University of Washington researchers reveal a means to reduce the power consumption involved with wifi networks-- "Passive Wifi" using virtually no energy even when providing data transfer speeds of up to 11Mbps.
For the curious Passive Wifi energy consumption reaches up to 49.28 µW when pushing 11Mbps transmissions. Energy use is even lower during 1Mbps transmissions, being around 14.48µW. According to the researchers such a rate is 1000x lower than Bluetooth LE and ZigBee, or 10000x lower than existing wifi chipsets.
To achieve such power reductions Passive Wifi involves a redesign of the power-hungry radios making a router, creating a single device users plug into walls. The plug-in device generates a continuous wifi signal which in turn is reflected by passive devices, creating a chain of low-power transmitters.