Method for detecting and collecting load in NFC electric field

Abstract

The invention relates to the technical field of wireless communication, in particular to a method for detecting and collecting loads in an NFC electric field. Comprising the following steps: before an NFC card reader sends a card detection instruction, generating at least two radio frequency electric fields with different intensities by adjusting antenna current; sequentially using the radio frequency electric fields with different intensities to detect load changes in the electric fields, and recording corresponding load values; comparing the recorded load value with a preset threshold value, and judging the current load type; and matching corresponding card reading parameters according to the load type, and adjusting a subsequent card reading process to optimize data interaction performance. The invention provides a method capable of quickly and accurately detecting the load type before card detection and adaptively optimizing the card reading process according to the detection result, so as to solve the problems of low efficiency and insufficient adaptability in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and particularly to a method for detecting and collecting loads within an NFC electric field. Background Art

[0002] Near Field Communication (NFC) technology, as a short-range wireless communication technology based on radio frequency identification, is widely used in fields such as mobile payment, identity recognition, and data transmission. The NFC reader emits a carrier signal of 13.56 MHz to form a radio frequency electric field around it. When a card or mobile terminal device compliant with the ISO / IEC 14443 protocol enters this electric field, its conductor characteristics will cause changes in the electric field strength and distribution, and this change is called the "load effect". By detecting the load effect, the reader can determine the presence of the target device and initiate the subsequent communication process.

[0003] In the prior art, NFC readers usually use a radio frequency electric field of a single intensity for load detection and execute the data interaction process after sending the card detection instruction. However, such methods have the following limitations: (1) In the prior art, load detection is often integrated into the interaction stage after the card detection instruction, resulting in a timing conflict between the detection process and the normal communication process, prolonging the overall card reading time and possibly interfering with the stability of data interaction. (2) The detection of a single-intensity electric field has limited sensitivity to load changes. Especially when differentiating between single cards, multiple cards, or devices of different materials (such as mobile phones), it is difficult to accurately capture the subtle differences in electric field changes, resulting in misjudgment or missed detection. (3) Existing methods cannot dynamically adjust communication parameters (such as protocol selection, antenna current intensity, etc.) according to the load type, resulting in a significant reduction in the card reading success rate when facing complex load scenarios (such as multiple cards overlapping, device distance changes).

[0004] In addition, some technologies attempt to optimize the electric field range by adjusting the antenna current, but do not fully utilize the sensitivity differences between electric fields of different intensities. For example, the strong electric field generated by a larger current has a wide coverage range, but lower sensitivity to load changes; while the weak electric field generated by a smaller current has high sensitivity but a limited coverage range. The prior art fails to improve the accuracy and robustness of load identification through the collaborative detection of multi-level electric fields and the combination of different sensitivity characteristics. Summary of the Invention

[0005] The present invention provides a method that can quickly and accurately detect the load type before card detection and adaptively optimize the card reading process according to the detection result, so as to solve the problems of low efficiency and insufficient adaptability in the prior art.

[0006] The technical solution adopted by the present invention is: A method for detecting and collecting loads within an NFC electric field, comprising the following steps:

[0007] Step 1: Before the NFC card reader sends a card detection instruction, generate at least two different intensities of radio frequency electric fields by adjusting the antenna current;

[0008] Step 2: Sequentially use the radio frequency electric fields of different intensities to detect the load changes within the electric field and record the corresponding load values;

[0009] Step 3: Compare the recorded load values with a preset threshold to determine the current load type;

[0010] Step 4: Match the corresponding card reading parameters according to the load type and adjust the subsequent card reading process to optimize the data interaction performance.

[0011] As a further improvement of the present invention, in Step 1, N different intensities of radio frequency electric fields (N≥2) are generated by stepwise adjusting the antenna current, and the electric field intensities corresponding to each current increase and decrease in sequence.

[0012] As a further improvement of the present invention, the value of N is 5, and multi-level load detection is achieved by generating 5 different intensities of radio frequency electric fields.

[0013] As a further improvement of the present invention, in Step 2, the detection of the load value includes measuring the change amplitude of the electric field intensity and determining the physical characteristics of the load by comparing the change amplitude differences under different intensity electric fields.

[0014] As a further improvement of the present invention, in Step 3, the load types include a single card, multiple cards, and mobile terminal devices, and different types are distinguished according to the load value differences.

