Communication method, apparatus and system based on spectrum shift modulation and storage medium

Abstract

The application discloses a communication method, device and system based on spectrum shift modulation and a storage medium, and relates to the technical field of radio frequency identification. The method is applied to a reader-writer, and comprises the following steps: in the case that a radio frequency signal is received, performing low-frequency filtering processing on the radio frequency signal to obtain a sideband signal in the radio frequency signal; the sideband signal is obtained by performing chopper modulation on an incident carrier signal based on a first mixed signal by a passive tag, the first mixed signal is obtained by mixing a data stream of the passive tag with a subcarrier signal, and the frequency of the subcarrier signal is higher than the phase noise angular frequency of the reader-writer; and performing down-conversion processing on the sideband signal to obtain the data stream in the sideband signal. Through the above technical means, the data stream is shifted to the sideband frequency band of the incident carrier signal, and the data stream is recovered from the sideband signal, so that the phase noise is effectively filtered, the data stream is prevented from being submerged by the noise skirt, and the reliability of data stream acquisition is improved.

Description

Technical Field

[0001] This application relates to the field of radio frequency identification technology, and in particular to a communication method, apparatus, system and storage medium based on spectrum shift modulation. Background Technology

[0002] In recent years, passive radio frequency identification (RFID) tags have been widely used in scenarios such as item tracking, warehousing and logistics, retail inventory, and smart manufacturing due to their advantages such as not requiring built-in batteries, extremely low cost, small size, and long lifespan. The communication of passive tags relies on a backscattering mechanism; that is, the tag does not actively transmit a carrier wave, but instead modulates the incident continuous wave signal by changing the reflection coefficient of its own antenna, thereby reflecting the identification information stored in the tag to the reader.

[0003] In existing technologies, readers transmit high-frequency continuous waves, which serve both as the operating energy for passive tags and as the carrier signal for information transmission. Passive tags modulate the incident carrier signal by changing the impedance matching state of their antenna ports, thereby loading the stored data stream into the reflected signal. The reader simultaneously receives and demodulates this weak reflected signal at the same frequency, completing the data stream acquisition process. However, the high-frequency continuous waves emitted by the reader can leak into the reader's receiver due to insufficient transmission-reception isolation or environmental reflections, forming strong interference signals. Although the DC shunt in the strong interference signal can be filtered out by DC blocking capacitors, the phase noise introduced by the reader's transmitter is mainly concentrated near the incident carrier frequency, making it impossible to completely eliminate noise interference through simple filtering methods. Secondly, the modulation method used by passive tags concentrates the spectral energy of the data stream near the incident carrier frequency. When the receiver receives the data, the weak data stream happens to fall within the frequency band with the most severe phase noise, easily being completely submerged by the noise skirt, leading to a sharp deterioration in the signal-to-noise ratio. Therefore, the noise interference of the reader itself and the modulation method of the passive tag severely limit the communication distance and reliability of the communication system. Summary of the Invention

[0004] This application provides a communication method, apparatus, system, and storage medium based on spectrum shifting modulation. It uses a passive tag to shift a data stream to the sideband frequency band of the incident carrier signal, generating a sideband signal reflected to the reader. The reader performs low-frequency filtering on the received radio frequency signal to filter out phase noise signals near the incident carrier frequency, retaining the sideband signal carrying the data stream. The sideband signal is then up-converted to shift it to the baseband frequency band, thereby recovering the data stream. This achieves effective filtering of phase noise and avoids the data stream being submerged by noise skirts, improving the reliability of data stream acquisition and solving the problems of limited communication distance and low reliability in existing communication systems.

[0005] In a first aspect, this application provides a communication method based on spectrum shift modulation, applied to a reader / writer, the method comprising:

[0006] Upon receiving a radio frequency signal, the radio frequency signal is subjected to low-frequency filtering to obtain a sideband signal in the radio frequency signal; the sideband signal is obtained by a passive tag chopping and modulating the incident carrier signal based on a first mixing signal, the first mixing signal being obtained by mixing the data stream of the passive tag with a subcarrier signal, and the frequency of the subcarrier signal being higher than the phase noise angular frequency of the reader; The sideband signal is down-converted to obtain the data stream in the sideband signal.

[0007] Secondly, this application provides a communication device based on spectrum shift modulation, applied to a reader / writer, the device comprising: The signal filtering module is configured to perform low-frequency filtering on the received radio frequency signal to obtain a sideband signal in the radio frequency signal; the sideband signal is obtained by a passive tag chopping and modulating the incident carrier signal based on a first mixing signal, the first mixing signal is obtained by mixing the data stream of the passive tag with a subcarrier signal, and the frequency of the subcarrier signal is higher than the phase noise angular frequency of the reader; The data stream acquisition module is configured to perform down-conversion processing on the sideband signal to obtain the data stream in the sideband signal.

