1. A radio frequency identification, RFID, tag, the RFID tag comprising: the device comprises a logic processing unit, a rectangular wave generator, a first load, a second load, a load switch and an antenna; the load switch comprises a control end and a connecting end;

the logic processing unit is connected with the rectangular wave generator and is used for transmitting an information bit stream to the rectangular wave generator and instructing the rectangular wave generator to convert the information bit stream into a square wave signal with a first frequency or a low level;

the rectangular wave generator is connected with the control end of the load switch; the rectangular wave generator is used for receiving the information bit stream, converting a first identifier in the information bit stream into a square wave signal with a first frequency, converting a second identifier in the information bit stream into a low level, and transmitting the converted signal to the control end of the load switch; wherein the converted signal is used for controlling the connection terminal of the load switch to connect the first load or the second load, so that the antenna is connected with the first load or the second load through the connection terminal of the load switch;

the load switch is used for switching on the first load or the second load through the connecting end according to the converted signal; the antenna is used for sending a modulation signal to a tag reader according to the condition that the first load and the second load are switched on by the load switch;

the difference value of the resistances of the first load and the antenna is smaller than a first preset threshold value, and the difference value of the resistances of the second load and the antenna is larger than a second preset threshold value.

2. The RFID tag of claim 1, wherein the rectangular wave generator comprises: a configuration port, an enable port and an output port; the rectangular wave generator is connected with the logic processing unit through the configuration port and the enabling port respectively; the rectangular wave generator is connected with the control end of the load switch through the output port;

the configuration port is used for receiving the first frequency configured by the logic processing unit; the enabling port is used for receiving the information bit stream output by the logic processing unit; and the output port is used for transmitting the converted signal to the control end of the load switch.

3. An RFID tag as claimed in claim 1 or 2, wherein the first identity is a binary number "1" and the second identity is a binary number "0"; alternatively, the first identifier is a binary number "0" and the second identifier is a binary number "1".

4. An RFID tag as claimed in any one of claims 1 to 3, wherein the load switch is particularly adapted to:

switching on the first load when the converted signal indicates a high level of a first frequency; turning on the second load when the square wave signal indicates a low level of a first frequency; keeping the second load switched on when the converted signal indicates a continuous low level; alternatively, the first and second electrodes may be,

switching on the first load when the converted signal indicates a low level of a first frequency; turning on the second load when the square wave signal indicates a high level of a first frequency; keeping the first load switched on when the converted signal indicates a continuous low level.

5. RFID tag according to any of claims 1 to 4, wherein the antenna is particularly adapted for:

receiving a radio frequency signal from the tag reader, wherein the frequency of the radio frequency signal is a second frequency; and the number of the first and second groups,

when the load switch is switched between a first load and a second load at the first frequency, transmitting a modulation signal of a third frequency to the tag reader; when the time length of the load switch for switching on the second load is longer than the preset time length, transmitting a modulation signal of a second frequency to the tag reader;

wherein the third frequency is the first frequency + the second frequency.

6. A tag reader, characterized in that the tag reader comprises: a logic processing unit, a receiver, a transmitter and at least one antenna; the logic processing unit is connected with the receiver and the transmitter; the receiver and the transmitter are connected with the at least one antenna;

the receiver includes: the device comprises a band-pass filter, an envelope detector and a comparator, wherein the band-pass filter is connected with the envelope detector, and the envelope detector is connected with the comparator; the band-pass filter is used for suppressing the radio-frequency signal from the transmitter and enabling the first signal to pass through; the first signal is one or more modulated signals from one or more RFID tags; the envelope detector is used for respectively converting one or more modulation signals in the first signals into envelope signals; the comparator is used for demodulating to obtain information bit streams from the one or more RFID tags according to the envelope signal and a preset reference voltage;

wherein the one or more modulation signals are all different in frequency.

7. The tag reader of claim 6, further comprising: a self-interference cancellation circuit; the self-interference cancellation circuit is disposed between the transmitter and the receiver; the self-interference cancellation circuit comprises an analog self-interference cancellation circuit; the analog self-interference cancellation circuit is arranged between the transmitter and the receiver; the analog self-interference cancellation circuit is used for canceling an analog radio frequency signal leaked by the transmitter to the receiver.

8. The tag reader of claim 7, wherein the tag reader comprises a receiving antenna and a transmitting antenna; the receiver is connected with the receiving antenna, and the transmitter is connected with the transmitting antenna.

9. The tag reader of claim 8, wherein the receive antenna and the transmit antenna are polarized differently.

10. The tag reader of claim 7, wherein said tag reader comprises an antenna, said receiver and said transmitter each being connected to said antenna.

11. The tag reader of claim 7 or 10, wherein the self-interference cancellation circuit further comprises: a transmit-receive port isolation circuit; the transceiver port isolation circuit is used for inhibiting the radio frequency signal coupled to the receiver by the transmitter.

12. The tag reader of claim 11, wherein said transmit-receive port isolation circuit comprises a circulator; the circulator comprises a first port, a second port and a third port, wherein the first port is connected with the transmitter, the second port is connected with the receiver, and the third port is connected with the antenna.

13. The tag reader of any of claims 6-12, wherein the one or more modulated signals comprises a modulated signal of a third frequency f 3;

the band-pass filter is specifically configured to: -suppressing radio frequency signals from said transmitter to pass a modulated signal of said third frequency f 3;

the envelope detector is specifically configured to: converting the modulation signal of the third frequency f3 into an envelope signal;

the comparator is specifically configured to: and demodulating the information bit stream from the RFID label which sends out the modulation signal of the third frequency f3 according to the envelope signal and a preset reference voltage.

14. A radio frequency identification, RFID, method, applied to an RFID tag, the RFID tag comprising: the device comprises a logic processing unit, a rectangular wave generator, a first load, a second load, a load switch and an antenna; the load switch comprises a control end and a connecting end, the logic processing unit is connected with the rectangular wave generator, and the rectangular wave generator is connected with the control end of the load switch; the resistance difference value between the first load and the load of the antenna is smaller than a first preset threshold value, and the resistance difference value between the second load and the load of the antenna is larger than a second preset threshold value; the method comprises the following steps:

the logic processing unit transmits an information bit stream to the rectangular wave generator and instructs the rectangular wave generator to convert the information bit stream into a square wave signal of a first frequency or a low level;

the rectangular wave generator receives the information bit stream, converts a first identifier in the information bit stream into a square wave signal with a first frequency, converts a second identifier in the information bit stream into a low level, and transmits the converted signal to the control end of the load switch; wherein the converted signal is used for controlling the connection terminal of the load switch to connect the first load or the second load, so that the antenna is connected with the first load or the second load through the connection terminal of the load switch;

the load switch is used for switching on the first load or the second load through the connecting end according to the converted signal;

and the antenna sends a modulation signal to a tag reader according to the condition that the first load and the second load are switched on by the load switch.

15. The method according to claim 14, wherein the load switch switches on the first load or the second load through the connection terminal according to the converted signal, specifically comprising:

when the converted signal indicates a high level of a first frequency, the load switch turns on the first load through the connection terminal; when the square wave signal indicates a low level of a first frequency, the load switch switches on the second load through the connection terminal; when the converted signal indicates a continuous low level, the load switch keeps the second load connected through the connecting end unchanged; alternatively, the first and second electrodes may be,

when the converted signal indicates a low level of a first frequency, the load switch turns on the first load through the connection terminal; when the square wave signal indicates a high level of a first frequency, the load switch switches on the second load through the connection terminal; when the converted signal indicates a continuous low level, the load switch keeps the first load connected through the connecting end unchanged.

16. The method of claim 15, wherein the first identifier is a binary number "1", and wherein the second identifier is a binary number "0"; alternatively, the first identifier is a binary number "0" and the second identifier is a binary number "1".

