A research team as Stanford University led by Sachin Katti, an associate professor of electrical engineering and of computer science, is developing a tiny, ultra-low-energy wireless radio.
The HitchHike radio promises to be able to transmit at 300kbps at a range of 50m. The innovation is that it is able to transmit using just micro-watts of energy by hitch hiking on radio signals, including existing WiFi. The low-power could enable the devices to operate or a decade or longer using existing batteries, or devices might harvest power from existing wireless waves.
http://news.stanford.edu/2016/11/16/miniature-wifi-device-developed-supplies-missing-link-internet-things
