Detecting a presence of near field communications (nfc) devices

Near field communication device and method for detecting the existence of near field communication device

DETECTING A PRESENCE OF NEAR FIELD COMMUNICATIONS (NFC) DEVICES

The present invention relates to near field communication (NFC), and more specifically, to detecting the presence of an NFC capable device.

Near Field Communication (NFC) devices are being incorporated into mobile devices, such as smart phones, to facilitate the use of these mobile devices for daily transactions. For example, the credit information provided by the credit card can be loaded into the NFC device and stored in it for use when needed, instead of carrying a lot of credit cards. The NFC device simply taps on the credit card terminal to forward the credit information to the terminal to complete the transaction. As another example, ticket writing systems, such as those used in bus and train terminals, can simply write fare information into NFC devices instead of providing paper tickets to passengers. Passengers simply touch the NFC device to the card reader to ride a bus or train without using a paper ticket.

Generally, NFC includes a polling mode of operation to establish communication between NFC devices. The first conventional method detects the magnetic field of the first conventional NFC device for the second NFC device according to a predefined polling program. In this first conventional method, the first conventional NFC device generates a magnetic field without any information during a predetermined period. The predetermined period is usually called a guard time, which depends on different technologies. Then, the first conventional NFC device uses the conventional polling command to detect the magnetic field of the first technology type (for example, type A, type B, or type F as partial examples) for the second NFC device after the protection time expires. The regular polling command includes, for example, a regular request command of type A (REQA), a regular request command of type B (REQB), or a regular request command of type F (REQF). Then, the first conventional NFC device is in another A guard time generates a magnetic field without any information, and if no response is received from the second conventional NFC device, a conventional polling command is used to detect the second technical type of magnetic field for the second NFC device. The first conventional method is described in more detail in the "NFC Forum: NFC Activity Specification: Technical Specification, NFC Forum" published on November 18, 2010.^TMIn Activity 1.0 NFCForum-TS-Activity-1.0", the entire content is incorporated into this article by reference.

The guard time of the first conventional method consumes energy unnecessarily. Generally, the protection time is about 5 milliseconds when detecting NFC devices of type A and type B, and the protection time may exceed 20 milliseconds when detecting NFC devices of type F. In addition, the first conventional NFC device must generate a magnetic field without any information during more than one guard time, and use more than one polling command to detect the magnetic field for some technologies. For example, the first conventional method usually polls type A devices, then type B devices, and then type F devices. In this example, the first conventional NFC device generates protection times for type A, B, and F devices, and provides REQA, REQB, and REQF commands to establish communication with type F NFC devices.

The second conventional method sends detection pulses with substantially the same amplitude to detect the presence of the NFC device. The first NFC device continuously provides detection pulses until the amplitude change of one of the detection pulses is detected. This change indicates that there is a second NFC device within the magnetic field of the first NFC device. The second conventional method is more described in U.S. Patent Application No.: 12/446,591 filed on April 22, 2009 according to 35 U.SC §371(c), the entire content of which is incorporated herein by reference.

However, this simple detection of pulse changes is sensitive to changes in the environment. For example, moving the first NFC device around the environment may cause one or more Changes in the amplitude of each detection pulse. As another example, the entry of an object in the environment (such as a metal object or other devices that cannot NFC as part of the example) into the magnetic field may cause the amplitude of one or more detection pulses to change. This change may be caused by environmental changes alone, rather than by a second NFC present in the magnetic field. Inevitably, the first NFC device may incorrectly determine that there is a second NFC device.

Therefore, it is necessary to overcome the aforementioned shortcomings to detect the presence of another NFC device in the magnetic field. According to the following detailed description, more aspects and advantages of the present invention will become apparent.

One aspect of the present invention relates to a near field communication (NFC) device, including: a modulator module configured to modulate a detection signal on a carrier to provide a modulated detection signal; an antenna module configured to apply the modulated detection signal To the inductive coupling element to generate a magnetic field to provide a detection sequence; a demodulation module configured to demodulate the detection sequence to provide an observed detection sequence; and a controller module configured to provide an observed detection sequence when the When the signal is nonlinearly related to the previously observed detection signal, it indicates that the magnetic field memory is in the second NFC device.

In the NFC device of this aspect, it is preferable that the detection signal is a monotonically increasing signal.

In the NFC device of this aspect, it is preferable that the detection signal is a ramp signal.

In the NFC device of this aspect, preferably, the controller module is further configured to compare the signal metric of the observed detection signal with the signal metric of the previously observed detection signal.

In the NFC device of this aspect, it is preferable that the signal metric of the observed detection signal is the signal envelope of the observed detection signal, and the signal metric of the previously observed detection signal is the previously observed signal. The signal envelope of the detected signal.

In the NFC device of this aspect, preferably, the controller module is further configured to indicate that there is no second NFC device when the observed detection signal is linearly related to the previously observed detection signal.