17. The method according to any one of claims 14 to 16, wherein the antenna transmits a modulated signal to a tag reader according to a condition that the load switch turns on the first load and the second load, specifically comprising:

the antenna receives a radio frequency signal from the tag reader, and the frequency of the radio frequency signal is a second frequency;

if the load switch is switched between a first load and a second load at the first frequency, the antenna sends a modulation signal of a third frequency to the tag reader; if the time length for switching on the first load by the load switch is longer than the preset time length, the antenna sends a modulation signal with a second frequency to the tag reader;

wherein the third frequency is the first frequency + the second frequency.

18. A radio frequency identification, RFID, method, for use with a tag reader, the tag reader comprising: a logic processing unit, a receiver, a transmitter and at least one antenna; the receiver includes: the device comprises a band-pass filter, an envelope detector and a comparator, wherein the band-pass filter is connected with the envelope detector, and the envelope detector is connected with the comparator; the method comprises the following steps:

the band-pass filter suppresses the radio-frequency signal from the transmitter and allows the first signal to pass; the first signal is one or more modulated signals from one or more RFID tags;

the envelope detector converts one or more modulation signals in the first signals into envelope signals respectively;

the comparator demodulates according to the envelope signal and a preset reference voltage to obtain an information bit stream from the one or more RFID tags;

wherein the one or more modulation signals are all different in frequency.

19. The method of claim 18, wherein the tag reader further comprises: a self-interference cancellation circuit; the self-interference cancellation circuit is disposed between the transmitter and the receiver; the self-interference cancellation circuit comprises an analog self-interference cancellation circuit; the analog self-interference cancellation circuit is arranged between the transmitter and the receiver; the method further comprises the following steps:

the analog self-interference cancellation circuit cancels analog radio frequency signals leaked by the transmitter to the receiver.

20. The method of claim 19, wherein the tag reader includes one antenna, the receiver and the transmitter each being coupled to the one antenna; the self-interference cancellation circuit further comprises: a transmit-receive port isolation circuit; the method further comprises the following steps:

the transmit-receive port isolation circuit suppresses radio frequency signals coupled from the transmitter to the receiver.

Background

The RFID technology is an automatic identification technology for performing non-contact two-way communication using induction, radio waves, or microwaves for the purpose of identification and data exchange. The target object can be tracked, managed and the like through the RFID system.

An RFID system may include a tag reader, an RFID tag, and a host. The basic principle of RFID is: the tag reader transmits a radio frequency signal (such as a carrier signal) with a specific frequency through a transmitting antenna; after receiving the electromagnetic wave, the RFID tag generates an induced current, thereby obtaining energy to modulate information stored in the chip, and then transmits the modulated information through the built-in antenna. After receiving the modulated signal, the receiving antenna of the tag reader transmits the modulated signal to a signal processing module of the tag reader, and the signal processing module demodulates and decodes the signal and transmits the signal to the host. Then, the host identifies the identity of the RFID tag according to the logical operation, performs corresponding processing and control aiming at different settings, and finally sends a signal to control the tag reader to complete different read-write operations.

However, the tag reader receives the radio frequency signal transmitted by the transmitting antenna when receiving the modulated signal transmitted by the RFID tag. Since the modulated signal and the rf signal are very close in frequency spectrum, for a tag reader in which the transmitting antenna and the receiving antenna are disposed at the same position, the rf signal may interfere with demodulation of the modulated signal by the tag reader.

Disclosure of Invention

The application provides an RFID tag, a tag reader, an RFID method and an RFID system, which can solve the problem that the tag reader interferes with demodulation modulation signals due to the self-interference problem.

In order to achieve the above purpose, the embodiment of the present application adopts the following technical solutions:

in a first aspect, there is provided an RFID tag comprising: the device comprises a logic processing unit, a rectangular wave generator, a first load, a second load, a load switch and an antenna, wherein the load switch comprises a control end and a connecting end; the logic processing unit is connected with the rectangular wave generator and is used for transmitting the information bit stream to the rectangular wave generator and instructing the rectangular wave generator to convert the information bit stream into a square wave signal with a first frequency or a low level; the rectangular wave generator is connected with the control end of the load switch; the rectangular wave generator is used for receiving the information bit stream, converting a first identifier in the information bit stream into a square wave signal with a first frequency, converting a second identifier in the information bit stream into a low level and transmitting the converted signal to the control end of the load switch; the converted signal is used for controlling the connecting end of the load switch to be connected with the first load or the second load, so that the antenna is connected with the first load or the second load through the connecting end of the load switch; the load switch is used for switching on the first load or the second load through the connecting end according to the converted signal; the antenna is used for sending a modulation signal to the tag reader according to the condition that the load switch is switched on the first load and the second load; the resistance difference value between the first load and the load of the antenna is smaller than a first preset threshold value, and the resistance difference value between the second load and the load of the antenna is larger than a second preset threshold value.

In the technical solution provided by the first aspect, the RFID tag manages the working average (e.g. the first frequency) of the rectangular wave generator through the logic processing unit, generates the information bit stream, and instructs the rectangular wave generator to output a square wave signal including the first frequency and/or a converted signal of a continuous low level according to the first frequency, so as to control the load switch to turn on the first load or the second load having a difference in impedance value, thereby controlling the frequency of the modulation signal transmitted to the tag reader. By the mode, the frequency difference between the modulation signal and the self-interference signal of the tag reader can be ensured, so that the tag reader can simply and quickly filter the self-interference signal.

In one possible implementation, the rectangular wave generator includes: a configuration port, an enable port and an output port; the rectangular wave generator is connected with the logic processing unit through a configuration port and an enabling port respectively; the rectangular wave generator is connected with the control end of the load switch through an output port; the configuration port is used for receiving a first frequency configured by the logic processing unit; the enabling port is used for receiving the information bit stream output by the logic processing unit; the output port is used for transmitting the converted signal to the control end of the load switch. The rectangular wave generator receives management (such as adjustment) of the working frequency of the logic processing unit through the configuration port arranged on the rectangular wave generator, acquires the information bit stream from the logic processing unit through the enabling port, and transmits a converted signal to the control end of the load switch through the output port, so that the rectangular wave generator can flexibly output a signal for controlling the load switch to be switched on or switched off.

In a possible implementation manner, the first identifier is a binary number "1", and the second identifier is a binary number "0"; alternatively, the first identification is a binary number "0" and the second identification is a binary number "1".

In a possible implementation manner, the load switch is specifically configured to: switching on the first load when the converted signal indicates a high level of the first frequency; turning on the second load when the square wave signal indicates a low level of the first frequency; keeping the second load switched on when the converted signal indicates a continuous low level; or, when the converted signal indicates a low level of the first frequency, turning on the first load; turning on the second load when the square wave signal indicates a high level of the first frequency; when the converted signal indicates a continuous low level, the first load is kept switched on. By the control mode, the RFID label can output a modulation signal with a frequency different from that of a radio frequency signal from the label reader when the information bit stream indicates binary number '1', so that the label reader can conveniently eliminate interference and demodulate the modulation signal.

In a possible implementation manner, the antenna is specifically configured to: receiving a radio frequency signal of a second frequency from a tag reader, and sending a modulation signal of a third frequency to the tag reader when a load switch switches connection between a first load and a second load at the first frequency; when the time length of the load switch for switching on the first load is longer than the preset time length, transmitting a modulation signal of a second frequency to the tag reader; wherein the third frequency is the first frequency + the second frequency. By the control mode, the RFID label can output a modulation signal with a frequency different from that of a radio frequency signal from the label reader when the information bit stream indicates binary number '1', so that the label reader can conveniently eliminate interference and demodulate the modulation signal.

