From Tufts to 5G

Tufts electrical engineering professor Mai Vu and Ph.D. student Lisa Pinals are making the next generation of cellular networks faster, clearer, and more power efficient

As a high school student in Billerica, Massachusetts, Lisa Pinals knew she liked math and science, but had no idea that she wanted to be an engineer. Then, as part of technology program for teenagers run by University of Massachusetts, Lowell, Pinals got her first taste of hands-on programming — hacking the world’s most popular robot vacuum.

“They taught us how to program Roombas,” says Pinals, now a Ph.D. student in electrical engineering at the Tufts University School of Engineering. “You start out pretty simple, going around a maze. And at the end, our big project was to find different colored balls, pick them up, and try to score a goal — soccer for Roombas.”

Pinals found her future. She went on to major in electrical engineering at Tufts, where she landed a coveted internship with MIT Lincoln Laboratory, a research and development lab that dreams up advanced technologies for the Department of Defense. At Lincoln Laboratory that Pinals found inspiration from an unexpected source: radio waves.

“I had heard of wireless communications, but hadn’t taken a wireless class yet,” says Pinals. “During the internship, we collected a FM radio signal, and I was able to do some processing and get some cool results from it. To get a signal and then turn it into a song that I recognized from the radio was really incredible. It seemed like magic at the time.”

The wireless radio technology that powers everyday gadgets like cell phones can seem like magic. But the hardware, software, and network upgrades that move wireless technology from one generation to the next — 3G to 4G to 5G in 2020 — requires collaboration and innovation from experts across a number of scientific, engineering, technology, and mathematical disciplines.

As a doctoral student at Tufts, Pinals is one of those innovators. In her first year, she has already co-authored two papers on a new wireless network scheme for transmitting more data with less required power than today’s best cellular networks.

Pinals’ Ph.D. advisor and co-author is Mai Vu, who runs the Tufts Laboratory for communIcation in NetworKed Systems (LiNKS). In June 2014, Vu won a grant from the Office of Naval Research (ONR) to push the performance of wireless networks, something critically important to communications between a fleet of moving vessels. Vu’s idea was to focus on the concept of a relay network.

To send data from one phone to another in a cellular network, the data — voice, text, video, etc. — must first travel to the nearest fixed base station and then to the destination phone.

Relays are simply additional nodes in the network that extend the reach of wireless signals — more “bars” at the edge of the network — and transmit data back to the base stations more quickly. Relay points can either be fixed infrastructure nodes or moving nodes, including the idle cell phones of strangers.

Vu and Pinals have devised a novel set of algorithms to determine the most efficient coding technique for data to travel from point A to point B. This is much harder than it sounds. Because point A and point B might both be moving, the network must continuously re-route traffic between relays and base stations to adjust for changing signal strength and link conditions.

To solve this issue, Vu and Pinals took two existing data transmission schemes and merged them into a novel hybrid.

“Our composite scheme for the two-way relay channel actually performs as well or better, depending on the channel conditions, than the existing techniques,” says Pinals. “And by doing this, we get a better data rate and save power at the relay, which neither of the existing schemes did. So this is a pretty significant result.”

Vu: “There’s no shortage of jobs for a Ph.D. in electrical engineering. I know a lot of companies and research labs that want to hire Ph.D.s. They need to keep this innovation going, especially in terms of cellular. If you’re going to go into a new generation, you need a lot of new techniques, new hardware and new algorithms to build that network. This can only come from intellectual property. It’s not that you take something existing and implement it; you have to invent something new. That’s why the demand for Ph.D.s is high.” 

Companies that have hired Tufts graduates include:

  • Apple
  • Qualcomm
  • Raytheon
  • BAE Inc.
  • Bose
  • Texas Instruments
  • MIT Lincoln Lab
  • BBN Technologies
  • Draper Labs
  • Pfizer
  • OmniVision

The 2014 IEEE GlobeCom conference in Austin, Texas, accepted Pinals and Vu’s first paper.  Normally, a grad student must pay her own way to a conference, but Pinals covered her travel expenses through her IEEE Life Members Graduate Study Fellowship in Electrical Engineering, a two-year, $20,000 grant awarded to a single first-year graduate student nationally.

Pinals is quick to credit Vu for her active mentorship and support as an advisor. It’s part of the “community feel” of the School of Engineering that drew Pinals back for her doctoral work. Vu, who earned her Ph.D. at Stanford and has taught at much larger schools like McGill University, loves the collegial atmosphere and close faculty-student interaction at Tufts.

“I meet with graduate students usually once a week, but sometimes two or three times a week when work is progressing fast or a deadline is approaching,” says Vu. “You usually don’t get that kind of attention at bigger schools. If you’re a Ph.D. student and are going to spend four or five years at a place, Tufts is small enough that you’ll get a lot of mentoring while doing state-of-the-art work. You’ll also get to know everyone!”

Learn more about Tufts’ culture of collaboration and our more than 45 top-ranked graduate programs across the arts, sciences and engineering.