In the NFC device of this aspect, preferably, the controller module is further configured to indicate that there is no second NFC device when the observed detection signal is substantially equal to the previously observed detection signal.

In the NFC device of this aspect, preferably, the controller module is further configured to compare the signal metric of the observed detection signal with the signal metric of the previously observed detection signal to determine the signal metric change.

In the NFC device of this aspect, preferably, the controller module is further configured to characterize the signal metric change between the detection signals as non-linear or linear, so that when the signal metric change is characterized as basic When it is non-linear, it indicates that the magnetic field memory is in the second NFC device, and when the signal metric change is characterized as substantially linear, it indicates that there is no second NFC device in the magnetic field.

Another aspect of the present invention relates to a near field communication (NFC) device, including: a modulator module configured to modulate a detection signal on a carrier to provide a modulated detection signal; an antenna module configured to modulate the modulated detection signal Applied to the inductive coupling element to generate a magnetic field to provide a detection sequence; a demodulation module configured to demodulate the detection sequence to provide an observed detection sequence; and a controller module configured to Heartbeat and the When the detection signal is non-linearly correlated, it indicates that the magnetic field memory is in the second NFC device.

In the NFC device of the other aspect, it is preferable that the detection signal is a monotonically increasing signal.

In the NFC device of the other aspect, it is preferable that the detection signal is a ramp signal.

In the NFC device of this other aspect, preferably, the controller module is further configured to compare the signal metric of the observed detection signal with the signal metric of the detection signal.

In the NFC device of the other aspect, it is preferable that the signal metric of the observed detection signal is the signal envelope of the observed detection signal, and the signal metric of the detection signal is the signal envelope of the detection signal.

In the NFC device of the other aspect, preferably, the controller module is further configured to indicate that there is no second NFC device when the observed detection signal is linearly related to the detection signal.

In the NFC device of the other aspect, preferably, the controller module is further configured to indicate that there is no second NFC device when the observed detection signal is substantially equal to the detection signal.

In the NFC device of the other aspect, preferably, the controller module is further configured to compare the observed signal metric of the detection signal with the signal metric of the detection signal to determine the signal metric change.

In the NFC device of the other aspect, preferably, the controller module is further configured to characterize the signal metric change between the detection signals as non-linear or linear, so that the signal metric change is characterized as basic When it is non-linear, it indicates that the magnetic field memory is in the second NFC device, and when the signal metric change is characterized as substantially linear, it indicates that it is not in the magnetic field. There is a second NFC device.

The embodiments of the present invention will be described with reference to the drawings. In the figures, the same reference signs indicate the same or similar elements. In addition, the leftmost digit or digits of the reference symbol determine the figure in which the reference symbol first appears.

The present invention will be described with reference to the drawings. In the drawings, the same reference signs generally indicate the same, functionally similar and/or structurally similar elements. The figure where the component appears for the first time is indicated by the leftmost number or digits in the reference symbol.

The following detailed description refers to the accompanying drawings to illustrate exemplary embodiments consistent with the present invention. The "an exemplary embodiment", "exemplary embodiment", "example of exemplary embodiment", etc. referred to in the detailed description indicate that the described exemplary embodiment may include specific functions, structures, or features, but does not Each exemplary embodiment must be able to include the specific function, structure, or feature. Furthermore, such phrases do not necessarily refer to the same exemplary embodiment. In addition, regardless of whether there is a clear description, when a specific function, structure, or feature is described in conjunction with the exemplary embodiment, such a function can be used in other exemplary embodiments within the knowledge of a person of ordinary skill in the relevant field. , Structure, or characteristic.

The exemplary embodiments described herein are provided for illustrative purposes, and not limitative. There may be other exemplary embodiments, and changes may be made to these exemplary embodiments within the spirit and scope of the present invention. Therefore, this detailed description is not meant to limit the present invention. More precisely, the scope of the present invention is limited only by the scope of patent applications and their equivalents.

The implementation of the present invention can be implemented by hardware, firmware, software, or any of them. What combination to implement. The embodiments of the present invention can also be implemented as instructions stored on a machine-readable medium, which can be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (such as a computing device). For example, machine-readable media may include read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; Other forms of propagated signals (such as carrier waves, infrared signals, digital signals, etc.) and other media. In addition, the firmware, software, routines, and commands in this article can be described as performing certain actions. However, it should be understood that this description is only for convenience, and in fact such actions are the results of firmware, software, routines, instructions, etc. executed by a computing device, processor, controller, or other device.

The detailed description of the following exemplary embodiments will fully reveal the general essence of the present invention so that, without undue experimentation and without departing from the spirit and scope of the present invention, others can make use of the knowledge of those of ordinary skill in the relevant fields, It is easy to change and/or modify such exemplary embodiments for various applications. Therefore, according to the teachings and guidelines provided herein, such modifications and changes are included in the meaning of the exemplary embodiment and the scope of various equivalents. It should be understood that the terms or terms in this specification are for the purpose of description and are not limited thereto. Therefore, the terms or terms in this specification are interpreted by those of ordinary skill in the relevant art according to the teachings herein.

