Active RFID system frequency band adaptation method and device

Abstract

The application discloses a kind of active RFID system frequency band adaptation method and device, the present application detects antenna S 11 Minimum point offset, white noise on the receiving radio frequency card side, determine the working frequency band and center frequency point of the radio frequency card side antenna through white noise, and then adaptively adjust the frequency hopping table and receiving frequency of wireless transceiver module, realize frequency band adaptation, maximize guarantee system uplink and downlink communication, effectively prevent antenna S 11 Minimum point offset leads to communication quality deterioration or even interruption.

Description

Technical Field

[0001] This invention relates to a frequency band adaptation method and apparatus for an active RFID system, belonging to the field of radio frequency identification. Background Technology

[0002] The articles "High temperature polymer film dielectrics for aerospace powerconditioning capacitor applications" and "Research on flexible antennas based on nanomaterials" explain that antennas based on flexible thin films... 11 The minimum point shifts to the left with increasing temperature and curvature, especially in long-range active RFID systems. The antenna design on the RFID card side prioritizes high gain, resulting in a generally narrow 3dB bandwidth of approximately 20MHz (for example, a 915MHz RFID system). Therefore, the system transmission quality is highly dependent on the antenna's gain. 11 The minimum point of the antenna S is more sensitive to changes. 11 The shift at the minimum point means a change in the antenna gain characteristics, which can lead to a deterioration in the communication quality of the RFID system or even a communication interruption. Summary of the Invention

[0003] This invention provides a method and apparatus for frequency band adaptation in an active RFID system, solving the problem of antenna S 11 The problem of local minimum point offset.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A frequency band adaptation method for an active RFID system includes:

[0006] In response to the detection of antenna S 11 Minimum point offset, receiving white noise from the RF card side;

[0007] Based on the white noise, the operating frequency band and center frequency of the RF card side antenna are inferred;

[0008] If the inferred center frequency of the RF card side antenna does not exceed the carrier frequency range of its own wireless transceiver module, the inferred center frequency of the RF card side antenna is sent to the RF card side. The inferred center frequency of the RF card side antenna is used as the receiving frequency of its own wireless transceiver module. Based on the inferred operating frequency band of the RF card side antenna, a new frequency hopping table for its own wireless transceiver module is generated, and the old frequency hopping table for its own wireless transceiver module is replaced with the new frequency hopping table.

[0009] Based on white noise, the operating frequency band and center frequency of the RF card-side antenna are inferred, including:

[0010] Perform a Fast Fourier Transform on the white noise to obtain its spectrum;

[0011] Based on the spectrum of white noise, the operating frequency band and center frequency of the RF card-side antenna are inferred.

[0012] An active RFID system frequency band adaptation device, comprising:

[0013] The white noise receiving module responds to the detection of antenna S. 11 Minimum point offset, receiving white noise from the RF card side;

[0014] The frequency band and frequency point inference module infers the operating frequency band and center frequency point of the RF card-side antenna based on white noise;

[0015] The first adaptation module, if the inferred center frequency of the RF card-side antenna does not exceed the carrier frequency range of its own wireless transceiver module, sends the inferred center frequency of the RF card-side antenna to the RF card side, uses the inferred center frequency of the RF card-side antenna as the receiving frequency of its own wireless transceiver module, generates a new frequency hopping table for its own wireless transceiver module based on the inferred operating frequency band of the RF card-side antenna, and replaces the old frequency hopping table of its own wireless transceiver module with the new frequency hopping table.

[0016] The frequency band and frequency point inference module performs a fast Fourier transform on the white noise to obtain the spectrum of the white noise, and infers the operating frequency band and center frequency point of the RF card side antenna based on the spectrum of the white noise.

[0017] A frequency band adaptation method for an active RFID system includes:

[0018] In response to the detection of antenna S 11 The minimum point is offset, and white noise is sent to the reader side; the white noise covers the operating frequency band of the antenna on its own side.

[0019] In response to receiving the inferred center frequency of the RFID card antenna from the reader, a new frequency hopping table identical to that of the reader is generated based on the inferred center frequency of the RFID card antenna and the operating frequency band of its own antenna. The old frequency hopping table of its own wireless transceiver module is then replaced with the new frequency hopping table.

