Near field communication method, module, device, equipment, medium and product

Abstract

The embodiment of the invention provides a near field communication method, a module, a device, equipment, a medium and a product. The scheme comprises the following steps: a slave device obtains a first radio frequency signal sent by a master device of near field communication, can extract signal characteristics of the first radio frequency signal, and generates a first modulated radio frequency signal; the phase and / or amplitude of the first modulation radio frequency signal is different from that of the first radio frequency signal; then the first modulation radio frequency signal of a first duration is sent; after the first duration, switching the slave device from the first impedance state to a second impedance state and keeping the state for a second duration; the sum of the first duration and the second duration is smaller than the period duration of the low-power-consumption signal sent by the master device. Therefore, the master device is promoted to exit from the low-power-consumption mode in an active and passive modulation mode, and the stability of near field communication is improved.

Description

Technical Field

[0001] This specification relates to one or more embodiments in the field of near-field communication technology, and particularly to a method for near-field communication. This specification also relates to a near-field communication module, a near-field communication device, a near-field communication apparatus, a computing device, a computer-readable storage medium, and a computer program product. Background Technology

[0002] With the continuous development of computer technology, Near Field Communication (NFC) technology has been widely applied in various scenarios due to its convenience, security, and broad device compatibility. These include payment scenarios, access control scenarios, and turnstile scenarios. In everyday consumption environments such as retail stores, public transportation, vending machines, and restaurants, users can use NFC-enabled smartphones, smartwatches, or other wearable devices to perform fast, contactless payment transactions.

[0003] LPCD (Low) Power Card Detection (LPCD) mode is a power-saving mechanism in the NFC controller to reduce power consumption. It detects the presence of cards or card-simulated devices by periodically emitting radio frequency signals. When LPCD is enabled, the NFC controller only performs polling operations after detecting a proximity event, thereby significantly reducing overall power consumption and improving device battery life and user experience.

[0004] In real-world scenarios, the NFC antennas of smartphones and other smart devices are relatively small, and users are often unaware of the exact location of their device's NFC antennas. When users try to detect tags using their smartphones, the coupling between the antennas may be poor, causing the device to fail to detect the tag and remain in LPCD mode, or to take an extended period to detect it. This results in a generally poor user experience.

[0005] Therefore, how to encourage devices such as smartphones to exit LPCD mode, ensure communication stability, and improve user experience is an urgent technical problem to be solved. Summary of the Invention

[0006] In view of this, one or more embodiments of this specification provide a method, module, device, medium, and product for near-field communication to improve the stability of near-field communication.

[0007] According to a first aspect of one or more embodiments of this specification, a method for near-field communication is provided, comprising: Acquire the first radio frequency signal emitted by the master device of near-field communication; The signal features of the first radio frequency signal are extracted to generate a first modulated radio frequency signal; the phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal. Transmit the first modulated radio frequency signal for a first duration; After the first duration, the slave device is switched from the first impedance state to the second impedance state and maintained for the second duration; the sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

[0008] According to a second aspect of one or more embodiments of this specification, a near-field communication module is provided, including: a field detection module, a modulation signal generation module, a load switching module, and a control module; The field detection module is connected to the near-field antenna of the slave device. The near-field antenna is used to acquire the first radio frequency signal emitted by the master device. After the near-field antenna acquires the first radio frequency signal emitted by the master device, the field detection module generates a trigger signal. The modulation signal generation module is connected to the field detection module. If the trigger signal is obtained, the signal characteristics of the first radio frequency signal are extracted to generate a first modulated radio frequency signal. The phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal. The control module is connected to the modulation signal generation module and the near-field antenna, and is used to control the near-field antenna to transmit the first modulated radio frequency signal for a first duration. The control module is also connected to the load switching module and is used to switch the slave device from a first impedance state to a second impedance state and maintain it for a second time after the first duration; the sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

[0009] According to a third aspect of one or more embodiments of this specification, a near-field communication apparatus is provided, the apparatus comprising: The signal acquisition module is used to acquire the first radio frequency signal emitted by the master device of near-field communication. A modulation signal generation module is used to extract the signal features of the first radio frequency signal and generate a first modulated radio frequency signal; the phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal. The signal transmitting module is used to transmit the first modulated radio frequency signal for a first duration; The state switching module is used to switch the slave device from a first impedance state to a second impedance state and maintain it for a second time after the first duration; the sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

[0010] According to a fourth aspect of one or more embodiments of this specification, a near-field communication device is provided, the device being used to perform the near-field communication method described above; or, the device comprising the near-field communication module described above.

[0011] According to a fifth aspect of one or more embodiments of this specification, a computing device is provided, including a memory and a processor; the memory is used to store computer programs / instructions, and the processor is used to execute the computer programs / instructions, which, when executed by the processor, implement the steps of the near-field communication method described above.

[0012] According to a sixth aspect of one or more embodiments of this specification, a computer-readable storage medium is provided that stores computer instructions which, when executed by a processor, implement the steps of the near-field communication method described above.

[0013] According to a seventh aspect of the embodiments of this specification, a computer program product is provided, including a computer program / instructions that, when executed by a processor, implement the steps of the near-field communication method described above.

[0014] One embodiment of this specification can achieve at least the following beneficial effects: After acquiring the radio frequency signal emitted by the master device, the slave device of near-field communication can generate a modulated radio frequency signal with a different amplitude or phase than the radio frequency signal of the master device, and after sending the modulated radio frequency signal for a period of time, switch the impedance state of the slave device and improve the impedance value of the slave device. In this way, during one pulse cycle of the radio frequency signal of the master device, the sensing on the master device side can be affected by the modulation signal and the change of load impedance, so as to promote the master device to exit the low power mode.

[0015] On the other hand, after receiving the radio frequency signal from the master device, the slave device can influence the master device as quickly as possible by performing steps of modulating the radio frequency signal and changing impedance, regardless of whether the radio frequency signal is a low-power signal or a normal card search signal. This allows the master device in low-power mode to exit low-power mode as quickly as possible. In addition, sending modulated radio frequency signals to promote the master device to exit low-power mode improves the wake-up speed and efficiency of the master device. At the same time, the slave device can send modulated radio frequency signals with different phases or amplitudes from the radio frequency signal sent by the master device, instead of sending excitation signals that are unrelated to the radio frequency signal of the master device. This can effectively reduce the probability of the master device mistakenly entering card emulation mode and improve communication stability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram illustrating an application scenario of a near-field communication method provided in one embodiment of this specification. Figure 2 This is a flowchart illustrating a near-field communication method provided in one embodiment of this specification; Figure 3 This is a flowchart illustrating a near-field communication method provided in one embodiment of this specification; Figure 4 This is a schematic diagram of the structure of a near-field communication module provided in one embodiment of this specification; Figure 5 This is a schematic diagram of the structure of a load switching module provided in one embodiment of this specification; Figure 6 This is a schematic diagram of a near-field communication device provided in one embodiment of this specification; Figure 7 This is a structural block diagram of a computing device provided in one embodiment of this specification. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0019] This specification uses specific terms to describe embodiments thereof. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those different embodiments or examples, without contradiction.

[0020] The terminology used in one or more embodiments of this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the one or more embodiments of this specification. The singular forms “a,” “an,” “an,” “the,” and “the” as used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in one or more embodiments of this specification includes any or all possible combinations of one or more associated listed items.

[0021] The terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, product, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, product, or apparatus. Without further limitation, the presence of additional identical or equivalent elements in the process, method, product, or apparatus that includes said elements is not excluded.

[0022] Although the terms "first," "second," etc., may be used to describe various information in one or more embodiments of this specification, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, "first" may also be referred to as "second," and similarly, "second" may also be referred to as "first," without departing from the scope of one or more embodiments of this specification. Ordinal numbers such as "first," "second," etc., do not necessarily indicate order; often they are used to facilitate the distinction of objects. For example, "first server" and "second server" usually refer to two servers. To distinguish these two servers, they are described as "first server" and "second server." Of course, sometimes these two servers may be the same server.

[0023] The word “if” as used in one or more embodiments of this specification may be interpreted as “when”, “when”, or “in response to determination”, depending on the context.

[0024] In this specification, unless explicitly stated otherwise, "receiving and sending data" does not necessarily mean direct receiving and sending; it can also mean indirect receiving and sending. For example, A receiving data sent by B can be understood as A directly receiving the data sent by B, or it can be understood as A indirectly receiving the data sent by B through other entities such as C. Similarly, B sending data to A can be understood as B sending the data directly to A, or it can be understood as B indirectly sending the data to A through other entities such as C. Here, C can be one entity, or it can be two or more entities.

[0025] In this specification, unless explicitly stated otherwise, the relationships between structures can be direct or indirect. For example, when describing "A is connected to B," unless it is explicitly stated that A and B are directly connected, it should be understood that A can be directly connected to B or indirectly connected to B. Similarly, when describing "A is on top of B," unless it is explicitly stated that A is directly above B (AB is adjacent and A is above B), it should be understood that A can be directly above B or indirectly above B (AB is separated by other elements, and A is above B). And so on.

[0026] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in one or more embodiments of this specification are all information and data authorized by the user or fully authorized by all parties. The collection, use and processing of related data shall comply with the relevant laws, regulations and standards of the relevant regions, and corresponding operation entry points shall be provided for users to choose to authorize or refuse.

[0027] The following explains the terms and concepts used in one or more embodiments of this specification.

[0028] NFC (Near Field Communication) is a short-range wireless communication technology operating at a frequency of 13.56 MHz, with a communication distance typically within 10 centimeters. This technology supports fast, secure, two-way communication between devices and is widely used in mobile payments, access control, public transport cards, and smart identification scenarios. In NFC communication, the device that actively transmits a card-finding signal can be called the master device or the transmitting device, such as an NFC card reader or a device in card reader mode. The device that passively responds to the signal transmitted by the master device can be called the slave device or the target device, such as an NFC tag, a device in card emulation mode, or a device with an NFC tag.

