CN111327349B - Vehicle identification method and RFID reader-writer - Google Patents
Vehicle identification method and RFID reader-writer Download PDFInfo
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- CN111327349B CN111327349B CN201811519482.6A CN201811519482A CN111327349B CN 111327349 B CN111327349 B CN 111327349B CN 201811519482 A CN201811519482 A CN 201811519482A CN 111327349 B CN111327349 B CN 111327349B
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- 238000004590 computer program Methods 0.000 claims description 19
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- H04B5/77—
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10118—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the sensing being preceded by at least one preliminary step
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
Abstract
The invention discloses a vehicle identification method and an RFID reader-writer, wherein the method comprises the following steps: the RFID reader-writer comprises a radio frequency front-end circuit and a processing module; the radio frequency front-end circuit converts a first baseband signal generated by the processing module into a first radio frequency signal and transmits the first radio frequency signal to the antenna; the antenna transmits the first radio frequency signal to an electronic tag on the vehicle; the antenna receives a second radio frequency signal (carrying identification information of the vehicle) fed back by the electronic tag; the radio frequency front-end circuit couples the second radio frequency signal into a part of signals, converts the second radio frequency signal obtained after coupling out the part of signals into a second baseband signal (carrying first clutter and identification information), and cancels the first clutter by adopting the part of signals; the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is offset to the processing module, so that the processing module can identify the vehicle according to the identification information. In this way, the accuracy of the RFID reader-writer for identifying the vehicle can be improved.
Description
Technical Field
The invention relates to the technical field of communication, in particular to a vehicle identification method and an RFID reader-writer.
Background
An Electronic Identification (ERI) Of an automobile is also called an Electronic Identification card Of The automobile and is commonly called an Electronic license plate, namely, information such as a license plate number is stored in a Radio Frequency Identification (RFID) tag. In order to conveniently monitor and identify the vehicle, the RFID reader-writer is arranged on the road, and the RFID reader-writer can automatically and contactlessly identify and monitor the vehicle in the driving process of the vehicle. Specifically, when a vehicle passes through the RFID reader, the RFID reader sends a radio frequency signal to an electronic tag (RFID tag) of the vehicle, the electronic tag feeds back a response signal after receiving the radio frequency signal, and the RFID reader identifies the vehicle according to identification information of the vehicle carried in the response signal.
In the prior art, the identification process of the RFID reader to the vehicle is as follows: the RFID reader converts a baseband signal of the RFID reader into a radio frequency signal, transmits the radio frequency signal to the electronic tag through the antenna, converts the radio frequency signal returned by the electronic tag into a baseband signal, and processes the baseband signal (for example, identifies identification information of a vehicle carried in the baseband signal). Therefore, the RFID reader-writer passes through the conversion process of the radio frequency signal and the baseband signal in the process of identifying the vehicle. However, generally, the signal carries noise in the transmission process, and in the prior art, the RFID reader only eliminates the noise in the radio frequency signal, and cannot eliminate the noise in the baseband signal. Therefore, the accuracy of the RFID reader-writer in reading and writing the vehicle is reduced.
Disclosure of Invention
The embodiment of the invention provides a vehicle identification method and an RFID reader-writer, which are used for improving the accuracy of the RFID reader-writer in identifying a vehicle.
In a first aspect, an embodiment of the present invention provides a vehicle identification method, which is applied to a radio frequency identification RFID reader; the RFID reader-writer comprises a radio frequency front-end circuit and a processing module; the method comprises the following steps:
the radio frequency front-end circuit converts a first baseband signal generated by the processing module into a first radio frequency signal;
the radio frequency front-end circuit transmits the first radio frequency signal to an antenna so that the antenna transmits the first radio frequency signal to an electronic tag on a vehicle; the antenna receives a second radio frequency signal fed back by the electronic tag; the second radio frequency signal carries identification information of the vehicle; wherein the identification information is used to uniquely identify the vehicle;
the radio frequency front-end circuit couples the second radio frequency signal into a partial signal and converts the second radio frequency signal obtained after the partial signal is coupled into a second baseband signal; the second baseband signal carries a first clutter and the identification information;
the radio frequency front-end circuit adopts the partial signal to offset the first clutter; and the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is counteracted to the processing module so that the processing module identifies the vehicle according to the identification information.