[0020] After sending white noise, the system controls its own wireless transceiver module to switch to receive mode, traverses the carrier frequency range generated by its own wireless transceiver module, and switches the receiving frequency of its own wireless transceiver module until it receives the inferred center frequency of the RF card antenna sent by the reader side; during the traversal process, it prioritizes traversing the frequency range that the system has previously shifted to and cannot work properly.

[0021] An active RFID system frequency band adaptation device, comprising:

[0022] The white noise transmission module responds to the detection of antenna S. 11 The minimum point is offset, and white noise is sent to the reader side; the white noise covers the operating frequency band of the antenna on its own side.

[0023] The second adaptation module, in response to receiving the inferred center frequency of the RFID card antenna sent by the reader side, generates a new frequency hopping table identical to that of the reader side based on the inferred center frequency of the RFID card antenna and the operating frequency band of its own antenna, and replaces the old frequency hopping table of its own wireless transceiver module with the new frequency hopping table.

[0024] It also includes a frequency sweeping module. After sending white noise, it controls its own wireless transceiver module to switch to receiving mode, traverses the carrier frequency range generated by its own wireless transceiver module, and switches the receiving frequency of its own wireless transceiver module until it receives the inferred center frequency of the RF card antenna sent by the reader. During the traversal, it prioritizes traversing the frequency range that the system has previously shifted to and cannot work properly.

[0025] An active RFID system includes an RFID card-side sensor, an RFID card-side main control module, an RFID card-side wireless transceiver module, an RFID card-side antenna, a reader-side antenna, a reader-side wireless transceiver module, and a reader-side main control module. The RFID card-side sensor, RFID card-side main control module, RFID card-side wireless transceiver module, and RFID card-side antenna are connected in sequence, and the reader-side antenna, reader-side wireless transceiver module, and reader-side main control module are also connected in sequence. The system also includes an RFID noise signal source and a digital signal processor.

[0026] The radio frequency noise signal source is connected to the RF card-side antenna and the RF card-side main control module. The RF noise signal source is equipped with a white noise transmission module. The RF card-side main control module is equipped with a second adapter module and a frequency sweeping module.

[0027] The digital signal processor connects the reader-side antenna and the reader-side main control module. The digital signal processor is equipped with a white noise receiving module and a frequency band inference module; the reader-side main control module is equipped with a first adapter module.

[0028] The active RFID system also includes a high-frequency switching switch on the RFID card side and a high-frequency switching switch on the reader side. The RFID noise signal source and the RFID card side wireless transceiver module are both connected to the RFID card side antenna through the RFID card side high-frequency switching switch, and the digital signal processor and the reader wireless transceiver module are both connected to the reader antenna through the reader high-frequency switching switch.

[0029] The beneficial effects achieved by this invention: This invention detects antenna S 11Minimum point offset, receiving white noise from the RF card side, determines the operating frequency band and center frequency of the RF card side antenna, and then adaptively adjusts the frequency hopping table and receiving frequency of the wireless transceiver module to achieve frequency band adaptation, maximizing uplink and downlink communication of the system and effectively preventing antenna S 11 Minimum point offset can lead to deterioration or even interruption of communication quality. Attached Figure Description

[0030] Figure 1 This is a block diagram of an active RFID system.

[0031] Figure 2 For antenna S 11 Simulation diagram showing the shift of the minimum point as bending characteristics change;

[0032] Figure 3 A flowchart illustrating the workflow of an active RFID system;

[0033] Figure 4 This is a broadband diagram of white noise transmission and reception. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0035] A frequency band adaptation method for an active RFID system includes an RFID card-side method and a reader-side method;

[0036] RFID card-side methods include:

[0037] 1) Response to the detection of antenna S 11 The minimum point is offset, and white noise is sent to the reader side; the white noise covers the operating frequency band of the antenna on its own side.

[0038] 2) In response to receiving the inferred center frequency of the RFID card antenna from the reader, a new frequency hopping table identical to that of the reader is generated based on the inferred center frequency of the RFID card antenna and the operating frequency band of its own antenna. The old frequency hopping table of its own wireless transceiver module is replaced with the new frequency hopping table.

