Radio frequency identification system, signal processing method therefor, and storage medium

Abstract

The present disclosure relates to a radio frequency identification system, its signal processing method, and storage medium, the radio frequency identification system including an upper device, a reader, a first communication device, an exciter, and an RFID tag, the upper device is used to obtain the current working state of the reader, and if the current working state is active, it determines the MAC addresses and IP addresses of the reader and the exciter and activates a wired network mode between the reader and the exciter, the reader is used to send a forward carrier signal to the exciter via a network switching device of the first communication device in response to the wired network mode being activated, the exciter is used to send the forward carrier signal via air, and the RFID tag is used to modulate the forward carrier signal to generate a reverse transmission signal in response to receiving the forward carrier signal, and transmit the reverse transmission signal via air to the reader.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to a Chinese patent application bearing application number 202310990968.2 and entitled "Radio frequency identification system and its signal processing method, storage medium," filed with the State Intellectual Property Office of the People's Republic of China on August 7, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to the field of communication technology, and in particular to a radio frequency identification system and its signal processing method and storage medium. [Background technology]

[0003] Ultra-high frequency (UHF) radio frequency identification (RFID) technology has the advantages of being able to read multiple tags at once, having high transparency, being capable of multiple reads and writes, having large data storage capacity, low cost compared to passive electronic tags, being small in size, being convenient to use, and having high reliability and service life, and is therefore being applied to an increasing number of fields and industries.

[0004] Currently, UHF RFID systems generally employ two types of readers: fixed readers and mobile readers. Both types of readers have a radio frequency transmitting link and a radio frequency receiving link in the same device. This limits the size of the device, resulting in low isolation between the radio frequency transmitting link and the radio frequency receiving link. This results in poor receiver sensitivity and limits the operating distance of the UHF RFID system. Summary of the Invention [Problem to be solved by the invention]

[0005] The technical problem that the present disclosure aims to solve is the problem that the isolation between the radio frequency transmitting link and the radio frequency receiving link of the reader adopted in the conventional UHF RFID system is small, resulting in poor receiving sensitivity of the reader and limiting the operating distance of the UHF RFID system. [Means for solving the problem]

[0006] To solve the above technical problems, embodiments of the present disclosure provide a radio frequency identification system, a signal processing method thereof, and a storage medium.

[0007] A radio frequency identification system, comprising: a host device, a reader, a first communication device, an exciter, and an RFID tag, wherein the host device is communicatively coupled to the reader, and the reader and the exciter communicate with each other via the first communication device; The upper device is used to obtain the current working state of the reader, and if the current working state is active, it configures the MAC addresses and IP addresses of the reader and the exciter and activates a wired network mode between the reader and the exciter; the reader is adapted to transmit a forward carrier signal to the exciter via a network switching device of the first communication device in response to the wired network mode being activated; the exciter is used to transmit the forward carrier signal over the air; In response to receiving the forward carrier signal, the RFID tag is used to modulate the forward carrier signal to generate a reverse transmission signal and transmit the reverse transmission signal over the air to the reader.

[0008] A method of signal processing applied to a radio frequency identification system provided in any embodiment of the present application, the method comprising: The upper device acquires the current operating status of the reader; The upper device configures MAC addresses and IP addresses of the reader and an exciter associated with the reader according to the current operating state being an active state; The upper device activates a wired network mode between the reader and the exciter, so that the reader sends a forward carrier signal to the exciter via a network switching device of the first communication device; the exciter transmitting the forward carrier signal over the air; In response to receiving the forward carrier signal, the RFID tag modulates the forward carrier signal to generate a reverse transmission signal and transmits the reverse transmission signal over the air to the reader.

[0009] A computer-readable storage medium having computer-executable instructions stored therein, the computer-executable instructions, when executed by a processor, causing the processor to implement a signal processing method provided in any of the embodiments of the present application.

[0010] A computer program product, the computer program product comprising a computer program, which when executed by a processor causes the processor to implement the method of signal processing provided in any embodiment of the present application.

[0011] The details of one or more embodiments of the present application are set forth in the drawings and description that follow. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram of a configuration of a radio frequency identification system provided in one embodiment of the present disclosure; [Figure 2] FIG. 10 is a schematic diagram of a configuration of a radio frequency identification system provided in another embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of a configuration of a radio frequency identification system provided in another embodiment of the present disclosure. [Figure 4] FIG. 10 is a schematic diagram of a configuration of a radio frequency identification system provided in yet another embodiment according to the present disclosure. [Figure 5] FIG. 10 is a schematic diagram of a configuration of a radio frequency identification system provided in yet another embodiment according to the present disclosure. [Figure 6] FIG. 2 is a schematic diagram of an exemplary embodiment of the present disclosure in which different exciters transmit forward carrier signals at different frequencies. [Figure 7] 1 is a schematic diagram of a configuration of a radio frequency identification system according to a specific embodiment of the present disclosure; [Figure 8] FIG. 1 is a schematic diagram of a radio frequency identification system according to another specific embodiment of the present disclosure. [Figure 9] 1 is a schematic diagram of a process of a signal processing method provided in one embodiment of the present disclosure; [Figure 10] FIG. 10 is a schematic diagram of a process of a signal processing method provided in another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] As the application field of UHF RFID continues to expand, there is an increasing market demand for long-range UHF RFID systems with operating distances of over 50 meters. To increase the operating distance of UHF RFID systems, UHF RFID system readers must have high receiving sensitivity. Furthermore, to promote large-scale application of UHF RFID systems, it is necessary to further reduce the cost, power consumption, and size of readers. Furthermore, with the development of the Internet of Passive Things, facilitating networking between UHF RFID readers and improving inventory efficiency are also new requirements for UHF RFID systems.

