6G is a technology for the 2030s,” said Ryuji Wakikawa, Vice President and Head of the Advanced Technology Division at SoftBank, after unveiling the company’s 6G concept at an event held on July 14, 2021. “Right now, it is still at a fundamental level of research and development that is going on mainly at universities.” He noted that for the past four years, “we’ve been collaborating with over ten universities on a range of 6G technologies and applications.
6G mobile networks will transmit and receive data at higher radio frequencies than the wireless waves carrying data employed in 5G. The higher the frequency, the more bandwidth is available for data to travel along at greater speeds. As for 6G frequencies, we’re talking 100s of gigahertz (billions of cycles measured in hertz and shortened to GHz) rising to terahertz (THz or 1,000 GHz). Compare those frequencies to the 10s of GHz at which 5G operates, or the single-digit gigahertz range for 4G.
Though much still has to be agreed on to nail down a technology standard for 6G, one general goal mobile network operators are set on achieving is microsecond latency in communications: that means data arriving almost instantly with a delay of mere millionths of a second versus throughput in thousandths of a second for 5G’s millisecond latency. Certainly, the mobile network operators believe they will be able to provide data rates of 1 terabit a second.
One research topic Wakikawa talked about is telehealth. To provide fast, dependable diagnostics and treatments remotely for, say, stroke victims, terabits-a-second (Tb/s) communication is going to be the goal.
SoftBank currently has over 200,000 base stations, covering all of Japan from Hokkaido in the north to Okinawa in the southwest of the Japanese archipelago. Yet even when upgrading all this equipment for 6G, coverage will still not meet the demands of the new applications that SoftBank has in mind. But it turns out to be too impractical to achieve this blanket coverage simply by building additional base stations on the ground. Just to cover the northern island of Hokkaido, for instance, would require 7,000 base stations.
Instead, SoftBank has started developing Non-Terrestrial Networks (NTN)—an infrastructure in the air—to provide all-encompassing connectivity from the stratosphere and space once it is integrated with the ground base stations.