[0039] Reader-side methods include:

[0040] s1) In response to the detection of antenna S 11 Minimum point offset, receiving white noise from the RF card side;

[0041] s2) Based on the white noise, infer the operating frequency band and center frequency of the RF card-side antenna;

[0042] s3) If the inferred center frequency of the RF card side antenna does not exceed the carrier frequency range of its own wireless transceiver module, send the inferred center frequency of the RF card side antenna to the RF card side, use the inferred center frequency of the RF card side antenna as the receiving frequency of its own wireless transceiver module, generate a new frequency hopping table for its own wireless transceiver module based on the inferred working frequency band of the RF card side antenna, and replace the old frequency hopping table of its own wireless transceiver module with the new frequency hopping table.

[0043] The above method detects antenna S 11 Minimum point offset, receiving white noise from the RF card side, determines the operating frequency band and center frequency of the RF card side antenna, and then adaptively adjusts the frequency hopping table and receiving frequency of the wireless transceiver module to achieve frequency band adaptation, maximizing uplink and downlink communication of the system and effectively preventing antenna S 11 Minimum point offset can lead to deterioration or even interruption of communication quality.

[0044] When an active RFID system is first started, both the RFID card side and the reader side generate and store frequency hopping tables. Before transmitting data, the RFID card antenna switches to receive mode and checks the RSSI value at each frequency according to the frequency hopping table. When the channel is idle, the RSSI value is often lower than a preset value X, which can be obtained by combining the specification data and actual testing. When the RSSI is greater than X, it is considered that a signal is being transmitted or there is significant interference. In this case, to avoid signal collision, the data transmission will be canceled or delayed. When the RSSI is lower than X, it is considered that no signal is being transmitted in the channel, and the system switches to transmit mode to transmit data normally. If the reader side reads the data normally, the RFID card antenna is considered to be functioning correctly. 11 If the minimum point does not have a large offset, and the bit error rate of the read data is too high, it can be assumed that the RF card side antenna S... 11 Excessive deviation from the minimum point results in RSSI being at a low power level.

[0045] After detecting antenna S 11 After the minimum point shifts, the above method is activated, that is, the RFID card side generates white noise covering the antenna operating frequency band and sends the white noise to the reader side. Due to the limitation of the antenna operating frequency band, the white noise on the RFID card side can only feed out the power within the antenna gain frequency band.

[0046] After the RFID card sends out white noise, it controls its own wireless transceiver module to switch to receive mode, traverses the carrier frequency range generated by its own wireless transceiver module, and switches the receiving frequency of its own wireless transceiver module until it receives the inferred center frequency of the RFID card antenna sent by the reader. During the traversal, it can prioritize traversing the frequency range that the system has previously shifted to and cannot work properly.

[0047] The reader receives white noise transmitted from the RFID card side, performs a Fast Fourier Transform on the white noise to obtain its spectrum, and infers the operating frequency band and center frequency of the RFID card side antenna based on the spectrum. If the center frequency of the RFID card side antenna exceeds the carrier frequency range of its own wireless transceiver module, communication is considered impossible, and the reader will throw an exception and notify manual maintenance. If the inferred center frequency of the RFID card side antenna does not exceed the carrier frequency range of its own wireless transceiver module, the reader sends the inferred center frequency of the RFID card side antenna to the RFID card side. After transmission, the reader controls its own wireless transceiver module to switch to receive mode, using the inferred center frequency of the RFID card side antenna as the receiving frequency of its own wireless transceiver module. Based on the inferred operating frequency band of the RFID card side antenna, a new frequency hopping table is generated for its own wireless transceiver module, replacing the old frequency hopping table.

[0048] After the above adaptation is completed, normal communication will continue. If communication is blocked again, the above adaptation method will be repeated, and so on.

[0049] Based on the same technical solution, the present invention also discloses a software device for the above method, an active RFID system frequency band adaptation device, including an RFID card side device and a reader side device.

[0050] The RFID card side device includes:

[0051] The white noise transmission module responds to the detection of antenna S. 11 The minimum point offset sends white noise to the reader side; the white noise covers the operating frequency band of its own side antenna.

[0052] After sending white noise, the frequency sweeping module controls its own wireless transceiver module to switch to receive mode, traverses the carrier frequency range generated by its own wireless transceiver module, and switches the receiving frequency of its own wireless transceiver module until it receives the inferred center frequency of the RF card antenna sent by the reader side; during the traversal process, it prioritizes traversing the frequency range that the system has previously deviated to and cannot work properly.

