PASSIVELY POWERED IOT DEVICES
Technologies are generally described for passively powering wireless IoT devices. An actively powered transmitter may transmit a radio frequency (RF) signal over a common channel and information associated with parameters of a reply signal to various passively powered wireless devices. The wireless devices may extract power from the RF signal or other signals in the ambient environment, use the extracted power to perform operations, and backscatter a reply signal over a different channel defined by the RF signal. The reply signal from the passively powered wireless devices may be received by a base station or an actively powered device in the vicinity and forwarded to the base station. Various multiplexing schemes may be employed to prevent collision of reply signals from the passively powered wireless devices.
1 - 22 . (canceled)
23 . A system to passively power wireless devices, the system comprising:
a plurality of wireless devices, each wireless device comprising electronic circuitry, a modulator, and an antenna, wherein each wireless device is configured to:
extract operating power from a received radio frequency (RF) signal;
perform an operation using the extracted operating power; and
transmit a backscatter signal associated with the performed operation through the antenna;
a transmitter configured to transmit a common synchronization signal at a first frequency and a communication signal at a second frequency, wherein
the first and second frequencies are distinct,
the first frequency is common for all of the plurality of wireless devices, and
the common synchronization signal identifies one or more backscatter parameters; and
one or more receivers to receive the backscatter signal at the second frequency.
24 . The system of claim 23 , wherein the plurality of wireless devices are Internet of Things (IOT) devices.
25 . The system of claim 24 , wherein the one or more receivers include an at-location hub device, an actively powered IoT device, or a base station.
26 . The system of claim 25 , wherein the at-location hub device and the actively powered IoT device are configured to forward the received backscatter signal to the base station.
27 . The system of claim 23 , wherein the plurality of wireless devices are configured to transmit the backscatter signal in one of a wireless local area network (WLAN) frequency band or a cellular frequency band.
28 . The system of claim 23 , wherein the plurality of wireless devices are configured to transmit the backscatter signal in a cellular frequency band according to a 5G-compliant protocol.
29 . The system of claim 23 , wherein the one or more backscatter parameters define the second frequency, a modulation format, or a modulation code and wherein the modulation code includes a frequency in a frequency diversity scheme, a code in a Code Division Multiple Access (CDMA) modulation scheme, or a code in an Orthogonal Frequency-Division Multiplexing (OFDM) modulation scheme.
30 . The system of claim 23 , wherein the transmitter is configured to assign one or more different values for the second frequency when two or more wireless devices backscatter to the one or more receivers in a temporally overlapping manner.
31 . The system of claim 23 , wherein the transmitter and at least one of the one or more receivers are part of a single device.
32 . An Internet of Things (IOT) device comprising:
a power extraction circuit configured to extract operating power from a received radio frequency (RF) signal;
electronic circuitry configured to perform operations using the extracted operating power;
a modulator configured to modulate a backscatter signal associated with the performed operation; and
an antenna configured to transmit the backscatter signal, wherein
one or more backscatter parameters for the backscatter signal are received through a common synchronization signal at a first frequency from an actively powered transmitter,
the backscatter signal is transmitted at a second frequency defined by the one or more backscatter parameters, and
the first and second frequencies are distinct.
33 . The IoT device of claim 32 , wherein one or both of the first frequency and the second frequency are in a wireless local area network (WLAN) frequency band or a cellular frequency band.
34 . The IoT device of claim 32 , wherein the second frequency is in a cellular frequency band according to 5G protocol.
35 . The IoT device of claim 32 , wherein the one or more backscatter parameters define the second frequency, a modulation format, or a modulation code and wherein the modulation code includes a frequency in a frequency diversity scheme, a code in a Code Division Multiple Access (CDMA) modulation scheme, or a code in an Orthogonal Frequency-Division Multiplexing (OFDM) modulation scheme.
36 . A method to passively power wireless devices, the method comprising:
receiving, at a passively powered wireless device, a radio frequency (RF) common synchronization signal at a first frequency from an actively powered transmitter;
extracting power from the received RF common synchronization signal;
performing an operation using the extracted power; and
transmitting a backscatter signal associated with the performed operation at a second frequency to be received by one or more actively powered receivers, wherein
the first and second frequencies are distinct, and
the RF common synchronization signal identifies one or more backscatter parameters.
37 . The method of claim 36 , wherein the wireless device is an Internet of Things (IOT) device and the one or more receivers include an at-location hub device, an actively powered IoT device, or a base station.
38 . The method of claim 36 , wherein transmitting the backscatter signal associated with the performed operation comprises transmitting the backscatter signal in one of a wireless local area network (WLAN) frequency band or a cellular frequency band.
39 . The method of claim 36 , wherein transmitting the backscatter signal associated with the performed operation comprises transmitting the backscatter signal in a cellular frequency band according to a 5G-compliant protocol.
40 . The method of claim 36 , wherein transmitting the backscatter signal associated with the performed operation comprises transmitting the backscatter signal according to the one or more backscatter parameters that define the second frequency, a modulation format, or a modulation code.
41 . The method of claim 40 , wherein the modulation code includes a frequency in a frequency diversity scheme, a code in a Code Division Multiple Access (CDMA) modulation scheme, or a code in an Orthogonal Frequency-Division Multiplexing (OFDM) modulation scheme.
42 . The method of claim 36 , further comprising:
determining or predicting backscatter signal strengths at one or more locations; and
selecting one or more receivers to be used for receiving backscatter signal from particular IoT devices based on the determination or prediction.