Real-time wireless power transfer control for passive backscattering devices

A method for delivering power to an RF-energy harvesting backscatter sensor tag, the method comprising:

• transmitting, using a transmitter of a base station, a first waveform in an RF channel;
• measuring, using a receiver of the base station, a backscattered signal from the sensor tag, the backscattered signal resulting from the sensor tag performing modulated scattering of the first waveform as incident upon the sensor tag;
• computing adjustments to the first waveform based on measurements of the backscattered signal to compensate for impairments in the RF channel and applying the adjustments to create a second waveform;
• and
• transmitting the second waveform to the sensor tag so that the sensor tag receives an incident waveform as a result of the transmitted second waveform, the incident waveform substantially resembling the first waveform as transmitted by the base station prior to creating the second waveform.

An article of manufacture having one or more recordable media storing instructions thereon which when executed by a system cause the system to perform a method for delivering power to an RF-energy harvesting backscatter sensor tag, the method comprising:

• transmitting, using a transmitter of a base station, a first waveform in an RF channel;
• measuring, using a receiver of the base station, a backscattered signal from the sensor tag, the backscattered signal resulting from the sensor tag performing modulated scattering of the first waveform as incident upon the sensor tag;
• computing adjustments to the first waveform based on measurements of the backscattered signal to compensate for impairments in the RF channel and applying the adjustments to create a second waveform;
• and
• transmitting the second waveform to the sensor tag so that the sensor tag receives an incident waveform as result of the transmitted second waveform, the incident waveform substantially resembling the first waveform as transmitted by the base station prior to creating the second waveform.

A base station for use in a communication system having at least one RF harvesting backscatter sensor tag, the base station comprising:

• a transmitter to transmit a first waveform and a second waveform;
• a receiver to receive a backscattered signal from the sensor tag, the backscattered signal resulting from the sensor tag performing modulated scattering of the first waveform;
• a measurement unit coupled to the receiver to obtain measurements of the backscattered signal;
• a memory coupled to the measurement unit to store the measurements;
• and
• a controller, coupled to the memory, the transmitter, the receiver and the measurement unit, to compute adjustments to the first waveform based on the measurements of the backscattered signal and to cause the transmitter to transmit the second waveform to the sensor tag, the second waveform representing the first waveform with the adjustments applied thereto, so that the sensor tag receives an incident waveform as a result of the transmitted second waveform, the incident waveform substantially resembling the first waveform as transmitted by the base station prior to computing adjustments to the first waveform.