[0053] The second adaptation module, in response to receiving the inferred center frequency of the RFID card antenna sent by the reader side, generates a new frequency hopping table identical to that of the reader side based on the inferred center frequency of the RFID card antenna and the operating frequency band of its own antenna, and replaces the old frequency hopping table of its own wireless transceiver module with the new frequency hopping table.

[0054] The reader-side device includes:

[0055] The white noise receiving module responds to the detection of antenna S. 11 Minimum point offset, white noise is sent from the receiving RF card side.

[0056] The frequency band and frequency point inference module performs a fast Fourier transform on the white noise to obtain its spectrum. Based on the spectrum of the white noise, it infers the operating frequency band and center frequency of the RF card-side antenna.

[0057] The first adaptation module, if the inferred center frequency of the RF card-side antenna does not exceed the carrier frequency range of its own wireless transceiver module, sends the inferred center frequency of the RF card-side antenna to the RF card side, uses the inferred center frequency of the RF card-side antenna as the receiving frequency of its own wireless transceiver module, generates a new frequency hopping table for its own wireless transceiver module based on the inferred operating frequency band of the RF card-side antenna, and replaces the old frequency hopping table of its own wireless transceiver module with the new frequency hopping table.

[0058] Based on the same technical solution, this invention also discloses an active RFID system, such as... Figure 1 As shown, it includes an RFID card-side sensor, an RFID card-side main control module, an RFID card-side wireless transceiver module, an RFID card-side antenna, a reader-side antenna, a reader-side wireless transceiver module, a reader-side main control module, an RFID noise signal source, a digital signal processor, an RFID card-side high-frequency switching switch, and a reader-side high-frequency switching switch.

[0059] The RFID card-side sensor, RFID card-side main control module, RFID card-side wireless transceiver module, RFID card-side high-frequency switching switch, and RFID card-side antenna are connected sequentially. An RFID noise signal source is connected to the RFID card-side antenna via the RFID card-side high-frequency switching switch, and the RFID noise signal source is connected to the RFID card-side main control module. The RFID noise signal source is located at antenna S... 11 When the minimum point is offset, white noise is sent, that is, a white noise sending module is loaded. This signal source is controlled by the main control module on the RF card side. In addition to performing traditional data processing, the main control module on the RF card side also implements the functions of the second adapter module and the frequency sweep module, that is, the second adapter module and the frequency sweep module are loaded.

[0060] The reader-side antenna, reader-side wireless transceiver module, reader-side high-frequency switching switch, and reader-side main control module are connected sequentially. The digital signal processor (DSP) is connected to the reader-side antenna via the reader-side high-frequency switching switch and is also connected to the reader-side main control module. The DSP is located at antenna S... 11When the minimum point shifts, the receiving RFID card side transmits white noise. A Fast Fourier Transform is performed on the white noise to obtain its spectrum. Based on the spectrum, the operating frequency band and center frequency of the RFID card side antenna are inferred. This involves installing a white noise receiving module and a frequency band / center frequency inference module. This processor is controlled by the reader-side main control module. In addition to traditional data processing, the reader-side main control module, provided the center frequency of the external RFID card side antenna does not exceed the carrier frequency range of its own wireless transceiver module, generates a new frequency hopping table for its own wireless transceiver module based on the operating frequency band of the RFID card side antenna. This new table replaces the old one, and the center frequency of the RFID card side antenna is used as the receiving frequency of its own wireless transceiver module (i.e., the first adapter module is installed). If the center frequency of the external RFID card side antenna exceeds the carrier frequency range of its own wireless transceiver module, an additional exception is thrown.

[0061] In the above system, the main control module uses STMicroelectronics' STM32F103 microcontroller, which integrates 16K to 512K bytes of FLASH memory and two SPI interfaces.

[0062] The wireless transceiver module uses the nRF905 manufactured by Nordic, which integrates an SPI interface to communicate with the main control module. It also integrates two memories, CH_NO and HFREQ_PLL, used to set the operating frequency f (MHz), which can be represented as:

[0063] f=(422.4+(CH_NO / 10))×(1+HFREQ_PLL)

[0064] When CH_NO is 0, the frequency resolution is 100kHz; when it is 1, the resolution is 200kHz. The frequency range of this module can be set from 845MHz to 947MHz.