Optionally, the coupling, by the rf front-end circuit, the second rf signal into a partial signal, and converting the second rf signal obtained after the partial signal is coupled into a second baseband signal, where the coupling includes:
the radio frequency front-end circuit extracts a second frequency band which can be identified by the processing module from the second radio frequency signal and amplifies the second frequency band;
the radio frequency front-end circuit couples the amplified partial signals out of the second frequency band;
and the radio frequency front-end circuit performs down-conversion on a second frequency band obtained after the partial signal is coupled out to convert the second frequency band into a second baseband signal.
Optionally, the rf front-end circuit cancels the first spur using the partial signal, and includes:
the radio frequency front-end circuit filters second clutter carried in the partial signals;
the radio frequency front-end circuit reversely amplifies the part of the signals after the second noise wave is filtered;
the radio frequency front-end circuit extracts a first signal segment from a part of reversely amplified signals, wherein the size of the first signal segment is the same as that of the first clutter, and the direction of the first signal segment is opposite to that of the first clutter;
the radio frequency front-end circuit cancels the first clutter by using the first signal segment.
Optionally, the rf front-end circuit converts the first baseband signal generated by the processing module into a first rf signal, and includes:
the radio frequency front-end circuit carries out forming filtering on the first baseband signal;
the radio frequency front-end circuit performs Amplitude Shift Keying (ASK) on the first baseband signal after the forming and filtering to modulate the first baseband signal into a first radio frequency signal.
Optionally, the radio frequency front-end circuit transmits the first radio frequency signal to an antenna, including:
the radio frequency front-end circuit amplifies the first radio frequency signal;
the radio frequency front-end circuit eliminates a first carrier generated when the first radio frequency signal is amplified;
the radio frequency front-end circuit extracts a first frequency band which can be identified by the electronic tag from a first radio frequency signal after the first carrier is eliminated;
and the radio frequency front-end circuit transmits the first frequency band to the antenna.
Optionally, the radio frequency front-end circuit includes a directional module, a first path and a second path; the radio frequency front-end circuit transmits the first radio frequency signal to an antenna, and comprises: the processing module transmits the first radio frequency signal to the orientation module through the first path;
the directional module transmits the first radio frequency signal to the antenna;
the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is cancelled to a processing module, and the radio frequency front-end circuit comprises:
the orientation module sends the second baseband signal to the processing module through the second path; the first and second pathways are different.
Optionally, the directional module comprises a directional coupler or a circulator.
In a second aspect, an embodiment of the present invention provides a radio frequency identification RFID reader, including:
a processing module for generating a first baseband signal;
a radio frequency front end circuit for converting the first baseband signal into a first radio frequency signal;
the radio frequency front-end circuit is further used for transmitting the first radio frequency signal to an antenna so that the antenna transmits the first radio frequency signal to an electronic tag on a vehicle; the antenna receives a second radio frequency signal fed back by the electronic tag; the second radio frequency signal carries identification information of the vehicle; wherein the identification information is used to uniquely identify the vehicle;
the radio frequency front-end circuit is further configured to couple the second radio frequency signal to a part of signals, and convert a second radio frequency signal obtained after the part of signals is coupled to a second baseband signal; the second baseband signal carries a first clutter and the identification information;
the radio frequency front-end circuit is further used for adopting the partial signal to offset the first clutter; and the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is counteracted to the processing module so that the processing module identifies the vehicle according to the identification information.
Optionally, the rf front-end circuit includes:
the band-pass filter is used for extracting a second frequency band which can be identified by the processing module from the second radio frequency signal;
the low-noise amplifier is used for amplifying the second frequency band;
a second directional coupler for coupling out said portion of the signal from the amplified second frequency band;
and the mixer is used for carrying out down-conversion on a second frequency band obtained after the partial signal is coupled out to obtain a second baseband signal.
Optionally, the rf front-end circuit includes:
the detector is used for filtering second clutter carried in the partial signals;
the reverse amplifier is used for reversely amplifying the part of the signals after the second noise wave is filtered;
the third low-pass filter is used for extracting a first signal segment from the reversely amplified partial signal, and the size of the first signal segment is the same as that of the first clutter and the direction of the first signal segment is opposite to that of the first clutter;
the third low pass filter is further configured to cancel the first spur with the first signal segment.
Optionally, the rf front-end circuit includes:
a first low-pass filter for shaping filtering the first baseband signal;
and the electrically-tuned attenuator is used for carrying out Amplitude Shift Keying (ASK) on the first baseband signal after the forming and filtering to modulate the first baseband signal into a first radio frequency signal.