[0015] As a further improvement of the present invention, in Step 4, adjusting the card reading process includes at least one of the following methods: selecting corresponding communication protocol parameters according to the load type; triggering a user prompt when multiple cards are detected; dynamically adjusting the antenna current to adapt to the card distance.

[0016] As a further improvement of the present invention, the recording of the load value is associated with the execution result of the subsequent card detection instruction. If no response is received for the card detection instruction, the current load is determined to be an empty load or an invalid load.

[0017] As a further improvement of the present invention, the adjustment range of the current intensity of the radio frequency electric field satisfies that the change sensitivity of the electric field intensity generated by the minimum current is higher than that of the electric field generated by the maximum current.

[0018] An NFC card reader adopts the above method for detecting and collecting the load in the NFC electric field to achieve the load adaptive card reading function.

[0019] As a further improvement of the present invention, it includes a multi - level current control module, a load detection module, and a parameter adaptation module. The multi - level current control module is used to generate radio frequency electric fields of different intensities, the load detection module is used to collect and analyze the load value, and the parameter adaptation module is used to dynamically adjust the card - reading parameters.

[0020] Advantages of the present invention: (1) By using radio frequency electric fields of multiple different intensities in cooperation for detection before sending the card - checking instruction, the present invention significantly improves the sensitivity to load changes and the recognition accuracy, and can particularly effectively distinguish different load types such as single cards, multiple cards, and mobile terminal devices, avoiding misjudgment or missed detection problems.

[0021] (2) According to the load detection results, the present invention dynamically adjusts key parameters such as communication protocol parameters and antenna current intensity, and supports multi - scenario adaptation (such as multi - card overlap prompt, card distance adaptation), significantly improving the card - reading success rate and data interaction efficiency in complex scenarios.

[0022] (3) By providing real - time feedback on the load status (such as multi - card prompt) and automatic parameter adjustment, the present invention reduces the complexity of user operations, reduces card - reading failures caused by misoperations, and improves the usability and reliability of NFC devices. Specific embodiments

[0023] In order to make the technical problems, technical solutions, and beneficial effects to be solved by the present application clearer, the following further details the present application with reference to embodiments. It should be understood that the embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] The present invention provides a method for detecting and collecting loads in the NFC electric field, including the following steps:

[0025] Step 1: Before the NFC card reader sends a card - checking instruction, at least two radio frequency electric fields of different intensities are generated by adjusting the antenna current.

[0026] Step 2: The load changes in the electric field are detected in turn using the radio frequency electric fields of different intensities, and the corresponding load values are recorded.

[0027] Step 3: The recorded load values are compared with a preset threshold to determine the current load type.

[0028] Step 4: Corresponding card - reading parameters are matched according to the load type, and the subsequent card - reading process is adjusted to optimize the data interaction performance.

[0029] In step 1 of the present invention, N radio frequency electric fields of different intensities (N≥2) are generated by step - by - step adjusting the antenna current, and the electric field intensity corresponding to each current increases or decreases in turn. The value of N is 5, and multi - level load detection is realized by generating 5 radio frequency electric fields of different intensities.

[0030] In step 2 of the present invention, the detection of the load value includes measuring the change amplitude of the electric field strength, and determining the physical characteristics of the load by comparing the change amplitude differences under electric fields of different strengths.

[0031] In step 3 of the present invention, the load types include single card, multiple cards, and mobile terminal devices, and different types are distinguished according to the load value differences.

[0032] In step 4 of the present invention, adjusting the card reading process includes at least one of the following methods: selecting corresponding communication protocol parameters according to the load type; triggering a user prompt when multiple cards are detected; dynamically adjusting the antenna current to adapt to the card distance.

[0033] The recording of the load value in the present invention is associated with the execution result of the subsequent card detection instruction. If no response is received for the card detection instruction, it is determined that the current load is an empty load or an invalid load. The adjustment range of the current intensity of the radio frequency electric field satisfies that the electric field strength change sensitivity generated by the minimum current is higher than that generated by the maximum current.

[0034] An NFC card reader adopts the above method for detecting and collecting the load in the NFC electric field to realize the load adaptive card reading function. It includes a multi-stage current control module, a load detection module, and a parameter adaptation module. The multi-stage current control module is used to generate radio frequency electric fields of different strengths. The load detection module is used to collect and analyze the load value. The parameter adaptation module is used to dynamically adjust the card reading parameters.

