Visible-frequency wireless works by flickering all the lights in a room ever so slightly -- so slightly, in fact, that the human eye could never detect it. Incandescent and fluorescent bulbs can't flicker fast enough, so the scheme does require LED lighting, but the connection doesn't require any kind of specialized fixture, just commercial LEDs. And, though standard LEDs also have a limited bandwidth, the researchers were able to expand that bandwidth drastically by filtering out all but the blue light.