HK1178336B - Method and apparatus for reducing nfc multi-protocol polling duration and power consumption - Google Patents

Abstract

The invention is directed to a method and apparatus for reducing NFC multi-protocol polling duration and power consumption. A NFC device polls for devices by first maintaining an unmodulated carrier field active for a specific period of time. The NFC device then polls using a first modulation and waits for a response. If there is no response, and without again maintaining another unmodulated carrier field for a specific period of time, the NFC device polls using a second modulation that is greater than the first modulation and waits again for a response.

Description

Method and apparatus for reducing NFC multi-protocol polling time and power consumption

Technical Field

The present invention relates to Near Field Communication (NFC), and more particularly, to reducing multi-protocol polling time and, thus, power consumption for polling NFC devices.

Background

Near Field Communication (NFC) requires that NFC devices exist within a relatively small distance of each other so that their respective magnetic fields can exchange information. Ranges of up to several centimeters (typically 0.1 meter maximum) are common for NFC devices. Typically, the first NFC device transmits or generates a magnetic field modulated with information, such as credit information or fare information. The magnetic field is inductively coupled to a second NFC device proximate to the first NFC device. The second NFC device may respond to the first NFC device by transmitting or generating its own modulated magnetic field and inductively coupling the magnetic field to the first NFC device.

An NFC reader is a type of NFC device that can operate in an initiator mode to initiate communication with another NFC enabled device. An NFC tag is a type of NFC device that can operate in a target mode to respond to an initiator communication of another NFC enabled device. An NFC communicator is an NFC device of the type that can operate in either an initiator mode or a target mode and can switch between the two modes.

In a conventional polling process, an NFC readerOr the NFC communicator generates a magnetic field and detects the magnetic field of the NFC tag or another NFC communicator. Conventional polling processing considers a variety of techniques, including type a techniques, type B techniques, and type F (FeliCa) techniques. Differences between different technologies include modulation methods, coding schemes, and protocol initialization processes. "NFC Forum: NFC Activity Specification: Technical Specification, NFCForum (TM) Activity 1.0 NFCForum-TS-Activity-1.0" (hereinafter referred to simply as "NFC behavior Specification") published on 18.11.2010 and "NFC Forum: NFC Digital protocol: Technical Specification, NFC Forum" published on 17.11.2010^TMAn example of a conventional polling process is described in Digital 1.0NFCForum-TS-Digital protocol-1.0 (hereinafter referred to simply as "NFC Digital protocol"), the entire contents of which are incorporated herein by reference.

Conventional polling processes require the NFC reader or NFC communicator to initially generate a magnetic field between 5ms and 20ms (commonly referred to as a guard time), depending on the type of tag technology used. The duration of the magnetic field generation for the guard time requires the use of a large amount of current (typically up to 250 mA) to generate the magnetic field. For each type of technology, before transmitting the polling command, a time is claimed: 5ms for type A and type B and 20ms for type F.

There is a need for a method and apparatus for detecting the magnetic field of NFC devices of different technology types and which reduces the duration of the magnetic field generated before sending a polling command to reduce the amount of power consumed during the polling process.

Disclosure of Invention

The invention provides a method for detecting a Near Field Communication (NFC) device, comprising: polling with a first polling command using a first modulation on a carrier field after a first guard time; maintaining a carrier field without modulation for a first response period to detect a response of the NFC device to the first polling command; polling a carrier field with a second polling command using a second modulation greater than the first modulation without waiting for a second guard time; and maintaining the unmodulated carrier field for a second response period to detect a response of the NFC device to the second polling command.

In a preferred embodiment according to the present invention, the method further comprises: maintaining the carrier field without modulation during the first guard time; and communicating with the NFC device if a response is received from the NFC device while waiting during the first reply period.

In a preferred embodiment according to the present invention, the method further comprises: to poll a third polling command on the carrier field using a third modulation; maintaining the unmodulated carrier field for a third reply period to detect a response of the NFC device to the third polling command; and communicating with the NFC device if a response is received from the NFC device while waiting during the third due period, wherein the third polling command is in accordance with a proprietary standard.

In a preferred embodiment according to the present invention, wherein the first polling command relates to a type B NFC technology tag, and wherein the second polling command relates to a type a NFC technology tag.

