MIT CSAIL's prototype system, known as MoVR, uses millimeter waves to send data from a transmitter that's hooked up to a computer to the headset's receiver. These high-frequency radio waves are capable of maintaining wireless connections at speeds over 6 Gbps -- enough bandwidth to stream the two, high-definition feeds required for VR -- but the signal doesn't penetrate objects well. As VR games and experiences typically require you move around in physical space, there is a high chance of your floor-standing lamp or flailing arms blocking the signal and impacting performance, in turn breaking the immersion.
To solve this problem, CSAIL's system includes a millimeter wave "mirror" -- an intermediate device that receives the original broadcast and tracks the position and orientation of the wearer in real-time, always aiming the signal directly at the headset receiver. In this way, the millimeter waves can avoid furniture, limbs and anything else that could interfere and impact performance.
As the image of the signal bouncer above shows, the system is still very much a prototype, though researchers hope to create neater, smartphone-sized hardware in the future that could be used with any VR headset. Subsequent work will also entail measuring and potentially improving the latency of the system -- on paper, this shouldn't be too much of an issue, but the team has primarily focused on developing the mirror thus far.
With various companies, including headset manufacturers themselves, and researchers working on solving the finer problems of wireless VR, hopefully it won't be too long before we can forget that inelegant, stop-gap solutions like backpack PCs were ever a thing.