[0014] In conventional UHF RFID systems, common readers include fixed readers and mobile readers, both of which have a radio frequency transmitting link and a receiving link in the same device. The advantages are that the radio frequency transmitting link and the receiving link share a clock source, the carrier signal is eliminated using self-interference cancellation technology, and the transmitting link and the receiving link are in the same device, which reduces the reader size to some extent. However, when the reader size is limited, the separation between the radio frequency transmitting link and the receiving link is small, and the carrier signal power is high, it is difficult to completely eliminate the interference, which affects the receiving sensitivity of the reader and causes the operating distance of the UHF RFID system to be limited.

[0015] Furthermore, some UHF RFID systems are built using a dedicated reader chip as a reader, and the dedicated reader chip uses a switch time-division switching method to realize time-division use of the radio frequency transmission link and the reception link, thereby achieving the effect of separating the radio frequency transmission link and the reception link. However, in this time-division use of the transmission link and the reception link, the dedicated card reader chip still cannot transmit a carrier signal during the process of receiving a tag signal through the reception link, and there is a frequency offset between the transmission link and the reception link, so the traditional dedicated card reader chip cannot eliminate carrier signals from different sources, and as a result, the dedicated card reader chip is affected by the carrier signal, its reception sensitivity is not high, and it cannot achieve long-distance reception.

[0016] To address the above-mentioned problems, the present disclosure provides a radio frequency identification system that uses an exciter to transmit the forward carrier signal emitted by the reader, thereby separating the transmitting side of the forward carrier signal from the receiving side of the reverse transmission signal, reducing the interference of the forward carrier signal with the reader receiving the reverse transmission signal of the RFID tag, and further improving the receiving sensitivity of the reader. In the solution of the present disclosure, the upper device acquires the current working state of the reader. If the acquired current working state is an active state, it configures the MAC addresses and IP addresses of the reader and the exciter and activates a wired network mode between the reader and the exciter, so that signals can be transmitted between the reader and the exciter via the network switching device of the first communication device. Compared with the technology of transmitting signals between the reader and the exciter using a wireless networking method, using a network switching device to realize signal transmission in a wired manner has better signal demodulation quality and is less susceptible to interference caused by the wireless channel environment. In addition, signal transmission between the reader and the exciter can be realized by using the existing switching network in the actual environment. This not only reduces the system deployment cost, but also has the following beneficial effects:

[0017] (1) Compared with the prior art technology that uses wireless networking to transmit signals between the reader and the exciter, this solution uses a network switching device to realize a wired networking between the reader and the exciter, which makes the demodulation quality of the information exchange signal better and less susceptible to interference from the wireless channel environment. In addition, the current 840-845M frequency band is regulated by equipment, and there is little wireless frequency band resource available between the reader and the exciter. Using a wired networking method avoids the limitation of limited wireless frequency band resource, and ensures that when the reader uses different frequency points to simultaneously transmit signals to multiple exciters, interference between signals is reduced, making the information transmitted between the reader and the exciter via the wired networking method more reliable.

[0018] (2) By using a network switching device to realize a wired networking method, it is possible to support Power Over Ethernet (POE) for the exciter, which facilitates quick networking of the exciter and reduces the installation labor required for power acquisition of the exciter device during construction.

[0019] (3) In conventional technologies using wireless network mode between a reader and an exciter, the modulation time interval of the pulse interval encoding (PIE) signal using RFID is usually set to 6.25 μs to 25 μs. Due to the different modulation time interval settings, when considering the digital signal demodulation processing time, the delay between the exciter receiving and demodulating the reader's forward link signal is greater than 10 μs. However, this solution uses a network switching device to realize wired networking between the reader and the exciter, and transmits signals using wired TCP-IP packets, ensuring that the delay is less than 10 μs. This effectively solves the problem of long delays in conventional wireless transmission methods and can meet the delay requirements for exciter-to-reader transmission.

[0020] (4) By using a network switching device to realize a wired networking method, it can better meet the transmission scenarios where the reader and exciter have large data volumes and low real-time requirements. For example, the reader can perform software updates to the exciter and transmit the software update package more effectively than in wireless scenarios.

[0021] 1 is a schematic diagram of the configuration of a radio frequency identification system provided in one embodiment of the present disclosure. As shown in FIG. 1, the radio frequency identification system 10 includes an upper device 160, a reader 110, a first communication device 120, an exciter 130, and an RFID tag 150. The upper device 160 is communicatively connected to the reader 110. The communicative connection may be wireless or wired, and the present disclosure is not limited thereto. The reader 110 and the exciter 130 exchange information via the first communication device 120. The dashed lines in FIG. 1 indicate messages transmitted through air.

[0022] The exciter 130 may also be a digital demodulation amplify-and-transfer exciter, including multiple units such as an analog-to-digital converter (AD), a field programmable gate array (FPGA), a digital-to-analog converter (DA), and a power amplifier (PA), or the exciter 130 may be an analog amplify-and-transfer exciter, including an analog signal amplification unit.

