Rice University to study massive MU-MIMO thanks to $2.4M grant

Researchers at Houston's Rice University won $2.4 million from the National Science Foundation (NSF) to conduct research into the use of massive multi-user, multi-input multi-output (MU-MIMO) for upcoming 5G standards. They said their research will help the wireless industry determine whether and how to include MU-MIMO in upcoming 5G wireless standards.

Rice University researchers will use base stations with more than 100 antennas apiece in a 5G wireless test network. (Photo credit: Jeff Fitlow/Rice University

"Early tests of many-antenna technology at Rice and elsewhere suggest that wireless carriers could use this technology to serve many times more data than can be served with today's 4G networks," said Lin Zhong, associate professor of electrical and computer engineering and of computer science at Rice and the principal investigator on the new grant, in a statement. "But there are still many questions about how to scale this technology for real-world implementation. Those are the challenges we'll be tackling with the new research."

The research will make use of ArgosNet, a many-antenna experimental test bed that Zhong's Efficient Computing Group is building thanks to a 2014 NSF infrastructure grant. ArgosNet will eventually include up to a half-dozen programmable base stations, each with 100 or more antennas.

Zhong said the new experimental research with ArgosNet, which draws its name from the many-eyed giant of Greek mythology, could provide the answer that wireless carriers need for the coming bandwidth crunch. ArgosNet uses its antennas to beam information directly to numerous users simultaneously on the same frequency; this is done by constantly computing where each user is and altering the signal to each antenna to direct a focused beam directly to each user.

Clayton Shepard, a Ph.D. student who's building the ArgosNet base stations and mobile clients, said the team is exploring how to make ArgosNet compatible with existing smartphones and wireless devices, but the current base stations are not compatible with existing technology. For Rice's tests, Shepard and other members of Zhong's team will use reprogrammable, battery-powered test units.

The project team includes Rice's Edward Knightly, professor and department chair of electrical and computer engineering and director of the Rice Wireless Network Group; Rice's Ashutosh Sabharwal, professor of electrical and computer engineering; and Ohio State University's Ness Shroff, the Ohio Eminent Scholar in Networking and Communications and professor of electrical and computer engineering and of computer science and engineering.

Millimeter wave technology is getting increased attention as the wireless industry sets its sights on 5G. It was almost a year ago when New York University (NYU) Wireless researchers recounted how their mmWave measurements from the Manhattan and Brooklyn rooftops of NYU were positioning the United States to take advantage of high-frequency radio waves. Professor Ted Rappaport, director of NYU Wireless, and student co-authors in Microwave Journal described a new tool that used National Instruments technology to measure mmWave channels. The researchers tested in the 28 and 73 gigahertz bands, both outdoors and in the complex interior environment of a simulated office.

Marcus Weldon, Bell Labs president and CTO of Alcatel-Lucent (NYSE: ALU), recently told FierceWirelessTech that millimeter wave technology is "better than you think it's going to be," but it's not easy. While it's relatively straightforward, what's still not easy is outdoor-to-outdoor settings and indoor-to-indoor. Trying to make it work with outdoor hotspots-to-outdoor-handsets is a little harder because there are buses, trees, buildings and other obstacles in the way.

The expectation is there will be low-band spectrum for going through buildings and tinted windows and high band spectrum that goes through windows and wood, and both will be used indoors and outdoors. "We think it will be a complementary approach," with low and high bands paired to provide the best connections for different environments, he said. Weldon will serve as CTO of the innovation and operations business unit after Nokia (NYSE:NOK) completes its acquisition of Alcatel-Lucent next year.

In a demonstration for industry analysts at its facilities in San Diego, Qualcomm Technologies (NASDAQ:QCOM) recently showcased its work in millimeter wave using a base station antenna design prototype with 128 antenna elements and 16 controllable RF channels. The 28 GHz system was designed to show how using intelligent, directional beam forming can be used to "mobilize" millmeter wave so that it can be used when people might want to move around in a non-line-of-sight, dense, urban environment.

For more:
- see this Rice University press release

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