Although the description of the present invention is described in terms of NFC, those of ordinary skill in the related art will recognize that the present invention is applicable to other communications using near-field and/or far-field without departing from the spirit and scope of the present invention. . For example, although the present invention is described as using NFC-enabled communication devices, those of ordinary skill in the relevant fields will recognize that these NFC-enabled communication devices The function of the communication device can be applied to other communication devices that use the near field and/or the far field without departing from the spirit and scope of the present invention.

Exemplary Near Field Communication (NFC) environment

FIG. 1 shows a block diagram of an NFC environment according to an exemplary embodiment of the present invention. The NFC environment 100 provides wireless communication information such as one or more commands and/or data between the first NFC device 102 and the second NFC device 104, and the NFC devices are sufficiently close to each other. The first NFC device 102 and/or the second NFC device 104 can be implemented as a standalone device or a separate device, or can be combined or coupled to another electrical device or host device, such as mobile phones, portable devices, etc. Computing devices, other computing devices (e.g. personal computers, portable computers or desktop computers), computer peripherals such as printers, portable audio and/or video players, payment systems, receipt writing systems (e.g. Parking ticketing system, bus ticketing system, train ticketing system or entrance ticketing system), or in ticket reading systems, toys, games, posters, packaging, advertising materials, product inventory detection systems and/or without departing from the spirit of the present invention In the case of the scope and scope, it is obvious to a person of ordinary skill in the relevant field in any other suitable electronic device.

The first NFC device 102 detects the existence of the second NFC device 104, so that information communication between the first NFC device 102 and the second NFC device 104 is possible. Generally, as to whether there is a second NFC device 104, the first NFC device 102 observes its magnetic field. The first NFC device 102 observes the change in the magnetic field of the second NFC device when it enters the magnetic field.

Routine detection mode of operation

Conventionally, the first conventional NFC device is operated in the conventional detection mode of operation to detect the presence of the second conventional NFC device. Once the first Two conventional NFC devices, the first conventional NFC enters the conventional polling mode of operation to establish communication with the second conventional NFC device.

FIG. 2 shows a conventional operation detection method used by the first conventional NFC device to detect the presence of the second conventional NFC device. The first conventional NFC device provides detection pulses with substantially the same amplitude until a change in the amplitude of a conventional detection pulse is detected. This amplitude change indicates that the second conventional NFC device has entered the magnetic field provided by the first conventional NFC device. Once the second regular NFC device is detected, the first regular NFC enters the regular polling mode of operation to establish communication with the second regular NFC device.

As shown in figure 202, the first conventional NFC device provides one or more conventional detection pulses 206.1 to 206.N, and each conventional detection pulse of 206.1 to 206.N is characterized as having substantially the same magnitude (magnitude) . For example, the amplitude of the conventional detection pulse 206.1 is substantially the same as the amplitude of the conventional detection pulse 206.2, and the amplitude of the conventional detection pulse 206.2 and the conventional detection pulse 206.N are substantially the same. In addition, as shown in FIG. 202, after the regular detection pulse 206.N, the first regular NFC enters the regular polling mode 208 of operation to establish communication with the second regular NFC device. An example of the conventional polling mode 208 of operation is described in the "NFC Forum: NFC Activity Specification: Technical Specification, NFC Forum" published on November 18, 2010.^TMIn Activity 1.0 NFCForum-TS-Activity-1.0", the entire content is incorporated into this article by reference.

As shown in figure 204, the first conventional NFC device observes one or more conventional detection pulses 206.1 to 206.N, which are referred to as one or more observed conventional detection pulses 210.1 to 210.N. One or more detected test pulses Punches 210.1 to 210. (N-1) are characterized as having substantially the same amplitude. The substantially same amplitude of the observed one or more detection pulses 210.1 to 210. (N-1) indicates that there is no second conventional NFC device in the magnetic field. In addition, as shown in diagram 204, the amplitude of the observed detection pulse 210.N is not substantially the same as the observed detection pulse 210.(N-1). This difference in amplitude indicates (indicates) that the second conventional NFC device entered the magnetic field during the conventional detection pulse 206.N. Therefore, the first regular NFC device can enter the regular polling mode 208 of operation to establish communication with the second regular NFC device. The conventional polling mode 208 in which the first conventional NFC device continuously observes operation is referred to as the polling mode 212 of observed operation to verify that the second conventional NFC device remains within the magnetic field. The conventional detection mode of operation is more described in U.S. Patent Application No.: 12/446,591 filed on April 22, 2009 according to 35 U.SC §371(c), the entire contents of which are incorporated herein by reference.