[0008] Thirdly, this application provides a communication system based on spectrum shifting modulation, including a passive tag and a reader / writer, wherein: The passive tag is used to mix the data stream with the subcarrier signal to obtain a first mixed signal, chop and modulate the incident carrier signal based on the first mixed signal to obtain a sideband signal, and reflect the radio frequency signal to the reader; the frequency of the subcarrier signal is higher than the phase noise angular frequency of the reader. The reader / writer is configured to perform low-frequency filtering on the received radio frequency signal to obtain a sideband signal in the radio frequency signal; and to perform down-conversion processing on the sideband signal to obtain a data stream in the sideband signal.

[0009] Fourthly, this application provides a computer-readable storage medium storing a program that, when executed by a processor, implements the communication method based on spectrum shift modulation as described in the first aspect.

[0010] In this application, a passive tag mixes a subcarrier signal with a frequency higher than the reader's phase noise angular frequency with a data stream to obtain a first mixed signal. Upon receiving the reader's incident carrier signal, the first mixed signal is used to chop and modulate the incident carrier signal to obtain a sideband signal, which is then reflected back to the reader. After receiving the radio frequency (RF) signal, the reader performs low-frequency filtering to obtain the sideband signal within the RF signal; this sideband signal is then down-converted to obtain the data stream within it. Through these techniques, because the subcarrier frequency is higher than the reader's phase noise angular frequency, the first mixed signal is used to chop and modulate the incident carrier signal, shifting the data information of the data stream to the carrier's sideband frequency band to form a sideband signal. This avoids the carrier's center frequency band, where phase noise is strongest, preventing the data stream from being submerged by noise. The reader performs low-frequency filtering on the RF signal to remove strong phase noise near the carrier frequency, retaining the sideband signal carrying the data information, thus improving the received signal-to-noise ratio. Down-conversion of sideband signals to shift them to the baseband frequency band and recover the data stream significantly improves the communication distance and reliability of the communication system. Attached Figure Description

[0011] Figure 1 This is a flowchart of a communication system based on spectrum shifting modulation provided in an embodiment of this application; Figure 2 This is one of the structural schematic diagrams of the passive tag provided in the embodiments of this application; Figure 3 This is the second schematic diagram of the passive tag structure provided in the embodiments of this application; Figure 4 This is a flowchart of obtaining sideband signals in a radio frequency signal provided in an embodiment of this application; Figure 5 This is a flowchart of the process of acquiring the data stream in the sideband signal provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a communication device based on spectrum shift modulation provided in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of a communication device based on spectrum shift modulation provided in an embodiment of this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application will be described in further detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely for explaining this application and not for limiting it. It should also be noted that, for ease of description, only the parts relevant to this application are shown in the drawings, not all of them. Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. A process can be terminated when its operation is completed, but it may also have additional steps not included in the drawings. A process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0013] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0014] In common existing implementations, the reader transmits a high-frequency continuous wave, which serves both as the power source for the passive tag and as the carrier signal for information transmission. The passive tag modulates the incident carrier signal by changing the impedance matching state of its antenna port, thereby loading the stored data stream into the reflected signal. The reader simultaneously receives and demodulates this weak reflected signal at the same frequency, completing the data stream acquisition process. However, the high-frequency continuous wave transmitted by the reader can leak into the reader's receiver due to insufficient transmission-reception isolation or environmental reflections, forming a strong interference signal. Although the DC shunt in the strong interference signal can be filtered out by DC blocking capacitors, the phase noise introduced by the reader's transmitter is mainly concentrated near the incident carrier frequency, and cannot be completely eliminated by simple filtering methods. Secondly, the modulation method used by the passive tag concentrates the spectral energy of the data stream near the incident carrier frequency. When the receiver receives the data, the weak data stream happens to fall into the frequency band with the most severe phase noise, and is easily completely submerged by the noise skirt, resulting in a sharp deterioration in the signal-to-noise ratio. Therefore, the noise interference of the reader itself and the modulation method of the passive tag severely limit the communication distance and reliability of the communication system.

[0015] To address the aforementioned technical problems, this application proposes a communication method based on spectrum shifting modulation. This method uses passive tags to shift the data stream to the sideband frequency band of the incident carrier signal, generating a radio frequency (RF) signal reflected to the reader. The reader performs low-frequency filtering on the RF signal to filter out phase noise near the incident carrier frequency, retaining the sideband signal carrying the data stream. The sideband signal is then up-converted to shift to the baseband frequency band, thus recovering the data stream. This method effectively filters phase noise and prevents the data stream from being overwhelmed by noise skirts, improving the reliability of data stream acquisition.