[0065] The RFID card side antenna is a self-made flexible antenna based on polyester (PET) film, with a frequency range of 902MHz to 928MHz, a voltage standing wave ratio (VSWR) of ≤1.3:1, a gain of >9dBi, linear polarization, and an input impedance of 50Ω. The reader side antenna is a BRA series RFID antenna from Shenzhen Boway Intelligent Identification Technology Co., Ltd., with a frequency range of 824MHz to 960MHz, a VSWR of ≤1.5:1, a gain of >3dBi, linear polarization, and an input impedance of 50Ω.

[0066] The radio frequency noise signal source used is the NC302 from Shanghai Yihang Information Technology Co., Ltd., with an output noise frequency range of 10Hz to 3GHz, an output impedance of 50Ω, and an output power-to-noise ratio of 30dB to 35dB.

[0067] The digital signal processor used is the Texas Instruments TMS320C64x, which includes a DSP core for performing spectrum estimation algorithms such as Fast Fourier Transform to evaluate the peak power spectral density, i.e., the antenna S. 11 The offset state at the minimum point integrates multiple interfaces for communication with the main control module. The I / O voltage is 3.3V and the core voltage is 1.2V. When the clock frequency is 600MHz, the maximum power consumption of the DSP is less than 1.6W.

[0068] The high-frequency switching switch used is the ADG1236 from Analog Devices (ADI). The ADG1236 is a single-chip CMOS device containing two independently selectable SPDT switches with a bandwidth of 1000MHz. The high-frequency switching switch is used to switch between the two connected modules. During normal operation, both the RFID card and the reader's high-frequency switching switches are switched to the wireless transceiver module for communication. When communication abnormalities occur due to a frequency shift in the flexible antenna on the RFID card side, the RFID card's high-frequency switching switch switches to the RF noise signal source, while the reader's high-frequency switch switches to the digital signal processor for frequency adaptation.

[0069] Antenna S 11 A schematic diagram showing the shift of the minimum point as a function of antenna bending characteristics is shown below. Figure 2 As shown, S1,1 is the graph without curvature, S1,1_bend_back_200 is the graph with increasing curvature, and S1,1_bend_back_100 is the graph with the maximum curvature. Figure 2 It can be seen that antenna S 11 The minimum point shifts to the left as the degree of antenna curvature increases, where 100 / 200 represents the curvature radius, and the larger the radius, the flatter the surface.

[0070] The workflow of the above system is as follows: Figure 3 As shown:

[0071] Step 1: When the system starts up for the first time, the main control module on the RFID card side generates a random frequency hopping table for the wireless transceiver module on the RFID card side. The frequency hopping range is equal to the bandwidth of the antenna on the RFID card side. The frequency hopping table is sent to the reader side through the unoffset operating frequency of the antenna. After verification, the frequency hopping table is stored in the non-volatile FLASH memory protected by power failure of the main control module on the reader side, and then communication is carried out.

[0072] Step 2: Before transmitting data, the RFID card-side antenna switches to receive mode and checks the RSSI value at each frequency according to the frequency hopping table. When the channel is idle, the RSSI value is often lower than a preset value X. This value can be obtained by combining the specification data and actual testing. When the RSSI is greater than X, it can be considered that a signal is being transmitted or there is significant interference. In this case, to avoid signal collision, the data transmission will be canceled or delayed. When the RSSI is lower than X, it can be considered that no signal is being transmitted in the channel, and the antenna switches to transmit mode to transmit data normally. If the reader reads the data normally, the RFID card-side antenna is considered to be in good condition. 11 If the minimum point does not have a large offset, and the bit error rate of the read data is too high, it can be assumed that the RF card side antenna S... 11 Excessive deviation from the minimum point results in RSSI being at a low power level;

[0073] Step 3: Activate the radio frequency noise signal source and digital signal processor to perform frequency band adaptation.

[0074] like Figure 4 As shown, the radio frequency noise signal source will generate broadband white noise of 10Hz to 3GHz (completely covering the antenna operating frequency band). On the antenna gating axis, 1 indicates that the frequency falls within the antenna gain frequency band, and 0 indicates that it falls outside the antenna gain frequency band. At this time, due to the limitation of the flexible antenna operating frequency band, the white noise can only feed out the power within the antenna gain frequency band, and the noise power outside the band is filtered out.