[0029] LPCD (Low-Power Card Detection): An energy-saving mechanism used by NFC controllers. It detects the presence of cards or card emulators nearby by periodically emitting radio frequency signals. Upon detecting a card or card emulator, the NFC controller is activated and enters normal operating mode.

[0030] Polling: The process by which an NFC controller actively searches its surroundings for other NFC devices, cards, or tags. By sending specific query signals, the NFC controller can detect available targets and initiate communication. The initiating device can sequentially try different communication protocols to detect the presence of interactive passive devices nearby.

[0031] PLL (Phase-Locked Loop): A feedback system that allows a locally generated oscillation signal to follow the input reference in phase and / or frequency.

[0032] NFC (Near Field Communication) evolved from contactless radio frequency identification (RFID) and interconnection technologies, providing a very secure and fast communication method for various electronic products. With the continuous development of NFC technology and the increasing market, more and more smartphones and smart terminals are equipped with this technology.

[0033] NFC works by using electromagnetic coupling induction technology. The active device (also known as the master device) emits a 13.56MHz electromagnetic field signal, transmitting energy and data to the target device (also known as the slave device) through near-field coupling. The target device can modulate the magnetic field to return the data to the active device, completing the communication. NFC has two main operating modes: reader mode and card emulation mode. The former corresponds to the active device, while the latter corresponds to the passive device (also known as the slave device). Smartphones and other smart terminals can support both modes simultaneously. However, when used as a card reader, smartphones and other smart terminals face several challenges. Compared to traditional card readers, smartphones and other smart terminals are battery-powered and highly sensitive to power consumption. When used as a card reader, the power consumption during polling is relatively high. Therefore, smartphones and other smart terminals disable card reading when the screen is off. Most smartphones and other smart terminals will only attempt a few normal card readings after unlocking the screen, and then switch to low-power card detection mode (LPCD) or a mixed mode (using both normal card search and LPCD modes).

[0034] In LPCD mode, the NFC controller of the card reader device (such as a smartphone) periodically sends short-duration electromagnetic signals, typically lasting tens of microseconds, and detects antenna detuning to wake up the NFC controller and enable normal polling. However, in real-world scenarios, the NFC antennas of smartphones are relatively small, and users are often unaware of their phone's NFC antenna location. When a user tries to sense a tag with their phone, the coupling between the antennas may be poor, causing the phone to fail to detect the tag and remain in LPCD mode, or to take an extended period to detect the tag. For users, this results in a poor overall experience and lower reliability.

[0035] In related technologies, when a device detects the LPCD signal characteristics of a main device such as a mobile phone, it can send an NFC electromagnetic signal for a certain period of time to stimulate the main device to exit LPCD mode. However, this kind of active stimulation method may not be effective for all main devices such as mobile phones. Furthermore, for some main devices, the sent stimulation signal may cause the main device to enter card emulation mode, popping up system wallets or application card packs, which affects the user experience.

[0036] The technical solutions provided in the various embodiments of this specification are described in detail below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram illustrating an application scenario of a near-field communication method provided in one embodiment of this specification. Figure 1 As shown, the master device 100 of near-field communication (NFC) acts as a NFC reader device and can emit radio frequency (RF) signals to detect the presence of slave devices. In practical applications, to reduce power consumption, the master device 100 can first emit low-power RF signals in LPCD mode to detect the presence of nearby NFC slave devices, such as NFC cards. After sensing the RF signal emitted by the master device 100, the near-field antenna of the slave device 200 can generate electromagnetic coupling with the near-field antenna in the master device 100. This causes a change in the signal parameters in the master device 100. If the change in parameters in the master device 100 exceeds a threshold, the master device 100 can determine that the slave device 200 is nearby and can exit LPCD mode to conduct short-range communication with the detected slave device 200 through normal polling.

[0038] In one embodiment of this specification, in order to facilitate the master device 100 to exit LPCD mode as quickly as possible, the slave device 200, after receiving the radio frequency signal emitted by the master device, can extract the signal characteristics of the radio frequency signal without distinguishing whether the radio frequency signal is a low-power signal or a normal card-finding signal, generate a modulated radio frequency signal with a different phase and / or amplitude than the radio frequency signal, and adjust the impedance value of the slave device after transmitting for a period of time. It can perform active modulation and passive modulation on a single probe signal emitted by the master device, thereby promoting the master device to exit the low-power mode and enter the normal card-finding polling mode through various influence methods.

[0039] The main device 100 can be a device with near-field communication (NFC) card reader functionality, such as a smartphone, smartwatch, wristband, laptop, tablet, or other portable terminal device; it can also be a smart home device, in-vehicle device, or a POS machine, self-service checkout device, or other payment device. The slave device 200 can be a device with an NFC tag or a device that can simulate an NFC tag. For example, the slave device 200 can be a device used for processing payment transactions, such as a payment device used at a cashier or self-service checkout; or it can be a device for handling check-in, login, access control, turnstiles, etc., such as a device for checking in at work, school, or events using NFC; a device for member login or application login using NFC; an access control device for residential or office buildings; a card reader for public transportation such as buses and subways; or a device for identity or ticket verification at tourist attractions, events, or concerts. The specific types of the main and slave devices are not limited here.

[0040] This application provides a method for near-field communication, and also relates to a near-field communication module, a near-field communication device, a computing device, a computer-readable storage medium, and a computer program product, which will be described in detail in the following embodiments.

[0041] Figure 2 This is a flowchart illustrating a near-field communication method provided in one embodiment of this specification.

[0042] From a programming perspective, the execution entity of the process can be a program embedded in a slave device of near-field communication. It can be understood that this method can be executed by any device, equipment, platform, or cluster of devices with computing and processing capabilities.

[0043] like Figure 2 As shown, the process may include the following steps: Step 202: Acquire the first radio frequency signal emitted by the master device of near-field communication.

[0044] In practical applications, the master device of near-field communication (NFC) acts as a card reader device and can actively emit radio frequency (RF) signals to detect the presence of NFC cards nearby. If the master device has an LPCD (Low Power Discrete) operating mode, the RF signal emitted by the master device can be an LPCD mode signal. Alternatively, if the master device is operating in normal card search mode, the RF signal emitted by the master device can also be a normal polling signal. To facilitate the master device's exit from low-power mode as quickly as possible, in one or more embodiments of this specification, the slave device, after receiving the first RF signal emitted by the master device, may not determine whether the signal is a low-power signal or a normal card search signal, and can directly perform active modulation or passive modulation. Optionally, the first RF signal is a low-power signal emitted by the master device in low-power mode, or a non-low-power signal emitted by the master device in non-low-power mode.

[0045] The first radio frequency (RF) signal is an RF signal actively emitted by the master device. It can be a normal polling signal or a low-power signal emitted in LPCD mode. RF signals can represent electromagnetic waves with frequencies ranging from 3kHz to 300GHz. In the Near Field Communication (NFC) scenario, RF signals can represent electromagnetic waves with a 13.56MHz carrier wave and its modulation scheme.

[0046] NFC slave devices (such as card emulators) can be passive or active, relying on the radio frequency field emitted by the master device to obtain power and communicate. Alternatively, NFC slave devices can also communicate with the master device through their own power supply. In practical applications, the slave device's antenna coil can sense the alternating magnetic field generated by the master device's antenna to obtain the radio frequency signal emitted by the master device.

[0047] Step 204: Extract the signal features of the first radio frequency signal to generate a first modulated radio frequency signal; the phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal.

[0048] Signal characteristics can represent the carrier phase reference and timing information of the first radio frequency signal, specifically including parameters such as phase, frequency, and envelope that can be used to generate a coherent signal. In practical applications, the carrier phase, frequency, or clock edge information of the first radio frequency signal can be obtained through hardware (such as PLL) or digital signal processing.

[0049] The first modulated radio frequency signal can be a radio frequency signal with a different phase and / or amplitude generated based on the signal characteristics of the first radio frequency signal. It can be used as an active disturbance signal to affect the master device. If the master device is in LPCD low power mode, it can promote the master device to exit the low power mode.

[0050] As one implementation, the above-mentioned extraction of signal features of the first radio frequency signal to generate a first modulated radio frequency signal includes: generating an initial modulation signal consistent with the first radio frequency signal using a phase-locked loop; adding a first offset phase and / or offset amplitude to the initial modulation signal to obtain the first modulated radio frequency signal; wherein the first offset phase is any phase from 0° to 360°.

[0051] A phase-locked loop (PLL) is an electronic control system that automatically adjusts the phase of its output signal to track the phase of its input reference signal. It can be used for clock recovery, frequency synthesis, and coherent demodulation. In one embodiment of this specification, a PLL can be used to quickly extract carrier phase and other information from a signal emitted by a master device.

[0052] The initial modulation signal can be a signal that is synchronized with the first radio frequency signal in frequency and phase (i.e., in phase and frequency), and serves as the reference for subsequent offset operations.

[0053] The first offset phase can represent the additional angular offset introduced on top of the initial signal phase. The first offset phase can be any phase from 0° to 360°, and can support arbitrary phase perturbations, such as 0° in-phase enhancement, 180° out-of-phase attenuation, 90° quadrature, etc.

[0054] The offset amplitude can represent the scaling of the signal amplitude to control the disturbance intensity. After phase or amplitude offset, a modulated radio frequency signal can be obtained.

[0055] In practical applications, the device can input the detected first radio frequency signal, or amplified and limited signal, into the phase detector (PD) of the PLL. The voltage-controlled oscillator (VCO) of the PLL can output a 13.56MHz signal, which is fed back to the PD after frequency division / buffering. The PD compares the phase of the input signal with the feedback signal and outputs an error voltage. The error voltage is smoothed by a loop filter and then controls the VCO, making the output phase gradually approach the input signal. After locking, the VCO outputs the initial modulation signal. For phase shift, the initial modulation signal output by the PLL can be sent to a digitally controlled phase shifter (such as a delay line controlled by a CPLD or a DDS module) to generate a fixed phase shift according to a preset value (such as 180°). For amplitude shift, the signal amplitude can be adjusted using a variable gain amplifier (VGA) or a digital attenuator.