[0023] In an embodiment of the present disclosure, the upper device 160 obtains the current operating status of the network adapter in the reader 110. If the current operating status is active, the upper device 160 configures the MAC (Media Access Control Address) and IP address of the reader 110 and the exciter 130, and activates a wired network mode between the reader 110 and the exciter 130. In response to the activation of the wired network mode, the reader 110 transmits a forward carrier signal to the exciter 130 via a network switching device of the first communication device 120, where the network switching device may be, for example, a switch, a hub, etc. After receiving the forward carrier signal, the exciter 130 transmits the forward carrier signal through the air via an antenna of the exciter 130. As can be understood, when the reader 110 and the exciter 130 transmit signals via the network switching device, they transmit based on the configured MAC address and IP address. In response to the received forward carrier signal, the RFID tag 150 modulates the forward carrier signal to generate a reverse transmission signal, which may include bit information including, but not limited to, a product code, sensing data, environmental data, etc. The RFID tag 150 then transmits the generated reverse transmission signal through the air to the reader 110, so that the reader 110 can demodulate and store the included bit information from the reverse transmission signal and complete an inventory for the RFID tag 150.

[0024] Additionally, the forward carrier signal may be, but is not limited to, a single-tone carrier signal, a narrowband constant envelope phase modulated signal, or a wideband phase modulated / frequency modulated signal.

[0025] In an embodiment of the present disclosure, information is exchanged between the reader 110 and the exciter 130 via a network switching device of the first communication device 120, and compared to a switching method using wireless communication, communication is performed using the network switching device of the first communication device 120, thereby allowing the reader 110 to transmit a forward carrier signal with lower power to the exciter 130, thereby reducing the power of the signal transmitted by the reader 110.

[0026] In an embodiment of the present disclosure, the first communication device 120 includes at least a network switching device, thereby realizing wired networking between the reader 110 and the exciter 130. The reader 110 can transmit a forward carrier signal to the exciter 130 via the wired network, transmit broadcast messages and synchronization messages to the exciter 130 based on TCP-IP packets, and receive confirmation messages, access request messages, etc. returned by the exciter 130 based on TCP-IP packets. When the reader 110 transmits a message to the exciter 130 based on TCP-IP packets, it can also transmit a control message to the exciter 130 to instruct the exciter 130 to transmit a forward carrier signal. The control message may include a message such as a period for transmitting the forward carrier signal and a frequency of the forward carrier signal. Thus, after receiving the control message, the exciter 130 generates a forward carrier signal based on the period and frequency included in the control message and periodically transmits the forward carrier signal, eliminating the need for the reader 110 to continuously transmit the forward carrier signal to the exciter 130.

[0027] In an embodiment of the present disclosure, the reader 110 supports Dynamic Host Configuration Protocol (DHCP) and manual static configuration as a method for allocating the IP address of the exciter 130 managed by the reader 110. The association relationship between the reader 110 and the exciter 130 can be realized by binding the serial number (SN) of the reader 110 to the SN of the exciter 130, and the binding process is executed by the host device 160. Specifically, the host device 160 can acquire the SN of the reader 110 and the SN of the exciter 130. The SN acquisition can be performed by manual input or automatic reading. After acquiring the SN of the reader 110 and the SN of the exciter 130, the host device 160 binds the SN of the reader 110 to the SN of the exciter 130 that the reader 110 needs to manage, for example, by the method of "SN of reader 110 + SN of exciter 130". One leader 110 can manage multiple exciters 130, and the SN of the leader 110 and the SN of the exciters 130 have a one-to-many relationship. In practical applications, one leader 110 can bind with up to 32 exciters 130, and one or two stages of network switching devices can be used for networking between the leader 110 and the exciter group (i.e., multiple exciters 130 managed by the leader 110).

[0028] In addition, in the embodiment of the present disclosure, the reader 110 can communicate with multiple exciters 130 via the first communication device 120, and there are usually multiple RFID tags 150 in the environment. FIG. 1 illustrates the present disclosure using only one exciter 130 and one RFID tag 150 as an example, but this is not intended to limit the present disclosure.

[0029] In a radio frequency identification system according to an embodiment of the present disclosure, an upper device acquires the current working state of a reader. If the acquired current working state is active, the upper device configures the MAC addresses and IP addresses of the reader and the exciter and activates a wired network mode between the reader and the exciter, thereby enabling signal transmission between the reader and the exciter via a network switching device of a first communication device. Compared with a technology that transmits signals between the reader and the exciter using a wireless networking method, using a network switching device to transmit signals in a wired manner has better signal demodulation quality and is less susceptible to environmental interference in the wireless channel. Furthermore, signal transmission between the reader and the exciter can be achieved using an existing network switching device in the actual environment, thereby reducing system deployment costs. In this solution, after activating the wired network mode between the reader and the exciter, the reader transmits a forward carrier signal to the exciter via the network switching device of the first communication device, and the exciter then transmits the forward carrier signal over the air. When the RFID tag receives the forward carrier signal, it modulates the forward carrier signal to generate a reverse transmission signal, and then transmits the reverse transmission signal to the reader through the air. By adopting the solution disclosed in the present disclosure, an exciter is used to transmit the forward carrier signal emitted by the reader, thereby separating the transmitting side of the forward carrier signal and the receiving side of the reverse transmission signal, thereby reducing the interference of the forward carrier signal with the reader receiving the reverse transmission signal of the RFID tag, and further improving the receiving sensitivity of the reader.

[0030] In one optional embodiment of the present disclosure, the upper device 160 is further configured to activate a wireless network mode between the reader 110 and the exciter 130 when the current operating state is an inactive state. In response to the activation of the wireless network mode, the reader 110 is further configured to transmit a forward carrier signal to the exciter 130 via a power divider and combiner of the first communication device 120. Upon receiving the forward carrier signal, the exciter 130 transmits the forward carrier signal over the air. In response to receiving the forward carrier signal, the RFID tag 150 modulates the forward carrier signal to generate a reverse transmission signal, which may include bit information, including, but not limited to, a product code, sensing data, environmental data, etc. The RFID tag 150 then transmits the generated reverse transmission signal over the air to the reader 110, which then demodulates and stores the bit information contained in the reverse transmission signal to complete an inventory of the RFID tag 150.

