Research ‘in the weeds’ powers data in the air
The demand for wireless broadband has exploded over the last 15 years. A number of both improved and new applications are driving this data consumption over a rapidly growing number of mobile devices. The rollout of 5G — the fifth-generation cellular mobile network, with higher speeds and lower latency — will further increase that demand. University researchers, including myself, have been working on 5G for more than 10 years and are tackling the underpinning technologies that help make this data flow possible.
The numbers are staggering. Cisco estimates that, globally, mobile data traffic will increase sevenfold from 2017 to 2022. In that time, the number of global mobile devices will grow from 8.6 billion to 12.3 billion — of which more than 422 million will be 5G-capable. Nearly 12 percent of global mobile traffic will be carried on 5G cellular connectivity by 2022.
Obvious 5G applications include enhancements to video and gaming. Virtual reality games are becoming more immersive and will soon have improved sensory feedback; for example, users will be able to wear a glove that recreates the feeling of touching a surface. Adding this tactile feedback to a game or video in real time puts amazing strains on the communication system. The dominant constraint is latency — the time required for a bit to reach the user. 5G targets a 1-millisecond latency in low-latency mode, compared with 10 ms in 4G networks.
Autonomous driving is also spurring 5G. Connected vehicles generate tremendous amounts of data: Intel’s analysis has shown that a connected vehicle could spew out 4 terabytes of data each day. Though the benefits of vehicle-to-vehicle and vehicle-to-everything (roadside/infrastructure) communications are clear, there is much debate over the best way to implement these advancements. 5G systems will be widely available soon, and it is possible that future vehicles will be built with cellular vehicular communications.
There are numerous other 5G applications, from controlling devices in a smart home, building or city, to the sensor-driven data flood from the Internet of Things (IOT), to remote surgery, to many more. The technological challenge is to stream this data so fast that the lag between transmission and reception will not compromise any activity.
5G data will travel over radio frequencies. Most of the radio frequency (RF) devices used today (and for the last 100 years) have been in sub-6 GHz frequencies. These are preferred because of their propagation properties — wide coverage, building penetration — and relatively inexpensive hardware. But these bands are extremely popular and heavily utilized, and the RF technology isn’t well-suited to accommodate the interference and congestion that are likely with the widespread adoption and use of 5G.
To overcome this hurdle, researchers are looking at frequencies in the so-called “millimeter” wave bands, or mmWave, where the Federal Communications Commission has freed up huge amounts of bandwidth. This is roughly the 20–100 GHz frequencies, where faster speeds, lower latencies and more available spectrum — by most counts, tens of gigahertz — could be used for commercial wireless broadband.
Purdue faculty and students have shaped the 5G millimeter wave discussion and standardization. We showed how the antenna arrays and directional transmitters that form and steer 5G radio beams can attain high user throughput and track users in mobile environments, for which we were awarded the Institute of Electrical and Electronic Engineers (IEEE) Stephen O. Rice Prize for best paper in the field of communications theory. We also are working on massive multiple-input, multiple-output (MIMO) systems to leverage multiple antennas at the transmitter (base station) and receiver (user device) to support more users simultaneously; this research has been recognized with an IEEE Signal Processing Society best paper award.
Rapid 5G deployment will usher in a new era of global interconnectivity and competitive advantage that is critical to business, science, consumers, and the U.S. writ large. That’s why the FCC strategy is to Facilitate America’s Superiority in 5G Technology (the 5G FAST Plan) — with a focus on making more spectrum available for 5G services.
We engineers “in the weeds” are doing our part to get that data flowing through the air.
David J. Love, IEEE Fellow, and Nick Trbovich Professor of Electrical and Computer Engineering and Leader of Efficient Spectrum Usage Preeminent Team, Purdue University College of Engineering