In a second aspect, there is provided a tag reader comprising: a logic processing unit, a receiver, a transmitter and at least one antenna; the logic processing unit is connected with both the receiver and the transmitter; the receiver and the transmitter are connected with at least one antenna; the receiver includes: the device comprises a band-pass filter, an envelope detector and a comparator, wherein the band-pass filter is connected with the envelope detector which is connected with the comparator; the band-pass filter is used for suppressing the radio-frequency signal from the transmitter and enabling the first signal to pass through; the first signal is one or more modulated signals from one or more RFID tags; the envelope detector is used for converting one or more modulation signals in the first signal into envelope signals respectively; the comparator is used for demodulating to obtain information bit streams from one or more RFID tags according to the envelope signal and a preset reference voltage; wherein the frequencies of the one or more modulation signals are different.

According to the technical scheme provided by the second aspect, the tag reader filters the self-interference signal through the band-pass filter according to the difference between the self-interference signal and the frequency of the modulation signal from the RFID tag, and the modulation signal from the RFID tag is reserved, so that the self-interference signal is simply and quickly filtered, and the interference caused by the fact that the sub-interference signal demodulates the modulation signal from the RFID tag to the tag reader is avoided.

In a possible implementation manner, the tag reader further includes: a self-interference cancellation circuit; the self-interference cancellation circuit is arranged between the transmitter and the receiver; the self-interference elimination circuit comprises an analog self-interference elimination circuit; the analog self-interference elimination circuit is arranged between the transmitter and the receiver; the analog self-interference cancellation circuit is used for canceling an analog radio frequency signal leaked by a transmitter to the receiver. The analog self-interference elimination circuit is arranged between the transmitter and the receiver to calculate the analog radio frequency signal leaked to the receiver by the transmitter, so that the interference of the leaked analog radio frequency signal to the receiver can be eliminated.

In one possible implementation, the tag reader includes a receiving antenna and a transmitting antenna; the receiver is connected with the receiving antenna, and the transmitter is connected with the transmitting antenna. The application is equally applicable to tag readers that receive and transmit separately.

In one possible implementation, the polarization directions of the receive antenna and the transmit antenna are different. The receiving antenna and the transmitting antenna with different polarization directions are respectively responsible for receiving and transmitting signals, so that the isolation between the receiving antenna and the transmitting antenna can be ensured, and the mutual interference is reduced.

In one possible implementation, the tag reader includes an antenna, and the receiver and the transmitter are both connected to the antenna. The method is also applicable to the tag reader with the same antenna for receiving and transmitting.

In a possible implementation manner, the self-interference cancellation circuit further includes: a transmit-receive port isolation circuit; the receiving and transmitting port isolation circuit is used for inhibiting the radio frequency signal coupled to the receiver by the transmitter. For a tag reader that receives and transmits multiplexed with the same antenna, a transmit-receive port isolation circuit may be provided at the interface of the antenna, receiver, and transmitter to suppress the coupling of the transmitter to the radio frequency signal of the receiver.

In a possible implementation manner, the transceiver port isolation circuit includes a circulator; the circulator comprises a first port, a second port and a third port, wherein the first port is connected with the transmitter, the second port is connected with the receiver, and the third port is connected with the antenna. A receiving and sending port isolation circuit formed by a circulator is arranged at the interface of the antenna, the receiver and the transmitter so as to inhibit the radio frequency signal coupled to the receiver by the transmitter.

In a possible implementation manner, the one or more modulation signals include a modulation signal of a third frequency f 3; the band-pass filter is specifically used for: suppressing the radio frequency signal from the transmitter and passing the modulated signal of a third frequency f 3; the envelope detector is specifically configured to: converting the modulated signal of the third frequency f3 into an envelope signal; the comparator is specifically configured to: the RFID tag emitting the modulated signal of the third frequency f3 is determined from the envelope signal. The tag reader filters the self-interference signal through the band-pass filter according to the difference of the frequency of the self-interference signal and the frequency of the modulation signal from the RFID tag, and keeps the modulation signal from the RFID tag, so that the self-interference signal is simply and quickly filtered. The modulated signal at the third frequency f3 is then converted into an envelope signal by an envelope detector, and finally decoded by a comparator to obtain an information bit stream from the RFID tag emitting the modulated signal at the third frequency f 3.

In a third aspect, an RFID method is provided, which is applied to an RFID tag, the RFID tag comprising: the device comprises a logic processing unit, a rectangular wave generator, a first load, a second load, a load switch and an antenna; the load switch comprises a control end and a connecting end, the logic processing unit is connected with the rectangular wave generator, and the rectangular wave generator is connected with the control end of the load switch; the resistance difference value between the first load and the load of the antenna is smaller than a first preset threshold value, and the resistance difference value between the second load and the load of the antenna is larger than a second preset threshold value; the method comprises the following steps: the logic processing unit transmits the information bit stream to the rectangular wave generator and instructs the rectangular wave generator to convert the information bit stream into a square wave signal of a first frequency or a low level; the method comprises the steps that a rectangular wave generator receives an information bit stream, converts a first identifier in the information bit stream into a square wave signal with a first frequency, converts a second identifier in the information bit stream into a low level, and transmits the converted signal to a control end of a load switch; the converted signal is used for controlling the connecting end of the load switch to be connected with the first load or the second load, so that the antenna is connected with the first load or the second load through the connecting end of the load switch; the load switch is connected with the first load or the second load through the connecting end according to the converted signal; the antenna transmits a modulation signal to the tag reader according to the condition that the load switch switches on the first load and the second load.

In the technical solution provided by the third aspect, the RFID tag manages the working average (e.g. the first frequency) of the rectangular wave generator through the logic processing unit, generates the information bit stream, and instructs the rectangular wave generator to output a square wave signal including the first frequency and/or a converted signal of a continuous low level according to the first frequency, so as to control the load switch to turn on the first load or the second load having a difference in impedance value, thereby controlling the frequency of the modulation signal transmitted to the tag reader. By the mode, the frequency difference between the modulation signal and the self-interference signal of the tag reader can be ensured, so that the tag reader can simply and quickly filter the self-interference signal.

In a possible implementation manner, the switching of the load switch through the connection terminal to the first load or the second load according to the converted signal specifically includes: when the converted signal indicates a high level of the first frequency, the load switch turns on the first load through the connection terminal; when the square wave signal indicates the low level of the first frequency, the load switch is connected with the second load through the connecting end; when the converted signal indicates a continuous low level, the load switch keeps the second load connected through the connecting end unchanged; or, when the converted signal indicates a low level of the first frequency, the load switch turns on the first load through the connection terminal; when the square wave signal indicates the high level of the first frequency, the load switch is connected with the second load through the connecting end; when the converted signal indicates a continuous low level, the load switch keeps the first load connected through the connection terminal. By the control mode, the RFID label can output a modulation signal with a frequency different from that of a radio frequency signal from the label reader when the information bit stream indicates binary number '1', so that the label reader can conveniently eliminate interference and demodulate the modulation signal.

In a possible implementation manner, the first identifier is a binary number "1", and the second identifier is a binary number "0"; alternatively, the first identification is a binary number "0" and the second identification is a binary number "1".

In a possible implementation manner, the transmitting, by the antenna, the modulation signal to the tag reader according to a condition that the load switch is turned on with the first load and the second load includes: the antenna receives a radio frequency signal of a second frequency from the tag reader; if the load switch is switched and connected between the first load and the second load at the first frequency, the antenna sends a modulation signal of a third frequency to the tag reader; if the time length for switching on the first load by the load switch is longer than the preset time length, the antenna sends a modulation signal of a second frequency to the tag reader; wherein the third frequency is the first frequency + the second frequency. By the control mode, the RFID label can output a modulation signal with a frequency different from that of a radio frequency signal from the label reader when the information bit stream indicates binary number '1', so that the label reader can conveniently eliminate interference and demodulate the modulation signal.