However, this simple detection of changes in conventional detection patterns is sensitive to changes in the environment. For example, moving the first NFC device around the environment may cause one or more conventional detection pulses to vary in amplitude from 206.1 to 210.N. As another example, objects in the environment (for example, metal objects or other devices that cannot be NFC) entering the magnetic field may cause one or more conventional detection pulses to vary in amplitude from 206.1 to 210.N. However, these changes are caused by changes in the environment, not from the second conventional NFC present in the magnetic field. Inevitably, the first conventional NFC device may incorrectly determine that the second conventional NFC device is present in the magnetic field, and enter the conventional polling mode 208 of operation when the second conventional NFC device is not in the magnetic field.

Generally, these environmental changes can be characterized as linear. However, it is produced by another NFC capable device that exists in the magnetic field. The change can be characterized as non-linear. For example, once other NFC-capable devices enter the magnetic field, they cause non-linear changes in the magnetic field and begin to derive or harvest energy. However, the conventional detection mode of operation cannot distinguish the difference between linear and non-linear changes; therefore, the conventional detection mode can easily misjudge the environmental change as the second sign of the presence of the conventional NFC in the magnetic field.

Exemplary detection mode of operation

However, the present invention can distinguish the difference between the linear change and the non-linear change, so that when the environment changes, the detection pulse change characterized as linear in the present invention can be ignored. The detection pulse change characterized as non-linear in the present invention can be identified as being caused by another NFC capable device existing in the magnetic field.

FIG. 3A shows a detection signal of the first NFC-enabled device for detecting the presence of the second NFC-enabled device within its magnetic field in an exemplary embodiment of the present invention. Generally, the first NFC-capable device (such as the first NFC device 102 as an example) is configured to operate in an initiator mode of operation or a reader mode of operation, and the second NFC-capable device The device (such as the second NFC device 104 as an example) is configured to operate in a target mode of operation or a bookmark operation mode.

The first NFC-enabled device provides a detection sequence including one or more detection signals 302.1 to 302.N to detect the presence of the second NFC-enabled device within its magnetic field. Generally, one or more detection signals 302.1 to 302.N are characterized as substantially the same ramp function. In an exemplary embodiment, the ramp function may approximately use a step function or a step function with continuously increasing amplitude. However, one or more detection signals 302.1 to 302.N are not It is limited to the ramp function; without departing from the spirit and scope of the present invention, those of ordinary skill in the related art can use other suitable monotonic increasing and/or decreasing functions to implement one or more detection signals 302.1 to 302.N. The first NFC capable device can modulate one or more detection signals 302.1 to 302.N on the carrier to provide a detection sequence.

The first NFC-capable device observes the detection sequence to recover one or more of the observed detection signals 304.1 to 304.N to detect changes in the magnetic field. Changes in the magnetic field may indicate that there may be a second NFC capable device in the magnetic field. For example, the first NFC-enabled device can compare one of the observed detection signals 304.1 to 304.N with the previously observed detection signal among the observed detection signals 304.1 to 304.N to detect changes in the magnetic field. . As another example, the first NFC-enabled device can compare one of the observed detection signals 304.1 to 304.N with a corresponding one of one or more detection signals 302.1 to 302.N to detect the magnetic field. Variety.

Generally, the first NFC-enabled device may observe its magnetic field unchanged, linearly and/or non-linearly. For example, as shown in FIG. 3B, each of the observed detection signals 304.1 to 304.N is basically the same, indicating that the magnetic field of the first NFC-capable device has not changed. As another example, also shown in FIG. 3B, each of the detected detection signals 304.1 to 304.N has substantially the same signal envelope as their corresponding one or more detection signals 302.1 to 302.N. , Indicating that the magnetic field of the first NFC-enabled device has not changed. There is no change in the magnetic field shown in these examples of FIG. 3B, indicating that there is no second NFC-enabled device within the magnetic field of the first NFC-enabled device.

Objects in the environment (such as metal objects or other devices that are not capable of NFC as some examples) may enter the magnetic field of the first device capable of NFC. field. These objects may cause linear changes in the magnetic field of the first NFC-enabled device. For example, as shown in FIG. 3C, each of the observed detection signals 304.1 to 304. (N-1) is basically the same, indicating that the magnetic field of the first NFC-capable device has not changed. However, the observed detection signal 304.N is different from the observed detection signals 304.1 to 304.(N-1), indicating a change in the magnetic field of the first NFC-capable device. As another example, also shown in FIG. 3C, each of the observed detection signals 304.1 to 304. (N-1) has one or more detection signals 302.1 to 302. (N-1) corresponding to them. The same signal envelope indicates that the magnetic field of the first NFC-enabled device has not changed. However, the observed detection signal 304.N has a different signal envelope from the detection signal 302.N, indicating a change in the magnetic field of the first NFC-capable device. The magnetic field changes shown in these examples of Figure 3C can be characterized as a linear change in the magnetic field of the first NFC-enabled device. For example, the observed detection signal 304.N is linearly related to the detection signal 304.N and/or the observed detection signals 304.1 to 304(N-1). The first NFC-enabled device can recognize that the linear change of the magnetic field is caused by objects in the environment entering the magnetic field of the first NFC-enabled device.