[0031] In this embodiment, the first communication device 120 further includes a power divider and combiner, which are used by the reader 110 to transmit broadcast messages, synchronization messages, etc. to control the exciter 130 based on the radio frequency signal, and to receive confirmation messages, access request messages, etc. returned by the exciter 130 based on the radio frequency signal, and also to receive combined signals sent by the combined network to the reader 110. The reader 110 transmits a forward carrier signal to the power divider and combiner of the first communication device 120 based on the radio frequency signal, and the forward carrier signal is forwarded to the exciter 130 by the power divider and combiner of the first communication device 120. In this communication method, the reader 110 needs to continuously transmit a forward carrier signal to the exciter 130.

[0032] As can be understood, the exciter 130 transmits a forward carrier signal through the air, transmitting in all directions and not directional to the RFID tag 150, so that not only the RFID tag 150 can receive the forward carrier signal transmitted by the exciter 130, but also the reader 110 can receive the forward carrier signal transmitted by the exciter 130 through the air, that is, the air interface signal received by the reader 110 through the air not only includes the forward carrier signal from the exciter 130, but also includes the backward transmission signal from the RFID tag 150, and the forward carrier signal from the exciter 130 will interfere with the reader 110 receiving the backward transmission signal of the RFID tag 150 through the air, and affect the reader 110's discrimination of the backward transmission signal. Based on this, in one alternative embodiment of the present disclosure, based on the example shown in Fig. 1, as shown in Fig. 2, the radio frequency identification system 10 further includes a combining network 140, where the exciter 130 not only transmits the forward carrier signal over the air upon receiving the forward carrier signal, but also transmits the forward carrier signal to the combining network 140, which combines the forward carrier signals emitted by the exciter 130 to generate a combined signal. The combining network 140 and the reader 110 are connected via the first communication device 120, and the generated combined signal is transmitted to the reader 110 via a power divider and combiner of the first communication device 120. The reader 110 then uses the received combined signal to cancel interference from the air interface signal received over the air, thereby canceling the interference of the forward carrier signal with the reverse transmission signal of the air interface signal.

[0033] Here, the combining network 140 generates a combined signal based on the forward carrier signal, for example, the forward carrier signal can be used as the combined signal. Since the combined signal does not contain any noise signals other than the forward carrier signal, the combined signal can be used to remove interference from the air interface signal, for example, by subtracting the air interface signal from the combined signal, thereby effectively removing the forward carrier signal in the air interface signal, and further removing interference from the reverse transmission signal, thereby improving the receiving sensitivity of the reader 110.

[0034] In one optional embodiment of the present disclosure, when the reader 110 uses the combined signal to cancel interference from the air interface signal received by the air interface, the reader 110 can first modulate the combined signal according to a stepping scheme to obtain a modulated signal, where the width and / or phase of the combined signal can be modulated according to a stepping scheme, then subtract the modulated signal from the air interface signal to generate a combined signal, then obtain the power of the combined signal, compare the power of the combined signal with a preset power threshold, and if the power of the combined signal is less than the power threshold, determine that the cancellation effect has converged and interference cancellation has been completed, and then demodulate the combined signal, thereby demodulating the product code, sensing data, environmental data, etc. transmitted by the RFID tag 150 from the combined signal. If the power of the current combined signal is greater than or equal to the power threshold, modulate the combined signal again according to the stepping method to generate a new modulated signal, and subtract the new modulated signal from the air interface signal to generate a new combined signal, determine whether the power of the new combined signal is less than the power threshold, and repeat the above process until the power of the combined signal is less than the power threshold, and then complete the interference cancellation and demodulate the combined signal whose power is less than the power threshold.

[0035] It should be noted that step modulation is a currently common signal modulation method, and the present disclosure does not describe the specific process of step modulation in detail.

[0036] In an alternative embodiment of the present disclosure, the host device 160 may also be used to manage the networking parameters of the reader 110 and, by the reader 110, the networking parameters of the exciter 130.

[0037] For example, the networking parameters of the reader 110 and the exciter 130 managed by the upper device 160 may include, but are not limited to, physical layer configuration parameters of the reader 110 and the exciter 130, including frequency point, bandwidth, encoding method, forward link message, inventory mode (cache mode or real-time mode), exciter transmit power, synchronization mode, etc.

[0038] In an embodiment of the present disclosure, when the host device 160 manages the networking parameters of the reader 110, it transmits the networking parameter configuration information of the reader 110 to the reader 110, and the reader 110 configures the networking parameters based on the received networking parameter configuration information. When the host device 160 manages the networking parameters of the exciter 130, it transmits the networking parameter configuration information of the exciter 130 to the reader 110, and the reader 110 then transfers the networking parameter configuration information to each exciter 130 within its coverage area, and each exciter 130 configures its own networking parameters based on the received networking parameter configuration information.

[0039] In an embodiment of the present disclosure, there may be one or more readers 110 communicatively connected to the host device 160. The host device 160 can simultaneously manage multiple readers 110, and although FIG. 1 illustrates an example in which one reader 110 is connected to the host device 160, this is not intended to limit the present disclosure.

[0040] In an embodiment of the present disclosure, by allowing a host device to be communicatively connected to a reader, the host device can simultaneously set networking parameters for multiple readers, realizing rapid deployment of a radio frequency identification system; multiple readers can be connected to multiple exciters, thereby identifying multiple RFID tags, realizing continuous coverage of the deployment area, and efficiently identifying related information attached to a large number of RFID tags.