[0056] As another implementation, the modulated radio frequency signal can also be generated by combining open-loop phase estimation with direct digital synthesis (DDS). For example, the first radio frequency signal can be sampled using a high-speed analog-to-digital converter (ADC); its instantaneous phase and frequency can be estimated using digital signal processing (such as FFT, zero-crossing detection, correlation algorithms); and the estimation results can be fed into a direct digital synthesizer (DDS) to generate a modulated radio frequency signal with a specified offset phase.

[0057] Alternatively, a debugging RF signal can be generated by using envelope detection combined with a fixed phase delay line. For example, a fixed analog delay line (such as an LC delay network or transmission line) can be used to apply a preset time delay to the detected RF signal; combined with envelope triggering, the delayed modulated RF signal is transmitted immediately after the signal is detected.

[0058] Alternatively, a phase template can be pre-stored, and a matching modulation radio frequency signal can be selected from known backup modulation radio frequency signals with different phases. For example, the first radio frequency signal can be superimposed with each backup modulation radio frequency signal, and then the envelope amplitude of each superimposed signal can be calculated. The backup modulation radio frequency signal with the largest or smallest envelope amplitude, or whose envelope amplitude meets a preset threshold, can be selected as the first modulation radio frequency signal and transmitted.

[0059] In practical applications, if a free oscillator is used directly, the phase is random, and the superposition effect is uncontrollable. In one embodiment of this specification, a phase-locked loop (PLL) is used to achieve real-time phase tracking of the master device's radio frequency (RF) signal, providing a high-precision synchronization reference for subsequently generating a perturbation signal with a defined phase relationship, significantly improving the effectiveness and repeatability of active modulation. Furthermore, in one embodiment of this specification, the time from acquiring the master device's RF signal to determining the modulated RF signal to be transmitted can be relatively short, such as a few microseconds or tens of microseconds, enabling rapid active modulation of the master device and improving the user experience.

[0060] Step 206: Send the first modulated radio frequency signal for a first duration.

[0061] After determining the modulated radio frequency signal to be transmitted, the slave device can transmit it outward through its device antenna. The device antenna for transmitting the modulated radio frequency signal and the device antenna for receiving the radio frequency signal transmitted by the master device can be the same antenna or different antennas.

[0062] During the transmission of modulated RF signals by the slave device, the master device can be transmitting RF signals simultaneously. For example, while the slave device is transmitting the first modulated RF signal, the master device can be continuously transmitting the first RF signal. There is no need to wait for the master device to transmit a pulse of RF signal and then transmit the modulated RF signal again during the intervals between different pulses of RF signal transmission. The slave device can select the target modulated RF signal to transmit after determining the RF signal transmitted by the master device. In this way, the slave device can transmit the modulated RF signal immediately after receiving the first RF signal from the master device. Optionally, the time from the slave device sensing the first RF signal from the master device to transmitting the first modulated RF signal can be less than the pulse duration of a single RF signal transmitted by the master device. During the transmission of the first RF signal by the master device, the slave device can influence the first RF signal without waiting for the master device to transmit multiple cycles of RF signals before transmitting the modulated signal to influence the master device, thus enabling the master device to exit low-power mode more quickly.

[0063] In practical applications, if the master device (such as a mobile phone or POS machine) continuously transmits a low-power 13.56MHz carrier wave in LPCD mode, forming an alternating magnetic field; the slave device is originally in a passive state, relying solely on inductive power. In one embodiment of this specification, the slave device may have an active modulation circuit capable of generating modulated radio frequency signals with different phases or amplitudes. The slave device can actively inject a radio frequency field into the near-field space, which is spatially superimposed on the original field of the master device. The superposition result will significantly change the load impedance, Q value, or resonance characteristics of the master device's antenna circuit, specifically manifested as abrupt changes in antenna current, voltage amplitude, or phase. When the control unit of the master device detects this abnormal disturbance (such as exceeding the noise threshold and lasting for a certain period of time), it can exit LPCD mode and switch to the normal card search mode that sends Polling commands.

[0064] The first preset duration can represent the pre-defined modulation duration, which can be set according to actual needs. For example, it can be a duration in the range of 20µs to 60µs, or it can be a duration in other microseconds. For example, after the slave device detects the RF signal of the master device, it performs active modulation with a 90° phase signal for 50µs. During this period, the master device continuously samples the antenna current. If it finds a significant and stable shift in impedance, it can determine that a card is approaching. If the master device is in low-power mode, it can exit low-power mode and send a Polling command.

[0065] Step 208: After the first duration, the slave device is switched from the first impedance state to the second impedance state and held for the second duration; the sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

[0066] The slave device can have components with adjustable impedance values, such as resistors, capacitors, and inductors that can be turned on or off; or it can have components with adjustable impedance values, such as variable resistors, variable capacitors, and variable inductors. The slave device has different impedance values ​​in the first impedance state and the second impedance state, and can thus influence the master device through passive load adjustment, prompting the master device to switch to normal card search mode.

[0067] Optionally, the first impedance state can represent the default matching impedance state of the slave device (such as impedance matching between the antenna and the chip, minimizing reflection), and the resonant frequency can be consistent with that of the master device or conform to the communication protocol requirements. The second impedance state can represent the state in which the overall impedance is reduced or increased by connecting components such as resistors, capacitors, and inductors in parallel or series, resulting in an increase or decrease in the load on the master device's antenna and a more significant change in current.

[0068] The second duration can represent the duration of passive load modulation (e.g., 20µs). The period duration of the low-power signal can represent the time interval between two adjacent RF pulses in a low-power card detection mode (e.g., LPCD) by the master device, including the pulse time and silence time. This period duration can be determined according to the communication protocol or through experimental measurement.

[0069] As one implementation, after the first duration t1, an analog or digital switch can be turned on to connect the modulation resistor to the antenna matching network; after maintaining this state for a second duration w1, the switch is turned off to restore the first impedance state. The entire process (t1+w1) can be controlled to be less than or equal to 1ms, which is less than the typical LPCD period (100–500ms).

[0070] In practical applications, some master devices' LPCD detection mechanisms may be more sensitive to purely passive load changes but not to active signals. One embodiment in this specification applies passive load modulation immediately after active modulation, which can cover more models and provides better overall wake-up performance. Furthermore, the total duration of the two-stage operation can be less than the low-power signal cycle, expanding compatibility with different master device wake-up mechanisms and avoiding filtering by the master device's environmental calibration mechanism due to cross-cycle operations, thus improving wake-up robustness.

[0071] While one or more embodiments of this specification provide method steps as described in the embodiments or flowcharts, it is understood that the order of steps listed in the embodiments or flowcharts is merely one possible execution order among many steps and does not represent the only possible execution order. The order of some steps may be adjusted according to actual needs, or some steps may be omitted. When the claims involve method steps, changes in the order of such steps, or parallel execution between steps, are also within the scope of protection of the claims.

[0072] Figure 2 The method described above allows the slave device to sequentially perform phase / amplitude controllable active modulation signal transmission and impedance state switching after detecting the master device's RF signal. The total duration of the two-stage operation can be less than the period of the low-power detection signal, thus enabling the coordinated application of both active and passive perturbations within a single detection cycle. This avoids filtering out signals from the master device's environmental calibration mechanism and is compatible with the differences in detuning responses among different brands of terminals. It significantly improves the success rate of the master device exiting low-power mode and enhances the user experience.

[0073] based on Figure 2 In addition to the method described herein, this specification also provides some improvements or specific implementation methods of the method, which will be described below.

[0074] In practical applications, a single active or passive modulation attempt may not be sufficient to successfully exit the low-power mode for the master device. As one implementation, in one embodiment of this specification, after the slave device switches from a first impedance state to a second impedance state and maintains this state for a second duration, the process may further include: determining whether the master device has exited the low-power mode; if the master device has not exited the low-power mode, generating a second modulated radio frequency signal based on a second radio frequency signal; the second radio frequency signal is a radio frequency signal emitted by the master device after it emits the first radio frequency signal; the phase and / or amplitude of the second modulated radio frequency signal is different from that of the second radio frequency signal; and transmitting the second modulated radio frequency signal for a third duration.

[0075] One method to determine whether the master device has exited low-power mode is to detect whether it has received polling commands such as REQA / WUPA that conform to near-field communication standards (such as ISO / IEC 14443); or to observe whether the master device's radio frequency signal changes from a short pulse to a continuous carrier; or to determine whether the signal interval changes from a typical LPCD period (such as 200 ms) to a high-frequency polling sequence (such as millisecond-level continuous); or other related technologies can also be used.

[0076] If the master device has not exited low-power mode, after receiving the second radio frequency signal sent by the master device, it can generate a second modulated radio frequency signal with a different phase and / or amplitude than the second radio frequency signal, and then send the modulated radio frequency signal for a third duration. If the master device has exited low-power mode, it can skip the modulation steps and instead perform normal signaling interaction with the master device, such as responding to acknowledgments and transmitting tag information.

[0077] The second radio frequency signal can be the next pulse signal emitted by the master device after emitting the first radio frequency signal. The second modulated radio frequency signal can reuse the modulated signal generated by the generation logic of the first modulated radio frequency signal, or it can be a modulated signal generated using different processing logic.

[0078] In one embodiment of this specification, a multi-round fault-tolerant wake-up mechanism is implemented by adding a judgment on the status of the master device after the first round of wake-up operation and performing a new round of modulation perturbation based on subsequent signals when the wake-up fails. This effectively addresses the problem of single wake-up failure caused by poor coupling position, environmental noise, or high wake-up threshold of the master device, and significantly improves the overall card detection success rate and user experience certainty.