Optionally, the rf front-end circuit includes:
the power amplifier is used for amplifying the first radio frequency signal;
the carrier wave elimination module is used for eliminating a first carrier wave generated when the first radio frequency signal is amplified;
the second low-pass filter is used for extracting a first frequency band which can be identified by the electronic tag from the first radio-frequency signal after the first carrier is eliminated;
the second low pass filter is further configured to transmit the first frequency band to the antenna.
Optionally, the rf front-end circuit further includes:
a first path for transmitting the first radio frequency signal to the directional module;
the directional module is used for transmitting the first radio frequency signal to the antenna;
the orientation module is further configured to send the second baseband signal to a second channel;
the second path is used for sending the second baseband signal to the processing module; the first and second pathways are different.
Optionally, the orientation module comprises a first orientation coupler or a circulator.
In a third aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores a computer program, where the computer program includes program instructions, and the program instructions, when executed by a computer, cause the computer to execute the first aspect or any one of the possible design methods of the first aspect.
In a fourth aspect, an embodiment of the present invention provides a computer program product, in which a computer program is stored, the computer program comprising program instructions that, when executed by a computer, cause the computer to perform the first aspect or any one of the possible design methods of the first aspect.
The invention has the following beneficial effects:
in the technical scheme of the embodiment of the invention, the RFID reader comprises a radio frequency front-end circuit and a processing module; the radio frequency front-end circuit converts a first baseband signal generated by the processing module into a first radio frequency signal; the radio frequency front-end circuit transmits the first radio frequency signal to the antenna so that the antenna transmits the first radio frequency signal to an electronic tag on the vehicle; the antenna receives a second radio frequency signal fed back by the electronic tag; the second radio frequency signal carries identification information of the vehicle; wherein the identification information is used for uniquely identifying the vehicle; the radio frequency front-end circuit couples the second radio frequency signal into a part of signals, and converts the second radio frequency signal obtained after coupling out the part of signals into a second baseband signal; the second baseband signal carries the first clutter and the identification information; the radio frequency front-end circuit adopts partial signals to offset first clutter; the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is offset to the processing module, so that the processing module can identify the vehicle according to the identification information. In this way, the accuracy of the RFID reader-writer for identifying the vehicle can be improved.
Drawings
FIG. 1 is a schematic diagram of an application scenario provided in the practice of the present invention;
FIG. 2 is a schematic structural diagram of an RFID reader/writer according to an embodiment of the present invention;
FIG. 3 is a schematic flow chart illustrating a vehicle identification method according to an embodiment of the present invention;
fig. 4 is a schematic diagram illustrating a structure of an rf front-end circuit according to an embodiment of the present invention;
fig. 5 is a schematic diagram illustrating a detailed structure of an rf front-end circuit according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The shapes and sizes of the various elements in the drawings are not to scale and are merely intended to illustrate the invention.
Fig. 1 is a schematic diagram of an application scenario according to an embodiment of the present invention. The application scenario can be applied to places such as parking lots and road traffic management, and the embodiment of the invention is not limited. As shown in fig. 1, the application scenario may include an RFID reader 100, an antenna 101, and a vehicle 102. Wherein, the RFID reader 100 is connected with an antenna 101; the vehicle 102 may have an electronic tag therein that may have stored therein identification information of the vehicle 102 (which may uniquely identify the vehicle 102). With continued reference to fig. 1, the RFID reader 100 may wirelessly communicate with the vehicle 102 through the antenna 101 to obtain the identification information stored in the electronic tag in the vehicle 102, and the RFID reader 100 completes the identification of the vehicle 102 according to the identification information.
For example, the RFID reader 100 transmits a first radio frequency signal to an electronic tag in the vehicle 102 through the antenna 101. The electronic tag feeds back a second radio frequency signal to the RFID reader 100, where the second radio frequency signal carries identification information of the vehicle 102. The antenna 101 transmits the received second radio frequency signal to the RFID reader 100, so that the RFID reader 100 identifies the vehicle 102 according to the identification information carried by the second radio frequency signal. Specifically, in the embodiment of the present invention, the communication process between the RFID reader 100 and the vehicle 102 also goes through the conversion process between the radio frequency signal and the baseband signal, but the RFID reader 100 may filter the clutter in the baseband signal, so as to improve the accuracy of the RFID reader 100 in identifying the vehicle.
