Range extension and dynamic power control for localization on commercial UHF RFID reader
The present disclosure relates to a mobile agent in an RFID system with reduced power consumption and increased localization capabilities. In one aspect, a relay circuit attached to a mobility mechanism such as a drone or robot is in communication with an RFID reader and a backend host computer. The mobile agent moves around a warehouse, for instance, in which landmark RFID tags are arranged. The mobile agent can transmit with an adjustable power to identify a single landmark tag and associate it with object tags of one or more objects within the range of the mobile agent. The host computer can communicate with the mobile agent to instruct it to adjust its power when multiple landmark tags are detected.
1 . A relay circuit comprising:
radio frequency (RF) circuitry to:
receive an instruction signal from an RF identification (RFID) reader to cause the relay circuit to (i) enter a sleep mode for a time period based on a determination that a relay range of the relay circuit overlaps with multiple RFID readers, and (ii) power back on after expiration of the time period; and
receive signals from one or more RFID tags within the relay range of the relay circuit;
instructions; and
at least one processor circuit to be programmed based on the instructions to configure the RF circuitry to:
relay signals received from the RFID reader to the one or more RFID tags, the relayed signals having a power level that is adjustable based on commands from the RFID reader; and
relay the signals from the one or more RFID tags to the RFID reader, the signals from the one or more RFID tags including responses to the signals from the RFID reader.
2 . The relay circuit of claim 1 , wherein the signals from the RFID reader and the signals from the one or more RFID tags are to identify one or more landmark RFID tags and one or more object RFID tags.
3 . The relay circuit of claim 2 , including one or more on-board RFID tags, wherein:
at least one of the on-board RFID tags includes an interface to one or more of the at least one processor circuit; and
based on multiple ones of the landmark RFID tags and the one or more object RFID tags being within the relay range of the relay circuit, one or more of the at least one processor circuit is to reduce the power level until a single landmark RFID tag of the one or more landmark RFID tags is within the relay range of the relay circuit.
4 . The relay circuit of claim 2 , including one or more on-board RFID tags, wherein:
at least one of the on-board RFID tags includes an interface to one or more of the at least one processor circuit; and
based on multiple landmark RFID tags and the one or more object RFID tags being within the relay range of the relay circuit, one or more of the at least one processor circuit is to reduce the power level to reduce a number of landmark RFID tags within the relay range of the relay circuit.
5 . The relay circuit of claim 1 , including one or more on-board RFID tags, wherein:
at least one of the on-board RFID tags includes an interface to one or more of the at least one processor circuit;
the RF circuitry is to receive select and query signals for the one or more on-board RFID tags from the RFID reader; and
one or more of the at least one processor circuit is to:
associate respective bit values with ones of the on-board RFID tags based on whether the ones of the on-board RFID tags have been selected and queried by the RFID reader; and
adjust the power level based on the bit values.
6 . The relay circuit of claim 5 , wherein an individual one of the one or more on-board RFID tags is to trigger an interrupt of one or more of the at least one processor circuit based on the individual one of the one or more on-board RFID tags being selected and queried.
7 . The relay circuit of claim 1 , including an on-board RFID tag, wherein:
the RF circuitry is to receive select and write signals from the RFID reader to cause the on-board RFID tag to write data to a user memory of the on-board RFID tag; and
one or more of the at least one processor circuit is to adjust the power level based on the data in the user memory.
8 . The relay circuit of claim 1 , wherein one or more of the at least one processor circuit is to adjust the power level based on a density of RFID tags within the relay range of the relay circuit.
9 . The relay circuit of claim 1 , including:
a printed circuit board to be carried by a mobility mechanism, wherein the RF circuitry, and one or more of the at least one processor circuit are disposed on the printed circuit board.
10 . The relay circuit of claim 1 , wherein one or more of the at least one processor circuit is to:
track a signal strength of an active RFID tag; and
navigate toward the active RFID tag based on the tracked signal strength.
11 . The relay circuit of claim 1 , wherein the RF circuitry includes:
a downlink path to relay the signals from the RFID reader at the power level to the one or more RFID tags; and
the downlink path includes a digital attenuator to set the power level.