[0079] In practical applications, the LPCD detection circuit of the main device typically has a wake-up threshold. If the disturbance is too weak, the change is below the threshold, and it cannot be triggered; if the disturbance is too strong, it may be suppressed by the filter as abnormal noise. Optionally, the second phase difference between the second modulated RF signal and the second RF signal is different from the first phase difference between the first modulated RF signal and the first RF signal; or, the second amplitude difference between the second modulated RF signal and the second RF signal is different from the first amplitude difference between the first modulated RF signal and the first RF signal.

[0080] The first phase difference can represent the phase offset of the first modulated RF signal relative to the second RF signal (e.g., 180°). The second phase difference can represent the phase offset of the second modulated RF signal relative to the second RF signal (e.g., 0° or 90°). For example, in the first round of operation, the first phase difference is set to 180°; then, if it is determined that the master device has not exited the LPCD, the phase difference is changed to 0° (or the next value in the preset list) in the second round; the new offset can be dynamically configured by a digitally controlled phase shifter (e.g., a delay line controlled by a DDS module or CPLD); the second modulated RF signal is generated based on the new offset.

[0081] The first amplitude difference can represent the ratio or difference between the amplitude of the first modulated RF signal and the amplitude of the first RF signal (e.g., the modulated signal is 0.8 times the amplitude of the original signal); the second amplitude difference can represent the ratio or difference between the amplitude of the second modulated RF signal and the amplitude of the second RF signal (e.g., changed to 0.5 times or 1.2 times). For example, a high amplitude is used in the first round (e.g., V1 = 1.0 times the amplitude of the main signal); if wake-up fails, the amplitude is reduced in the second round (e.g., V2 = 0.6 times) to avoid over-excitation; or conversely, the first round is conservative (0.5 times), and the second round is stronger (1.0 times); amplitude adjustment is achieved through a variable gain amplifier (VGA) or a digital attenuator.

[0082] In one embodiment of this specification, by employing different phase differences or amplitude differences in multiple wake-up cycles, it is possible to adapt to the different sensitivity characteristics of different master devices to electromagnetic field changes, adapt to the sensitivity threshold and noise suppression characteristics of the master device's LPCD detection circuit, effectively avoid continuous wake-up failures caused by failure in a single disturbance direction, significantly improve cross-platform compatibility and final card detection success rate, and enhance system robustness.

[0083] In practical applications, the pulse width of the master device in LPCD (Low Power Card Detection) mode may vary depending on the device model, battery level, temperature, or firmware version. To improve the wake-up success rate, the first duration may optionally differ from the third duration.

[0084] As one implementation method, multiple sets of duration parameters can be preset during the initialization phase (e.g., t1=50μs, t3=30μs or t3=70μs). For the first round of operation, the first duration (e.g., t1) can be used to send the first modulated radio frequency signal. Subsequently, if it is determined that the master device has not exited LPCD mode, a different third duration (e.g., t3) can be selected in the second round. The on / off time of the radio frequency transmitter can be controlled by a timer or state machine to ensure precise duration. In practical applications, t3 can also be dynamically selected by combining historical wake-up records.

[0085] In one embodiment of this specification, by making the third duration different from the first duration, the duration of the active perturbation can be dynamically adjusted according to the difference in the LPCD pulse width of the master device or the first round of wake-up results. This can avoid the perturbation being invalid due to insufficient duration, and can also prevent protocol misjudgment or application mis-triggering caused by excessive duration. It can also be applied to different master devices, thereby achieving more accurate and secure wake-up enhancement in multiple rounds of retries.

[0086] To further improve the wake-up success rate of the master device, the second radio frequency signal can also be subjected to passive load modulation after active modulation. This allows the master device, which is not sensitive to active modulation, to exit low-power mode through passive load modulation. Optionally, the method in one embodiment of this specification may further include: after the third duration, switching the slave device from a third impedance state to a fourth impedance state and maintaining this state for a fourth duration; the sum of the third duration and the fourth duration is less than the period of the low-power signal emitted by the master device.

[0087] The third duration can represent the duration of transmitting the second modulated radio frequency signal, or the duration of the second round of active perturbation. The fourth duration can represent the length of time to maintain the fourth impedance state, specifically on the order of tens of microseconds.

[0088] The third impedance state can represent the default impedance state of the device before the start of the second round of operation, such as a state with good antenna matching and minimal reflection. This third impedance state can be the same as the first impedance state mentioned above, or it can have a different impedance value. The fourth impedance state can represent a state in which the overall impedance is reduced or increased by connecting impedance components such as resistors, capacitors, and inductors in series or parallel, resulting in a heavier or lighter load on the master device's antenna and a more significant change in current / voltage. This fourth impedance state can be the same as the second impedance state mentioned above, or it can have a different impedance value. The connection state of the slave device's antenna matching network can be changed by electronic switches (such as MOSFETs or analog switches), thereby changing its external impedance.

[0089] For example, at the moment the third duration ends, the control electronic switch is turned on, connecting the modulation resistor to the antenna matching circuit; this state is maintained for a fourth duration (e.g., 20μs); after the fourth duration ends, the switch is turned off, restoring the third impedance state (i.e., the default matching state); the entire second round of operation (third duration + fourth duration) can be completed within one LPCD cycle.

[0090] In practical applications, the master device's LPCD module typically has an environmental self-calibration function. If no effective change is detected within multiple cycles, the current state (including tag proximity) will be treated as a static environment and calibrated, causing subsequent disturbances to fail. If the second round of disturbance spans multiple cycles or lasts for a long time, the disturbance may be split into two cycles, and the master device may calibrate the tag state to background in the next cycle, leading to wake-up failure. By limiting the total duration of the second round of disturbance to less than the LPCD cycle, the master device's environmental calibration mechanism can be prevented from filtering out the disturbance, ensuring the effectiveness of retry operations and maintaining the reliability of the multi-round wake-up mechanism in real-world usage scenarios.

[0091] Optionally, the impedance difference between the first and second impedance states can be the same as or different from the impedance difference between the third and fourth impedance states. In multi-round wake-up, the intensity of the passive load modulation (i.e., the impedance change) can remain consistent or be dynamically adjusted. Maintaining a consistent impedance difference is suitable for scenarios where the master device characteristics are stable, simplifying the control logic. Different impedance differences are suitable for scenarios requiring testing different load intensities to match the master device's sensitivity, and can be applied to different master devices. In practical applications, the impedance difference can be set according to the usage scenario requirements of the slave device. For example, if the model of the master device interacting with the slave device is relatively simple or the wake-up strategy is relatively simple, the impedance difference can remain consistent; if the model of the master device interacting with the slave device is relatively complex or the wake-up strategy is relatively diverse, different impedance differences can be used.

[0092] In one embodiment of this specification, by performing a dual perturbation of active modulation followed by passive impedance switching in the second round of wake-up operation, and ensuring that its total duration is less than the cycle length of the low-power card detection signal of the main device, the retry phase has wake-up strength and compatibility comparable to the first round. This covers the types of main devices that are sensitive to load changes and avoids being filtered out by the environmental calibration mechanism due to cross-cycle operation, thereby significantly improving the overall card detection success rate and system robustness under multiple attempts.

[0093] As one implementation method, the second duration can be different from the fourth duration. By dynamically adjusting the time window of the passive disturbance based on the sensitivity of the master device to the duration of load changes or the result of the first round of wake-up, it is possible to avoid insufficient disturbance energy due to the duration being too short, and to prevent failure due to smoothing by the filter due to the duration being too long. This results in more accurate and efficient passive wake-up enhancement in multiple rounds of retries.

[0094] As one implementation, if the phase or amplitude difference between the second modulated RF signal and the second RF signal is different from the phase or amplitude difference between the first modulated RF signal and the first RF signal, or if the impedance difference between the first impedance state and the second impedance state is different from the impedance difference between the third impedance state and the fourth impedance state, the aforementioned second duration and fourth duration can also be the same. The relative relationships between the phase difference, impedance difference, and duration can be set according to actual needs and are not limited here.

[0095] To reduce the impact on subsequent communication, as one implementation, after switching the slave device from the first impedance state to the second impedance state and maintaining it for a second duration, the process may further include: restoring the slave device from the second impedance state to the first impedance state.

[0096] In NFC communication, the impedance state of a slave device can affect the load on the master device's antenna, the slave device's own energy harvesting efficiency, power supply and operational stability, and the signal integrity of subsequent normal communication. If the slave device is not restored to the first impedance state after completing the second period of load modulation, it may cause the slave device to be in a state of high reflection or low efficiency for a long time, which may lead to a reset due to insufficient power supply; or, the master device may mistakenly judge that the card has a continuous abnormal load, interfering with subsequent polling or data exchange; or, in multi-round wake-up or continuous interaction scenarios, accumulated impedance mismatch may cause communication failure, and so on.

[0097] In one implementation, at the end of the second timeout period, a control signal can be triggered to turn off or on the electronic switch (such as a MOSFET or analog switch) connected to the modulation resistor, causing the antenna matching network to return to its original topology and present a first impedance state to the outside world. The antenna voltage or current can also be monitored to confirm that it has stabilized back to the default state.

[0098] In one embodiment of this specification, by restoring the device to the default impedance matching state after the passive load modulation is completed, the energy harvesting efficiency, chip power supply instability, or subsequent communication failure caused by long-term impedance mismatch can be effectively avoided. It can also avoid the impact on the normal polling and data interaction of the master device, thereby improving the stability and protocol compatibility of the system.

[0099] Optionally, for the passive load modulation in the second round mentioned above, the slave device can be restored from the fourth impedance state to the third impedance state, or restored to the first impedance state, during the fourth duration.