It should be noted that, the above application scenario is an example in which the RFID reader 100 identifies one vehicle, and of course, the RFID reader 100 may also identify multiple vehicles, and the embodiment of the present invention is not limited thereto. The vehicle can be different types of vehicles such as buses, automobiles and trucks, and only the vehicle is provided with the electronic tag, and the embodiment of the invention does not specifically limit the vehicle.
The structure of the RFID reader 100 is described below, and for example, please refer to fig. 2, which is a schematic structural diagram of an RFID reader according to an embodiment of the present invention. As shown in fig. 2, the RFID reader 200 may include a processing module 201 and a radio frequency front end circuit 202. The rf front-end circuit 202 may be connected to an antenna (not shown in fig. 2).
Taking the RFID reader shown in fig. 2 as an example, a process of the RFID reader communicating with the electronic tag in the vehicle (i.e., a process of the RFID reader identifying the vehicle) will be described with reference to fig. 1 to 3.
Fig. 3 is a schematic flow chart of a vehicle identification method according to an embodiment of the present invention. As shown in fig. 3, the method includes:
s301: the radio frequency front-end circuit converts a first baseband signal generated by the processing module into a first radio frequency signal.
S302: the radio frequency front-end circuit transmits the first radio frequency signal to the antenna so that the antenna transmits the first radio frequency signal to an electronic tag on the vehicle; the antenna receives a second radio frequency signal fed back by the electronic tag; the second radio frequency signal carries identification information of the vehicle; wherein the identification information is used to uniquely identify the vehicle.
S303: the radio frequency front-end circuit couples the second radio frequency signal into a part of signals, and converts the second radio frequency signal obtained after coupling out the part of signals into a second baseband signal; the second baseband signal carries the first spur and the identification information.
S304: the radio frequency front-end circuit adopts partial signals to offset first clutter; the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is offset to the processing module, so that the processing module can identify the vehicle according to the identification information.
The process of the RFID reader shown in fig. 2 transmitting the first radio frequency signal to the electronic tag of the vehicle will be described.
Referring to fig. 2, optionally, the rf front-end circuit 202 may perform shaping filtering on the first baseband signal, and perform amplitude shift keying ASK modulation on the shaped and filtered first baseband signal to modulate the first baseband signal into a first rf signal, i.e., S301.
Optionally, the rf front-end circuit 202 may amplify the first rf signal and cancel the first carrier generated when the first rf signal is amplified. The rf front-end circuit 202 may extract a first frequency band that can be identified by the electronic tag from the first rf signal after the first carrier is removed, and transmit the first frequency band to an antenna (not shown in fig. 2, please refer to fig. 1), i.e., S302. The antenna transmits the first frequency band to an electronic tag on a vehicle (not shown in fig. 2, please refer to fig. 1).
The process of receiving the second radio frequency signal fed back by the electronic tag of the vehicle by the RFID reader shown in fig. 2 is described below.
Optionally, the antenna may transmit a second radio frequency signal (which carries the identification information of the vehicle) fed back by the electronic tag to the radio frequency front-end circuit 202. Wherein the identification information is used to uniquely identify the vehicle.
Optionally, as shown in fig. 2, the rf front-end circuit 202 may couple a part of the second rf signal out, and convert the second rf signal obtained after coupling the part of the second rf signal out into a second baseband signal, i.e., S303. The second baseband signal carries the first clutter and the identification information.
Specifically, the rf front-end circuit 202 may extract a second frequency band that can be identified by the processing module 201 from the second rf signal, and amplify the second frequency band. The rf front-end circuit 202 may couple the amplified second frequency band to a partial signal, and down-convert the second frequency band coupled with the partial signal into a second baseband signal (the second baseband signal carries identification information of a vehicle). The rf front-end circuit 202 cancels the first clutter using the partial signal, and sends a second baseband signal obtained after canceling the first clutter to the processing module 201, so that the processing module 201 identifies the vehicle according to the identification information.
The operation of the rf front-end circuit is described below (the operation of the rf front-end circuit with its specific internal structure is described later).
For example, please refer to fig. 4, which is a schematic structural diagram of an rf front-end circuit according to an embodiment of the present invention. As shown in fig. 4, the rf front-end circuit 300 may include a first path 301, a vibration source module 302, a carrier cancellation module 303, a directional module 304, and a second path 305.