Generally, the second NFC-enabled device generates or obtains energy from one or more detection signals 302.1 to 302.N. After obtaining enough energy from one or more detection signals 302.1 to 302.N, turn on the second NFC-enabled device. The activation of the second NFC-enabled device and the acquisition of energy can cause a nonlinear change in the magnetic field of the first NFC-enabled device.

For example, as shown in FIG. 3D, each of the observed detection signals 304.1 to 304. (N-1) is basically the same, indicating that the magnetic field of the first NFC-capable device has not changed. However, the observed detection signal 304.N is different from the observed detection signal 304.1 to 304.(N-1), indicating that the first one can The magnetic field of the NFC device changes. As another example, also shown in Figure 3D, each of the observed detection signals 304.1 to 304. (N-1) has one or more detection signals 302.1 to 302. (N-1) corresponding to them. The same signal envelope indicates that the magnetic field of the first NFC-enabled device has not changed. However, the observed detection signal 304.N has a different signal envelope from the detection signal 302.N, indicating a change in the magnetic field of the first NFC-capable device. The magnetic field changes shown in these examples of Figure 3D can be characterized as a non-linear change in the magnetic field of the first NFC-enabled device. For example, the observed detection signal 304.N is non-linearly related to the detection signal 302.N and/or the observed detection signals 304.1 to 304.(N-1). The first NFC-enabled device can recognize that the non-linear change in the magnetic field is caused by the entry of the second NFC-enabled device into its magnetic field.

It should be noted that the linear change as shown in FIG. 3C and the non-linear change as shown in FIG. 3D are only for illustrative purposes. Without departing from the spirit and scope of the present invention, those of ordinary skill in the art It will be recognized that other linear and/or non-linear changes are possible.

Referring again to FIG. 1, once the presence of the second NFC-enabled device 104 in its magnetic field is detected, the first NFC-enabled device 102 can enter the polling mode (for example, the normal polling mode 208 of operation or without departing from the original Under the spirit and scope of the invention, any other suitable polling mode that is obvious to a person of ordinary skill in the art) can be used to establish communication with a second NFC-enabled device.

By applying the modulated information communication to the first antenna to provide the first information communication 152, the first NFC device 102 modulates its corresponding information onto the first carrier and generates a first magnetic field. Once the information is sent to the second NFC device 104, the first NFC device 102 continues to apply The first carrier of information to continue to provide the first information communication 152. The first NFC device 102 is close enough to the second NFC device 104 so that the first information communication 152 is inductively coupled to the second antenna of the second NFC device 104.

The second NFC device 104 generates or obtains energy from the first information communication 152 to recover, process, and/or provide a response to the information. The second NFC device 104 demodulates the first communication information 152 to recover and/or process the information. By applying its corresponding information to the first carrier, the second NFC device 104 can respond to the information, and the first carrier is inductively coupled to the second antenna to provide a second modulated information communication 154.

The operation of the first NFC device 102 and/or the second NFC device 104 can refer to the international standard ISO/IE 18092:2004(E), "Information Technology-Telecommunications and Information Exchange Between Systems-" published on April 1, 2004. Near Field Communication-Interface and Protocol (NFCIP-1)" and the international standard ISO/IE 21481:2005(E) published on January 15, 2005, "Information Technology-Telecommunications and Information Exchange Between Systems-Near Field Communication- Interface and Protocol-2 (NFCIP-2)".

Although FIG. 1 and FIGS. 3A to 3D describe the initiator mode operation and the target operation mode, those of ordinary skill in the art will recognize that without departing from the spirit and scope of the present invention, The first NFC device 102 and/or the second NFC device 104 described in FIG. 1, and/or the first NFC capable device and/or the second NFC capable device described in FIGS. 3A to 3D The device can alternatively be configured to operate in communicator mode (communicator mode of operation). These NFC devices and/or NFC-enabled devices are configured to operate in an initiator operation mode and/or a target operation mode, and can switch between these operation modes in the communicator operation mode.

Method for detecting NFC capable device

FIG. 4 is a flowchart of exemplary operation steps for detecting the existence of an NFC-enabled device in a magnetic field in an exemplary embodiment according to the present invention. The present invention is not limited to the description of this operation. More precisely, it is obvious to a person of ordinary skill in the art that, according to the disclosure herein, other operation control procedures are within the scope and spirit of the present invention. The following discussion describes the steps in Figure 4.