[0035] Embodiment:

[0036] The following combines specific implementation scenarios to elaborate in detail on a method for detecting and collecting the load in the NFC electric field described in the present invention. This embodiment takes the typical application of an NFC card reader as an example, but the protection scope of the present invention is not limited thereto.

[0037] (1) Hardware configuration

[0038] The NFC card reader adopted in this embodiment includes the following core modules: (1) Multi-stage current control module: composed of a programmable current source and an antenna drive circuit, supporting stepped adjustment of the antenna current to generate 5 radio frequency electric fields of different strengths (for example, the current values are 10 mA, 20 mA, 30 mA, 40 mA, 50 mA respectively), and the corresponding electric field strengths increase in sequence. (2) Load detection module: integrated with a high-precision electric field sensor and a signal processing unit, used to detect the change amplitude of the load under each electric field strength in real time and record it as the load value. (3) Parameter adaptation module: built-in storage unit (storing preset thresholds and parameter mapping tables) and a logic control unit, used to dynamically adjust communication protocol parameters, trigger user prompts, or adjust the antenna current according to the load type.

[0039] (2) Operation Process

[0040] Step 1: Generate a multi-level RF electric field:

[0041] After the NFC card reader is started, the multi-level current control module outputs 5 different intensities of current (10 mA to 50 mA) in sequence, and the duration of each current is 2 ms.

[0042] Through the antenna drive circuit, 5 RF electric fields with gradually increasing coverage and decreasing sensitivity are generated in sequence.

[0043] Step 2: Detect and record the load value:

[0044] The load detection module measures the instantaneous change amplitude ΔE of the electric field intensity through the electric field sensor at each electric field intensity.

[0045] For example: (1) When there is no load, ΔE of each electric field intensity approaches 0; (2) When a single card enters the electric field, ΔE corresponding to a small current (10 mA) is significantly higher than ΔE corresponding to a large current (50 mA); (3) When multiple cards overlap, the increase amplitude of ΔE tends to level off as the electric field intensity increases.

[0046] Record 5 groups of ΔE values and transmit them to the parameter adaptation module.

[0047] Step 3: Determine the load type:

[0048] The parameter adaptation module compares the recorded ΔE values with preset thresholds (calibrated through experiments): (1) Single card determination: If ΔE of the small current electric field (10 mA) exceeds the threshold T1, while ΔE of the large current electric field (50 mA) does not exceed the threshold T2, it is determined to be a single card; (2) Multiple cards determination: If the increase amplitude of ΔE of the multi-level electric field shows non-linear attenuation as the current increases and the difference exceeds the threshold T3, it is determined to be multiple cards; (3) Mobile terminal determination: If the change pattern of ΔE under different electric fields conforms to the conductor characteristics of the mobile terminal (such as the electric field distortion characteristics caused by metal materials), it is determined to be a mobile phone or other device.

[0049] Step 4: Dynamically adjust the card reading process:

[0050] Perform the following optimization operations according to the load type: (1) Single card scenario: Select ISO / IEC 14443A protocol parameters, keep the default antenna current (30 mA), and directly execute the card detection instruction; (2) Multiple cards scenario: Trigger user prompts (such as LED flashing or buzzer alarm) and switch to the anti-collision protocol mode; (3) Mobile terminal scenario: Dynamically adjust the antenna current to 20 mA to adapt to a closer communication distance and enable the high-speed data transmission mode.

[0051] (3) Application Scenario Examples

[0052] Scenario 1, Single Card Reading:

[0053] The user places an NFC card above the card reader. The system detects that the ΔE of a small current electric field (10 mA) is 0.8 V (exceeding T1 = 0.5 V), while the ΔE of a large current electric field (50 mA) is 0.3 V (lower than T2 = 0.4 V), and determines it as a single card. The card reader calls the 14443A protocol and completes the data interaction at a current of 30 mA, taking only 50 ms.

[0054] Scenario 2, Multiple Cards Misplaced:

[0055] The user accidentally places two cards overlapping. The system detects that the 5 groups of ΔE are [0.9 V, 0.7 V, 0.6 V, 0.5 V, 0.4 V] respectively, and its attenuation trend conforms to the characteristics of multiple cards. The card reader triggers the buzzer alarm and switches to the multiple card polling mode to read the card information one by one.

[0056] Scenario 3, Mobile Phone Approaching:

[0057] The user brings an NFC-enabled mobile phone close to the card reader. The system detects that the ΔE has abnormal fluctuations (metal back cover causes electric field distortion) at a medium current (30 mA), and determines it as a mobile terminal. The card reader adjusts the current to 20 mA to enhance the near-field sensitivity and enables the high-speed transmission protocol to complete the payment process.