Alternatively, the rf front-end circuit 300 may include two processes when operating. For example, one process may be divided into a process in which the first path 301 cooperates with the vibration source module 302, the carrier wave elimination module 303, and the orientation module 304; another process can be divided into a process in which the second path 305 works in cooperation with the vibration source module 302, the carrier wave elimination module 303, and the orientation module 304.
The process of the first path 301 cooperating with the vibration source module 302, the carrier cancellation module 303 and the orientation module 304 is described below.
Referring to fig. 4, optionally, the first path 301 may perform shaping filtering on the first baseband signal generated by the processing module (the first path 301 is connected to the processing module, and is not shown in fig. 4), and perform Amplitude-Shift Keying (ASK) on the shaped and filtered first baseband signal according to the local oscillator signal output by the oscillator source module 302 to modulate the first baseband signal into a first radio frequency signal.
Alternatively, the first path 301 may amplify the first radio frequency signal, and extract a first frequency band required by an electronic tag in a vehicle (not shown in fig. 4) from the amplified first radio frequency signal (i.e., the first frequency band is a frequency band that can be received by the electronic tag), which will be described later.
Optionally, the first path 301 may transmit the first frequency band to the orientation module 304, so that the orientation module 304 transmits the first frequency band to the electronic tag through an antenna (not shown in fig. 4), and the electronic tag may receive and identify the first frequency band.
It should be noted that, during the process of transmitting the first frequency band to the directional module 304 through the first path 301, the carrier wave elimination module 303 may eliminate the first carrier wave generated when the first radio frequency signal is amplified (the first carrier wave is also transmitted in the process).
The process of the second path 305 cooperating with the vibration source module 302, the carrier cancellation module 303 and the orientation module 304 is described below.
Alternatively, the directional module 304 may transmit a second radio frequency signal (the second radio frequency signal is a response signal fed back by the electronic tag, where the second radio frequency signal carries identification information of the vehicle) received by the antenna (the directional module 304 is connected to the antenna, and is not shown in fig. 4) to the second path 305. During the transmission, the carrier cancellation module 303 may cancel the second carrier carried by the second rf signal.
Optionally, the second path 305 may extract a second frequency band (carrying identification information of the vehicle) from the second rf signal after the second carrier is removed, and amplify the second frequency band. The second frequency band is a frequency band that can be identified by the processing module, and a specific process will be described later.
Optionally, the second path 305 may couple the amplified second frequency band out of a portion of the signal and filter out second spurs carried in the portion of the signal.
Optionally, the second path 305 may down-convert a second frequency band obtained after coupling out the partial signal into a second baseband signal (the second baseband signal carries identification information of the vehicle and a first clutter, where the first clutter may include a direct current and a low frequency signal), amplify the second baseband signal, and send the amplified second baseband signal to the processing module, so that the processing module may obtain the identification information of the vehicle according to the amplified second baseband signal.
Alternatively, the second path 305 may inversely amplify the partial signal from which the second noise has been filtered, and extract the first signal segment from the inversely amplified partial signal. The first signal segment and the first clutter have the same size and opposite direction.
Alternatively, the second path 305 may cancel the first spur using the first signal segment and amplify a second baseband signal resulting from the cancellation of the first spur.
Optionally, the second path 305 may send the amplified second baseband signal to the processing module, so that the processing module obtains the identification information from the second baseband signal, and further, the processing module identifies the vehicle according to the identification information.
It should be noted that, by eliminating the second carrier wave carried in the transmission process of the second radio frequency signal and the first clutter carried in the transmission process of the second baseband signal, the influence of the second carrier wave on the second radio frequency signal and the influence of the first clutter on the second baseband signal can be avoided, so that the identification information acquired by the processing module is not distorted, and the accuracy of the RFID reader for identifying the vehicle is improved.
The operation of the rf front-end circuit with its specific internal structure is described below.
For example, please refer to fig. 5, which is a schematic diagram illustrating a specific structure of an rf front-end circuit according to an embodiment of the present invention. Referring to fig. 4 and 5, the first path 301 may include a first low pass filter 4-1. Optionally, the first low-pass filter 4-1 may shape-filter the first baseband signal generated by the processing module (not shown in fig. 5).
