an evolution. Theoretically, if you had enough cell towers that went 10k+ feet high, you could use 5G for some version of a more accurate localized “radar.” But of course, outside of the range it would be blind.
There is a program in Europe looking to do something similar, where they would have cell towers that have the transponder antennas pointing up vertically to provide 5G coverage to airliners. Right now, airlines and cruise ships use a satellite called Inmarsat that connects to satellites which relay the information to and from ground stations. But, allowing 5G directly to the ground would allow for much higher data bandwidth.
Cell technology is inherently “cooperative,” where you need to have a handset for example negotiate a link with the ground station. You could do the same in a radar application as long as the target you are tracking was cooperative. This is essentially what IFF for airliners do (send data back to the FAA when the ground station pings the airliners). If you were trying to track an “unfriendly” target, naturally, they wouldn’t respond to these pings. With 5G, the multiple antennas improve power efficiency since more energy is pointed where it needs to be. And, with steering, multiple targets can be tracked.
Written by Alexander Fleiss & Edited by Derek Chiang & Paolo Pignatelli