In a fourth aspect, there is provided an RFID method, which is applied to a tag reader, the tag reader comprising: a logic processing unit, a receiver, a transmitter and at least one antenna; the receiver includes: the device comprises a band-pass filter, an envelope detector and a comparator, wherein the band-pass filter is connected with the envelope detector which is connected with the comparator; the method comprises the following steps: the band-pass filter suppresses the radio-frequency signal from the transmitter and allows the first signal to pass; the first signal is one or more modulated signals from one or more RFID tags; the envelope detector converts one or more modulation signals in the first signal into envelope signals respectively; the comparator demodulates according to the envelope signal and a preset reference voltage to obtain an information bit stream from one or more RFID tags; wherein the frequencies of the one or more modulation signals are different.

According to the technical scheme provided by the fourth aspect, the tag reader filters the self-interference signal through the band-pass filter according to the difference between the self-interference signal and the frequency of the modulation signal from the RFID tag, and the modulation signal from the RFID tag is reserved, so that the self-interference signal is simply and quickly filtered, and the interference caused by the fact that the sub-interference signal demodulates the modulation signal from the RFID tag to the tag reader is avoided.

In a possible implementation manner, the tag reader further includes: a self-interference cancellation circuit; the self-interference elimination circuit is arranged between the transmitter and the receiver; the self-interference elimination circuit comprises an analog self-interference elimination circuit; the analog self-interference elimination circuit is arranged between the transmitter and the receiver; the method further comprises the following steps: the analog self-interference cancellation circuit cancels analog radio frequency signals leaked by the transmitter to the receiver. The analog self-interference elimination circuit is arranged between the transmitter and the receiver to calculate the analog radio frequency signal leaked to the receiver by the transmitter, so that the interference of the leaked analog radio frequency signal to the receiver can be eliminated.

In a possible implementation manner, the tag reader includes an antenna, and the receiver and the transmitter are both connected to the antenna; the self-interference cancellation circuit further comprises: a transmit-receive port isolation circuit; the method further comprises the following steps: for a tag reader which receives and transmits a multiplexed antenna, a receiving and transmitting port isolation circuit may be arranged at an interface of the antenna, the receiver and the transmitter to inhibit a radio frequency signal which is coupled to the receiver by the transmitter.

In a fifth aspect, there is provided an RFID tag comprising a memory for storing computer program code, the computer program code comprising instructions; the radio frequency circuit is used for transmitting and receiving wireless signals; a processor configured to execute the above instructions to enable the RFID tag to implement the RFID method as described in any one of the possible implementation manners of the third aspect.

In a sixth aspect, a tag reader is provided, the tag reader comprising a memory for storing computer program code, the computer program code comprising instructions; the radio frequency circuit is used for transmitting and receiving wireless signals; a processor configured to execute the above instructions to enable the tag reader to implement the RFID method as described in any one of the possible implementation manners of the fourth aspect.

In a seventh aspect, an RFID system is provided, which includes the RFID tag described in any one of the possible implementation manners of the first aspect or the fifth aspect and the tag reader described in any one of the possible implementation manners of the second aspect or the sixth aspect.

In an eighth aspect, a computer-readable storage medium is provided, which has stored thereon computer-executable instructions, which when executed by a processor, implement the RFID method as described in any one of the possible implementations of the third aspect or the fourth aspect.

In a ninth aspect, a chip system is provided, where the chip system includes a processor and a memory, and the memory stores instructions; the instructions, when executed by the processor, implement the RFID method as described in any one of the possible implementations of the third aspect or the fourth aspect. The chip system may be formed by a chip, and may also include a chip and other discrete devices.

A tenth aspect provides a computer program product enabling, when running on a computer, an RFID method as described in any one of the possible implementations of the third or fourth aspect.

Drawings

FIG. 1 is a diagram of three network architectures provided by embodiments of the present application;

fig. 2 is a diagram of an RFID tag structure provided in an embodiment of the present application;

FIG. 3 is a schematic diagram of a process for determining a modulated signal waveform by an RFID tag according to an embodiment of the present application;

FIG. 4 is a schematic diagram of several modulation methods provided in the embodiments of the present application;

fig. 5A is a structural diagram of a first tag reader according to an embodiment of the present application;

fig. 5B is a schematic filtering diagram of a band-pass filter according to an embodiment of the present disclosure;

fig. 6 is a structural diagram of a second tag reader according to an embodiment of the present application;

fig. 7 is a diagram illustrating a structure of an analog self-interference cancellation circuit according to an embodiment of the present disclosure;

fig. 8 is a diagram illustrating an effect of self-interference cancellation of a tag reader according to an embodiment of the present application;

FIG. 9 is a block diagram of a third tag reader according to an embodiment of the present application;

FIG. 10 is a block diagram of a fourth tag reader provided in an embodiment of the present application;

FIG. 11 is a diagram of a tag reader and an RFID tag according to an embodiment of the present disclosure;

FIG. 12 is a flow chart of an RFID method provided by an embodiment of the present application;

fig. 13 is a flowchart of a receiver of a tag reader processing a signal according to an embodiment of the present disclosure;

fig. 14 is a schematic structural diagram of an RFID tag provided in an embodiment of the present application;

fig. 15 is a schematic structural diagram of a tag reader according to an embodiment of the present application.

Detailed Description

For ease of understanding, concepts and terms that may appear in the present application are explained below.

RFID label: also known as electronic tags, smart labels, RFID transponders or RFID data carriers, etc. Typically consisting of a coupling element and a chip, each RFID tag has a unique electronic code. In some scenarios, an RFID tag may be attached to an object for identifying the object.

A tag reader: also known as a reader, a scanner, a reader, a communicator or a reader/writer (depending on whether the RFID tag can wirelessly rewrite data), etc. Typically for reading (and sometimes also writing) RFID tag information. For example, the tag reader may be a handheld or stationary device.

Carrier wave signal: the carrier signal is a radio frequency signal obtained by applying a signal such as sound or image to a high frequency signal having a predetermined frequency. When no sound, image, or other signal is applied, the amplitude, phase, or the like of the high-frequency signal is usually fixed. The amplitude or phase of the high frequency signal loaded with the sound, image, etc. signal will change with the change of the amplitude of the sound, image, etc. signal.

Square wave signal: the quality of a signal in a circuit system, which can be transmitted from a source end to a receiving end without distortion within a required time, is called a square wave signal. An ideal square wave signal has only two values, high and low.

The technical solution in the present application is described below with reference to the accompanying drawings.

It can be understood that tag readers (readers) can be classified into the following three categories according to antenna structures: 1) the tag reader comprises an antenna for receiving and transmitting; 2) the tag reader comprises a receiving antenna and a transmitting antenna, and the receiving antenna and the transmitting antenna are arranged at the same place; 3) the tag reader comprises a receiving antenna and a transmitting antenna, wherein the receiving antenna and the transmitting antenna are respectively arranged at different places.

Referring to fig. 1, fig. 1 shows a network architecture to which the above three structures are applied. Among them, the tag reader 110 shown in fig. 1 (a) includes an antenna 101 for both receiving and transmitting a signal. The radio frequency signal transmitted by the antenna 101 is also received by the antenna 101 and interferes with the tag reader 110 demodulating the signal from the RFID tag 120 (i.e., self-interference). The tag reader 110 shown in (b) of fig. 1 includes a receiving antenna 103 and a transmitting antenna 104. The receive antenna 103 is used for receiving signals and the transmit antenna 104 is used for transmitting signals. The radio frequency signal transmitted by the transmitting antenna 104 will also be received by the receiving antenna 103, and therefore, the above-mentioned self-interference problem will also exist. The tag reader 110 shown in (c) of fig. 1 includes a receiving antenna 105 and a transmitting antenna 106. Wherein the receiving antenna 105 and the transmitting antenna 106 are respectively disposed at different positions. Since the radio frequency signal transmitted by the transmitting antenna 106 needs to propagate in space to reach the receiving antenna 105, the tag reader self-interference is small compared to the structures described in 1) and 2) above. However, the above self-interference problem still exists if the receiving antenna 105 and the transmitting antenna 106 are located closer together. Therefore, the scheme provided by the embodiment of the application is applicable to the tag readers with the three structures. And, the scheme provided by the embodiment of the present application is applicable to all three network structures shown in fig. 1.