Optionally, the first path 301 may further include an electrically tunable attenuator 4-2, and the vibration source module 302 may include a local oscillator 4-3. Optionally, the electrically tuned attenuator 4-2 may perform ASK modulation on the first baseband signal after the shaping filtering to modulate the first radio frequency signal according to a local oscillator signal output by the local oscillator 4-3.
Optionally, the first path 301 may also include a power amplifier 4-4. Optionally, the power amplifier 4-4 may amplify the first radio frequency signal.
Optionally, the first path 301 may further comprise a second low pass filter 4-5. Optionally, the second low-pass filter 4-5 may extract a first frequency band that can be identified by an electronic tag in a vehicle (not shown in fig. 5) from the amplified first radio frequency signal.
Optionally, the directional module 304 may include a first load 4-6 and a first directional coupler 4-7. Optionally, the first directional coupler 4-7 may transmit the first frequency band to the antenna 4-8, so that the antenna 4-8 transmits the first frequency band to the electronic tag, and further the electronic tag may receive the first frequency band, so that the first frequency band reads the identification information stored in the electronic tag by performing a read-write operation on the electronic tag.
Optionally, the carrier wave elimination module 303 may eliminate the first carrier wave generated when the first rf signal is amplified during the transmission of the first frequency band to the first directional coupler 4-7 by the second low pass filter 4-5 (the first carrier wave is also transmitted during the transmission).
Optionally, the second path 305 may include a band pass filter 4-9. Optionally, the first directional coupler 4-7 may transmit a second radio frequency signal (which carries the identification information of the vehicle) received by the antenna 4-8 to the band pass filter 4-9. During the transmission, the carrier cancellation module 303 may cancel the second carrier carried by the second rf signal. Optionally, the band pass filter 4-9 may extract a second frequency band (the second frequency band carries identification information of the vehicle) from the second radio frequency signal. Wherein the frequency band is identifiable by the processing module.
Optionally, the second path 305 may also include low noise amplifiers 4-10. Alternatively, the low noise amplifier 4-10 may amplify the second frequency band.
Optionally, the second path 305 may further include a second load 4-11, a second directional coupler 4-12, a detector 4-13, and a mixer 4-14. Alternatively, the second directional coupler 4-12 may couple a portion of the amplified second frequency band to the detector 4-13 and may couple a portion of the amplified second frequency band to the mixer 4-14.
Optionally, the second path 305 may also include inverting amplifiers 4-15. The inverting amplifier 4-15 may inversely amplify the partial signal obtained by filtering the second noise carried by the partial signal by the detector 4-13.
Optionally, the second path 305 may also include a third low pass filter 4-16. Alternatively, the third low-pass filter 4-16 may extract the first signal segment from the inversely amplified partial signal. The first signal segment and the first clutter have the same size and opposite direction.
Optionally, the mixer 4-14 may down-convert the local oscillation signal output by the local oscillator 4-3 and the second frequency band obtained by coupling out a part of the signal into a second baseband signal.
Optionally, the second path 305 may also include baseband filters 4-17. Alternatively, the baseband filters 4-17 may filter out other waves carried by the second baseband signal that have the first spur removed.
Optionally, the second path 305 may also include baseband amplifiers 4-18. Alternatively, the baseband filters 4-18 may amplify the second baseband signal and transmit the amplified second baseband signal to the processing module, so that the identification information of the vehicle is obtained according to the amplified second baseband signal.
It should be noted that, in the process of transmitting the second baseband signal to the mixer, the first signal segment cancels the first clutter carried by the second baseband signal, so as to avoid the first clutter from affecting the transmission of the second baseband signal, so that the amplified second baseband signal received by the processing module is not distorted, and the accuracy of the RFID reader for identifying the vehicle is further improved.
It should be noted that the first load and the second load may be the same (for example, both are resistors of 50 Ω), or may be different, and the embodiment of the present invention is not limited.
It should be noted that, the above description is taken as an example that the directional module includes the first directional coupler and the first load, and of course, the directional module may further include a circulator.