[0058] (4) Effect Verification

[0059] Through comparative experiments, the card reader of this embodiment has significantly better performance than the traditional single electric field detection scheme in the following scenarios: (1) Card reading success rate: The success rate in the single card scenario is increased from 92% to 99%, and in the multiple card scenario, it is increased from 75% to 95%; (2) Response time: The average time-consuming of the overall card reading process is shortened by 30% (from 100 ms to 70 ms); (3) False operation prompt: The accuracy rate of the multiple cards misplaced prompt reaches 98%, and the user operation error rate is reduced by 40%.

[0060] As can be seen from the above embodiments, the method of the present invention realizes the efficient and accurate identification of the load in the NFC electric field through multi-level radio frequency electric field collaborative detection and dynamic parameter adjustment. Compared with the traditional technology, the present invention not only significantly improves the card reading success rate and response speed, but also effectively reduces the misoperation rate, enhancing the user experience and practicality of NFC devices.

[0061] In summary, a method for detecting and collecting loads in the NFC electric field of the present invention realizes the all-round monitoring and adaptive optimization of loads in the NFC electric field through innovative hardware configuration and intelligent algorithms. In practical applications, this method demonstrates excellent performance and wide applicability, not only improving the card reading efficiency and accuracy, but also bringing a more convenient and reliable NFC usage experience to users. In the future, with the continuous progress of technology and the expansion of application scenarios, the present invention is expected to play a greater role in multiple fields such as smart payment, access control management, and public transportation, bringing more convenience and surprises to people's lives.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting a load within an NFC electric field during acquisition, characterized in that, It includes the following steps: Step 1: Before the NFC card reader sends a card detection instruction, generate at least two different intensities of radio frequency electric fields by adjusting the antenna current; Step 2: Sequentially use the radio frequency electric fields of different intensities to detect the load change within the electric field and record the corresponding load values; Step 3: Compare the recorded load values with a preset threshold to determine the current load type; Step 4: Match the corresponding card reading parameters according to the load type and adjust the subsequent card reading process to optimize the data interaction performance.

2. The method for detecting and collecting a load in an NFC electric field according to claim 1, wherein In the above Step 1, N different intensities of radio frequency electric fields (N≥2) are generated by stepwise adjusting the antenna current, and the electric field intensity corresponding to each current increases or decreases sequentially.

3. The method for detecting and collecting a load within an NFC electric field according to claim 2, characterized in that, The value of N is 5, and by generating 5 different intensities of radio frequency electric fields, multi-level load detection is achieved.

4. A method for detecting and collecting loads in an NFC electric field according to claim 1, characterized in that, In the above Step 2, the detection of the load value includes measuring the change amplitude of the electric field intensity, and determining the physical characteristics of the load by comparing the change amplitude differences under different intensity electric fields.

5. A method for detecting and collecting a load in an NFC electric field according to claim 1, characterized in that, In the above Step 3, the load types include a single card, multiple cards, and mobile terminal devices, and different types are distinguished according to the load value differences.

6. The method for detecting and collecting a load in an NFC electric field according to claim 1, characterized in that, In the above Step 4, adjusting the card reading process includes at least one of the following methods: selecting the corresponding communication protocol parameters according to the load type; triggering a user prompt when multiple cards are detected; dynamically adjusting the antenna current to adapt to the card distance.

7. A method for detecting and collecting a load within an NFC electric field according to claim 1, characterized in that, The recording of the load value is associated with the execution result of the subsequent card detection instruction. If no response is received for the card detection instruction, it is determined that the current load is an empty load or an invalid load.

8. The method for detecting and collecting a load in an NFC electric field according to claim 1, characterized in that, The adjustment range of the current intensity of the radio frequency electric field satisfies that the change sensitivity of the electric field intensity generated by the minimum current is higher than that of the electric field generated by the maximum current.

9. An NFC card reader, characterized in that, Adopt the method for detecting and collecting the load within the NFC electric field as described in any one of claims 1-8 to achieve the load adaptive card reading function.

10. An NFC card reader according to claim 9, characterized in that, It includes a multi-level current control module, a load detection module, and a parameter adaptation module. The multi-level current control module is used to generate radio frequency electric fields of different intensities. The load detection module is used to collect and analyze the load values. The parameter adaptation module is used to dynamically adjust the card reading parameters.