The embodiment of the application provides an RFID label, a label reader and an RFID system consisting of the RFID label and the label reader. Through the RFID system, the influence on the identification of the RFID tag, the information acquisition and the like caused by the self-interference problem of the tag reader can be reduced. The scheme provided by the embodiment of the application can be applied to the fields of logistics, transportation, identity recognition, anti-counterfeiting, asset management, food, information statistics, transaction, reference application, safety control and the like. For example, the system is applied to book management, logistics management, water, electricity, gas charging, access control management, shelf management, industrial production line management and the like. The scheme provided by the application is not limited to specific application scenarios.

The RFID technology can be classified into active RFID (also called active RFID), passive RFID and semi-active RFID according to the power supply method of the RFID tag. Correspondingly, RFID tags can be classified into active RFID tags, passive RFID tags, and semi-active RFID tags. The power for the active RFID tag operation is provided by a power source, such as a battery. The passive RFID tag obtains energy to supply power to the passive RFID tag for a short time by receiving a radio frequency signal transmitted by a tag reader and generating induction current through an electromagnetic induction coil so as to complete information exchange with the tag reader. A power source (e.g., a battery) is provided in the semi-active RFID tag, but the power source only powers the internal circuitry of the RFID tag when the RFID tag is in a sleep state and activates the RFID tag when the RFID tag is within the magnetic field range of the tag reader. The energy source of the subsequent treatment process after the RFID tag enters the working state is similar to that of a passive RFID tag. The present application does not limit the power supply method of the RFID tag.

As shown in fig. 2, fig. 2 shows a structure diagram of an RFID tag provided in an embodiment of the present application. As shown in fig. 2, the RFID tag 120 may include a logic processing unit 201, a rectangular wave generator 202, a first load Z0203, a second load Z1204, a load switch 205, and an antenna 206. The load switch includes a control terminal 2051 and a connection terminal 2052. The logic processing unit 201 is connected with a rectangular wave generator 202. The load switch 205 is used to turn on the first load 203 or the second load 204. The rectangular wave generator 202 is connected to the load switch 205 via a control terminal 2051.

In the embodiment of the present application, the logic processing unit 201 is configured to configure an operating frequency (e.g., a first frequency) for the rectangular wave generator 202. And, for inputting the information bit stream to the rectangular wave generator 202, enabling the rectangular wave generator 202, so that the rectangular wave generator 202 converts the information bit stream acquired from the logic processing unit 201 into a square wave signal of the first frequency or into a low level. Wherein, the information bit stream input by the logic processing unit 201 to the rectangular wave generator 202 is the information bit stream after being encoded and modulated by the logic processing unit 201. The information bit stream may be used to represent at least identification information of the RFID tag and/or information stored in the RFID tag.

In some possible configurations, as shown in fig. 2, the rectangular wave generator 202 may include three ports: configuration port a, enable port b, and output port c. Wherein, the rectangular wave generator 202 is connected with the logic processing unit 201 through a configuration port a and an enable port b respectively. The rectangular wave generator 202 is connected to the control terminal 2051 of the load switch 205 through the output port c. The port a is configured to receive an operating frequency configured by the logic processing unit 201 for the rectangular wave generator 202, i.e., the first frequency f 1. The enable port b is used for receiving the information bit stream output by the logic processing unit 201. The output port c is used for outputting the converted signal (including the square wave signal of the first frequency and/or the continuous low level), and more specifically, the output port c is used for transmitting the converted signal to the control terminal 2051 of the load switch 205.

The converting of the information bit stream into the square wave signal/low level by the rectangular wave generator 202 (for example, an Oscillator (OSC) may specifically include: if the information bit stream input from the enable port b indicates a first flag (e.g., binary number "1"), the output port c outputs a square wave signal of a first frequency f1 (e.g., 15MHz), wherein the square wave signal includes a High level (High, H) and a Low level (Low, L) alternating according to the first frequency; if the information bit stream inputted from the enable port b indicates a second flag (e.g., binary "0"), the output port c outputs a low level. Alternatively, if the information bit stream input from the enable port b indicates a binary number "0", the output port c outputs a square wave signal of a first frequency f1 (e.g., 15 MHz); if the information bit stream input from the enable port b indicates a binary number "1", the output port c outputs a low level. For example, signal 1 in fig. 3 shows an information bit stream "… … 1101 … …" input from the enable port b to the rectangular wave generator 202 by the logic processing unit 201. Signal 2 shows the converted signal output from output port c after signal 1 has been processed by the square wave generator 202.

In the present application, the converted signal output from the output port c of the rectangular wave generator 202 is used to control the load switch 205 to turn on the first load 203 or the second load 204. So that the antenna 206 is connected to the first load 203 or the second load 204 through the connection terminal 2052 of the load switch 205. Specifically, when the converted signal obtained at the control terminal 2051 of the load switch 205 indicates a high level of the first frequency, the connection terminal 2052 of the load switch 205 turns on the first load Z0203; when the converted signal indicates a low level of the first frequency, the connection terminal 2052 of the load switch 205 turns on the second load Z1204. When the converted signal indicates a continuous low level, the connection 2052 of the load switch 205 remains connected to the second load Z1204. Or, when the converted signal obtained by the control terminal 2051 of the load switch 205 indicates a low level of the first frequency, the connection terminal 2052 of the load switch 205 turns on the first load Z0203; when the converted signal indicates a high level of the first frequency, the connection 2052 of the load switch 205 turns on the second load Z1204. When the converted signal indicates a continuous low level, the connection 2052 of the load switch 205 remains connected to the first load Z0203.

The resistance difference value between the Z0 and the load of the antenna is smaller than a first preset threshold value, and the resistance difference value between the Z1 and the load of the antenna is larger than a second preset threshold value. For example, the first preset threshold is 0.1, and the second preset threshold is 10.

It will be appreciated that when the external load is equal to or close to the load of the antenna (i.e., the external load is impedance matched to the load of the antenna), the antenna 206 is in a fully reflective state, in which case the antenna 206 may reflect the rf signal from the tag reader 110 to a greater extent. When the external load is far from the antenna load (i.e., the external load and the antenna load are not matched in impedance), the antenna 206 will reflect the rf signal from the tag reader 110 less. Regarding the working principle of the antenna, reference may be made to the description in the conventional technology, and details are not described here.

Taking the frequency of the radio frequency signal from the tag reader 110 as the second frequency f2, and the output port c of the rectangular wave generator 202 outputs the square wave signal including the first frequency f1 and the converted signal of the continuously low level, which is shown as the signal 2 in fig. 3, to the control terminal 2051 of the load switch 205, the load switch 205 controls the connection terminal 2052 to turn on Z0 → Z1 → Z0 → Z1 → Z0 → Z1 → Z0 → Z1 → Z1 → Z1 → Z1 → Z1 → Z0 → Z1 → Z0 → Z1, respectively, through the control terminal 2051 according to the signal 2. The antenna 206 transmits a modulated signal of a third frequency f3 to the tag reader 110 when the connection terminal 2052 of the load switch 205 is switched between Z0 and Z1 at the first frequency f1, wherein f3 is f1+ f 2; the duration of time that Z1 is turned on at connection 2052 of load switch 205 is greater than a preset duration (as shown in fig. 2)) The modulated signal of the second frequency f2 is transmitted to the tag reader 110. As shown in fig. 3, signal 3 in fig. 3 shows a radio frequency signal from the tag reader 110. The radio frequency signal is a carrier signal having a frequency of 890MHz, i.e. the second frequency f 2. Assuming the operating frequency of the rectangular wave generator 202 (i.e., the first frequency f1 is 15MHz), signal 4 in fig. 3 shows the modulated signal emitted by the antenna 206. Wherein the modulation signal has a frequency of 905MHz (i.e., f3) when the information bit stream indicates a binary number "1", and a frequency of 890MHz (i.e., f2) when the information bit stream indicates a binary number "0".