[0100] In practical applications, to further increase the probability of the master device exiting low-power mode, a new round of active modulation can be performed after the second round of active and passive modulation. Optionally, in one embodiment of this specification, after the slave device switches from the third impedance state to the fourth impedance state and maintains it for a fourth duration, it may further include: Determine whether the main device has exited low-power mode; If the master device has not exited the low-power mode, a third modulated radio frequency signal is generated based on the third radio frequency signal; the third radio frequency signal is the radio frequency signal emitted by the master device after emitting the second radio frequency signal; the phase and / or amplitude of the third modulated radio frequency signal are different from those of the third radio frequency signal. The third modulated radio frequency signal of the fifth duration is transmitted.

[0101] After completing the second round of passive modulation (fourth duration), a listening window can be opened to detect whether a command conforming to the near-field communication protocol, such as the 7-bit REQA command of ISO / IEC 14443 Type A, is received; or to monitor whether the radio frequency signal changes from intermittent pulses (such as 200 ms intervals) to continuous carriers. If the above characteristics are not detected, it can be determined that the master device has not exited the low-power mode. After obtaining the third radio frequency signal sent by the master device, a third modulated radio frequency signal matching the third radio frequency signal can be generated.

[0102] The third radio frequency signal can represent another pulse signal emitted by the master device in the next cycle after emitting the second radio frequency signal. In practical applications, if the master device has exited low-power mode, the slave device can start the normal communication process with the master device without having to perform the process of generating and transmitting the third modulated radio frequency signal.

[0103] The third modulated radio frequency signal is a modulated radio frequency signal generated based on the signal characteristics of the third radio frequency signal. The specific generation logic can be found in the generation logic of the first modulated radio frequency signal or the second modulated radio frequency signal in the previous embodiments, and will not be repeated here.

[0104] Similar to the first modulated RF signal or the second debugging RF signal mentioned above, the third modulated RF signal can be an RF signal that has a phase difference or amplitude difference with the third RF signal. Specifically, the phase difference can be any phase from 0° to 360°. The amplitude difference can also be set according to actual needs. For example, the amplitude of the third modulated RF signal can be 2 times, 0.5 times, or a certain preset amplitude value, etc., and is not limited here.

[0105] In practical applications, if the phase difference and amplitude difference are zero, the third modulated RF signal and the third RF signal can also be RF signals with the same phase and amplitude. Similarly, the first modulated RF signal and the first RF signal can also be RF signals with the same phase and amplitude, or the second modulated RF signal and the second RF signal can also be RF signals with the same phase and amplitude.

[0106] To avoid the main device weakening the newly acquired debugging RF signal due to the calibration mechanism, as one implementation, the third phase difference between the third modulated RF signal and the third RF signal is different from the second phase difference between the second modulated RF signal and the second RF signal; or, the third amplitude difference between the third modulated RF signal and the third RF signal is different from the second amplitude difference between the second modulated RF signal and the second RF signal.

[0107] In practical applications, different master devices may have different sensitivities to perturbation dimensions. Some master devices are sensitive to phase direction (e.g., 180° is effective, 0° is ineffective); others are sensitive to amplitude intensity (e.g., weak perturbations are effective, strong perturbations are suppressed). If the first two strategies (e.g., 180°, 0°) fail, a third perturbation dimension (e.g., 90° or amplitude adjustment) can be tried. For example, a perturbation strategy sequence can be pre-stored: the phase difference set is [180°, 0°, 90°] or the amplitude difference set is [1.0×, 0.6×, 0.4×]. The third round can automatically select the next untried parameter in the sequence; a new phase / amplitude configuration can be implemented through DDS or VGA. By using different perturbation parameters in the third round compared to the second round, diverse exploration of perturbation strategies can be achieved, effectively covering master device types sensitive to specific phases or amplitudes, and improving the final wake-up success rate after multiple attempts.

[0108] Alternatively, the phase difference or amplitude difference between different modulated radio frequency signals can be the same. For example, the phase difference between the first modulated radio frequency signal and the second modulated radio frequency signal can be 180°, and the phase difference between the second modulated radio frequency signal and the second radio frequency signal can also be 180°. This can be set according to the actual needs of the scenario.

[0109] The fifth duration can represent the duration of the third round of active modulation. Similar to the first two rounds, the fifth duration can be controlled within tens of microseconds to ensure that the disturbance acts on the LPCD detection window, thus avoiding misjudgment as a valid card response or interference with subsequent communication. For details on the duration control method, please refer to the description in the aforementioned embodiments, which will not be repeated here.

[0110] As one implementation method, the fifth duration can be different from the third duration. This allows for dynamic adjustment of the third round of perturbation time window based on the master device's sensitivity to the duration of active perturbation or the results of the first two rounds of wake-up. This avoids insufficient perturbation energy due to a too short duration, while also preventing suppression by the filter due to a too long duration, thereby achieving more accurate and efficient active wake-up enhancement through multiple attempts.

[0111] In one embodiment of this specification, active and passive modulation can be performed from multiple dimensions such as active modulation duration, phase difference, amplitude difference, and passive modulation duration, enabling the system to flexibly respond to diverse mobile terminals, improve the final card detection certainty, and have high robustness.

[0112] As another implementation method, the fifth duration can also be the same as the third duration or the first duration, which can simplify the control logic and improve the response speed.

[0113] Similar to the passive modulation process described above, a passive modulation process can also be added for the third round of active modulation to further facilitate the master device exiting the low-power mode. In one embodiment of this specification, after the fifth duration, the slave device can be switched from the fifth impedance state to the sixth impedance state and maintained for the sixth duration; the sum of the fifth duration and the sixth duration is less than the period of the low-power signal emitted by the master device.

[0114] The fifth impedance state represents the default impedance matching state of the slave device before the start of the third round of operation. It can be the same as or different from the first and third impedance states mentioned above. When the slave device is in the fifth impedance state, parameters such as resonant frequency and quality factor can meet the requirements of near-field communication, and the slave device can perform normal near-field communication with the master device.

[0115] The sixth impedance state can represent a state where the overall impedance decreases or increases by connecting parallel or series modulation resistors, used to generate a load change that can be detected by the master device. The sixth impedance state can be the same as or different from the second and fourth impedance states described above. For specific processing logic, please refer to the impedance state switching logic in the previous embodiments, which will not be repeated here.

[0116] The sixth duration represents the length of time the sixth impedance state is maintained, which can be on the order of tens of microseconds. Similarly, the sum of the fifth and sixth durations can be less than the period of a low-power signal. For example, the sum of the durations can be within 1 ms.

[0117] In practical applications, the LPCD detection mechanism of some master devices may be sensitive to passive load changes but not to active signals. Applying passive load modulation immediately after an active disturbance can cover master device types sensitive to impedance changes and avoid being filtered out by the environmental calibration mechanism due to cross-cycle operations. This maintains the same wake-up strength and compatibility in each round of attempts in the three-round progressive fault-tolerant architecture, thereby improving the final card detection success rate and system robustness.

[0118] Similar to the first and second modulated radio frequency signals mentioned above, the third modulated radio frequency signal can also be sent from the slave device to the master device during the master device's transmission of the third radio frequency signal. The impedance switching process following the third modulated radio frequency signal can also be performed during the master device's transmission of the third radio frequency signal. This allows for both active and passive influence on the master device within a single pulse cycle, prompting the master device to exit low-power mode.

[0119] In practical applications, there may be master devices that are not sensitive to phase or amplitude. To wake up the master device as much as possible, in one embodiment of this specification, the master device can be prompted to exit the low-power mode by actively transmitting an excitation signal after active and passive modulation. Optionally, after the slave device switches from the fifth impedance state to the sixth impedance state and maintains it for a sixth duration, the process may further include: determining whether the master device has exited the low-power mode; if the master device has not exited the low-power mode, then sending a pulse excitation signal of a seventh duration.

[0120] The specific logic for determining whether the master device has exited low-power mode can be found in the description of the aforementioned embodiments, and will not be repeated here. The pulse excitation signal can represent a short-duration radio frequency pulse generated autonomously by the device and independent of the phase synchronization of the master device's radio frequency signal. It can be a pulse signal with a fixed frequency (e.g., 13.56MHz), a fixed phase (e.g., 0°), or a random phase. The seventh duration indicates the duration of the pulse excitation signal.

[0121] The pulse excitation signal can be a pulse signal of a preset frequency (e.g., 13.56 MHz) generated by the device's local free oscillator (e.g., an RC oscillator or a crystal oscillator divided by a frequency divider), which can be transmitted outward through a near-field antenna. The antenna transmitting the excitation signal and the antenna receiving the RF signal from the main device can be the same or different antennas.

[0122] In one embodiment of this specification, an autonomous pulse excitation signal can be sent even after multiple rounds of phase synchronization disturbance failures, which can effectively cover the main equipment that is not sensitive to phase synchronization disturbances and improve the final card detection success rate.

[0123] As one implementation method, actively emitting an excitation signal can be used as a fallback. To facilitate the master device's exit from low-power mode as much as possible, the duration of the actively emitted excitation signal can be slightly longer. Optionally, the seventh duration can be greater than the sum of the fifth and sixth durations. For example, the seventh duration can be 3ms, or it can be any other duration. This ensures that the autonomous pulse excitation signal has sufficient energy injection time and signal continuity, effectively overcoming wake-up failures caused by low sensitivity of the master device's LPCD circuit, high noise threshold, or detection window offset, and improving the final card detection success rate.

[0124] In practical applications, to more effectively encourage the master device to exit low-power mode via excitation signals, the method in one embodiment of this specification may optionally include: determining whether the pulse characteristics of the master device meet preset characteristics based on the first radio frequency signal, the second radio frequency signal, and the third radio frequency signal; the pulse characteristics include pulse width and / or pulse period.

[0125] The aforementioned transmission of pulse excitation signal may include: if the pulse characteristics of the master device meet preset characteristics, then the pulse excitation signal is transmitted.

[0126] The first, second, and third radio frequency (RF) signals represent short-duration pulse signals emitted by the main device within three consecutive pulse cycles, which can be used to construct time-series observation samples. The pulse width represents the duration of a single pulse signal (i.e., the RF signal). The pulse period represents the time interval between two adjacent pulse signals, including the pulse width and the silence time.