[0016] The spectrum shift modulation-based communication method provided in this embodiment can be executed by a spectrum shift modulation-based communication device. This device can be implemented through software and / or hardware, and can consist of two or more physical entities, or a single physical entity. For example, the spectrum shift modulation-based communication device can be a spectrum shift modulation-based communication system. This system includes a passive tag and a reader / writer, wherein: the passive tag is used to mix the data stream with a subcarrier signal to obtain a first mixed signal; the incident carrier signal is chopper-modulated based on the first mixed signal to obtain a sideband signal; and the radio frequency signal is reflected to the reader / writer; the frequency of the subcarrier signal is higher than the phase noise angular frequency of the reader / writer; the reader / writer, upon receiving the radio frequency signal, performs low-frequency filtering on the radio frequency signal to obtain the sideband signal in the radio frequency signal; and down-converts the sideband signal to obtain the data stream in the sideband signal. In this embodiment, extracting the data stream from the radio frequency signal is the execution flow of the communication method; therefore, the spectrum shift modulation-based communication device can also be a reader / writer. Furthermore, the reader includes a transmitter and a receiver. The transmitter is used to send a carrier signal to the passive tag to activate the passive tag, and the receiver is used to receive and process the radio frequency signal reflected by the passive tag. That is, the communication device based on spectrum shift modulation can even be the receiver of the reader.

[0017] The spectrum-shifting modulation-based communication device is equipped with at least one type of operating system, including but not limited to Android, Linux, and Windows. The device can install at least one application based on the operating system; this application can be a built-in application of the operating system or an application downloaded from a third-party device or server. In this embodiment, the spectrum-shifting modulation-based communication device has at least one application capable of executing the spectrum-shifting modulation-based communication method.

[0018] For ease of understanding, this embodiment uses a reader / writer as the main body for implementing the communication method based on spectrum shifting modulation as an example.

[0019] Figure 1 A flowchart of a communication method based on spectrum shift modulation provided in an embodiment of this application is given. (Reference) Figure 1 The steps S110-S120 of the communication method based on spectrum shift modulation specifically include: S110. Upon receiving a radio frequency signal, the radio frequency signal is subjected to low-frequency filtering to obtain a sideband signal in the radio frequency signal. The sideband signal is obtained by the passive tag chopping and modulating the incident carrier signal based on the first mixing signal. The first mixing signal is obtained by mixing the data stream of the passive tag with the subcarrier signal. The frequency of the subcarrier signal is higher than the phase noise angular frequency of the reader.

[0020] The incident carrier signal is the carrier signal transmitted by the reader's transmitter. The data stream is the information that the passive tag actually feeds back to the reader, such as the tag's identification number or sensor readings. The subcarrier signal is a square wave clock signal generated internally by the passive tag. The phase noise angular frequency is the frequency point at which the reader's phase noise energy significantly decreases; when the signal frequency is higher than this phase noise angular frequency, the phase noise is greatly reduced. When the passive tag receives the incident carrier signal, it generates a weak alternating current (AC). This AC current is converted to direct current (DC) by the passive tag's built-in rectifier or charge pump and stored in a capacitor. After a period of energy accumulation, the capacitor's voltage reaches the operating voltage of the passive tag's digital logic circuit. At this point, the capacitor begins to power the digital logic circuit, and the digital logic circuit enters its working state. In this working state, the digital logic circuit generates a subcarrier signal and mixes the locally stored data stream with the subcarrier signal to obtain a first mixed signal. This first mixed signal is used to chop and modulate the incident carrier signal to shift the data stream to the sideband frequency band, forming a double-sideband signal.

[0021] For example, the frequency of the subcarrier signal is fsub, which is higher than the phase noise angular frequency to ensure that subsequent data streams can be moved to a lower noise frequency band. Since the data stream is a series of binary bits, when the data stream is mixed with the subcarrier signal, if a bit value is 0, the subcarrier signal is output; if a bit value is 1, an inverted subcarrier signal is output (i.e., a 180-degree phase flip). The resulting first mixed signal C(t) is a square wave whose phase rapidly jumps between 0° and 180° depending on the bit value of the data stream. The incident carrier signal is Cos(2π). t fc), where fc is the frequency of the incident carrier signal. The reflection frequency of the wireless tag to the incident carrier signal is equal to the frequency fsub of the first mixer signal C(t). Chopping the incident carrier signal based on the first mixer signal is equivalent to multiplying the incident carrier signal and the first mixer signal in the time domain. Time-domain multiplication is equivalent to spectral convolution. After the incident carrier signal and the first mixer signal are convolved spectrally, the main lobe of the incident carrier signal is shifted to two positions: fc+fsub and fc-fsub. That is, the main lobe is shifted to the two sidebands of the incident carrier frequency fc, forming a double-sideband signal. Since the phase of the first mixer signal carries the data stream, when the incident carrier signal and the first mixer signal are convolved spectrally to form a double-sideband signal, the data stream is transferred to the double-sideband signal.