[0041] In one alternative embodiment of the present disclosure, the number of readers 110 is multiple, the multiple readers 110 share a single network switching device, and the exciters 130 managed by different readers 110 are isolated by a port-based Virtual Local Area Network (VLAN).

[0042] In an embodiment of the present disclosure, the first communication device 120 may include at least one network switching device. When the upper device 160 manages multiple readers 110, the multiple readers 110 may share one network switching device or may be grouped together to use multiple network switching devices. When multiple readers 110 are installed in the same network switching device, the exciters 130 managed by each reader 110 are connected to the corresponding reader 110 via the same network switching device in the first communication device 120. To improve network security, the exciters 130 managed by different readers 110 are isolated by port VLANs, and all the exciters 130 managed by the same reader 110 are maintained in the same network segment. The network switching device is responsible for adding and separating VLAN identifiers.

[0043] In one alternative embodiment of the present disclosure, as shown in FIG. 3, based on the embodiment shown in FIG. 1, for example, the radio frequency identification system 10 may further include a second communication device 170, and the upper device 160 and the reader 110 are communicatively connected via the second communication device 170.

[0044] Illustratively, the second communication device 170 may be a network switching device or other communication devices such as WiFi, radio frequency communication devices, etc. The present disclosure does not limit the specific form of the second communication device. When the second communication device 170 is a network switching device, the upper device 160 and the reader 110 are connected via a network port of the network switching device, and the IP address of each reader 110 is managed by the upper device 160.

[0045] In an embodiment of the present disclosure, as shown in Fig. 3, the upper device 160 can connect to and manage multiple readers 110 via the second communication device 170, and the upper device 160 can exchange control messages with the multiple readers 110 via the second communication device 170. Fig. 3 only shows one reader 110 connected to the first communication device 120, and other readers 110 have a similar connection structure. Other readers 110 may be connected to exciters within the coverage area via other first communication devices, which are not shown in detail in Fig. 3.

[0046] In an alternative embodiment of the present disclosure, the radio frequency identification system provided by the present disclosure may further include a synchronization clock source to provide a clock reference signal and broadcast it to each network unit in the radio frequency identification system. As shown in FIG. 4, based on the embodiment shown in FIG. 1, for example, the radio frequency identification system 10 may further include a synchronization clock source 180 to transmit a clock reference signal to the host device 160 and the reader 110. The reader 110 is further used to transmit the clock reference signal to the exciter 130 via the first communication device 120. Upon receiving the clock reference signal, the network units such as the host device 160, the reader 110, and the exciter 130 can perform standard clock recovery based on the clock reference signal, thereby ensuring synchronization of the clocks of each network unit in the radio frequency identification system.

[0047] Furthermore, in one optional embodiment of the present disclosure, as shown in FIG. 5, based on the embodiment shown in FIG. 4, the radio frequency identification system 10 may further include a second communication device 170, wherein the communication connection between the upper device 160 and the reader 110 is via the second communication device 170, and the synchronization clock source 180 is connected to the second communication device 170.

[0048] In an embodiment of the present disclosure, the synchronous clock source 180 can provide a clock reference signal to broadcast to each network unit, including the reader 110, the host device 160, the exciter 130, etc., in the radio frequency identification system. Specifically, the synchronous clock source 180 can transmit the clock reference signal to the host device 160 and the reader 110 via the second communication device 170. Upon receiving the clock reference signal, the reader 110 not only recovers a standard clock based on the clock reference signal, but also transmits the clock reference signal to each exciter 130 within its coverage area via the first communication device 120. Upon receiving the clock reference signal, the network units, such as the host device 160, the reader 110, and the exciter 130, can recover a standard clock based on the clock reference signal, thereby ensuring clock synchronization of each network unit in the radio frequency identification system. Different exciters 130 connected to the same reader 110 can transmit forward carrier signals at the same frequency, and the signal received by the reader 110 will not be interfered with by frequency differences between the exciters 130.

[0049] In practical applications, multiple exciters 130 are typically connected within the coverage area of ​​one reader 110. When the multiple exciters 130 simultaneously transmit forward carrier signals, interference occurs between the forward carrier signals transmitted by each exciter 130. To avoid interference between the forward carrier signals, each exciter 130 needs to be controlled to transmit its forward carrier signal at a different time, so that only one exciter 130 transmits its forward carrier signal at the same time. However, transmitting the forward carrier signal in a time-division manner reduces the utilization rate of frequency domain resources. To address this issue, in one alternative embodiment of the present disclosure, for multiple exciters 130 connected to the same reader 110, the multiple exciters 130 transmit their forward carrier signals at the same time, and the frequencies of the forward carrier signals transmitted by any two exciters 130 are different.

[0050] For example, if four exciters are connected to one reader, the four exciters will simultaneously transmit forward carrier signals, and the frequencies of the transmitted forward carrier signals will be f0, f1, f2, and f3, respectively, as shown in Figure 6. That is, each exciter will transmit a forward carrier signal with a fixed frequency, and the frequencies of the forward carrier signals transmitted by different exciters will be different.

[0051] In an embodiment of the present disclosure, different exciters connected to the same reader simultaneously transmit forward carrier signals, and the frequencies of the transmitted forward carrier signals are different from each other. By transmitting forward carrier signals simultaneously, the efficiency of the reader's inventory of RFID tags can be improved. In addition, by transmitting forward carrier signals of different frequencies, the interference between the forward carrier signals can be avoided, and the interference caused by power leakage when different exciters transmit forward carrier signals asynchronously can be eliminated.