In step 402, the operation control process receives a detection signal, for example, one of one or more detection signals 302.1 to 302.N as an example. The operation control flow provides its environment with a detection sequence including detection signals. For example, the operation control process can use a carrier to modulate the detection signal and use the modulated detection signal to generate a magnetic field to provide a detection sequence. The detection signal is a monotonically increasing and/or decreasing signal (for example, a ramp signal as an example), and the signal is modulated onto a carrier.

In step 404, when the detection sequence is provided to its environment, the operation control flow observes the detection sequence from 402 to provide the observed detection sequence. The operation control demodulates the detection sequence from 402 to recover the observed detection signal, such as one of one or more of the observed detection signals 304.1 to 304.N as an example.

In step 406, the operation control process determines a signal metric change between the detection signals. For example, the operational control process may compare one or more signal metrics of the detection signal from step 402 with one or more signal metrics of the observed detection signal from step 404 to provide a signal metric change. As another example, the operational control process is comparable The one or more signal metrics of the observed detection signal from step 404 are compared with the one or more signal metrics of the one or more previously observed detection signals to provide a signal metric change. When the signal metric change is approximately equal to zero, the operation control flow may return to step 402 to receive another detection signal. Alternatively, when the signal metric change is less than and/or equal to the threshold, the operation control flow may return to step 402. In this alternative, the threshold is used to compensate for other factors that may be attributed to other factors (such as the generation of the detection sequence in step 406 and/or the recovery of the observed detection sequence in step 404 as a partial example), but not due to all factors. The signal metric of the NFC device that exists in the magnetic field changes. For example, the threshold can be used to compensate for linear and/or non-linear effects that may be attributed to the modulator, which is used to generate the detection sequence of step 406. As another example, the threshold may be used to compensate for linear and/or non-linear effects that may be attributed to the demodulator, which is used to recover the observed detection sequence of step 404. As another example, the threshold can be used to compensate for linear and/or non-linear effects that may be attributed to the communication channel.

When the signal metric change is greater than zero or greater than the threshold, the operation control flow determines that there may be a device capable of NFC in the magnetic field of step 402 and proceeds to step 408.

In step 408, the operation control flow characterizes the signal metric change in step 406 as non-linear or linear. For example, the operation control process can distinguish the signal metric change in step 406 to determine whether it is non-linear or linear. Generally, the derivative of a linear function is characterized as being substantially constant. When the derivative is substantially constant, the operation control flow may characterize the signal metric change in step 406 as linear, or when the derivative is not substantially constant, it may be characterized as non-linear. In addition, the operation control process can use the derivative as the input of the trigger counting device (for example, a binary counter as an example). here In the alternative, when the derivative changes, the count of the counting device changes from its current state to another state. In addition, in this alternative, when the count of the counting device is less than or equal to a preset value, the operation control flow can characterize the signal metric change in step 406 as linear, or when the count of the counting device is greater than or equal to a preset value. The value of is characterized as non-linear.

In step 410, the operation control flow characterizes the signal metric change in step 406 as caused by environmental changes. The operation control flow determines that there is no device capable of NFC in the magnetic field of step 402 and returns to step 402 to provide another detection signal for its environment.

In step 412, the operation control flow characterizes the signal metric change in step 406 as caused by the magnetic field memory of step 402 in the NFC-capable device.

The first exemplary NFC device

Fig. 5 shows a block diagram of an NFC device that can be used to detect the presence of other NFC-enabled devices in an exemplary embodiment of the present invention. The NFC device 500 may be configured to operate in a detection operation mode to detect the presence of another NFC-enabled device within its magnetic field. It should be noted that FIG. 5 only shows the detection mode of operation, and those of ordinary skill in the art will recognize that the NFC device 500 can be configured to operate in other modes of operation (such as point-to-point ( P2P) communication mode or reader/writer (R/W) communication mode) operation. The NFC device 500 includes a controller module 502, a modulator module 504, an antenna module 506, and a demodulator module 508. The NFC device 500 may be an exemplary embodiment of the first NFC device 102.

The controller module 502 controls the overall operation and/or configuration of the NFC device 500 Set. In the detection operation mode, the controller module 502 generates a detection signal 552, such as one of one or more detection signals 302.1 to 302.N as an example. The detection signal 552 may be a monotonically increasing and/or decreasing function (for example, a ramp function as an example), or a step function or a step function that is approximately a monotonically increasing and/or decreasing function.

The controller module 502 can generate a detection signal 552 in response to the command. Commands can be provided to the controller module 502 from one or more data storage devices, such as one or more contactless transponders, one or more contactless tags, one or more A contactless smart card, any other machine-readable medium, or any combination thereof that is obvious to a person of ordinary skill in the art without departing from the spirit and scope of the present invention. Other machine-readable media may include, but are not limited to, read-only memory (ROM), random access memory (RAM), magnetic disk memory media, optical storage media, flash memory devices, propagation signals ( Such as carrier wave, infrared signal, digital signal as some examples) electrical, optical, acoustic or other forms. The controller module 502 can also receive commands from a user interface, such as a touch screen display, an alphanumeric keyboard, a microphone, a mouse, a loudspeaker, and others in the field without departing from the spirit and scope of the present invention. Any other suitable user interface that is obvious to a person of ordinary skill is taken as a partial example of the user interface. The controller module 502 can also receive commands from other electrical devices or host devices coupled with the NFC device 500.