[0022] In one embodiment, Figure 2 This is one of the structural schematic diagrams of the passive tag provided in the embodiments of this application. For example... Figure 2 As shown, the passive tag includes a memory 10, a low-power oscillator 11, and an XOR gate 12. The low-power oscillator 11 generates a subcarrier signal, the memory 10 outputs the data stream of the passive tag, and the XOR gate 12 mixes the subcarrier signal generated by the low-power oscillator 11 with the data stream output by the memory 10 to obtain a first mixed signal. For example, the memory 10 can be an EEPROM or a register. When the accumulated voltage of the energy storage capacitor in the passive tag reaches a working threshold under the AC current of the carrier signal, the power management unit circuit of the passive tag is turned on to supply power to the memory 10 and the low-power oscillator 11 through the energy storage capacitor. After being powered on, the memory 10 outputs a data stream, while the low-power oscillator 11 generates a subcarrier signal. The low-power oscillator 11 can be a ring oscillator structure with low power consumption. The data stream output by the memory 10 and the subcarrier signal generated by the low-power oscillator 11 are input to the XOR gate 12, which performs an XOR operation on the input data stream and the subcarrier signal to output the first mixed signal. This embodiment uses a simple XOR gate to perform mixing processing of the data stream and the subcarrier signal, reducing the operating power consumption and implementation cost of the passive identifier.

[0023] refer to Figure 2The passive tag also includes an antenna 14 and an impedance switch 13. The control terminal of the impedance switch 13 is connected to the output terminal of the XOR gate 12, the input terminal of the impedance switch 13 is connected to the antenna, and the output terminal of the impedance switch 13 is grounded to GND. The impedance switch 13 can be a MOSFET transistor; that is, the output terminal of the XOR gate 12 is connected to the gate of the MOSFET transistor, the antenna 14 is connected to the drain of the MOSFET transistor, and the source of the MOSFET transistor is grounded to GND. A capacitor is typically connected in parallel between the drain and source of the MOSFET transistor. When the gate is connected to a high level, the MOSFET transistor is turned on. At this time, the antenna 14 is effectively connected to ground GND through a small resistor (the on-resistance of the MOSFET transistor) and the parallel capacitor, causing a severe impedance mismatch between the antenna 14 and the internal impedance of the passive tag. The incident carrier signal received by the antenna 14 is strongly reflected, causing the antenna 14 to reflect outwards. When the gate is connected to a low level, the MOSFET transistor is turned off. At this time, the antenna 14 mainly exhibits a very small parasitic capacitance. The impedance of the antenna 14 is close to an open circuit and nearly matched with the internal impedance of the passive tag. The incident carrier signal received by the antenna 14 is almost absorbed and not reflected. Ultimately, the reflection coefficient of the passive tag switches between approximately 1 and approximately 0, and the amplitude of the incident carrier signal changes accordingly to form a chopper-modulated double-sideband signal.

[0024] Understandable Figure 2 The passive tag shown reflects double-sideband signals back to the reader, meaning the reader can extract the data stream from the double-sideband signals.

[0025] However, both sidebands of a double-sideband signal carry data streams, occupying twice the bandwidth, and the valuable energy reflected by the tag is dispersed across the two sidebands, resulting in weakened intensity in both sidebands and wasted spectrum and energy. To address this, passive tags can modulate the incident carrier into a single-sideband signal based on the first mixer signal, while the sidebands still carry data streams. This single-sideband signal is then reflected back to the reader, saving spectrum and energy. For example, Figure 3 This is the second schematic diagram of the passive tag structure provided in the embodiments of this application. For example... Figure 3As shown, the passive tag also includes an antenna and a 90° phase generation network 15, a first impedance switch 17, a second impedance switch 16, a first impedance network 18, and a second impedance network 19. The output of the XOR gate 12 is connected to the input of the 90° phase generation network 15. The first output of the 90° phase generation network 15 is connected to the control terminal of the first impedance switch 17, and the second output of the 90° phase generation network 15 is connected to the control terminal of the second impedance switch 16. The inputs of the first impedance switch 17 and the second impedance switch 16 are connected to the antenna. The output of the first impedance switch 17 is connected to the input of the first impedance network 18, and the output of the first impedance network 18 is grounded. The output of the second impedance switch 16 is connected to the input of the second impedance network 19, and the output of the second impedance network 19 is grounded to GND. The 90° phase generation network 15 can be a digital frequency divider implemented using an RC phase-shifting network or a D flip-flop.