[0052] In one alternative embodiment of the present disclosure, the power of the forward carrier signal transmitted by the reader 110 to the exciter 130 is a first power, which is relatively small. To ensure that the forward carrier signal can successfully wake up the RFID tag 150, before transmitting the forward carrier signal, the exciter 130 may first power amplify the forward carrier signal to generate a forward carrier signal of a second power, and then transmit the forward carrier signal of the second power through the air, where the second power is greater than the first power.

[0053] 7 is a schematic diagram of the configuration of a radio frequency identification system according to a specific embodiment of the present disclosure. As shown in FIG. 7, the radio frequency identification system includes an upper device, a network switching device, multiple readers, a power divider / combiner, a coupling network, multiple exciters, and multiple groups of RFID tags, where each group of RFID tags may include multiple RFID tags. The upper device is communicatively connected to the multiple readers via the network switching device and is primarily used to manage the multiple readers and exciters in the network and collect and process information related to RFID tags in the system. A reader may be connected to the multiple exciters via the power divider / combiner and is primarily used to manage the multiple exciters within its coverage area and receive and process reverse transmission signals transmitted by RFID tags in the system. The power divider / combiner is used to transmit forward carrier signals, clock reference signals, broadcast messages, etc. based on radio frequency signals, and to receive access request messages, confirmation messages, etc. returned by the exciters based on radio frequency signals, and coupled signals generated by the coupling network. The exciter transmits a forward carrier signal through the air to energize the RFID tag and control it, and then continues to transmit the forward carrier signal, so that the woken-up RFID tag generates a reverse transmission signal by modulating the forward carrier signal. The exciter supports the function of analyzing the received reader broadcast message, and based on the radio frequency signal, analyzes and obtains networking parameters including information such as frequency point, bandwidth, encoding method, exciter transmission power, and synchronization mode, and transmits the access request message and confirmation message to the reader via the radio frequency signal.

[0054] As shown in FIG. 7, the exciter is provided with an analog-to-digital converter (AD), a field programmable gate array (FPGA), a digital-to-analog converter (DA), and a power amplifier (PA). Before transmitting a forward carrier signal, the exciter first performs analog-to-digital conversion on the forward carrier signal using the AD. The analog-to-digital converted signal is then digitally demodulated by the FPGA. The demodulated signal is then digital-to-analog converted by the DA. The resulting analog signal is then power-amplified by the PA. The power-amplified forward carrier signal is transmitted over the air interface and combined with a combining network to generate a combined signal, which is then transmitted to the reader via a power divider / combiner. The reader then uses the combined signal to perform interference cancellation, thereby reducing the interference of the forward carrier signal transmitted over the air by the exciter with the reverse transmission signal received by the reader, thereby improving the receiving sensitivity of the reader and further increasing the success rate of RFID tag inventory.

[0055] FIG. 8 is a schematic diagram of the configuration of a radio frequency identification system according to another specific embodiment of the present disclosure. As shown in FIG. 8, the radio frequency identification system includes an upper device, a network switching device, multiple readers, a power divider / combiner, a wired coupling network, multiple exciters, and multiple RFID tag groups, where each RFID tag group may include multiple RFID tags. Note that the functions of each network unit in this embodiment are the same as those of each network unit in the embodiment shown in FIG. 7, and to avoid redundancy, they will not be repeated here. As shown in FIG. 8, the exciter is provided with an analog signal amplification unit. Before the exciter transmits a forward carrier signal, the analog signal amplification unit first power amplifies the forward carrier signal. The power-amplified forward carrier signal is then transmitted through the air and coupled into the wired coupling network to generate a combined signal, which is then transmitted to the reader via the power divider / combiner. The reader then uses the combined signal to perform interference cancellation. In this embodiment, a wired coupling network is used for coupling to generate a coupled signal. Compared with the method of coupling via the air interface, the loss in the wired signal transmission process is smaller than that of wireless transmission, and wired transmission avoids interference from other signals in the air interface. This means that the signal quality of the coupled signal received by the reader is better, which is favorable for improving the cancellation effect, improving the receiving sensitivity of the reader, and further improving the success rate of RFID tag inventory.

[0056] The radio frequency identification system provided in the embodiments of the present disclosure can be quickly deployed in complex industrial application scenarios, efficiently identify relevant information attached to a large number of passive tags, and is applicable to the fields of ultra-high frequency RFID, passive Internet of Things, and mobile communications.

[0057] To realize the above embodiment, the present disclosure further provides a signal processing method, which is applied to the radio frequency identification system described in the above embodiment. The radio frequency identification system includes at least an upper device, a reader, a first communication device, an exciter, and an RFID tag, and the reader and the exciter exchange information via the first communication device. Figure 9 is a process schematic diagram of the signal processing method provided in one embodiment of the present disclosure. As shown in Figure 9, the signal processing method may include the following steps:

[0058] In step 301, the upper device obtains the current working status of the reader.

[0059] In an embodiment of the present disclosure, a host device and a reader of a radio frequency identification system are communicatively connected, and the host device can obtain the current operating status of the network adapter in the reader.

[0060] Here, the operating state of the network adapter includes two states, an active state and an inactive state, and the current operating state acquired by the higher-level device is either the active state or the inactive state.

[0061] In step 302, the upper device configures the MAC address and IP address of the reader and the exciter associated with the reader according to the current working state being active.

[0062] In an embodiment of the present disclosure, if the current operating state acquired by the upper device is an active state, the upper device can further configure the MAC address and IP address of the reader, and further configure the MAC address and IP address of the exciter associated with the reader, so as to perform wired network communication between the reader and the exciter.

[0063] In step 303, the upper device activates a wired network mode between the reader and the exciter, so that the reader sends a forward carrier signal to the exciter via a network switching device of the first communication device.