In a preferred embodiment according to the present invention, wherein the first polling command relates to a type F NFC technology tag, and wherein the second polling command relates to a type a NFC technology tag.

In a preferred embodiment according to the present invention, wherein said first modulation is a 10% amplitude modulation and wherein said second modulation is a 100% amplitude modulation.

In a preferred embodiment according to the present invention, wherein said first modulation is less than 100% amplitude modulation and wherein said second modulation is 100% amplitude modulation.

Another object of the present invention is to provide a method for detecting a Near Field Communication (NFC) device, comprising: receiving, from the NFC reader, a first polling command using a first modulation on a carrier field after a first guard time; acknowledging the first polling command from the NFC reader for a first acknowledgement period if the NFC device is configured for the first modulation; receiving, from the NFC reader, a second polling command that uses a second modulation on the carrier field that is greater than the first modulation without a second guard time; and if the NFC device is configured for a second modulation, replying to the second polling command from the NFC reader for a second reply period.

In another preferred embodiment according to the present invention, further comprising: during the first guard time, power is extracted from the carrier field without modulation.

In a preferred embodiment according to the present invention, further comprising: receiving a third polling command using a third modulation on the carrier field; answering the third polling command from the NFC reader for a third answering period if the NFC device is configured for the third modulation, wherein the third polling command is in accordance with a proprietary standard.

In another preferred embodiment according to the present invention, wherein the first polling command relates to a type B NFC technology tag, and wherein the second polling command relates to a type a NFC technology tag.

In another preferred embodiment according to the present invention, wherein said first polling command relates to a type F NFC technology tag, and wherein said second polling command relates to a type a NFC technology tag.

In another preferred embodiment according to the present invention, wherein said first modulation is a 10% amplitude modulation and wherein said second modulation is a 100% amplitude modulation.

In another preferred embodiment according to the present invention, wherein said first modulation is less than 100% amplitude modulation and wherein said second modulation is 100% amplitude modulation.

It is yet another object of the present invention to provide an apparatus for detecting a Near Field Communication (NFC) device, comprising: a first NFC device configured to: polling with a first polling command using a first modulation on a carrier field after a first guard time; maintaining a carrier field without modulation for a first response period to detect a response of the NFC device to the first polling command; polling a carrier field with a second polling command using a second modulation greater than the first modulation without waiting for a second guard time; and maintaining the unmodulated carrier field for a second response period to detect a response of the NFC device to the second polling command.

In yet another preferred embodiment according to the present invention, wherein the first device is further configured to: activating the carrier field; maintaining a carrier field without modulation during the first guard time; and communicating with the NFC device if a response is received from the NFC device while waiting during the first reply period.

In yet another preferred embodiment according to the present invention, wherein the first polling command relates to a type B NFC technology tag, and wherein the second polling command relates to a type a NFC technology tag.

In yet another preferred embodiment according to the present invention, wherein the first polling command relates to a type F NFC technology tag, and wherein the second polling command relates to a type a NFC technology tag.

In yet another preferred embodiment according to the present invention, wherein said first modulation is a 10% amplitude modulation and wherein said second modulation is a 100% amplitude modulation.

In yet another preferred embodiment according to the present invention, wherein said first modulation is less than 100% amplitude modulation and wherein said second modulation is 100% amplitude modulation.

Drawings

Embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Furthermore, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears.

Fig. 1 shows a block diagram of an NFC environment according to an exemplary embodiment of the invention;

fig. 2 is a flow chart of the conventional operational steps of polling a type a NFC technology tag;

fig. 3 is a flow chart of the operational steps of multi-protocol polling according to the NFC behavioral specification;

fig. 4 shows a polling signal using miller coding with 100% ASK modulation;

figure 5 shows a 10% ASK modulated polling signal using NRZ-L encoding;

FIG. 6 shows a polling signal using Manchester encoding that is less than 100% ASK modulated;

FIG. 7 is a flowchart illustrating exemplary operational steps for multi-protocol polling, in accordance with an exemplary embodiment of the present invention;

fig. 8 shows the signal flow that occurs when a first NFC device polls a second NFC device;

FIG. 9 illustrates signal flow and timing overlap that occurs in multi-protocol polling according to an exemplary embodiment of the present invention; and

fig. 10 shows a block diagram of an NFC device that may be used according to an exemplary embodiment of the invention.