[0026] For example, after the first mixing signal generated by the XOR gate is input into the 90° phase generation network, the first output terminal of the 90° phase generation network outputs a signal in phase with the first mixing signal, while the second output terminal outputs a signal with a 90° phase offset. That is, the first output terminal outputs an in-phase signal while the second output terminal outputs a quadrature signal. The first impedance switch and the first impedance network can be called the in-phase branch, and the second impedance switch and the second impedance network can be called the quadrature branch. The switch of the in-phase branch is controlled by the in-phase signal, while the switch of the quadrature branch is controlled by the quadrature signal. In order to achieve quadrature, the load impedance of the in-phase branch and the load impedance of the quadrature branch are designed to be 90 degrees out of phase on the original reflection coefficient diagram. Thus, when the in-phase branch exhibits a purely resistive change and the quadrature branch exhibits a purely reactive change, the phase difference between the two always remains at 90 degrees. Due to this phase difference, the reflected signal from the quadrature branch will undergo another 90° phase shift before merging with the reflected signal from the in-phase branch. The merged reflected signal will cancel out the fc-fsub sideband frequency band, forming a single-sideband signal that retains the fc+fsub sideband frequency band. This achieves modulation of the single-sideband signal, concentrating the reflected energy of the passive tag on a single sideband, thereby improving energy efficiency and spectral utilization.

[0027] For the reader, the received radio frequency signal includes not only the sideband signal reflected by the reader but also phase noise signal. This phase noise signal is generated by the receiver receiving the echo signal emitted by the transmitter. Therefore, the spectral energy of the phase noise is concentrated near the carrier frequency fc. In this embodiment, the passive tag modulates the incident carrier signal by shifting the spectrum, moving the spectrum carrying the data stream to the upper sideband frequency band fc+fsub and the lower sideband frequency band fc-fsub on both sides of the carrier, thus forming a sideband signal. The frequency of the sideband signal is much higher than the carrier frequency fc. When performing low-frequency filtering on the radio frequency signal, it can effectively filter out the phase noise in the radio frequency signal with frequencies near the carrier frequency fc while retaining the sideband signal carrying the data stream, achieving effective filtering of phase noise.

[0028] In one embodiment, Figure 4 This is a flowchart illustrating the acquisition of sideband signals in a radio frequency signal, provided in an embodiment of this application. For example... Figure 4 As shown, the steps for acquiring the sideband signal in the radio frequency signal specifically include S1101-S1102: S1101. Mix the radio frequency signal with the local incident carrier signal to obtain the baseband signal.

[0029] For example, the receiver mixes the radio frequency (RF) signal with the local incident carrier signal to shift the entire RF signal to the baseband, obtaining the baseband signal. That is, the frequency of the phase noise signal in the RF signal changes from the carrier frequency fc to 0Hz, meaning the phase noise is mainly concentrated in the low-frequency region. The frequency of the upper sideband signal changes from fc+fsub to +fsub, and the frequency of the lower sideband signal changes from -sub; these three are mixed to form the baseband signal.

[0030] S1102. The baseband signal is subjected to low-frequency filtering through a high-pass filter to obtain the sideband signal in the radio frequency signal.

[0031] For example, the baseband signal mainly consists of two components: a phase noise signal with a frequency near 0Hz and an effective signal with a frequency between ±fsub. By performing low-frequency filtering on the baseband signal using a high-pass filter, the phase noise signal with a frequency near 0Hz can be filtered out, while the effective signal with a frequency between ±fsub is retained, thus achieving effective filtering of the phase noise signal.

[0032] Furthermore, the cutoff frequency of the high-pass filter is half the frequency of the subcarrier signal. With a cutoff frequency of 0.5fsub, the high-pass filter can effectively filter phase noise signals at frequencies located at the carrier frequency fc, as well as the skirt signal of the phase noise and DC leakage signals, achieving effective filtering of various interference signals and significantly improving the signal-to-noise ratio.

[0033] S120. The sideband signal is down-converted to obtain the data stream in the sideband signal.

[0034] For example, after filtering the radio frequency signal to obtain the sideband signal, the data stream carried by the sideband signal is still modulated on the frequency fsub and cannot be directly interpreted. Therefore, the sideband signal needs to be downconverted to bring it back to the baseband, and finally the data stream can be extracted from the signal brought back to the baseband.

[0035] In one embodiment, Figure 5 This is a flowchart illustrating the acquisition of data stream in a sideband signal, provided in an embodiment of this application. For example... Figure 5 As shown, the steps for acquiring the data stream in the sideband signal specifically include S1201-S1202: S1201. Mix the sideband signal with the local subcarrier signal to obtain the second mixed signal.