[0064] In an embodiment of the present disclosure, if the current operating state acquired by the upper device is an active state, in addition to configuring the MAC address and IP address, it will activate a wired network mode between the reader and the exciter, and then the reader and the associated exciter can perform wired networking via the network switching device of the first communication device, and the reader will send a forward carrier signal to the exciter via the wired network provided by the network switching device.

[0065] Furthermore, the host device can further activate a wireless network mode between the reader and the exciter in response to the current operating state being an inactive state.

[0066] In an embodiment of the present disclosure, if the current working status acquired by the upper device is inactive, it means that the network adapter of the reader is unavailable, and at this time, the upper device can activate the wireless network mode between the reader and the exciter, thereby performing wireless networking between the reader and the associated exciter, and the reader sends a forward carrier signal to the exciter via a wireless network (e.g., a radio frequency signal).

[0067] In step 304, an exciter receives a forward carrier signal and transmits the forward carrier signal over the air.

[0068] In step 305, in response to receiving the forward carrier signal, the RFID tag modulates the forward carrier signal to generate a reverse transmission signal, and transmits the reverse transmission signal over the air to the reader.

[0069] Specifically, the forward carrier signal may be received by a reader or may be received by an RFID tag, where, when the forward carrier signal is received by the RFID tag, the forward carrier signal is modulated to generate a reverse transmission signal according to the forward carrier signal, and the generated reverse transmission signal is transmitted to the reader through the air, completing the signal processing of the transmission link and the reception link of the radio frequency identification system.

[0070] In the signal processing method of the embodiment of the present disclosure, the upper device obtains the current working state of the reader. If the current working state is an active state, the MAC address and IP address of the reader and the exciter associated with the reader are configured, and a wired network mode between the reader and the exciter is activated, so that the reader sends a forward carrier signal to the exciter via the network switching device of the first communication device. If the current working state is an inactive state, a wireless network mode between the reader and the exciter is activated, thereby realizing flexible networking between the reader and the exciter. When the reader and the exciter transmit signals via the network switching device, compared with the technology of transmitting signals between the reader and the exciter using a wireless networking method, using a network switching device to realize a wired transmission signal has better signal demodulation quality and is less susceptible to environmental interference in the wireless channel. In addition, by using an existing network switching device in a real environment, signal transmission between the reader and the exciter can be realized, thereby reducing the system construction cost.

[0071] In an alternative embodiment of the present disclosure, the radio frequency identification system may further include a combining network to generate a combined signal, which the reader may use to perform interference cancellation on the air interface signal and improve the receiving sensitivity of the reader. As shown in Figure 10, the signal processing method provided by the present disclosure and applied to the radio frequency identification system may further include the following steps:

[0072] In step 201, a combined signal is received via the first communication device, the combined signal being generated by the combining network combining forward carrier signals transmitted by the exciter.

[0073] Here, the first communication device may include a power divider and a combiner, or may further include a network switching device.

[0074] As described above, the exciter transmits a forward carrier signal through the air, and both the reader and the RFID tag within the radio coverage area can receive the forward carrier signal through the air. When the RFID tag receives the forward carrier signal, it modulates it to generate a reverse transmission signal. The reverse transmission signal may include a product code, environmental data, sensing data, etc., and then transmits the reverse transmission signal through the air to the reader. Therefore, the air interface signal received by the reader through the air includes not only the reverse transmission signal from the RFID tag but also the forward carrier signal from the exciter. To eliminate the interference of the forward carrier signal in the air interface signal, in an embodiment of the present disclosure, a combining network is provided in the radio frequency identification system. In addition to transmitting the forward carrier signal through the air, the exciter transmits the forward carrier signal to the combining network, combines the forward carrier signals through the combining network to generate a combined signal, and transmits the combined signal to the reader via the connected first communication device.

[0075] In step 202, the combined signal is used to perform interference cancellation on air interface signals received over the air, the air interface signals including the reverse transmission signal transmitted by the RFID tag and the forward carrier signal transmitted by the exciter.

[0076] In an embodiment of the present disclosure, when the reader receives the combined signal via the first communication device, the reader can perform interference cancellation on the air interface signal received over the air to remove the forward carrier signal in the air interface signal.

[0077] Illustratively, the air interface signal can be subtracted from the combined signal to achieve the purpose of eliminating interference.

[0078] In an embodiment of the present disclosure, a combining network is provided in the radio frequency identification system, which combines based on the forward carrier signal to generate a combined signal, and the reader can use the combined signal to perform interference cancellation on the air interface signal received through the air, and cancel the interference caused by the forward carrier signal in the air interface signal on the reverse transmission signal from the RFID tag, thereby reducing the upstream receiving interference power of the reader, further improving the receiving sensitivity of the reader, and increasing the operating distance and coverage of the radio frequency identification system.

[0079] In one optional embodiment of the present disclosure, when the reader uses the combined signal to perform interference cancellation on the air interface signal received over the air, the reader first modulates the combined signal according to a stepping method to obtain a modulated signal, subtracts the modulated signal from the air interface signal to generate a combined signal, obtains the power of the combined signal, and if the power of the combined signal is less than a power threshold, determines that the interference cancellation is complete, demodulates the combined signal, and can identify the product code, sensing data, environmental data, etc. contained in the reverse transmission signal.

[0080] Here, the power threshold can be set according to actual needs, and the present disclosure does not limit the specific value of the power threshold.

