In July 2016, the U.S. Federal antennas that use multiple beams for at UW-Madison is turning the Communications Commission made communications. This testbed is based Badger State into something of a waves in the wireless community by on a patented wireless technology wireless research hotspot. freeing up a whopping 11 gigahertz called CAP-MIMO, pioneered (one gigahertz is 1,000 megahertz) by Sayeed’s group, that is also “There’s a critical mass coming together worth of spectrum specifically for being developed for potential in Wisconsin, even though we’re 5G and mobile broadband. Two days commercialization in emerging millifar away from Silicon Valley later, the National Science Foundation meter-wave 5G applications. or Telecom Valley,” announced a seven-year, $400 million And newly renovated lab spaces initiative to make 5G a reality. on the third floor of Engineering Hall, —Akbar Sayeed— But taking advantage of those newly updated thanks to a generous gift from ECE available regions of spectrum won’t be as easy alumnus Peter Schneider (BSEE ’61, MSEE ’63 as switching stations on a car radio. The majority PhDEE ’66), are already starting to buzz with activity. fall in very high frequency ranges—above 24 GHz—which is “These new labs (in combination with the remodeling of the in the millimeter wave range of the spectrum. Unlike the longer, Plexus Collaboratory and the Qualcomm design labs) are a lower frequency waves used now, millimeter waves can’t pass fantastic asset for the department’s research in mobile systems,” through many obstacles such as walls or human bodies. says Electrical and Computer Engineering Professor Parmesh That requirement for an unobstructed path is among Ramanathan, who researches advanced computational myriad challenges for 5G wireless. But ongoing research at algorithms capable of processing millimeter wave signals into UW-Madison is turning the Badger State into something of a useful information. wireless research hotspot. “There’s a critical mass coming togethThe research isn’t only confined to labs on campus; citizens er in Wisconsin, even though we’re far away from in Madison have been field-testing advanced wireless systems Silicon Valley or Telecom Valley,” says Sayeed. ever since 2010, when two Madison Metro buses began Wisconsin engineers are not only developing new hardware connecting passengers to high-speed internet, thanks to a and software, but also setting up testbeds to help bridge the gap project called WiRover, led by Banerjee. Now Banerjee is between laboratory prototypes and market-ready products. setting the wheels in motion on a new initiative, named WiNest, In fact, Zhang’s laboratory was one of the first places to that promises to turn the entire city of Madison into a testbed ever send streaming video over 60 GHz millimeter waves on a for advanced wireless and mobile systems. platform called WiMi. Using that testbed, Zhang’s group figured Sayeed and Zhang also are heading a research coordination out a potential solution to obstructions in millimeter wave travel: network in the area of millimeter-wave wireless to foster Reflect the signal beam off a solid nearby object and steer collaboration among industry developers, academic scientists, around the obstacle. policymakers, and federal stakeholders as these normally WiMi is but one of many tools on campus through which disparate groups all start exploring the bold new frontiers of 5G researchers can tinker with new hardware and software schemes wireless. “This is a really exciting time,” says Sayeed. “5G will be for 5G wireless. Another testbed led by Sayeed is designed a clean slate because it is so different. The basic science and the to devise strategies for maintaining connections with multiple engineering are not well understood, and neither is the technology. moving users using state-of-the-art multi-input/multi-output Here at UW-Madison we’re pushing forward on all fronts.”
Waves on the electromagnetic spectrum can be described by the distances between their crests. These wavelengths can range from smaller than atoms, like gamma rays, or miles long, like time signals that set radio clocks. Currently, mobile wireless receives a few frequency bands in the neighborhood of 1.7 and 1.9 gigahertz, which means those waves range from about 2.5 to 6 inches—about the length and width of a dollar bill. 19
The University of Wisconsin-Madison College of Engineering magazine for alumni and friends.