[0036] For example, the receiver can generate a local subcarrier signal with a digital frequency of fsub, multiply the local subcarrier signal with the filtered sideband signal to obtain a second mixer signal, thereby shifting the upper sideband signal with a frequency of +fsub to 2fsub, and the lower sideband signal with a frequency of -fsub to 0Hz.

[0037] S1202. The second mixing signal is subjected to high-frequency filtering through a low-pass filter to obtain the data stream in the sideband signal.

[0038] For example, the second mixer signal is subjected to high-frequency filtering by a low-pass filter to filter out the high-frequency component at 2fsub in the second mixer signal and retain the data stream at 0Hz.

[0039] In summary, the communication method based on spectrum shifting modulation provided in this application involves mixing a subcarrier signal with a frequency higher than the phase noise angular frequency of the reader with a data stream using a passive tag to obtain a first mixed signal. Upon receiving the incident carrier signal from the reader, the first mixed signal is used to chop and modulate the incident carrier signal to obtain a radio frequency (RF) signal, which is then reflected back to the reader. After receiving the RF signal, the reader performs low-frequency filtering to obtain a sideband signal carrying the passive tag's data stream. This sideband signal is then down-converted to obtain the data stream within it. Through these techniques, since the subcarrier frequency is higher than the reader's phase noise angular frequency, the first mixed signal is used to chop and modulate the incident carrier signal to shift the data stream's information to the carrier's sideband frequency band, avoiding the carrier's center frequency band with the strongest phase noise and preventing the data stream from being submerged by noise skirts. The reader performs low-frequency filtering on the RF signal to remove strong phase noise near the carrier frequency, retaining the sideband signal carrying the data information and improving the received signal-to-noise ratio. Down-conversion of sideband signals to shift them to the baseband frequency band and recover the data stream significantly improves the communication distance and reliability of the communication system.

[0040] Based on the above embodiments, Figure 6 This is a schematic diagram of a communication device based on spectrum shift modulation, provided as an embodiment of this application. (Reference) Figure 6 The communication device based on spectrum shift modulation provided in this embodiment specifically includes: a signal filtering and processing module 21 and a data stream acquisition module 22.

[0041] Among them, the signal filtering processing module 21 is configured to perform low-frequency filtering processing on the received radio frequency signal to obtain the sideband signal in the radio frequency signal; the sideband signal is obtained by the passive tag chopping and modulating the incident carrier signal based on the first mixing signal, the first mixing signal is obtained by mixing the data stream of the passive tag with the subcarrier signal, and the frequency of the subcarrier signal is higher than the phase noise angular frequency of the reader; The data stream acquisition module 22 is configured to perform down-conversion processing on the sideband signal to obtain the data stream in the sideband signal.

[0042] Based on the above embodiments, the signal filtering processing module 21 includes: a first mixing unit configured to mix the radio frequency signal with a local incident carrier signal to obtain a baseband signal; and a first filtering processing unit configured to perform low-frequency filtering processing on the baseband signal through a high-pass filter to obtain a sideband signal in the radio frequency signal.

[0043] Based on the above embodiments, the cutoff frequency of the high-pass filter is half the frequency of the subcarrier signal.

[0044] Based on the above embodiments, the data stream acquisition module 22 includes: a second mixing unit configured to mix the sideband signal with the local subcarrier signal to obtain a second mixed signal; and a second filtering unit configured to perform high-frequency filtering on the second mixed signal through a low-pass filter to obtain the data stream in the sideband signal.

[0045] Based on the above embodiments, the passive tag includes a memory, a low-power oscillator, and an XOR gate. The low-power oscillator is used to generate a subcarrier signal, the memory is used to output the data stream of the passive tag, and the XOR gate is used to perform frequency mixing processing on the subcarrier signal generated by the low-power oscillator and the data stream output by the memory to obtain a first mixed signal.

[0046] Based on the above embodiments, the passive tag also includes an antenna and an impedance switch. The control terminal of the impedance switch is connected to the output terminal of the XOR gate, the input terminal of the impedance switch is connected to the antenna, and the output terminal of the impedance switch is grounded.

[0047] Based on the above embodiments, the passive tag also includes an antenna, a 90° phase generation network, a first impedance switch, a second impedance switch, a first impedance network, and a second impedance network. The output of the XOR gate is connected to the input of the 90° phase generation network. The first output of the 90° phase generation network is connected to the control terminal of the first impedance switch. The second output of the 90° phase generation network is connected to the control terminal of the second impedance switch. The inputs of the first and second impedance switches are connected to the antenna. The output of the first impedance switch is connected to the input of the first impedance network. The output of the first impedance network is grounded. The output of the second impedance switch is connected to the input of the second impedance network. The output of the second impedance network is grounded.