The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical or functionally identical, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.

Detailed Description

The following detailed description refers to the accompanying drawings that illustrate exemplary embodiments consistent with this invention. Reference in the detailed description to "one exemplary embodiment," "an exemplary illustrative embodiment," etc., means that the exemplary embodiment described may include a particular feature, structure, or characteristic, but every exemplary embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same exemplary embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an exemplary embodiment, it is submitted that it is within the knowledge of one skilled in the relevant art to affect such feature, structure, or characteristic in connection with other exemplary embodiments whether or not explicitly described.

The exemplary embodiments described herein are provided for illustrative purposes and are not intended to be limiting. Other exemplary embodiments are possible, and modifications may be made to the exemplary embodiments within the spirit and scope of the invention. Therefore, the detailed description is not intended to limit the invention. Rather, the scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.

Embodiments of the invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the invention may also be implemented as instructions stored on a machine-readable medium, which may 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 (e.g., a computing device). For example, a machine-readable medium may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, electrical, optical, acoustical or other form of propagated signals (such as carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, programs, and instructions are described herein that perform certain actions. However, it should be understood that such descriptions are merely for convenience and that in fact such actions are performed by a computing device, processor, controller or other device executing the firmware, software, programs, instructions or the like.

The following detailed description of exemplary embodiments will fully reveal the general idea of the invention so that one can, by applying ordinary skill in the relevant art, readily modify and/or adapt for various applications such exemplary embodiments, without undue experimentation, without departing from the spirit and scope of the present invention. Accordingly, such adaptations and modifications are intended to be within the meaning and range of equivalents of the exemplary embodiments based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings herein.

Although the description of the present invention is in terms of NFC devices and NFC enabled devices, those skilled in the relevant art will appreciate that the present invention may be applied to other communications using the near field and/or the far field without departing from the spirit and scope of the present invention. For example, although the present invention is described using NFC-enabled communication devices, those skilled in the relevant art will appreciate that the functionality of these NFC-enabled communication devices may be applied to other communications using 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 of information (such as one or more commands and/or data) between a first NFC device 102 and a second NFC device 104 that are sufficiently close to each other. The first NFC device 102 and/or the second NFC device 104 may be implemented as a stand-alone or discrete device, or may be incorporated into or coupled to another electronic device or host device, for example, a mobile phone, a portable computing device, other computing devices such as a laptop or desktop computer, computer peripherals such as a printer, portable audio and/or video player, a payment system, a ticket writing system such as a parking ticketing system, a public transportation ticketing system, a train ticketing system, or an entrance ticketing system to provide some examples, or in a ticket reading system, a toy, a game, a poster, packaging, advertising material, a product inventory check system, and/or any other suitable electronic device that would be apparent to one of skill in the relevant art without departing from the spirit and scope of the invention.

The first NFC device 102 generates a magnetic field and detects the magnetic field of the second NFC device 104. The second NFC device 104 may be implemented using type a technology, type B technology, or type F technology. Type A and type B technologies are further defined in the NFC behavioral Specification and/or ISO/IEC 14443-3, "Identification cards-contact integrated circuits(s) cards-ProximatoCards-Part 3: Initiation and chemistry", published on 11.6.1999, which is incorporated herein by reference in its entirety. The F-type technology is further defined in the NFC behavior specification, which is incorporated herein by reference in its entirety. Various conventional polling processes for detecting these technology types of magnetic fields are discussed below.

Regular operation of single protocol polling

Fig. 2 shows a flow chart of the conventional operational steps for polling a type a NFC technology tag. In step 201, the NFC reader initializes a flag (flag) FOUND _ a to 0.

At step 203, the NFC reader determines whether it is configured to poll for type a NFC technology tags. If the NFC reader is configured to poll for type a NFC technology tags, normal operation continues to step 207. Otherwise, the NFC reader ends the polling procedure in step 205.

At step 207, the NFC reader generates a magnetic field without a polling command, commonly referred to as an unmodulated carrier field. The unmodulated carrier field must be maintained for at least the amount of time specified by the NFC digital protocol to allow any type a NFC technology tag to obtain or obtain sufficient power within the unmodulated carrier field to communicate. For type a technology, the required time period (guard time) is set to a minimum of 5 ms.