The modulator module 504 uses any suitable analog or digital modulation technique to modulate the detection signal 552 on a carrier (for example, a radio frequency carrier with a frequency of approximately 13.56 MHz) to provide a modulated detection signal 554. Suitable analog or digital modulation techniques can include amplitude modulation (AM), frequency modulation (FM), phase modulation (PM), shift Phase Keying (PSK), Frequency Shift Keying (FSK), Amplitude Shift Keying (ASK), Quadrature Amplitude Modulation (QAM) and/or any other suitable modulation techniques obvious to those of ordinary skill in the art . In an exemplary embodiment, the modulator module 504 may include a direct digital synthesizer (DDS) under the control of the controller module 502 for generating the detection signal 552. In this exemplary embodiment, the modulator module 504 further includes an analog-to-digital converter (ADC) to convert the detection signal 552 from a digital representation to an analog representation according to the carrier wave to provide a modulation detection signal 554.

The antenna module 506 applies the modulated detection signal 554 to an inductive coupling element (such as a resonance tuning circuit as an example) to generate a magnetic field to provide a detection sequence 556. The antenna module 506 observes the detection sequence 556 to provide the observed detection sequence 560.

The demodulator module 508 demodulates the detection sequence 558 using any suitable analog or digital modulation technique to provide a recovered detection signal 560. Suitable analog or digital modulation techniques can include amplitude modulation (AM), frequency modulation (FM), phase modulation (PM), phase shift keying (PSK), frequency shift keying (FSK), amplitude shift keying (ASK), positive Cross-Amplitude Modulation (QAM) and/or any other suitable modulation technique obvious to those of ordinary skill in the art.

The controller module 502 can determine one of the multiple signal metrics of the detection signal 552 and/or the recovered detection signal 560. One or more signal metrics may include average voltage and/or current level (mean voltage and/or current level), average voltage and/or current level (average voltage and/or current level), transient voltage and/or current level , Root mean square voltage and/or current level, average power (mean power), average power (average power), transient power, root mean square power, signal envelope and/or without departing from the spirit and scope of the present invention Circumstances to those of ordinary skill in the art It is said that the obvious detection signal 552 and/or the recovered detection signal 560 are any other suitable signal metrics.

The controller module 502 may compare one of the multiple signal metrics of the recovered detection signal 560 with one or more previous signal metrics of the recovered detection signal 560 to provide a signal metric change. Alternatively, the controller module 502 may compare one of the multiple signal metrics of the recovered detection signal 560 with one of the multiple signal metrics of the detection signal 552 to provide a signal metric change.

The controller module 502 can compare the signal metric change with a threshold value to determine whether the signal metric change indicates a difference between the signal metrics. The threshold is used to compensate for the detection signal 552 and/or recovery detection that may be attributed to defects in the NFC device 500 (e.g., defects in the modulator module 504, antenna module 506, or demodulator module 508 as some examples) The difference between the signal 560. For example, a defect in the demodulator module 508 may cause undesired attenuation of the recovered detection signal 560. This undesired attenuation of the recovered detection signal 560 is not to be blamed on another NFC capable device in the magnetic field memory. Therefore, when the signal metric change may be attributed to the defect of the NFC device 500, the controller compares the signal metric change with the threshold value, so as to greatly reduce the controller modules interpretation of the signal metric change as caused by another NFC-capable device. possibility.

When the signal metric change is less than or equal to the threshold, the signal metric change indicates that there is no difference between the signal metrics. In this case, any difference between one of the multiple signal metrics of the recovered detection signal 560 and one of the multiple signal metrics of the detection signal 552 and/or one or more previous signal metrics of the recovered detection signal 560 The signal metric change can be attributed to a defect in the NFC device 500, rather than in the magnetic field memory in another NFC device.

When the signal metric change is greater than the threshold, the signal metric change indicates the difference between the signal metrics. The controller module 502 analyzes the signal metric change to determine whether another NFC capable device is in the magnetic field memory. For example, the control module 502 can distinguish the signal metric change to determine whether it is non-linear or linear. When the derivative is substantially constant, the controller module 502 can characterize the signal metric change as linear, or when the derivative is not substantially constant, it can be characterized as non-linear. In addition, the controller module 502 can use the derivative as an input to trigger a counting device (such as a binary counter as an example). In this alternative, when the derivative changes, the count of the counting device changes from its current state to another state. In addition, in this alternative, when the count of the counting device is less than or equal to a preset value, the controller module 502 can characterize the difference from step 406 as linear, or when the count of the counting device is greater than or equal to a predetermined value. The set value is characterized as non-linear.