As can be seen from the above description, in the technical solution of the embodiment of the present invention, the RFID reader includes a radio frequency front end circuit and a processing module; the radio frequency front-end circuit converts a first baseband signal generated by the processing module into a first radio frequency signal; the radio frequency front-end circuit transmits the first radio frequency signal to the antenna so that the antenna transmits the first radio frequency signal to an electronic tag on the vehicle; the antenna receives a second radio frequency signal fed back by the electronic tag; the second radio frequency signal carries identification information of the vehicle; wherein the identification information is used for uniquely identifying the vehicle; the radio frequency front-end circuit couples the second radio frequency signal into a part of signals, and converts the second radio frequency signal obtained after coupling out the part of signals into a second baseband signal; the second baseband signal carries the first clutter and the identification information; the radio frequency front-end circuit adopts partial signals to offset first clutter; the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is offset to the processing module, so that the processing module can identify the vehicle according to the identification information. In this way, the accuracy of the RFID reader-writer for identifying the vehicle can be improved.
Based on the same inventive concept, the embodiment of the invention provides a computer-readable storage medium. Optionally, the computer readable storage medium has a computer program comprising program instructions which, when executed by a computer, cause the computer to perform the steps of the above-described vehicle identification method. Since the computer program in the embodiment and the vehicle identification method shown in fig. 3 are based on the invention under the same concept, and the implementation process of the computer program in the embodiment can be clearly understood by those skilled in the art through the foregoing detailed description of the vehicle identification method, further description is omitted here for brevity of the description.
Based on the same inventive concept, embodiments of the present invention provide a computer program product, which stores a computer program, the computer program comprising program instructions that, when executed by a computer, cause the computer to perform the steps of the above-described vehicle identification method. Since the computer program product in this embodiment and the vehicle identification method shown in fig. 3 are based on the invention under the same concept, and the implementation process of the computer program product in this embodiment can be clearly understood by those skilled in the art through the foregoing detailed description of the vehicle identification method, so that no further description is provided herein for brevity of the description.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (15)
1. A vehicle identification method is applied to a Radio Frequency Identification (RFID) reader-writer and is characterized in that the RFID reader-writer comprises a radio frequency front-end circuit and a processing module; the method comprises the following steps:
the radio frequency front-end circuit converts a first baseband signal generated by the processing module into a first radio frequency signal;
the radio frequency front-end circuit transmits the first radio frequency signal to an antenna so that the antenna transmits the first radio frequency signal to an electronic tag on a vehicle; the antenna receives a second radio frequency signal fed back by the electronic tag; the second radio frequency signal carries identification information of the vehicle; wherein the identification information is used to uniquely identify the vehicle;
the radio frequency front-end circuit couples the second radio frequency signal into a partial signal and converts the second radio frequency signal obtained after the partial signal is coupled into a second baseband signal; the second baseband signal carries a first clutter and the identification information;
the radio frequency front-end circuit adopts the partial signal to offset the first clutter; and the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is counteracted to the processing module so that the processing module identifies the vehicle according to the identification information.
2. The method of claim 1, wherein the rf front-end circuit couples the second rf signal out of a portion of the signal, and converts the second rf signal resulting from coupling out of the portion of the signal into a second baseband signal, comprising:
the radio frequency front-end circuit extracts a second frequency band which can be identified by the processing module from the second radio frequency signal and amplifies the second frequency band;
the radio frequency front-end circuit couples the amplified partial signals out of the second frequency band;
and the radio frequency front-end circuit performs down-conversion on a second frequency band obtained after the partial signal is coupled out to convert the second frequency band into a second baseband signal.
3. The method of claim 1, wherein the rf front-end circuit cancels the first spur with the partial signal, comprising:
the radio frequency front-end circuit filters second clutter carried in the partial signals;
the radio frequency front-end circuit reversely amplifies the part of the signals after the second noise wave is filtered;
the radio frequency front-end circuit extracts a first signal segment from a part of reversely amplified signals, wherein the size of the first signal segment is the same as that of the first clutter, and the direction of the first signal segment is opposite to that of the first clutter;
the radio frequency front-end circuit cancels the first clutter by using the first signal segment.
4. The method of any of claims 1-3, wherein the RF front-end circuit converts a first baseband signal generated by the processing module to a first RF signal, comprising:
the radio frequency front-end circuit carries out forming filtering on the first baseband signal;
and the radio frequency front-end circuit performs Amplitude Shift Keying (ASK) on the first baseband signal after the molding and filtering to modulate the first baseband signal into a first radio frequency signal.
5. The method of any of claims 1-3, wherein the RF front-end circuit is to transmit the first RF signal to an antenna, comprising:
the radio frequency front-end circuit amplifies the first radio frequency signal;
the radio frequency front-end circuit eliminates a first carrier generated when the first radio frequency signal is amplified;
the radio frequency front-end circuit extracts a first frequency band which can be identified by the electronic tag from a first radio frequency signal after the first carrier is eliminated;
and the radio frequency front-end circuit transmits the first frequency band to the antenna.