[0081] In an embodiment of the present disclosure, the power of the currently generated combined signal is compared with a power threshold. If the power of the currently generated combined signal is greater than or equal to the power threshold, the combined signal is again modulated according to a stepping method to generate a new modulated signal, and the new modulated signal is subtracted from the air interface signal to generate a new combined signal. The power of the new combined signal is obtained and compared with the power threshold. If the power is still greater than or equal to the power threshold, the above process is repeated again until the power of the generated combined signal is smaller than the power threshold, and it is determined that interference cancellation is completed, and the current combined signal is demodulated.

[0082] In an embodiment of the present disclosure, the reader performs interference cancellation on the power of the received air interface signal until the power is smaller than a power threshold, so as to minimize the interference caused by the forward carrier signal transmitted by the exciter on the reader receiving the reverse transmission signal, thereby improving the sensitivity performance of the reader and increasing the success rate of the reader's inventory of RFID tags.

[0083] An embodiment of the present disclosure further provides a computer-readable storage medium, wherein computer-executable instructions are stored in the computer-readable storage medium, and when the computer-executable instructions are executed by a processor, the steps of each method embodiment described in the above embodiments are performed, and will not be repeated here to avoid redundancy.

[0084] An embodiment of the present disclosure further provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of each method embodiment described in the above embodiments are performed, and to avoid redundancy, they will not be repeated here. [Industrial Applicability]

[0085] The radio frequency identification system provided by the present disclosure uses an exciter to transmit the forward carrier signal emitted by the reader, thereby separating the transmitting side of the forward carrier signal from the receiving side of the reverse transmission signal, reducing the interference of the forward carrier signal with the reader receiving the reverse transmission signal of the RFID tag, and improving the receiving sensitivity of the reader.

Claims

1. 1. A radio frequency identification system comprising: The system includes a host device, a reader, a first communication device, an exciter, and an RFID tag, the host device is communicatively connected to the reader, and the reader and the exciter exchange information via the first communication device; The upper device is used to obtain the current working state of the reader, and when the current working state is an active state, it configures the MAC address and IP address of the reader and the exciter and activates a wired network mode between the reader and the exciter; the reader is adapted to transmit a forward carrier signal to the exciter via a network switching device of the first communication device in response to the wired network mode being activated; the exciter is used to transmit the forward carrier signal over the air; a radio frequency identification system, characterized in that the RFID tag is used to modulate the forward carrier signal to generate a reverse transmission signal in response to receiving the forward carrier signal, and to transmit the reverse transmission signal through the air to the reader.

2. The host device is further adapted to activate a wireless network mode between the reader and the exciter when the current working state is an inactive state; 2. The radio frequency identification system of claim 1, wherein the reader is further used to transmit a forward carrier signal to the exciter via a power divider and combiner of the first communication device in response to the wireless network mode being activated.

3. the radio frequency identification system further includes a coupling network; the exciter is further used to transmit the forward carrier signal to the combining network; the combining network is connected to the first communication device and is used to combine the forward carrier signals to generate a combined signal, and transmit the combined signal to the reader via a power divider and combiner of the first communication device; 3. The radio frequency identification system of claim 2, wherein the reader is further used to utilize the combined signal to cancel interference from air interface signals received over the air, the air interface signals including the reverse transmission signal and the forward carrier signal.

4. The reader further comprises: modulating the combined signal according to a stepping scheme to obtain a modulated signal; subtracting the air interface signal from the modulated signal to generate a combined signal; 4. The radio frequency identification system of claim 3, wherein if the power of the combined signal is less than a power threshold, it is determined that interference cancellation is complete and is used to demodulate the combined signal.

5. The radio frequency identification system according to any one of claims 1 to 4, characterized in that there are a plurality of readers, the plurality of readers share one of the network switching devices, and exciters managed by different readers are isolated by a port-based virtual local area network.

6. the radio frequency identification system further comprising a synchronous clock source; 6. A radio frequency identification system according to claim 1, wherein the synchronous clock source is used to transmit a clock reference signal to the host device and the reader, and the reader is further used to transmit the clock reference signal to the exciter via the first communication device.

7. the radio frequency identification system further includes a second communication device, and the host device and the reader are communicatively connected via the second communication device; 7. The radio frequency identification system of claim 6, wherein the synchronization clock source is connected to the second communication device and is used to transmit the clock reference signal to the host device and the reader via the second communication device.

8. 8. The radio frequency identification system of claim 6, wherein a plurality of the exciters are connected to the same reader, the plurality of exciters each transmit the forward carrier signal at the same time, and the frequencies of the forward carrier signals transmitted by any two of the exciters are different.

9. the power of the forward carrier signal is a first power; 6. The radio frequency identification system of claim 1, wherein the exciter is further used to power amplify the forward carrier signal to generate a forward carrier signal of a second power, and transmit the forward carrier signal of the second power over the air.

10. A method of signal processing applied to a radio frequency identification system according to any one of claims 1 to 9, comprising: The method comprises: The upper device acquires the current operating status of the reader; The upper device configures MAC addresses and IP addresses of the reader and an exciter associated with the reader according to the current operating state being an active state; The upper device activates a wired network mode between the reader and the exciter, so that the reader transmits a forward carrier signal to the exciter via a network switching device of the first communication device; the exciter transmitting the forward carrier signal over the air; the RFID tag, in response to receiving the forward carrier signal, modulates the forward carrier signal to generate a reverse transmission signal and transmits the reverse transmission signal over the air to the reader.

11. 1. A computer-readable storage medium, comprising:

11. A computer-readable storage medium having computer-executable instructions stored thereon, the computer-executable instructions, when executed by a processor, implementing the method of claim 10.

12. 1. A computer program product comprising: the computer program product includes a computer program; A computer program product, characterized in that the computer program, when executed by a processor, implements the method of claim 10.

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