[0127] Preset features can represent feature templates pre-stored in the slave device, such as pulse widths between 40μs and 120μs and pulse periods between 150ms and 300ms. The specific values ​​of these preset features can be determined based on actual test results, the actual communication protocol, statistically based on the success rate of communication between the slave and master devices, or through expert experience. Alternatively, in practical applications, some brands or models of master devices are not sensitive to phase or amplitude but are more sensitive to excitation signals. The aforementioned preset features can also be characteristics of the RF signals emitted by these master devices, and can be determined by the characteristics of the low-power RF signals emitted by such master devices.

[0128] In one embodiment of this specification, the pulse width and / or period of the master device are analyzed based on multi-cycle LPCD signals, and a pulse excitation signal is sent when the preset characteristics are met. This can effectively avoid false responses to non-target radio frequency sources or abnormal interference, improve the system's environmental adaptability, energy efficiency and protocol security, and enhance the overall reliability and practicality of the solution.

[0129] Correspondingly, if the pulse characteristics of the master device do not meet the preset characteristics, a pulse excitation signal can be sent to end the modulation process. Alternatively, a new round of active and passive modulation can be started. Optionally, in one embodiment of this specification, after sending the pulse excitation signal for the seventh duration, the process may further include: determining whether the master device has exited the low-power mode; if the master device has not exited the low-power mode, waiting for the fourth radio frequency signal sent by the master device; the fourth radio frequency signal is the radio frequency signal sent by the master device after the seventh duration; based on the fourth radio frequency signal, sending a fourth modulated radio frequency signal; the phase and / or amplitude of the fourth modulated radio frequency signal is different from that of the fourth radio frequency signal.

[0130] The fourth radio frequency (RF) signal can be another pulse signal emitted by the master device after the master device emits the third RF signal. The fourth modulated RF signal can be an RF signal generated by the slave device according to the above-described logic for generating modulated RF signals. The specific generation logic can be found in the description in the foregoing embodiments, and will not be repeated here.

[0131] In practical applications, the impedance state of the slave device can be adjusted after the fourth modulated radio frequency signal is transmitted, and the master device can be further promoted to exit the low power mode through active modulation and passive load modulation.

[0132] To avoid long waiting times for the user of the master device, as an alternative implementation, if the master device does not exit low-power mode after sending a pulse excitation signal of the seventh duration, the slave device can display or issue a prompt message to remind the user of the master device to re-touch the master device with the slave device.

[0133] In practical applications, if the master device exits low-power mode, the slave device can switch to normal communication mode to communicate and interact with the master device. Optionally, the method in one embodiment of this specification may further include: if the master device has exited low-power mode, sending near-field communication interaction information with the master device.

[0134] The master device has exited low-power mode, which means that the master device has ended the LPCD periodic pulse detection and entered the normal Polling communication mode, and has started to send commands that conform to standards such as ISO / IEC 14443 (such as REQA, WUPA, ANTICOLLISION, etc.).

[0135] Near-field communication interaction information can represent NFC protocol data that the device needs to respond to, including but not limited to: UID (Unique Identifier); ATQA / SAK (Response Request / Selection Confirmation); application data (such as access permissions, payment tokens, URL links, etc.).

[0136] In one embodiment of this specification, standard near-field communication interaction information is sent immediately after the master device confirms that it has exited low-power mode. This ensures that the wake-up result is effectively converted into actual data interaction, which can avoid the master device judging the card as invalid due to missing or delayed response, thereby improving the integrity and reliability of the user experience.

[0137] The various technical features in the above embodiments can be combined arbitrarily, as long as there is no conflict or contradiction between the combinations of features. However, due to space limitations, they have not been described one by one. Therefore, the arbitrary combination of various technical features in the above embodiments is also within the scope of this specification.

[0138] Based on the above description, this example illustrates the method provided in this specification using a combination of three active and passive modulations and one active excitation. Figure 3 This is a flowchart illustrating a near-field communication method provided in one embodiment of this specification.

[0139] like Figure 3 As shown, the slave device can initially complete NFC initialization, which may include configuring the parameters of the NFC tag, enabling the NFC signal source (such as setting the transmitter clock to its initial state), etc., putting the entire slave device into a STANDBY state. It can also enable NFC signal detection capabilities, for example, the field detection module can be enabled. In practical applications, the slave device can begin initialization after completing one or more rounds of active or passive modulation, or after the excitation signal has been transmitted, or even when the slave device is not communicating with the master device, or after the slave device has finished communicating with the master device, etc. The timing of initialization is not limited here, as long as it is completed before any interaction between the master device and the slave device.

[0140] When a master device approaches, for example, when a user brings their phone close to a slave device, the master device (such as the phone) periodically transmits radio frequency (RF) signals. As the distance between the two ends approaches, the amplitude of the signal received by the slave device gradually increases. When the wake-up threshold set by the slave device is reached, it can be recorded as the slave device detecting the master device's signal for the first time, which can be called the first RF signal. The detected signal (first RF signal) may be an LPCD signal or a polling signal, which can be ignored here. Then, two steps of control may be performed quickly. First, through active modulation, the slave device can generate a first modulated RF signal based on the acquired first RF signal and transmit a first modulated RF signal with a duration of t1 (first duration), an amplitude of V1, and a phase shift of α. This signal is an NFC signal. The master device will superimpose its own card reader signal with the first modulated RF signal emitted by the slave device, causing the signal change on the master device to increase. The master device may exit low-power mode under the influence of the first modulated RF signal.

[0141] After emitting the first modulated RF signal, the slave device performs a load modulation. Specifically, the impedance of the slave device can be adjusted by load switching, switching from the first impedance state to the second impedance state, for example, adjusting to an impedance of R1, for a duration of a second duration w1. Both steps aim to increase the probability of waking up the master device. The duration of active modulation can be controlled within 50 microseconds, which basically covers the duration of most master device LPCD signals. However, some mobile phones may still have LPCD signals lasting more than 100 microseconds. For these phones, the passive modulation switching in the second step will be effective in waking them up. The total duration of these two modulation steps can be controlled within 1ms. This ensures that even if the master device has started polling, subsequent communication will not be affected due to the master device's guard interval (a certain time interval between the pulse signals emitted by the master device).

[0142] If the master device fails to wake up under the first modulation RF signal and the first load switch, and does not exit low-power mode or enable polling, the master device will continue to send LPCD signals. In this case, the slave device will perform a second signal detection to obtain the second RF signal sent by the master device. After the slave device detects the second RF signal, the processing logic is the same as the first time, and it can attempt to perform two-step control again. The parameters used in the second modulation can be different from the first. Specifically, the slave device can transmit a second modulation RF signal with a duration of t2 (the third duration), an amplitude of V2, and a phase shift of β. After the third duration, the slave device can adjust its impedance through load switching, from the third impedance state to the fourth impedance state. For example, it can adjust to an impedance of R2 for a duration of the fourth duration w2. Afterward, if the master device still does not exit low-power mode or enable polling, it will continue to send LPCD signals. In this case, the slave device will perform a third signal detection to obtain the third RF signal sent by the master device. After the slave device detects the third RF signal, the processing logic is the same as the first and second steps. It can attempt another two-step control. The parameters used in the third modulation can differ from the second. Specifically, the slave device can transmit a third modulated RF signal with a duration of t3 (the fifth duration), an amplitude of V3, and a phase shift of γ. After the fifth duration, the slave device can adjust its impedance via load switching, changing from the fifth impedance state to the sixth impedance state. For example, it can adjust to an impedance of R3 for a duration of the sixth duration w3. R1, R2, and R3 can be the same or different.

[0143] If the master device fails to wake up after three attempts, meaning the master device has not started polling, the slave device can determine whether the radio frequency signal emitted by the master device conforms to preset characteristics based on the signal characteristics of the radio frequency signal emitted by the card reader in the first three detections. These characteristics may include the signal pulse width and signal interval period. If they do conform, the slave device can then use the NFC signal transmitter to send an NFC pulse signal with a duration of t4 (seventh duration). The t4 time can be controlled within 3ms. This method can achieve a higher wake-up rate for the master device.

[0144] If, at any of the above stages, it is determined that the master device has exited low-power mode and started polling, the slave device can exit modulation mode and perform normal NFC near-field communication processing and NFC signaling interaction with the master device until the communication with the master device ends.

[0145] If the master device still does not exit low-power mode after three active and passive modulations and one excitation signal, or if the signal pulse width and period interval of the master device are determined to be inconsistent with the preset requirements after three active and passive modulations, the active, passive, and excitation signal steps can be restarted. Alternatively, the slave device can also display a prompt message reminding the user to touch again.

[0146] In practical applications, the steps of acquiring the radio frequency (RF) signal emitted by the master device and determining whether the master device has exited low-power mode can be performed simultaneously, or the step of determining whether the master device has exited low-power mode can be performed after acquiring the RF signal emitted by the master device (such as a second RF signal or a third RF signal). For example, the master device can determine whether to start polling based on the acquired second or third RF signal. Figure 3 This is just an illustration. In actual applications, some steps in each process can be executed simultaneously or their order can be changed.

[0147] In practical applications, after one, two, or more than three active modulations and load modulations, if the master device has not exited the low-power mode, the slave device can execute the step of sending an excitation signal. For example, after switching the slave device from the first impedance state to the second impedance state and maintaining it for a second duration, it is determined whether the master device has exited the low-power mode. If it has not exited, a pulse excitation signal is sent; or it is determined whether the pulse characteristics of the master device meet preset characteristics. If they do, a pulse excitation signal is sent. As another example, after switching the slave device from the third impedance state to the fourth impedance state and maintaining it for a fourth duration, it is determined whether the master device has exited the low-power mode. If it has not exited, a pulse excitation signal is sent; or it is determined whether the pulse characteristics of the master device meet preset characteristics. If they do, a pulse excitation signal is sent.