6. The method of claim 1, wherein the radio frequency front end circuit comprises a directional module, a first path, and a second path; the radio frequency front-end circuit transmits the first radio frequency signal to an antenna, and comprises: the processing module transmits the first radio frequency signal to the orientation module through the first path;
the directional module transmits the first radio frequency signal to the antenna;
the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is cancelled to a processing module, and the radio frequency front-end circuit comprises:
the orientation module sends the second baseband signal to the processing module through the second path; the first and second pathways are different.
7. The method of claim 6, wherein the directional module comprises a directional coupler or a circulator.
8. A radio frequency identification, RFID, reader, comprising:
a processing module for generating a first baseband signal;
a radio frequency front end circuit for converting the first baseband signal into a first radio frequency signal;
the radio frequency front-end circuit is further used for transmitting the first radio frequency signal to an antenna so that the antenna transmits the first radio frequency signal to an electronic tag on a vehicle; the antenna receives a second radio frequency signal fed back by the electronic tag; the second radio frequency signal carries identification information of the vehicle; wherein the identification information is used to uniquely identify the vehicle;
the radio frequency front-end circuit is further configured to couple the second radio frequency signal to a part of signals, and convert a second radio frequency signal obtained after the part of signals is coupled to a second baseband signal; the second baseband signal carries a first clutter and the identification information;
the radio frequency front-end circuit is further used for adopting the partial signal to offset the first clutter; and the radio frequency front-end circuit sends a second baseband signal obtained after the first clutter is counteracted to the processing module so that the processing module identifies the vehicle according to the identification information.
9. The RFID reader of claim 8, wherein the radio frequency front end circuit comprises:
the band-pass filter is used for extracting a second frequency band which can be identified by the processing module from the second radio frequency signal;
the low-noise amplifier is used for amplifying the second frequency band;
a second directional coupler for coupling out said portion of the signal from the amplified second frequency band;
and the mixer is used for carrying out down-conversion on a second frequency band obtained after the partial signal is coupled out to obtain a second baseband signal.
10. The RFID reader of claim 8, wherein the radio frequency front end circuit comprises:
the detector is used for filtering second clutter carried in the partial signals;
the reverse amplifier is used for reversely amplifying the part of the signals after the second noise wave is filtered;
the third low-pass filter is used for extracting a first signal segment from the reversely amplified partial signal, and the size of the first signal segment is the same as that of the first clutter and the direction of the first signal segment is opposite to that of the first clutter;
the third low pass filter is further configured to cancel the first spur with the first signal segment.
11. The RFID reader of any one of claims 8-10, wherein the radio frequency front end circuitry includes:
a first low-pass filter for shaping filtering the first baseband signal;
and the electrically-tuned attenuator is used for carrying out Amplitude Shift Keying (ASK) on the first baseband signal after the forming and filtering to modulate the first baseband signal into a first radio frequency signal.
12. The RFID reader of any one of claims 8-10, wherein the radio frequency front end circuitry includes:
the power amplifier is used for amplifying the first radio frequency signal;
the carrier wave elimination module is used for eliminating a first carrier wave generated when the first radio frequency signal is amplified;
the second low-pass filter is used for extracting a first frequency band which can be identified by the electronic tag from the first radio-frequency signal after the first carrier is eliminated;
the second low pass filter is further configured to transmit the first frequency band to the antenna.
13. The RFID reader of claim 8, wherein the radio frequency front end circuit further comprises:
a first path for transmitting the first radio frequency signal to a directional module;
the directional module is used for transmitting the first radio frequency signal to the antenna;
the orientation module is further configured to transmit the second baseband signal to a second channel;
the second path is used for sending the second baseband signal to the processing module; the first and second pathways are different.
14. The RFID reader of claim 13, where the orientation module comprises a first orientation coupler or a circulator.
15. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program comprising program instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1-7.
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| CN201811519482.6A CN111327349B (en) | 2018-12-12 | 2018-12-12 | Vehicle identification method and RFID reader-writer |
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| CN201811519482.6A CN111327349B (en) | 2018-12-12 | 2018-12-12 | Vehicle identification method and RFID reader-writer |
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| CN111327349A (en) | 2020-06-23 |
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