While computers and smartphones often connect to Wi-Fi indoors to get the best data speeds, outdoor 5G base stations could someday replace Wi-Fi systems and provide high-speed connectivity both indoors and outdoors, preventing glitches when devices switch between networks, said Kun Woo Cho, a Ph.D. student in Princeton’s Department of Computer Science and the lead author of the research. Boosting 5G signals with technology like mmWall will be crucial to this broader adoption, she said.

Now, a team led by Princeton researchers has developed a new device to help higher-frequency 5G signals, known as millimeter-wave or mmWave, overcome this obstacle. The device, called mmWall, is about the size of a small tablet. It can steer mmWave signals to reach all corners of a large room, and, when installed in a window, can bring signals from an outdoor transmitter indoors. The researchers presented their work on mmWall at the USENIX Symposium on Networked Systems Design and Implementation in Boston on April 19.