[0075] The reader-side antenna is a broadband antenna. The digital signal processor performs a fast Fourier transform on the received white noise to obtain the white noise spectrum. Based on the spectrum, the operating frequency band and center frequency of the RFID card-side antenna can be inferred.

[0076] If the center frequency of the RFID card's antenna exceeds the carrier frequency range of its own wireless transceiver module, communication cannot continue, and the reader's main control module will throw an exception, which can further increase the robustness of the active flexible RFID system. Otherwise, the reader sends the inferred center frequency information of the RFID card's antenna to the RFID card. After the transmission is completed, it switches to the receiving mode, uses the center frequency of the RFID card's antenna as the receiving frequency of its own wireless transceiver module, generates a new frequency hopping table for its own wireless transceiver module based on the operating frequency band of the RFID card's antenna, and replaces the old frequency hopping table of its own wireless transceiver module with the new frequency hopping table.

[0077] After transmitting white noise, the RFID card first sets the wireless transceiver module to receive mode and switches the receiving frequency according to the preset frequency sweeping algorithm (i.e., the carrier frequency range traversal mentioned above) until the frequency sweeping algorithm receives the information of the center frequency point of the RFID card's antenna transmitted by the reader. Then, based on the offset center frequency point and the working frequency band, it generates the same frequency hopping table as the reader, stores it in the main control module, and then switches to transmit mode to enter the next round of communication attempts with the reader.

[0078] The frequency sweeping algorithm can traverse the range of carrier frequencies that the wireless transceiver module can generate, or it can refer to historical or empirical data to prioritize traversing the frequency range that the flexible antenna on the RFID card side has previously shifted to and could not work properly. This provides multi-faceted support for RFID systems based on different types of flexible substrate materials, enables rapid determination of the position after the shift of the S11 minimum point of the flexible antenna, and further increases the applicability of active flexible RFID systems.

[0079] The above system can complete the antenna S by adding an RF noise signal source on the RF card side and a digital signal processor on the reader side. 11 Frequency band adaptation at the minimum point offset does not require the use of complex reconfigurable antenna technology or methods such as standing wave detection to determine the offset of the antenna operating frequency, thus optimizing the hardware circuit with less additional cost.

[0080] The aforementioned system optimizes the traditional data reception mechanism by setting relevant chip registers on the reader side. The traditional mechanism misinterpreted a low RSSI register power level, assuming the channel was idle and switching to transmit mode for normal transmission. The system performs frequency band adaptation when the antenna S11 minimum point shifts, correcting the shortcomings of the traditional data reception mechanism that did not consider scenarios with poor uplink and downlink communication quality or even interruptions.

[0081] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0082] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can 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, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0083] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0084] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0085] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A frequency band adaptation method for an active RFID system, characterized in that, Implemented on the reader side, the method includes: In response to the detection of the RFID card side antenna S 11 Minimum point offset, receiving white noise from the RF card side; Based on the white noise, the operating frequency band and center frequency of the RF card side antenna are inferred; If the inferred center frequency of the RF card side antenna does not exceed the carrier frequency range of its own wireless transceiver module, the inferred center frequency of the RF card side antenna is sent to the RF card side. The inferred center frequency of the RF card side antenna is used as the receiving frequency of its own wireless transceiver module. Based on the inferred operating frequency band of the RF card side antenna, a new frequency hopping table for its own wireless transceiver module is generated, and the old frequency hopping table for its own wireless transceiver module is replaced with the new frequency hopping table.

2. The frequency band adaptation method for an active RFID system according to claim 1, characterized in that, Based on white noise, the operating frequency band and center frequency of the RF card-side antenna are inferred, including: Perform a Fast Fourier Transform on the white noise to obtain its spectrum; Based on the spectrum of white noise, the operating frequency band and center frequency of the RF card-side antenna are inferred.

3. A frequency band adaptation device for an active RFID system, characterized in that, Mounted on the reader side, the device includes: The white noise receiving module responds to the detection of the RFID card-side antenna S. 11 Minimum point offset, receiving white noise from the RF card side; The frequency band and frequency point inference module infers the operating frequency band and center frequency point of the RF card-side antenna based on white noise; The first adaptation module, if the inferred center frequency of the RF card-side antenna does not exceed the carrier frequency range of its own wireless transceiver module, sends the inferred center frequency of the RF card-side antenna to the RF card side, uses the inferred center frequency of the RF card-side antenna as the receiving frequency of its own wireless transceiver module, generates a new frequency hopping table for its own wireless transceiver module based on the inferred operating frequency band of the RF card-side antenna, and replaces the old frequency hopping table of its own wireless transceiver module with the new frequency hopping table.