It should be noted that fig. 2 is only an example of a structure of an RFID tag, although not shown in fig. 2, the RFID tag may further include other modules such as a power supply, and details are not described here.

It should be understood that the above-mentioned hardware modules included in the RFID tag shown in fig. 2 are only exemplary and are not limiting to the present application, and in fact, other hardware modules having an interactive relationship with the hardware modules shown in the figure may also be included in the RFID tag shown in fig. 2, and are not limited specifically here.

It should be noted that the signal 4 in fig. 3 is only an example of On-Off Keying (OOK), and is also called as ASK. The modulation method of the RFID tag provided in the embodiment of the present application may also be Phase Shift Keying (PSK) or Frequency Shift Keying (FSK). Referring to fig. 4, fig. 4 illustrates several binary modulation waveform examples. Binary OOK controls the on and off of the sine carrier by a binary symbol sequence (e.g. signal 2 in fig. 3). PSK is a modulation technique that uses the phase of a carrier to represent the information in an input signal. PSK may include both absolute and relative phase shifts. Phase modulation with reference to the phase of the unmodulated carrier is called absolute phase shifting. Taking binary PSK as an example, when a code element is taken as '1', the modulated carrier wave is in phase with the unmodulated carrier wave; when the code element is taken as '0', the modulated carrier wave and the unmodulated carrier wave are reversed; the "1" and "0" time are 180 ° out of phase with the modulated carrier. FSK uses the frequency of a carrier to transmit digital information. Taking binary FSK as an example, when the symbol is "1", the frequency of the modulated carrier is frequency 1; when the symbol is "0", the frequency of the modulated carrier is frequency 2 (different from frequency 1). For the detailed description of OOK, PSK, and FSK, reference may be made to the explanation and description in the conventional art, which are not repeated herein.

Referring to fig. 5A, fig. 5A is a block diagram illustrating a tag reader according to an embodiment of the present disclosure. As shown in fig. 5A, the tag reader 110 may include a logic processing unit 501, a receiver 502, a transmitter 503, and an antenna 504. The logic processing unit 501 is connected to both the receiver 502 and the transmitter 503. Both the receiver 502 and the transmitter 503 are connected to an antenna 504.

In the present embodiment, the antenna 504 is used for both transmitting and receiving signals. The logic processing unit 501 is configured to control the transmitter 503 to transmit the radio frequency signal through the antenna 504. For example, the rf signal is a carrier signal with a frequency f2 as shown in signal 3 in fig. 3. Receiver 502 is used to receive modulated signals from one or more RFID tags via antenna 504.

For example, signal 4 shown in FIG. 3 at frequency f3 from RFID tag 120 may be received by receiver 502 via antenna 504. As described above, since the receiver 502 and the transmitter 503 share one antenna, the rf signal transmitted by the antenna 504 is also received by the antenna 504. In addition, the antenna 504 will also receive the radio frequency signal reflected by the RFID tag 120. That is, the signal received by antenna 504 and transmitted to receiver 502 includes two parts, one part is the signal with frequency f2 (including a part of the radio frequency signal transmitted by antenna 504 and received by antenna 504 and reflected by RFID tag 120), and the other part is the signal with frequency f 3. For the receiver 502, the signal with frequency f2 is an interference signal (hereinafter referred to as "self-interference signal"). Therefore, the receiver 502 needs to filter out the signal with frequency f2 from the signal received by the antenna 504.

As shown in fig. 5A, the receiver 502 may include a band pass filter 5021, an envelope detector 5022, and a comparator 5023. The band-pass filter 5021 is connected to an envelope detector 5022, and the envelope detector 5022 is connected to a comparator 5023. A signal received from the antenna 504 passes through a band pass filter 5021, an envelope detector 5022 and a comparator 5023 in this order. Since the radio frequency signal with frequency f2 transmitted by the transmitter 503 through the antenna 504 is different in frequency from the modulated signal with frequency f3 from the RFID tag, the band pass filter 5021 is specifically used to suppress the self-interference signal (signal 3 with frequency f2 shown in fig. 3) but allow the modulated signal after frequency conversion (i.e., the first signal) from the RFID tag to pass through. For example, the first signal may be signal 4 shown in fig. 3 at frequency f 3. The envelope detector 5022 is used for converting the frequency-converted modulation signal from the RFID tag in the first signal into an envelope signal. The comparator 5023 is used for comparing the envelope signal converted by the envelope detector 5022 with a reference voltage and then outputting the comparison result. For example, if the voltage of the envelope signal is higher than the reference signal, a first flag (e.g., "binary 1") is output; if the voltage of the envelope signal is lower than the reference signal, a second flag (e.g., binary "0") is output. Or, if the voltage of the envelope signal is higher than the reference signal, outputting a binary number "0"; if the voltage of the envelope signal is lower than the reference signal, a binary number "1" is output.

Referring to fig. 5B, fig. 5B shows a filtering diagram of a band-pass filter. Fig. 5B illustrates an example of f1 being 15MHz, f2 being 890MHz, and band pass filter 5021 being a 902MHz-928MHz filter, and introduces a filtering process of the band pass filter, where as shown in fig. 5B, the band pass filter 5021 allows a signal with a frequency of f3 (i.e., a modulation signal with a frequency of 905MHz from the RFID tag) to pass through, but filters out a signal with a frequency of f2 (i.e., a self-interference signal of the RFID tag).

It should be noted that fig. 5B is an example in which a band-pass filter directly filters out a self-interference signal of an RFID tag. The embodiment of the application does not limit whether the band-pass filter directly filters the self-interference signal or suppresses the self-interference signal. The band-pass filter may suppress the self-interference signal to obtain an effect of a large attenuation of the self-interference signal, for example, an attenuation of 35 dB.

In some embodiments, the tag reader 110 may also include a self-interference cancellation circuit. For canceling signals leaked by the transmitter 503 to the receiver 502. Where the self-interference cancellation circuit is disposed between the receiver 502 and the transmitter 503.

The self-interference elimination circuit comprises a receiving and transmitting port isolation circuit. Illustratively, as shown in fig. 6, the transmit/receive port isolation circuit 505 may be formed by the circulator 505 shown in fig. 6. Circulator 505 includes three ports: port 1 (i.e., the first port), port 2 (i.e., the second port), and port 3 (i.e., the third port). Port 1 is connected to transmitter 503, port 2 is connected to receiver 502, and port 3 is connected to antenna 504. Port 1 and port 2 of circulator 5051 provide a degree of isolation to reduce the coupling of transmitter 503 to receiver 502.

In some embodiments, as shown in fig. 6, the self-interference cancellation circuitry may also include analog self-interference cancellation circuitry 506. The basic operation of the analog self-interference cancellation circuit 506 includes: the analog self-interference cancellation circuit 506 samples the radio frequency signal leaked from the transmitter 503 in analog form and then simulates the radio frequency signal leaked from the transmitter 503. The rf signal, modeled, is finally subtracted from receiver 502 to reduce the purpose of the signal coupled from transmitter 503 to receiver 502. Referring to fig. 7 as an example, fig. 7 shows a structural example of an analog self-interference cancellation circuit according to an embodiment of the present application.