Referring again to Figure 3A, once it is detected that the magnetic field memory is in the second NFC-enabled device as described in Figures 3A to 3D, the first NFC-enabled device can continue to provide one or more detection signals 302.1 to 302.1 to 302.N detection sequence to verify that the second NFC-capable device remains in the magnetic field. For example, as shown in Figure 6, the first NFC capable device observes the detection sequence to recover one or more of the observed detection signals 602.1 to 602.N. The first NFC capable device compares the corresponding one or more detected detection signals 602.1 to 602.N with the corresponding one or more of one or more detection signals 302.1 to 302.N to detect whether the first The two NFC capable devices remain within their magnetic field.

As shown in Figure 6, the signal envelopes of the observed detection signals 602.1 to 602. (N-1) correspond to those of their corresponding detection signals 302.1 to 302. (N-1). The signal envelope is basically different. In this case, the second NFC-enabled device continues to generate or obtain energy from one or more detection signals 302.1 to 302. (N-1). Therefore, the second NFC-enabled device remains within the magnetic field of the first NFC-enabled device. It should be noted that the difference in the signal envelope of one or more detection signals 602.1 to 602. (N-1) shown in FIG. 6 is for illustrative purposes only, and those of ordinary skill in the art will recognize that Without departing from the spirit and scope of the present invention, other differences in the signal envelope of the observed detection signals 602.1 to 602 (N-1) are possible.

However, the observed signal envelope of the detection signal 602.N is substantially similar to the signal envelope of the detection signal 302.N, indicating that the second NFC capable device no longer generates or obtains energy from the detection signal 302.N. Therefore, the second NFC-enabled device is not kept within the magnetic field of the first NFC-enabled device. Therefore, as discussed above, the first NFC-enabled device starts to detect the presence of the second NFC-enabled device.

in conclusion

It should be understood that the detailed description part is used to explain the scope of the patent application, not the abstract part. The abstract part may clarify one or more, but not all, exemplary embodiments of the present invention, and therefore, does not limit the scope of the present invention and the additional patent application in any way.

The described invention exemplarily illustrates the realization of its specific functions and relationships by means of functional component modules. For the convenience of description, the boundaries of these functional component modules have been arbitrarily defined. As long as its specific functions and relationships are appropriately implemented, other alternative boundaries can also be defined.

Without departing from the spirit and scope of the present invention, various modifications can be made in the form and details, which is very helpful to those of ordinary skill in the art. It is obvious. Therefore, the invention should not be limited by any of the above-described exemplary embodiments, but should only be limited by the claims and their equivalents.

<p>100NFC environment</p><p>102The first NFC device</p><p>104Second NFC device</p><p>152First Infocomm</p><p>154Second Modulation Information Communication</p><p>206.1~206.NConventional detection pulse</p><p>208Regular polling mode</p><p>210.1~210.NConventional detection pulse</p><p>212Polling mode</p><p>302.1~302.NDetection signal</p><p>304.1~302.NDetection signal</p><p>402Step</p><p>404Step</p><p>406Step</p><p>408Step</p><p>410Step</p><p>412Step</p><p>500NFC device</p><p>502controller module</p><p>504Modulator Module</p><p>506Antenna Module</p><p>508 Demodulator Module</p><p>552Detection signal</p><p>554Detection signal</p><p>556Detection sequence</p><p>558Detection sequence</p><p>560Detection signal</p><p>602.1~602.NDetection signal</p>

FIG. 1 shows a block diagram of NFC according to an exemplary embodiment of the present invention.

FIG. 2 shows a conventional detection mode (prior art) of the operation of the first conventional NFC device for detecting the presence of the second conventional NFC device.

Fig. 3A shows a detection signal of the first NFC-enabled device for detecting the presence of the second NFC-enabled device in its magnetic field in an exemplary embodiment of the present invention.

FIG. 3B shows the first possible change of the detection signal of the first NFC-enabled device for detecting the presence of the second NFC-enabled device in its magnetic field in an exemplary embodiment of the present invention.

FIG. 3C shows a second possible change in the detection signal of the first NFC-enabled device for detecting the presence of the second NFC-enabled device in its magnetic field in an exemplary embodiment of the present invention.

Fig. 3D shows a third possible change in the detection signal of the first NFC-enabled device for detecting the presence of the second NFC-enabled device in its magnetic field in an exemplary embodiment of the present invention.

4 is a flowchart of exemplary operation steps for detecting the existence of an NFC-enabled device within a magnetic field in an exemplary embodiment according to the present invention. Fig. 5 shows a block diagram of an NFC device that can be used to detect the presence of other NFC-enabled devices in an exemplary embodiment of the present invention.

Fig. 6 shows that in an exemplary embodiment of the present invention, the first NFC-enabled device is used to detect the first possible change of the detection signal of the second NFC-enabled device remaining in its magnetic field.