At step 209, the NFC reader transmits a polling command using a magnetic field (commonly referred to as a modulated carrier field) to a type a NFC technology tag that may be located within the magnetic field. The polling command lasts 86 microseconds. Only those tags that are type a NFC technology tags will provide a response to the polling command. The NFC reader waits 100 microseconds for a response from a type a NFC technology tag.

In step 211, if the NFC reader does not receive a response from any type a NFC technology tag, the NFC reader ends the polling by moving to step 205. Otherwise, if the NFC reader has received a response from a type a NFC technology tag, then normal operation proceeds to step 213.

In step 213, the NFC reader sets the flag FOUND _ a equal to 1, and ends polling and begins communicating with the detected device.

The operational steps for polling type B and type F NFC technology tags are substantially similar to those of polling type a. The protection time of a type B NFC technology tag is at least 5ms, as is the same for a type a NFC technology tag. However, the protection time of a type F NFC technology tag is a minimum of 20 ms.

Conventional method of multiprotocol polling

Typically, the NFC behavior specification provides a conventional polling loop for NFC readers to detect tags that may be of any particular technology type (A, B or F). A conventional polling loop first checks the type a NFC technology tag, then the type B NFC technology tag, then the type F NFC technology tag, and then allows polling of any other tags based on proprietary (proprietary) technology.

Fig. 3 illustrates a conventional polling loop 300 for polling A, B and type F NFC technology tags. In step 301, the NFC reader initializes flags FOUND _ A, FOUND _ B and FOUND _ F to 0.

At step 303, the NFC reader determines whether it is configured to poll for type a NFC technology tags. If the NFC reader is configured to poll for type a NFC technology tags, the NFC reader proceeds to step 305. Otherwise, the NFC reader proceeds to step 315 to start polling for type B NFC technology tags.

At step 305, the NFC reader generates an unmodulated carrier field. The unmodulated carrier field must remain for a guard time of at least 5ms to allow any NFC tag to draw or otherwise acquire sufficient power within the unmodulated carrier field to communicate.

At step 307, the NFC reader modulates the carrier field with a polling command for a type a NFC technology tag. The polling command lasts 86 microseconds. Only those tags that are type a NFC technology tags will provide a response to the polling command. The NFC reader waits 100 microseconds for a response from a type a NFC technology tag.

If the NFC reader does not receive a response from any type a NFC technology tag, step 309, the NFC reader ends the polling of the type a NFC technology tag and proceeds to step 315 to begin polling the type B NFC technology tag. Otherwise, if the NFC reader has received a response from a type a NFC technology tag, then the conventional polling loop 300 proceeds to step 311. In step 311, because the NFC reader has received a response, it sets the flag FOUND _ a equal to 1.

At step 313, the NFC reader checks whether it has been configured to jump out (rail out) after detecting one or more type a NFC technology tags. The NFC reader has been configured to jump OUT when the flag CON _ BAIL _ OUT _ a is set equal to 1 after detecting one or more type a NFC technology tags. When the flag is set to 1, the NFC reader proceeds to step 343 to end the polling procedure and start communication with the detected device. If the flag CON _ BAIL _ OUT _ a is not set equal to 1, the conventional polling loop 300 proceeds to step 315 to begin polling for type B NFC technology tags.

At step 315, the NFC reader determines whether it is configured to poll for type B NFC technology tags. If the NFC reader is configured to poll for type B NFC technology tags, the NFC reader proceeds to step 317. Otherwise, the NFC reader ends the polling process for type B NFC technology tags and moves to step 325.

In step 317, the NFC reader generates an unmodulated carrier field. The unmodulated carrier field must be maintained for a guard time of at least 5ms to allow any type B NFC technology tag to draw or acquire sufficient power within the unmodulated carrier field to communicate.

At step 319 the NFC reader modulates the carrier field with a polling command for a type B NFC technology tag. The polling command lasts 86 microseconds. Only those tags that are type B NFC technology tags will provide a response to the polling command. The NFC reader waits 100 microseconds for a response from a type B NFC technology tag.

If the NFC reader does not receive a response from any type B NFC technology tag, step 321, the NFC reader ends polling for type B NFC technology tags and proceeds to step 325. Otherwise, if the NFC reader has received a response from one or more type B NFC technology tags, the conventional polling loop 300 proceeds to step 323. In step 323, the NFC reader sets the flag FOUND _ B equal to 1 because it has received a response.