In some embodiments, the self-interference cancellation circuit may employ a single tapped delay line to provide isolation between the transmitter 503 and the receiver 502, such as 35dB of isolation. For specific principles of the single-tap delay line, reference may be made to explanations and illustrations in the conventional art, which are not described herein in detail.

The self-interference problem of the tag reader 110 can be greatly reduced by the transmit-receive port isolation implemented by the transmit-receive port isolation circuit (i.e., circulator 505) shown in fig. 6, the analog self-interference cancellation implemented by the analog self-interference cancellation circuit 506 shown in fig. 7, and the self-interference cancellation implemented by the receiver 502 having the structure shown in fig. 5A. Referring to fig. 8, fig. 8 shows an exemplary effect of self-interference cancellation of a tag reader. As shown in fig. 8, assuming that the transmission power of the radio frequency signal transmitted by the transmitter 503 through the antenna is 33dBm, the radio frequency signal reaches the RFID tag 120 after being attenuated by a part of the spatial loss. The RFID tag 120 reflects the rf signal away, causing a partial loss. The rf signal reflected by the RFID tag 120 is then attenuated by the spatial loss to reach the tag reader 110. In order to better avoid the interference caused by the signal of the second frequency to the demodulated signal of the tag reader 110, the interference signal can be filtered by the joint action of the transceiver port isolation (such as a circulator), the analog self-interference cancellation and the band-pass filter self-interference cancellation.

It should be noted that the transmit-receive port isolation circuit (i.e., circulator 505) shown in fig. 6 and the analog self-interference cancellation circuit 506 shown in fig. 7 are only examples. The embodiment of the application does not limit the specific working principle and structure of the transmitting-receiving port isolation circuit and the analog self-interference elimination circuit. For the isolation of the transceiving ports and the analog self-interference cancellation, reference may be made to descriptions and illustrations in the conventional technology, which are not described herein again.

As mentioned above, the tag reader 110 may also include two antennas: a receive antenna and a transmit antenna. Referring to fig. 9, fig. 9 is a block diagram of another tag reader according to an embodiment of the present disclosure.

As shown in fig. 9, the tag reader 110 may include a logic processing unit 501, a receiver 502, a transmitter 503, a transmitting antenna 901, and a receiving antenna 902. The logic processing unit 501 is connected to both the receiver 502 and the transmitter 503. The transmitting antenna 501 is connected to the transmitter 503, and the receiving antenna 902 is connected to the receiver 502.

In the present embodiment, the transmitting antenna 901 is used for transmitting signals from the transmitter 503. Receive antenna 902 is configured to receive signals and transmit the received signals to receiver 502 for further processing. In some embodiments, the polarization directions of the transmitting antenna 901 and the receiving antenna 902 are different, so as to ensure sufficient isolation between the transmitting antenna 901 and the receiving antenna 902 and reduce mutual interference.

The logic processing unit 501 is configured to control the transmitter 503 to transmit a radio frequency signal through the transmitting antenna 901. For example, the rf signal is a carrier signal with a frequency f2 as shown in signal 3 in fig. 3. Receiver 502 is used to receive modulated signals from one or more RFID tags via receive antenna 902.

For example, the receiver 502 may receive the signal 4 shown in fig. 3 from the RFID tag 120 with frequency f3 through the receiving antenna 902. As described above, for the case where the transmitting antenna 901 and the receiving antenna 902 are disposed at the same location, or the transmitting antenna 901 and the receiving antenna 902 are disposed at different locations but at a short distance, the radio frequency signal transmitted by the transmitting antenna 901 will also be received by the receiving antenna 902. That is, the signal transmitted by the receiving antenna 902 to the receiver 502 also includes two parts, one part is the signal with the frequency f2, and the other part is the signal with the frequency f 3. For the receiver 502, the signal with frequency f2 is an interference signal (more specifically, a self-interference signal). Therefore, the receiver 502 needs to filter out the signal with frequency f2 from the signal received by the antenna 504.

For the tag reader 110 of the structure shown in fig. 9, the receiver 502 may also have the structure shown in fig. 5A, as shown in fig. 9. For the structural description of the receiver 502, reference may be made to the description and illustration of fig. 5A, which is not repeated here.

In some embodiments, the tag reader 110 shown in FIG. 9 may also include self-interference cancellation circuitry. For canceling signals leaked by the transmitter 503 to the receiver 502. Where the self-interference cancellation circuit is disposed between the receiver 502 and the transmitter 503. More specifically, as shown in fig. 10, the self-interference cancellation circuit may be an analog self-interference cancellation circuit 1001. The structure and the operation principle of the analog self-interference cancellation circuit 1001 may refer to fig. 7 and the explanation and the description of fig. 7 in the foregoing, or refer to the explanation and the description in the conventional technology, which are not described herein again.

It should be noted that the tag reader 110 in the embodiment of the present application may provide services to a plurality of RFID tags at the same time. As shown in fig. 11, it is assumed that the tag reader 110 simultaneously provides services to the first RFID tag and the second RFID tag service. Wherein the first RFID tag and the second RFID tag can only be connectedHaving the structure shown in fig. 2. The first RFID tag and the second RFID tag differ in that: the operating frequency (i.e., the first frequency) of the rectangular wave generator in the first RFID tag and the second RFID tag is different. For example, the operating frequency f1 of the first RFID tag₁15MHz, operating frequency f1 of the second RFID tag₂Is 16 MHz. In this case, the signal received by the receiver 502 of the tag reader 110 includes: operating frequency f1 from the first RFID tag₁From the operating frequency f1 of the second RFID tag₂And a self-interference signal of frequency f 2.

For the scenario shown in fig. 11, the band-pass filter 5021 will first suppress (e.g., filter) the self-interference signal with frequency f2, such that the operating frequency f1₁Modulated signal and operating frequency f1₂The modulated signal of (a) passes through, and then enters the envelope detector 5022 and the comparator 5023 in sequence for post-processing.

It can be understood that since the operating frequency (i.e., the first frequency) of the rectangular wave generator is different in the first RFID tag and the second RFID tag, the signals from the different RFID tags can be distinguished from the mixed signal at the baseband by means of digital filtering.

It should be noted that fig. 11 is a process of the tag reader in the structure shown in fig. 5A for simultaneously processing signals from two RFID tags, and the structure of the tag reader is not limited. The same approach can be used to distinguish between multiple RFID tags for a tag reader having the configuration shown in fig. 6, 9, or 10, or other similar configurations. In addition, the number of RFID tags communicating with the tag reader is not limited in the embodiments of the present application, and may be, for example, 3, 4, … ….

Embodiments of the present application also provide an RFID method, which may be applied to a tag reader having the structure shown in fig. 5A, 6, 9, or 10, or other tag readers having similar structures, and an RFID tag having the structure shown in fig. 2 or having similar structures. Specifically, the RFID tag 120 includes a logic processing unit 201, a rectangular wave generator 202, a first load 203, a second load 204, a load switch 205, a transmitting antenna 901, and a receiving antenna 902. The load switch 205 includes a control terminal 2051 and a connection terminal 2052. The logic processing unit 201 is connected with the rectangular wave generator 202 through a configuration terminal a and an enabling terminal b. The output c of the rectangular wave generator 202 is connected to the control terminal 2051 of the load switch 205. The difference between the resistances of the first load 203 and the antenna load is smaller than a first preset threshold (e.g., 0.1), and the difference between the resistances of the second load 204 and the antenna load is larger than a second preset threshold (e.g., 10).

The following takes the tag reader 110 with the structure shown in fig. 9 and the RFID tag 120 with the structure shown in fig. 2 as an example, and specifically describes the RFID method provided by the embodiment of the present application.

