MIT develops wireless technology for VR headsets

Cutting the thick cord that connects VR headsets to PCs requires ultra-fast 6Gbps wireless technology

Researchers at Massachusetts Institute of Technology (MIT) have showed off a prototype that, they claim, will enable users of virtual reality (VR) headsets to use their devices wirelessly.

The system, dubbed "MoVR" enables untethered communications at multiple gigabits-per-second (Gbps) using high-frequency radio signals.

The challenge of creating wireless VR headsets is two-fold: first, the battery power required, which adds both weight and heat, as well as requiring frequent recharging; and, the extremely high bandwidth required to convey the detailed images from the computer to the headset.

The system developed by the team at MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) uses special high-frequency radio signals called "millimeter waves" (mmWaves), technology that may be deployed in 5G smartphones.

"It's very exciting to get a step closer to being able to deliver a high-resolution, wireless-VR experience," said MIT professor Dina Katabi, whose research group has developed the technology. "The ability to use a cordless headset really deepens the immersive experience of virtual reality and opens up a range of other applications."

Researchers tested the system on an HTC Vive headset, one of the most popular on the market due to its use on PCs via the Steam gaming service, but say that it can work with any headset.

One issue with conventional wireless technologies, such as Wi-Fi, is that they can not support advanced data-processing.

"Replacing the HDMI cable with a wireless link is very challenging since we need to stream high-resolution multi-view video in real-time," said Haitham Hassanieh, an assistant professor of electrical and computer engineering at the University of Illinois at Urbana Champaigna, who was not involved in the research.

"This requires sustaining data rates of more than six Gbps while the user is moving and turning, which cannot be achieved by any of today's systems."

Because VR platforms have to work in real-time, systems also can't use compression to accommodate the inadequate bandwidth.

However, mmWaves also has a number of limitations, mostly notably the requirement for a constant line of site between transmitter and receiver. MoVR therefore uses what CSAIL calls "programmable mirrors" that can reconfigure automatically to ensure that there is always a line of site from the computing device to the VR headset.

"With a traditional mirror, light reflects off the mirror at the same angle as it arrives. But with MoVR, angles can be specifically programmed so that the mirror receives the signal from the mmWave transmitter and reflects it towards the headset, regardless of its actual direction," said Abari.

Each MoVR device consists of two directional antennas that are each less than half the size of a credit card. The antennas use what are called "phased arrays" in order to focus signals into narrow beams that can be electronically steered at a timescale of microseconds.

The next step, according to Abari, is to make the devices smaller and, therefore, more practical.