At step 325, the NFC reader checks whether it has been configured to jump out after detecting one or more type B NFC technology tags. The NFC reader has been configured to jump OUT when the flag CON _ BAIL _ OUT _ B has been set equal to 1 after detecting one or more type B NFC technology tags. When it is set to 1, the NFC reader proceeds to step 327 to end the polling process and start communicating with the detected device. If the flag CON _ BAIL _ OUT _ A is not set equal to 1, the conventional polling loop 300 proceeds to step 327.

In step 327, the NFC reader checks whether the flag FOUND _ a or the flag FOUND _ B is set to 1. If either is set to 1, the conventional polling loop 300 proceeds to step 343 to end the polling process. If neither flag FOUND _ a nor flag FOUND _ B is set to 1, the conventional polling loop 300 continues to begin polling for F type NFC technology tags at step 329.

At step 329, the NFC reader determines whether it is configured to poll a type F NFC technology tag. If the NFC reader is configured to poll for type F NFC technology tags, the NFC reader proceeds to step 331. Otherwise, the NFC reader ends the polling process for the type F NFC technology tag and moves to step 339.

At step 331, the NFC reader generates an unmodulated carrier field. The unmodulated carrier field must be maintained for a guard time of at least 20ms to allow any type F NFC technology tags to draw or otherwise obtain sufficient power within the unmodulated carrier field to communicate.

At step 333, the NFC reader modulates the carrier field with a polling command for the type F NFC technology tag. The polling command lasts 86 microseconds. Only those tags that are type F NFC technology tags will provide a response to the polling command. The NFC reader waits 100 microseconds for a response from a type F NFC technology tag.

At step 335, if the NFC reader does not receive a response from any type F NFC technology tag, the NFC reader ends polling of the type F NFC technology tag and proceeds to step 339. Otherwise, if the NFC reader has received a response from a type F NFC technology tag, then the conventional polling loop 300 proceeds to step 337.

In step 337, because the NFC reader receives the response, it sets the flag FOUND _ F equal to 1.

In step 339, the NFC reader checks whether the flag FOUND _ a, the flag FOUND _ B, or the flag FOUND _ F has been set to 1. If either of these flags has been set to 1, the conventional polling loop 300 proceeds to step 343 to end the polling process. If neither of them is set to 1, the conventional polling loop 300 proceeds to step 341 to start polling for proprietary tags.

Step 341 comprises checking whether the NFC reader has been configured to poll for proprietary tags. If the NFC reader has been configured to poll for proprietary tags, the NFC reader waits for a protection time specified by the proprietary technology. The NFC behavior specification does not take into account proprietary processes and parameters within its scope and is therefore not included in the specification. After the NFC reader completes polling for the proprietary tag as needed, it ends the polling at step 343.

As can be seen from the above, when the conventional polling loop 300 checks both type a and type B NFC technology tags, the NFC reader generates a magnetic field for 10,372 μ s.

Conventional coding/modulation scheme

As described above, type a, type B, and type F technologies are characterized by having different modulation methods, coding schemes, and protocol initialization processes (some examples given).

Fig. 4 illustrates a conventional coding and modulation scheme used for polling signals for type a NFC technology tags. The conventional scheme uses an improved miller coding scheme with 100% amplitude keying (ASK) modulation. With 100% ASK modulation, when the amplitude of the polling signal changes by more than 95%, as shown in fig. 4, the type a NFC technology tag recognizes the modulation. There is no modulation at voltage amplitude 401, or 100% amplitude. When the polling signal is at a voltage 403 or less than 5% amplitude, there is modulation.

Fig. 5 illustrates a conventional coding and modulation scheme used for polling signals for type B NFC technology tags. This scheme uses NRZ-L coding with 10% ASK modulation. When the amplitude of the polling signal changes by 10%, the type B NFC technology tag recognizes the modulation. There is no modulation at the voltage amplitude 501, or 100% amplitude. A modulated state exists when the polling signal is at a voltage amplitude 503 or 90% amplitude. When the amplitude changes by 10% from the no modulation state, the type B NFC technology tag recognizes the polling signal.