As shown in fig. 12, the RFID method provided in the embodiment of the present application may include steps S1201-S1207:

s1201, the logic processing unit 201 of the RFID tag 120 transmits the information bit stream to the rectangular wave generator 202.

The information bit stream may be, for example, the information bit stream shown as signal 1 in fig. 3.

S1202, the logic processing unit 201 of the RFID tag 120 instructs the rectangular wave generator 202 to convert the information bit stream into a square wave signal of the first frequency or low level.

For example, the first frequency may be f1 shown in fig. 3.

S1203, the rectangular wave generator 202 of the RFID tag 120 converts the first identifier in the received information bit stream into a square wave signal with a first frequency, converts the second identifier in the information bit stream into a low level, and transmits the converted signal to the load switch 205.

Specifically, the rectangular wave generator 202 may transmit the converted signal to the control terminal 2051 of the load switch 205.

Wherein, if the information bit stream indicates a first flag (e.g. binary number "1"), the rectangular wave generator 202 outputs a square wave signal of a first frequency; if the information bit stream indicates a second flag (e.g., binary "0"), the rectangular wave generator 202 outputs a low level. Specifically, the outputting of the square wave signal of the first frequency by the square wave generator 202 includes: the rectangular wave generator 202 alternately outputs a high level and a low level at a first frequency. For example, the converted signal output by the square wave generator 202 may be the signal shown as signal 2 in fig. 3. Alternatively, if the information bit stream indicates a binary number "0", the rectangular wave generator 202 outputs a square wave signal of a first frequency; if the information bit stream indicates a binary "0", the rectangular wave generator 202 outputs a low level.

S1204, the load switch 205 of the RFID tag 120 turns on the first load 203 or the second load 204 according to the converted signal received from the rectangular wave generator 202.

Specifically, the load switch 205 switches on the first load 203 or the second load 204 through the connection terminal 2052 according to the converted signal received from the rectangular wave generator 202.

Wherein, if the converted signal indicates a high level of the first frequency, the connection terminal 2052 of the load switch 205 turns on the first load 203. If the converted signal indicates a low level of the first frequency, the connection 2052 of the load switch 205 turns on the second load 204. If the converted signal indicates a continuous low level, the second load 204 remains on.

S1205, the antenna 206 of the RFID tag 120 sends a modulation signal to the tag reader 110 according to the condition that the load switch 205 turns on the first load 203 and the second load 204.

Specifically, assuming that the frequency of the rf signal received by the antenna 206 from the tag reader 110 is the second frequency f2, and the operation average rate of the rectangular wave generator 202 is the first frequency f1, if the load switch 205 is switched between the first load 203 and the second load 204 at the first frequency f1, the antenna 206 sends a modulation signal of the third frequency f3 to the tag reader 110. If the load switch 205 continues to turn on the second load 204 for more than the predetermined time period, the antenna 206 transmits a modulated signal at the second frequency f2 to the tag reader 110. Wherein, f3 is f1+ f 2.

S1206, the receiving antenna 902 of the tag reader 110 receives the signal.

The signal received by the receiving antenna 902 may include at least: a radio frequency signal at a second frequency f2 from the transmitting antenna 901, and a first signal. The first signal is one or more modulated signals from one or more RFID tags 120. Wherein the frequencies of the one or more modulation signals are different. For example, the frequency of the modulated signal from the first RFID tag is 905MHz and the frequency of the modulated signal from the second RFID tag is 906 MHz.

S1207, the receiver 502 of the tag reader 110 processes the signal received by the antenna 902.

In the embodiment of the present application, as shown in fig. 13, the step S1207 may include the following steps S1301-S1303:

s1301, the band-pass filter 501 of the receiver 502 suppresses the radio frequency signal of the second frequency, and passes the first signal of the third frequency.

Specifically, the band-pass filter 501 may have a hardware configuration shown in fig. 5A. The bandwidth of the band-pass filter 501 may be set to allow the first signal (i.e., the modulated signal of the third frequency f3) to pass through, but to reject the radio frequency signal of the second frequency f 2. For example, the band-pass filter 501 may perform filtering using the filtering method shown in fig. 5B.

S1302, the envelope detector 502 of the receiver 502 converts one or more modulated signals of the first signal transmitted from the band pass filter 501 into envelope signals, respectively.

S1303, the comparator 503 of the receiver 502 distinguishes one or more RFID tags emitting modulated signals according to the envelope signal.

For the working principle and the specific working process of the above steps S1201-S1207 and the execution main bodies (such as the logic processing unit 201, the rectangular wave generator 202, the load switch 205, the antenna 206, the receiving antenna 902, the band-pass filter 501 in the receiver 502, the envelope detector 502, or the comparator 503) in the above steps S1301-S1303, reference may be made to the description and the explanation above, which are not repeated herein.

It is understood that the RFID tag 120 or the tag reader 110 includes corresponding hardware structures and/or software modules for performing the respective functions in order to realize the functions of any one of the above-described embodiments. Those of skill in the art would readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiment of the present application, functional modules may be divided for the RFID tag 120 or the tag reader 110, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, in the embodiment of the present application, the division of the module is schematic, and is only one logic function division, and there may be another division manner in actual implementation.

For example, in a case where each functional module is divided in an integrated manner, as shown in fig. 14, a structural block diagram of an RFID tag 120 provided in the embodiment of the present application is shown. RFID tag 120 may include memory 1410, radio frequency circuitry 1420, and processor 1430.

The memory 1410 may store therein a computer program code, which includes instructions for implementing the RFID method provided by the embodiments of the present application. And/or store other relevant information in the techniques described herein. The radio frequency circuit 1420 is used to enable the RFID tag 120 to perform step S1205 above, and/or other processes of the techniques described herein. Processor 1430 is configured to enable RFID tag 120 to perform steps S1201, S1202, S1203, or S1204, as described above, and/or other processes for the techniques described herein.

Fig. 15 is a block diagram of a tag reader 110 according to an embodiment of the present disclosure. The tag reader 110 may include a memory 1510, radio frequency circuitry 1520, and a processor 1530.

Among other things, the memory 1510 may store therein a computer program code, which includes instructions for implementing the RFID method provided by the embodiments of the present application. And/or store other relevant information in the techniques described herein. The radio frequency circuitry 1520 may be used to enable the tag reader 110 to perform step S1206, described above, and/or other processes for the techniques described herein. Processor 1530 is configured to enable tag reader 110 to perform steps S1207, S1301, SS1302, or S1303 described above, and/or other processes for the techniques described herein.

Generally, the radio frequency circuitry 1420 and/or 1520 include, but are not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, and the like. In addition, the radio frequency circuitry may also communicate with other devices via wireless communication. The wireless communication may use any communication standard or protocol including, but not limited to, global system for mobile communications, general packet radio service, code division multiple access, wideband code division multiple access, long term evolution, email, short message service, and the like.

In an alternative, when the data transfer is implemented using software, it may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are implemented in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied in hardware or may be embodied in software instructions executed by a processor. The software instructions may consist of corresponding software modules that may be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an ASIC. In addition, the ASIC may reside in a probing apparatus. Of course, the processor and the storage medium may reside as discrete components in the probe device.

Through the above description of the embodiments, it is clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device may be divided into different functional modules to complete all or part of the above described functions.

In an alternative aspect, the present application provides a chip system, where the chip system includes a processor and a memory, where the memory stores instructions; when executed by a processor, the instructions implement the RFID method of any one of the possible implementations provided herein. The chip system may be formed by a chip, and may also include a chip and other discrete devices.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the modules or units is only one logical functional division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another device, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may be one physical unit or a plurality of physical units, that is, may be located in one place, or may be distributed in a plurality of different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or partially contributed to by the prior art, or all or part of the technical solutions may be embodied in the form of a software product, where the software product is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, or the like) or a processor (processor) to execute all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.