4. The active RFID system frequency band adaptation device according to claim 3, characterized in that, The frequency band and frequency point inference module performs a fast Fourier transform on the white noise to obtain its spectrum. Based on the spectrum of the white noise, it infers the operating frequency band and center frequency of the RF card-side antenna.

5. A frequency band adaptation method for an active RFID system, characterized in that, Implemented on the RFID card side, the method includes: In response to the detection of its own side antenna S 11 The minimum point is offset, and white noise is sent to the reader side; the white noise covers the operating frequency band of the antenna on its own side. In response to receiving the inferred center frequency of the RFID card antenna from the reader, a new frequency hopping table identical to that of the reader is generated based on the inferred center frequency of the RFID card antenna and the operating frequency band of its own antenna. The old frequency hopping table of its own wireless transceiver module is then replaced with the new frequency hopping table.

6. The frequency band adaptation method for an active RFID system according to claim 5, characterized in that, After sending white noise, the system controls its own wireless transceiver module to switch to receive mode, traverses the carrier frequency range generated by its own wireless transceiver module, and switches the receiving frequency of its own wireless transceiver module until it receives the inferred center frequency of the RF card side antenna sent by the reader side. During the traversal process, priority is given to traversing the frequency ranges to which the system has previously deviated from functioning properly.

7. A frequency band adaptation device for an active RFID system, characterized in that, Mounted on the RFID card side, the device includes: The white noise transmission module responds to the detection of its own side antenna S. 11 The minimum point is offset, and white noise is sent to the reader side; the white noise covers the operating frequency band of the antenna on its own side. The second adaptation module, in response to receiving the inferred center frequency of the RFID card antenna sent by the reader side, generates a new frequency hopping table identical to that of the reader side based on the inferred center frequency of the RFID card antenna and the operating frequency band of its own antenna, and replaces the old frequency hopping table of its own wireless transceiver module with the new frequency hopping table.

8. The active RFID system frequency band adaptation device according to claim 7, characterized in that, It also includes a frequency sweeping module, which, after sending white noise, controls its own wireless transceiver module to switch to receiving mode, traverses the carrier frequency range generated by its own wireless transceiver module, and switches the receiving frequency of its own wireless transceiver module until it receives the inferred center frequency of the RF card side antenna sent by the reader side. During the traversal process, priority is given to traversing the frequency ranges to which the system has previously deviated from functioning properly.

9. An active RFID system, comprising an RFID card-side sensor, an RFID card-side main control module, an RFID card-side wireless transceiver module, an RFID card-side antenna, a reader-side antenna, a reader-side wireless transceiver module, and a reader-side main control module, wherein the RFID card-side sensor, RFID card-side main control module, RFID card-side wireless transceiver module, and RFID card-side antenna are connected in sequence, and the reader-side antenna, reader-side wireless transceiver module, and reader-side main control module are connected in sequence, characterized in that, It also includes radio frequency noise signal sources and digital signal processors; The radio frequency noise signal source is connected to the RF card-side antenna and the RF card-side main control module. The radio frequency noise signal source is equipped with the white noise transmission module as described in claim 7 or 8. The RF card-side main control module is equipped with the second adapter module and the frequency sweeping module as described in claim 8. The digital signal processor connects the reader-side antenna and the reader-side main control module. The digital signal processor is equipped with the white noise receiving module and the frequency band / frequency point inference module as described in claim 3 or 4. The reader-side main control module is equipped with the first adapter module as described in claim 3 or 4.

10. An active RFID system according to claim 9, characterized in that, The active RFID system also includes a high-frequency switching switch on the RFID card side and a high-frequency switching switch on the reader side. The RFID noise signal source and the RFID card side wireless transceiver module are both connected to the RFID card side antenna through the RFID card side high-frequency switching switch. The digital signal processor and the reader side wireless transceiver module are both connected to the reader side antenna through the reader side high-frequency switching switch.

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