[0148] One embodiment of this specification combines active modulation, passive load modulation, and active excitation. These three strategies work together to maximize the card detection performance of the master device in LPCD mode and provide better compatibility with various master devices, each compensating for the shortcomings of a single strategy. Active modulation is used as the primary strategy for waking up the phone to read the card, reducing the probability of the phone ejecting the SIM card and decreasing dependence on the coupling location, while also improving wake-up speed. Passive modulation following active modulation improves the wake-up success rate for master devices with longer LPCD signal durations. Finally, active excitation is used as a fallback, ultimately achieving a solution with a high overall wake-up success rate.

[0149] In one embodiment of this specification, a high-sensitivity NFC signal field detection and wake-up module (e.g., a field detection module containing an RF power meter) is used, employing RF front-end PLL phase synchronization and clock extraction methods to achieve a more precise and controllable modulation effect, greatly improving the wake-up speed and efficiency of the master device, and effectively reducing the probability of the master device ejecting the SIM card packet.

[0150] In one embodiment of this specification, a dynamic impedance switching strategy is added to active modulation to improve compatibility across different brand terminals.

[0151] In one embodiment of this specification, when neither active modulation nor passive impedance switching is effective, an additional active excitation compensation is performed, which further improves the determinism of the entire scheme. The entire scheme can achieve a wake-up success rate of 99% or higher for the master device.

[0152] Based on the same idea, one embodiment of this specification also provides a near-field communication module corresponding to the above method. Figure 4 This is a schematic diagram of a near-field communication module provided in one embodiment of this specification. This module can be applied to a slave device in near-field communication.

[0153] like Figure 4 As shown, the near-field communication module 400 may include a field detection module 402, a modulation signal generation module 404, a load switching module 406, and a control module 408.

[0154] The field detection module 402 can be connected to the near-field antenna 202 of the slave device. The near-field antenna 202 is used to acquire the first radio frequency signal emitted by the master device. After the field detection module 402 acquires the first radio frequency signal emitted by the master device, it generates a trigger signal. The modulation signal generation module 404 is connected to the field detection module 402. If the trigger signal generated by the field detection module is acquired, the signal characteristics of the first radio frequency signal are extracted to generate a first modulated radio frequency signal. The phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal. The control module 408 is connected to the modulation signal generation module 404 and the near-field antenna 202 and is used to control the near-field antenna 202 to transmit the first modulated radio frequency signal for a first duration. The control module 408 is also connected to the load switching module 406 and is used to switch the slave device from a first impedance state to a second impedance state and maintain it for a second duration after the first duration. The sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

[0155] like Figure 4As shown, the master device 100 may include a card reader antenna 102 and a card reader control unit 104. The slave device 200 may include a near-field antenna 202, a load switching module 406, a field detection module 402, a modulation signal generation module 404, a control module 408, etc. The control module can control the load switching module, modulation signal generation module, etc., via a communication bus or I / O interface. The slave device and the master device can exchange information via near-field electromagnetic coupling.

[0156] In one implementation, the modulation signal generation module may include a PLL phase-locked clock module and a phase shift module, which can generate a corresponding modulation radio frequency signal based on the radio frequency signal emitted by the master device.

[0157] The control module may include an auxiliary control module for controlling the modulation process and a device control module for controlling communication between the slave device and the master device. Alternatively, the modules for controlling the modulation process and the modules for controlling communication between the slave device and the master device may be the same control module, such as a microcontroller (MCU), a state machine, or a dedicated logic circuit control unit.

[0158] As one implementation method, the modulation signal generation module can, during the transmission of radio frequency signals by the master device, first extract the signal clock of the master device through the field detection module and the PLL phase-locked clock module. Then, based on this clock, a fixed or variable phase shift is performed to drive the signal source in the slave device to transmit a signal with a certain phase difference from the master device. If the original signal of the master device is... Received adjustment radio frequency signal sent from the device Afterwards, the final signal on the master equipment side can be This signal may cause significant changes in parameters such as voltage or current on the master device side, prompting the master device to exit low-power mode.

[0159] Optionally, the modulated radio frequency signal emitted by the slave device can be a signal with the same phase or opposite phase to the radio frequency signal emitted by the master device, or the phase difference between the modulated radio frequency signal and the radio frequency signal emitted by the master device can be any value between 0° and 360°. Opposite phase indicates that the phase difference between the modulated radio frequency signal and the original signal of the master device is... Around, or greater than, a certain threshold. Phase sameness means that the phase difference between the superimposed signal and the original signal is within [a certain range]. Around, or less than a certain threshold.

[0160] As one implementation method, such as Figure 5As shown, passive load modulation can represent a situation where the near-field antenna of a slave device is normally connected to the NFC chip after passing through a matching circuit. A modulation resistor Rm can be connected in parallel within the matching circuit, and modulation is controlled by a switch SW. For example, when switch SW is open, the slave device is in the default matched state; when switch SW is closed, load modulation is performed, which reduces the antenna impedance; or, when switch SW is closed, the slave device is in the default matched state; when switch SW is open, load modulation is performed, which increases the antenna impedance. This can cause changes in the parameters on the master device side, prompting the master device to exit low-power mode.

[0161] like Figure 5 As shown, the resistor can be connected in parallel with the matching circuit. One end of the resistor is connected to the matching circuit, and the other end is connected to the switch SW. The common terminal of the switch SW can be grounded (GND). The control unit can be connected to the switch SW to control the switching state of the switch SW.

[0162] In practical applications, the positions of the switch and resistor can be interchanged, and the switch can be connected between the resistor and the matching circuit. Alternatively, passive load modulation can be achieved by connecting capacitors, inductors, and other components in series or parallel.

[0163] The control unit can be part of the NFC chip or it can be set up independently. In one embodiment of this specification, the control unit can perform the steps of the near-field communication method described above, and can perform active modulation and passive load modulation multiple times. Further details are omitted here.

[0164] In one embodiment of this specification, such as Figure 4 As shown, the near-field communication module 400 may further include an excitation signal module 410, which can be connected to the control module 408. The control module 408 can control the excitation signal module 410 to generate and transmit pulse excitation signals after active modulation and passive load modulation. The excitation signal module 410 is also connected to the near-field antenna 202, and can transmit pulse excitation signals outward through the near-field antenna 202. The generation and transmission logic of the pulse excitation signal can be found in the description of the foregoing embodiments, and will not be repeated here. The above is a schematic scheme of a near-field communication module according to this embodiment. It should be noted that the technical solution of this near-field communication module and the technical solution of the above-described near-field communication method belong to the same concept. Details not described in detail in the technical solution of the near-field communication module can be found in the description of the technical solution of the above-described near-field communication method.

[0165] Based on the same idea, embodiments of this specification also provide apparatus corresponding to the above methods. Figure 6 This is a schematic diagram of a near-field communication device provided in one embodiment of this specification.

[0166] like Figure 6As shown, the device may include: Signal acquisition module 602 is used to acquire the first radio frequency signal emitted by the master device of near-field communication; The modulation signal generation module 604 is used to extract the signal features of the first radio frequency signal and generate a first modulated radio frequency signal; the phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal. Signal transmitting module 606 is used to transmit the first modulated radio frequency signal for a first duration; The state switching module 608 is used to switch the slave device from a first impedance state to a second impedance state and maintain it for a second time after the first duration; the sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

[0167] It is understood that the modules mentioned above refer to computer programs or program segments used to perform one or more specific functions. Furthermore, the distinction between these modules does not imply that the actual program code must also be separate.

[0168] For ease of description, the above devices are described by dividing them into various modules or units based on their functions. Of course, when implementing one or more of these specifications, the functions of each module or unit can be implemented in the same or different software and / or hardware, or a module that performs the same function can be implemented by a combination of multiple sub-modules or sub-units, etc. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0169] The above is a schematic scheme of a near-field communication device according to this embodiment. It should be noted that the technical solution of this near-field communication device and the technical solution of the near-field communication method described above belong to the same concept. For details not described in detail in the technical solution of the near-field communication device, please refer to the description of the technical solution of the near-field communication method described above.

[0170] Based on the same idea, one embodiment of this specification also provides a near-field communication device, which is used to perform the above-described near-field communication method, or the device may include the above-described near-field communication module.

[0171] Based on the same idea, the embodiments of this specification also provide computing devices corresponding to the above methods.

[0172] Figure 7 A structural block diagram of a computing device 700 provided according to one embodiment of this specification is shown.

[0173] The computing device 700 includes: Memory 710 and processor 720; The memory 710 is used to store computer programs / instructions, and the processor 720 is used to execute the computer programs / instructions, which, when executed by the processor 720, implement the steps of the above-described near-field communication method.

[0174] Specifically, the components of the computing device 700 include, but are not limited to, a memory 710 and a processor 720. The processor 720 is connected to the memory 710 via a bus 730, and the database 750 is used to store data.

[0175] The computing device 700 also includes an access device 740, which enables the computing device 700 to communicate via one or more networks 760. Examples of these networks include Public Switched Telephone Network (PSTN), Local Area Network (LAN), Wide Area Network (WAN), Personal Area Network (PAN), or combinations of communication networks such as the Internet. The access device 740 may include one or more of any type of wired or wireless network interface (e.g., a network interface card (NIC)), such as an IEEE 802.11 Wireless Local Area Network (WLAN) wireless interface, a Wi-MAX (Worldwide Interoperability for Microwave Access) interface, an Ethernet interface, a Universal Serial Bus (USB) interface, a cellular network interface, a Bluetooth interface, a Near Field Communication (NFC) interface, and so on.

[0176] In one embodiment of this specification, the above-described components of the computing device 700 and Figure 7 Other components, not shown, can also be connected to each other, for example, via a bus. It should be understood that... Figure 7 The block diagram of the computing device shown is for illustrative purposes only and is not intended to limit the scope of this application. Those skilled in the art can add or replace other components as needed.