12 . The relay circuit of claim 1 , wherein the RF circuitry includes:
a first antenna to receive the signals from the RFID reader;
a second antenna to receive the signals from the one or more RFID tags; and
a set of hardware (HW) elements to relay the signals from the RFID reader and the signals from the one or more RFID tags, the set of HW elements configurable by one or more of the at least one processor circuit.
13 . The relay circuit of claim 12 , wherein the first antenna is different than the second antenna, or the first and second antennas are a same antenna.
14 . The relay circuit of claim 12 , wherein the RF circuitry is to:
relay the signals from the RFID reader or the signals from the one or more RFID tags from at least one HW element of the set of HW elements to at least one other HW element of the set of HW elements.
15 . The relay circuit of claim 12 , wherein the RF circuitry is to:
receive the signals from the RFID reader through the first antenna;
relay the received signals from the RFID reader at the power level through a first subset of the set of HW elements to the second antenna for transmission to the one or more RFID tags;
receive the signals from the one or more RFID tags through the second antenna; and
relay the received signals from the one or more RFID tags through a second subset of the set of HW elements to the first antenna for transmission to the RFID reader.
16 . At least one non-transitory computer readable medium comprising instructions to cause a compute node to:
communicate with a mobile agent to identify one or more landmark radio frequency identification (RFID) tags and one or more object RFID tags within a relay range of the mobile agent;
send a first command to the mobile agent to reduce the relay range of the mobile agent when based on a determination that multiple landmark RFID tags are within the relay range of the mobile agent; and
send a second command to the mobile agent to set a sleep mode for a time period and power back on after expiration of the time period based on a determination that the relay range of the mobile agent overlaps with multiple RFID readers.
17 . The at least one non-transitory computer readable medium of claim 16 , wherein the instructions are to cause the compute node to:
based on the determination that multiple landmark RFID tags are within the relay range of the mobile agent, send additional commands to the mobile agent to repeatedly reduce the relay range of the mobile agent until a single landmark RFID tag of the multiple landmark RFID tags is within the relay range of the mobile agent.
18 . The at least one non-transitory computer readable medium of claim 17 , wherein the instructions are to cause the compute node to:
store data associating an identifier of the single landmark RFID tag with identifiers of the one or more object RFID tags.
19 . The at least one non-transitory computer readable medium of claim 17 , wherein the first command includes a command to select and query one or more RFID tags carried by the mobile agent.
20 . The at least one non-transitory computer readable medium of claim 16 , wherein the first command includes a command to write data to a user memory of one or more RFID tags carried by the mobile agent.
21 . A mobile agent comprising:
a plurality of radio frequency identification (RFID) chips;
instructions; and
processor circuitry coupled to the plurality of RFID chips, the processor circuitry to be programmed based on the instructions to:
associate respective bit values with ones of the RFID chips based on whether the ones of the RFID have been selected and queried by an RFID reader remote from the mobile agent;
perform a function based on the bit values; and
obtain an instruction from the RFID reader to (i) enter a sleep mode for a time period based on a landmark tag being within a relay range of the mobile agent, and (ii) power back on after expiration of the time period.
22 . The mobile agent of claim 21 , wherein:
a number of bits per command from the RFID reader is increased when a number of the RFID chips is increased.
23 . The mobile agent of claim 21 , wherein at least one of the RFID chips includes an inter-integrated circuit (I2C) interface to:
connect the at least one of the RFID chips to the processor circuitry, and
carry an interrupt signal to the processor circuitry based on the at least one of the RFID chips being selected and queried by the RFID reader.
24 . The mobile agent of claim 21 , including:
relay circuitry to relay signals from the RFID reader to a set of RFID tags within a relay range of the relay circuitry, wherein the function is to adjust a power level with which the relay circuitry is to relay the signals from the RFID reader.
25 . The mobile agent of claim 21 , including:
relay circuitry to relay signals from the RFID reader to a set of RFID tags within a relay range of the relay circuitry, wherein the function is to cause the relay circuitry to enter a sleep mode to prevent the relay circuitry from relaying signals from the RFID reader to the set of RFID tags for a time period.