The sensors are intended to allow the control of devices through small hand gestures, such as squeezing the tips of a finger and thumb together or sliding the tip of a thumb along the ridge of the index finger. They operate in the 60GHz ISM band and work by emitting the waves in a tight beam. Some of the energy is reflected back towards the radar antenna and Properties of the reflected signal, such as energy, time delay, and frequency shift provide information about the object’s characteristics and dynamics, including size, shape, orientation, material, distance, and velocity.
Project Soli is part of Google’s Advanced Technology and Projects group (ATAP) and the project was first announced back in 2015.
The FCC found that the sensors when operating under the specified conditions “pose minimal potential of causing harmful interference to other spectrum users and uses of the 57-64 GHz frequency band”. It also stated that granting the waiver request “will serve the public interest by providing for innovative device control features using touchless hand gesture technology” as “The aability to recognise users’ touchless hand gestures to control a device, such as a smartphone, could help people with mobility, speech, or tactile impairments…”
Google originally sought a waiver of FCC rules to allow the Soli sensors to operate in the band at power levels that comply with ETSI standard EN 305 550 which are higher than currently permitted under the FCC’s rules, arguing that compliance with the latter would prevent the sensors from working as intended.
After discussion with other parties, Google said that it could operate the sensors under a waiver that had a lesser peak power limit than it had originally sought, while adhering to a maximum duty cycle requirement. The company asserted that acceptable performance is possible if the sensors operate at a peak transmitter conducted output power of +10 dBm (instead of -10 dBm as permitted in FCC rules), and at a peak equivalent isotropically radiated power (EIRP) level of +13 dBm (instead of +10 dBm as permitted in FCC); as well as a peak power spectral density (PSD) level of +13 dBm/MHz. Google will also limit the transmit duty cycle to 10 per cent in any 33 millisecond interval.
The FCC announcement can be found here.