[0048] The communication device based on spectrum shifting modulation provided in this application embodiment, through a passive tag, mixes a subcarrier signal with a frequency higher than the phase noise angular frequency of the reader with a data stream to obtain a first mixed signal. Upon receiving the incident carrier signal from the reader, the reader performs chopping modulation on the incident carrier signal based on the first mixed signal to obtain a sideband signal, which is then reflected back to the reader. After receiving the radio frequency (RF) signal, the reader performs low-frequency filtering on the RF signal to obtain the sideband signal; it then performs down-conversion on the sideband signal to obtain the data stream within the sideband signal. Through these technical means, since the subcarrier frequency is higher than the reader's phase noise angular frequency, the first mixed signal is used to chop and modulate the incident carrier signal to shift the data information of the data stream to the carrier's sideband frequency band, thus forming a sideband signal. This avoids the carrier's center frequency band with the strongest phase noise, preventing the data stream from being submerged by noise skirts. The reader performs low-frequency filtering on the RF signal to remove strong phase noise near the carrier frequency, retaining the sideband signal carrying the data information in the RF signal, thereby improving the received signal-to-noise ratio. Down-conversion of sideband signals to shift them to the baseband frequency band and recover the data stream significantly improves the communication distance and reliability of the communication system.

[0049] The communication device based on spectrum shift modulation provided in this application can be used to execute the communication method based on spectrum shift modulation provided in the above embodiments, and has corresponding functions and beneficial effects.

[0050] Figure 7 This is a schematic diagram of the structure of a communication device based on spectrum shifting modulation provided in an embodiment of this application, with reference to... Figure 7 The spectrum-shifting modulation-based communication device includes a processor 31, a memory 32, a communication device 33, an input device 34, and an output device 35. The number of processors 31 and the number of memories 32 in the spectrum-shifting modulation-based communication device can be one or more. The processor 31, memory 32, communication device 33, input device 34, and output device 35 of the spectrum-shifting modulation-based communication device can be connected via a bus or other means.

[0051] The memory 32, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as program instructions / modules corresponding to the spectrum shift modulation-based communication method in any embodiment of this application (e.g., the signal filtering processing module 21 and data stream acquisition module 22 in a spectrum shift modulation-based communication device). The memory 32 may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function; the data storage area may store data created based on the use of the device, etc. Furthermore, the memory 32 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some instances, the memory may further include memory remotely located relative to the processor, and these remote memories can be connected to the device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0052] The communication device 33 is used for data transmission.

[0053] The processor 31 executes various functional applications and data processing of the device by running software programs, instructions and modules stored in the memory 32, thereby realizing the above-mentioned communication method based on spectrum shift modulation.

[0054] Input device 34 can be used to receive input digital or character information, and to generate key signal inputs related to user settings and function control of the device. Output device 35 may include display devices such as a display screen.

[0055] The communication device based on spectrum shifting modulation provided above can be used to execute the communication method based on spectrum shifting modulation provided in the above embodiments, and has corresponding functions and beneficial effects.

[0056] This application embodiment also provides a storage medium containing computer-executable instructions. When executed by a computer processor, the computer-executable instructions are used to execute a communication method based on spectrum shift modulation. The communication method based on spectrum shift modulation includes: upon receiving a radio frequency signal, performing low-frequency filtering on the radio frequency signal to obtain a sideband signal in the radio frequency signal; the sideband signal is obtained by a passive tag performing chopping modulation on an incident carrier signal based on a first mixing signal, the first mixing signal being obtained by mixing the data stream of the passive tag with a subcarrier signal, the frequency of the subcarrier signal being higher than the phase noise angular frequency of the reader; and down-converting the sideband signal to obtain the data stream in the sideband signal.

[0057] Storage medium – any type of memory device or storage device. The term “storage medium” is intended to include: mounting media, such as CD-ROM, floppy disk, or magnetic tape devices; computer system memory or random access memory, such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory, such as flash memory, magnetic media (e.g., hard disk or optical storage); registers or other similar types of memory elements, etc. Storage medium may also include other types of memory or combinations thereof. Furthermore, storage medium may reside in a first computer system in which the program is executed, or it may reside in a different second computer system connected to the first computer system via a network (such as the Internet). The second computer system can provide program instructions to the first computer for execution. The term “storage medium” can include two or more storage media residing in different locations (e.g., in different computer systems connected via a network). Storage medium may store program instructions (e.g., specifically implemented as a computer program) executable by one or more processors.

[0058] Of course, the computer-executable instructions provided in the embodiments of this application are not limited to the communication method based on spectrum shifting modulation as described above, but can also execute related operations in the communication method based on spectrum shifting modulation provided in any embodiment of this application.