[0177] The computing device 700 can be any type of stationary or mobile computing device, including mobile computers or mobile computing devices (e.g., tablet computers, personal digital assistants, laptop computers, notebook computers, netbooks, etc.), mobile phones (e.g., smartphones), wearable computing devices (e.g., smartwatches, smart glasses, etc.) or other types of mobile devices, or stationary computing devices such as desktop computers or personal computers (PCs). The computing device 700 can also be a mobile or stationary server.

[0178] The processor 720 executes the computer instructions to implement the steps of the above-described near-field communication method.

[0179] The above is an illustrative scheme of a computing device according to this embodiment. It should be noted that the technical solution of this computing device and the technical solution of the near-field communication method described above belong to the same concept. For details not described in detail in the technical solution of the computing device, please refer to the description of the technical solution of the near-field communication method described above.

[0180] An embodiment of this specification also provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the steps of the near-field communication method as described above.

[0181] The above is an illustrative scheme of a computer-readable storage medium according to this embodiment. It should be noted that the technical solution of this storage medium belongs to the same concept as the technical solution of the near-field communication method described above. For details not described in detail in the technical solution of the storage medium, please refer to the description of the technical solution of the near-field communication method described above.

[0182] An embodiment of this specification also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the above-described near-field communication method.

[0183] The above is an illustrative scheme of a computer program product according to this embodiment. It should be noted that the technical solution of this computer program product and the technical solution of the near-field communication method described above belong to the same concept. For details not described in detail in the technical solution of the computer program product, please refer to the description of the technical solution of the near-field communication method described above.

[0184] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the embodiments of apparatus, devices, media, and products, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The apparatus, devices, media, products, and methods provided in the embodiments of this specification are corresponding to each other, and therefore the apparatus, devices, media, and products also have similar beneficial technical effects as the corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the corresponding apparatus, devices, media, and products will not be repeated here.

[0185] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0186] In the 1990s, improvements to a technology could be clearly distinguished as either hardware improvements (e.g., improvements to the circuit structure of diodes, transistors, switches, etc.) or software improvements (improvements to methodology). However, with technological advancements, many methodological improvements today can be considered direct improvements to hardware circuit structures. Designers almost always obtain the corresponding hardware circuit structure by programming the improved methodology into the hardware circuit. Therefore, it cannot be said that a methodological improvement cannot be implemented using hardware physical modules. For example, a Programmable Logic Device (PLD) (such as a Field Programmable Gate Array (FPGA)) is such an integrated circuit whose logic function is determined by the user programming the device. Designers can program a digital system themselves to "integrate" it onto a PLD, without needing chip manufacturers to design and manufacture dedicated integrated circuit chips. Furthermore, nowadays, instead of manually manufacturing integrated circuit chips, this programming is mostly implemented using "logic compiler" software. Similar to the software compiler used in program development, the original code before compilation must also be written in a specific programming language, called a Hardware Description Language (HDL). There are many HDLs, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, and RHDL (Ruby Hardware Description Language). Currently, the most commonly used are VHDL (Very-High-Speed ​​Integrated Circuit Hardware Description Language) and Verilog. Those skilled in the art should also understand that by simply performing some logic programming on the method flow using one of these hardware description languages ​​and programming it into an integrated circuit, the hardware circuit implementing the logical method flow can be easily obtained.

[0187] The controller can be implemented in any suitable manner. For example, it can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicon Labs C8051F320. A memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art will also recognize that, in addition to implementing the controller in purely computer-readable program code form, the same functionality can be achieved by logically programming the method steps to make the controller take the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the means included therein for implementing various functions can also be considered as structures within the hardware component. Alternatively, the means for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0188] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0189] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0190] Those skilled in the art will understand that one or more embodiments of this specification can be provided as a method, system, or computer program product. Therefore, the invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0191] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0192] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0193] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0194] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0195] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0196] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital character versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0197] This application can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0198] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A near-field communication method, applied to a slave device in near-field communication, the method comprising: Acquire the first radio frequency signal emitted by the master device of near-field communication; Extract the signal features of the first radio frequency signal to generate a first modulated radio frequency signal; The phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal; Transmit the first modulated radio frequency signal for a first duration; After the first duration, the slave device is switched from the first impedance state to the second impedance state and maintained for the second duration; the sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

2. The method according to claim 1, wherein the first radio frequency signal is a low-power signal emitted by the master device in low-power processing mode, or a non-low-power signal emitted by the master device in non-low-power processing mode.

3. The method according to claim 1, wherein after the slave device switches from the first impedance state to the second impedance state and maintains it for a second duration, it further comprises: Determine whether the main device has exited low-power mode; If the master device has not exited the low-power mode, a second modulated radio frequency signal is generated based on the second radio frequency signal; The second radio frequency signal is the radio frequency signal emitted by the master device after it emits the first radio frequency signal; The phase and / or amplitude of the second modulated radio frequency signal are different from those of the second radio frequency signal; The second modulated radio frequency signal with a third duration is transmitted.

4. The method according to claim 3, further comprising: After the third duration, the slave device is switched from the third impedance state to the fourth impedance state and held for the fourth duration; the sum of the third duration and the fourth duration is less than the period of the low-power signal emitted by the master device.

5. The method according to claim 3, wherein the second phase difference between the second modulated radio frequency signal and the second radio frequency signal is different from the first phase difference between the first modulated radio frequency signal and the first radio frequency signal; or, the second amplitude difference between the second modulated radio frequency signal and the second radio frequency signal is different from the first amplitude difference between the first modulated radio frequency signal and the first radio frequency signal; Alternatively, the first duration may differ from the third duration.

6. The method according to claim 4, wherein the second duration is different from the fourth duration.

7. The method according to claim 1, further comprising, after switching the slave device from a first impedance state to a second impedance state and maintaining it for a second duration: The slave device is restored from the second impedance state to the first impedance state.

8. The method according to claim 4, wherein after the slave device switches from the third impedance state to the fourth impedance state and maintains it for the fourth duration, it further comprises: Determine whether the main device has exited low-power mode; If the master device has not exited the low-power mode, a third modulated radio frequency signal is generated based on the third radio frequency signal; The third radio frequency signal is a radio frequency signal emitted after the main device emits the second radio frequency signal; the phase and / or amplitude of the third modulated radio frequency signal are different from those of the third radio frequency signal. The third modulated radio frequency signal of the fifth duration is transmitted.

9. The method according to claim 8, further comprising: After the fifth duration, the slave device is switched from the fifth impedance state to the sixth impedance state and held for the sixth duration; The sum of the fifth duration and the sixth duration is less than the period duration of the low-power signal emitted by the master device.

10. The method of claim 9, wherein after the slave device switches from the fifth impedance state to the sixth impedance state and maintains it for the sixth duration, it further comprises: Determine whether the main device has exited low-power mode; If the master device has not exited the low-power mode, a pulse excitation signal of the seventh duration is sent.

11. The method according to claim 10, further comprising: Based on the first radio frequency signal, the second radio frequency signal, and the third radio frequency signal, determine whether the pulse characteristics of the master device meet the preset characteristics; The pulse characteristics include pulse width and / or pulse period; The transmission of the pulse excitation signal includes: If the pulse characteristics of the master device meet the preset characteristics, then a pulse excitation signal is sent.

12. The method according to any one of claims 3, 8, or 10, further comprising: If the master device has exited low-power mode, then send near-field communication interaction information with the master device.

13. The method according to claim 1, wherein extracting the signal features of the first radio frequency signal to generate the first modulated radio frequency signal comprises: An initial modulation signal consistent with the first radio frequency signal is generated using a phase-locked loop; The first modulated radio frequency signal is obtained by adding an offset phase and / or an offset amplitude to the initial modulated signal; the offset phase is any phase from 0° to 360°.

14. A near-field communication module, used as a slave device in near-field communication, comprising: Field detection module, modulation signal generation module, load switching module, and control module; The field detection module is connected to the near-field antenna of the slave device. The near-field antenna is used to acquire the first radio frequency signal emitted by the master device. After the near-field antenna acquires the first radio frequency signal emitted by the master device, the field detection module generates a trigger signal. The modulation signal generation module is connected to the field detection module. If the trigger signal is obtained, the signal features of the first radio frequency signal are extracted to generate the first modulation radio frequency signal. The phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal; The control module is connected to the modulation signal generation module and the near-field antenna, and is used to control the near-field antenna to transmit the first modulated radio frequency signal for a first duration. The control module is also connected to the load switching module and is used to switch the slave device from a first impedance state to a second impedance state and maintain it for a second time after the first duration; the sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

15. The module according to claim 14, further comprising: Excitation signal module; The excitation signal module is connected to the control module, and the control module controls the excitation signal module to emit pulse excitation signals.

16. A near-field communication apparatus, the apparatus comprising: The signal acquisition module is used to acquire the first radio frequency signal emitted by the master device of near-field communication. A modulation signal generation module is used to extract the signal features of the first radio frequency signal and generate a first modulated radio frequency signal. The phase and / or amplitude of the first modulated radio frequency signal are different from those of the first radio frequency signal; The signal transmitting module is used to transmit the first modulated radio frequency signal for a first duration; The state switching module is used to switch the slave device from a first impedance state to a second impedance state and maintain it for a second time after the first duration; the sum of the first duration and the second duration is less than the period of the low-power signal emitted by the master device.

17. A near-field communication device, the device being used to perform the method of any one of claims 1 to 13; or, the device comprising the module of claims 14 to 15.

18. A computing device, comprising: Memory and processor; The memory is used to store computer programs / instructions, and the processor is used to execute the computer programs / instructions, which, when executed by the processor, implement the steps of the method according to any one of claims 1 to 13.

19. A computer-readable storage medium storing computer instructions that, when executed by a processor, implement the steps of the method according to any one of claims 1 to 13.

20. A computer program product comprising a computer program / instructions that, when executed by a processor, implement the steps of the method according to any one of claims 1 to 13.

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