Fig. 6 illustrates a conventional coding and modulation scheme used for polling signals for type F NFC technology tags. This scheme uses manchester encoding with less than 100% ASK modulation. The type F NFC technology tag recognizes the modulation when the amplitude of the polling signal changes by an amplitude that is less than the amplitude used in the modulation of the type a NFC technology tag. There is no modulation at the voltage amplitude 601 or 100% amplitude. When the polling signal is at a voltage amplitude 603, there is modulation. When the amplitude changes 100% from the no modulation state, the type F NFC technology tag recognizes the modulated polling signal.

The present invention configures the polling loop such that the NFC reader first polls tags using less than 100% ASK modulation and then polls tags using 100% ASK modulation. In this way, tags using 100% ASK modulation see a substantially long guard time for a first poll of tags using less than 100% ASK modulation, thus eliminating the need for a second guard time before polling tags using 100% ASK modulation.

Exemplary method of multiprotocol polling

Fig. 7 illustrates a method of multi-protocol polling of an NFC device according to an exemplary embodiment of the present invention. The invention is not limited to this description. Rather, it will be apparent to those skilled in the relevant art from the teachings herein that other multi-protocol polling methods are within the scope and spirit of the invention. The following discussion describes the steps in FIG. 7.

At step 701, a first NFC device (e.g., the first NFC device 102 to provide an example) generates an unmodulated carrier field to allow a second NFC device (e.g., the second NFC device 104 to provide an example) to reset according to any previous spurious command.

At step 703, the first NFC device maintains the unmodulated carrier field for a first period of time to cause the second NFC device to draw or otherwise obtain power to allow communication between the devices.

At step 705, the first NFC device transmits a first polling command using a first modulation scheme on the carrier field, typically according to a first protocol, to provide a modulated carrier field. The first modulation scheme is characterized by a first amplitude. If the second NFC device responds to a different modulation scheme with a second amplitude greater than the first amplitude, it will not recognize the modulated carrier field that includes the first polling command. Instead, the modulated carrier field will be presented to the second NFC device as an unmodulated carrier field from which the second NFC device can derive or draw power.

At step 707, the first NFC device continues to provide the unmodulated carrier field for a second period of time to detect any response to the first polling command.

At step 709, the first NFC device transmits a second polling command, typically according to a second protocol, using a second modulation scheme on the carrier field to provide a modulated carrier field after expiration of a second time period. The second modulation scheme is characterized by a second amplitude that is greater than the first amplitude.

At step 711, the first NFC device continues to provide the unmodulated carrier field for a third period of time to detect any response to the second polling command.

The first NFC device then ends the polling process and switches off the carrier field if it does not detect any devices, step 713.

Fig. 8 illustrates a first polling process used by a first NFC device to poll a second NFC device according to an exemplary embodiment of the invention. The first NFC device 801 polls the second NFC device 803 using a first polling process. The first NFC device 801 and the second NFC device 803 may represent exemplary embodiments of the first NFC device 102 and the second NFC device 104, respectively.

As shown in fig. 8, the first NFC device 801 generates an unmodulated carrier field 805 for a first period of time to allow the second NFC device 803 sufficient time to take or acquire sufficient power to communicate. The first NFC device 801 modulates a polling command on the unmodulated carrier field using a first modulation scheme to provide a modulated carrier field 807. The first NFC device 801 generates an unmodulated carrier field 809 for a second period of time to allow the second NFC device 803 sufficient time to derive or acquire sufficient power to provide a response to the polling command.

In the exemplary embodiment as shown in fig. 8, the second NFC device 803 is configured to operate according to a first modulation scheme. Thus, during the second time period, the second NFC device 803 modulates the unmodulated carrier field 809 with a response 811 to the polling command.

Fig. 9 illustrates a second polling process used by the first NFC device to poll the second NFC device according to an exemplary embodiment of the invention. The first NFC device 901 also polls the second NFC device 903 using a second polling process. First NFC device 901 and second NFC device 903 may represent first NFC device 102 and second NFC device 104, respectively.

As shown in fig. 9, first NFC device 901 generates an unmodulated carrier field 905 for a first period of time to allow second NFC device 903 sufficient time to take or acquire sufficient power to communicate. First NFC device 901 modulates a first polling command on an unmodulated carrier field using a first modulation scheme to provide a modulated carrier field 907. The first NFC device 901 generates an unmodulated carrier field 909 for a second period of time to allow the second NFC device 903 sufficient time to take or acquire sufficient power to provide a response to the polling command.