[0059] The communication device, storage medium, and communication equipment based on spectrum shifting modulation provided in the above embodiments can execute the communication method based on spectrum shifting modulation provided in any embodiment of this application. For technical details not described in detail in the above embodiments, please refer to the communication method based on spectrum shifting modulation provided in any embodiment of this application.

[0060] The above description is merely a preferred embodiment and the technical principles employed in this application. This application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions that can be made by those skilled in the art will not depart from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of this application. The scope of this application is determined by the scope of the claims.

Claims

1. A communication method based on spectrum shift modulation, characterized in that, Applied to a reader / writer, the method includes: Upon receiving a radio frequency signal, the radio frequency signal is subjected to low-frequency filtering to obtain a sideband signal in the radio frequency signal; the sideband signal is obtained by a passive tag chopping and modulating the incident carrier signal based on a first mixing signal, the first mixing signal being obtained by mixing the data stream of the passive tag with a subcarrier signal, and the frequency of the subcarrier signal being higher than the phase noise angular frequency of the reader; The sideband signal is down-converted to obtain the data stream in the sideband signal.

2. The communication method based on spectrum shifting modulation according to claim 1, characterized in that, The step of performing low-frequency filtering on the radio frequency signal to obtain the sideband signal in the radio frequency signal includes: The radio frequency signal is mixed with the local incident carrier signal to obtain the baseband signal; The baseband signal is subjected to low-frequency filtering by a high-pass filter to obtain the sideband signal in the radio frequency signal.

3. The communication method based on spectrum shifting modulation according to claim 2, characterized in that, The cutoff frequency of the high-pass filter is half the frequency of the subcarrier signal.

4. The communication method based on spectrum shift modulation according to claim 1, characterized in that, The step of down-converting the sideband signal to obtain the data stream in the sideband signal includes: The sideband signal is mixed with the local subcarrier signal to obtain a second mixed signal; The second mixing signal is subjected to high-frequency filtering by a low-pass filter to obtain the data stream in the sideband signal.

5. The communication method based on spectrum shifting modulation according to claim 3, characterized in that, The passive tag includes a memory, a low-power oscillator, and an XOR gate. The low-power oscillator is used to generate a subcarrier signal, the memory is used to output the data stream of the passive tag, and the XOR gate is used to perform frequency mixing processing on the subcarrier signal generated by the low-power oscillator and the data stream output by the memory to obtain a first mixed signal.

6. The communication method based on spectrum shifting modulation according to claim 5, characterized in that, The passive tag also includes an antenna and an impedance switch. The control terminal of the impedance switch is connected to the output terminal of the XOR gate, the input terminal of the impedance switch is connected to the antenna, and the output terminal of the impedance switch is grounded.

7. The communication method based on spectrum shifting modulation according to claim 5, characterized in that, The passive tag also includes an antenna, a 90° phase generation network, a first impedance switch, a second impedance switch, a first impedance network, and a second impedance network. The output of the XOR gate is connected to the input of the 90° phase generation network. The first output of the 90° phase generation network is connected to the control terminal of the first impedance switch. The second output of the 90° phase generation network is connected to the control terminal of the second impedance switch. The inputs of the first and second impedance switches are connected to the antenna. The output of the first impedance switch is connected to the input of the first impedance network. The output of the first impedance network is grounded. The output of the second impedance switch is connected to the input of the second impedance network. The output of the second impedance network is grounded.

8. A communication device based on spectrum shift modulation, characterized in that, Applied to a reader / writer, the device includes: The signal filtering module is configured to perform low-frequency filtering on the received radio frequency signal to obtain a sideband signal in the radio frequency signal; the sideband signal is obtained by a passive tag chopping and modulating the incident carrier signal based on a first mixing signal, the first mixing signal is obtained by mixing the data stream of the passive tag with a subcarrier signal, and the frequency of the subcarrier signal is higher than the phase noise angular frequency of the reader; The data stream acquisition module is configured to perform down-conversion processing on the sideband signal to obtain the data stream in the sideband signal.

9. A communication system based on spectrum shift modulation, characterized in that, This includes passive tags and readers, among which: The passive tag is used to mix the data stream with the subcarrier signal to obtain a first mixed signal, chop and modulate the incident carrier signal based on the first mixed signal to obtain a sideband signal, and reflect the radio frequency signal to the reader; the frequency of the subcarrier signal is higher than the phase noise angular frequency of the reader. The reader / writer is configured to perform low-frequency filtering on the received radio frequency signal to obtain a sideband signal in the radio frequency signal; and to perform down-conversion processing on the sideband signal to obtain a data stream in the sideband signal.

10. A computer-readable storage medium, characterized in that, The storage medium stores a program that, when executed by a processor, implements the communication method based on spectrum shift modulation as described in any one of claims 1-7.

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