In the exemplary embodiment as shown in fig. 9, the second NFC device 903 is not configured to operate according to the first modulation scheme. Therefore, the second NFC device 903 does not provide a response to the first polling command during the second period.

The first NFC device 901 modulates the second polling command on the unmodulated carrier field using a second modulation scheme to provide a modulated carrier field 911. The first NFC device 901 generates the unmodulated carrier field 913 for a third period of time to allow the second NFC device 903 sufficient time to take or draw sufficient power to provide a response to the second polling command.

In the exemplary embodiment as shown in fig. 9, the second NFC device 903 is configured to operate according to a second modulation scheme. Thus, during the third time period, the second NFC device 903 provides a response 915 to the second polling command.

As shown in fig. 9, if first NFC device 901 does not receive a response to the first polling command, first NFC device 901 provides a second polling command using a second modulation scheme. The amplitude of the second modulation scheme is greater than the amplitude of the first modulation scheme such that when the first NFC device 901 transmits the first polling command in the first modulation scheme, the second NFC device 903 configured to operate according to the second modulation scheme does not recognize the first polling command according to the first modulation scheme. Because the first amplitude modulation of the first modulation scheme is lower than the second amplitude modulation of the second modulation scheme, the entire time 917 the first NFC device 901 polls using the first modulation scheme effectively appears as a long unmodulated carrier field to the second NFC device 903 using the second modulation scheme. Thus, time 917 appears as a long guard time during which second NFC device 903 draws or acquires power from first NFC device 901.

For example, the first modulation scheme may be characterized by an NRZ-L coding scheme with 10% ASK modulation as shown in fig. 5. The modulation scheme in fig. 5 uses 10% amplitude modulation or modulation varying from 100% voltage to 90% voltage amplitude. When this amplitude change occurs, the second NFC device 903 configured to operate according to the first modulation scheme recognizes the first polling signal and the response thereto. In contrast, if the second NFC device 903 is configured to operate according to a second modulation scheme (such as a modified miller coding version with 100% ASK modulation as shown in fig. 4), it typically identifies the first polling command as an unmodulated carrier field, with a smaller change in amplitude.

As another example, the first modulation scheme may be used to probe type B NFC technology tags and the second modulation scheme may be used to probe type a NFC technology tags. In this example, the second NFC device 903, when configured to operate as a type B NFC technology tag, recognizes the first polling command and the response thereto. In contrast, if the second NFC device 903 is configured to operate as a type a NFC technology tag, it typically recognizes the first polling command as an unmodulated carrier field, a small change in amplitude.

Further alternatively, the first modulation may be for type F NFC technology tags and the second modulation may be for type a NFC technology tags.

Referring again to fig. 1, after establishing communication with the second NFC enabled device 104, the first NFC device 102 modulates its respective information on a first carrier and generates a first magnetic field by applying the modulated information communication to the first antenna to provide a first information communication 152. Once the information has been transferred to the second NFC device 104, the first NFC device 102 continues to apply the first carrier without its corresponding information to continue to provide the first information communication 152. The first NFC device 102 is in sufficient proximity to the second NFC device 104 such that the first information communication 152 is inductively coupled to the second antenna of the second NFC device 104.

The second NFC device 104 draws or otherwise obtains power from the first information communication 152 to recover information, process information, and/or provide a response to information. The second NFC device 104 demodulates the first information communication 152 to recover and/or process the information. The second NFC device 104 may respond to the information by applying its respective information to a first carrier inductively coupled to a second antenna to provide a second modulated information communication 154.

Other operations of the first NFC device 102 and/or the second NFC device 104 are described in international standard ISO/IEC 18092:2004(E), "Information technology-Telecommunications and Information Exchange Interface and Protocol (NFCIP-1)" published on 4/1 2004 and international standard ISO/IEC 21481:2005 (E) "published on 1/5 2005, each of which is incorporated herein by reference in its entirety.

Exemplary apparatus for Multi-protocol Polling

Fig. 10 shows a block diagram of an NFC device that may be used according to an exemplary embodiment of the invention. NFC device 1000 may be configured to operate in an object or tag mode of operation to respond to a polling command from another NFC-enabled device operating in a polling mode of operation, such as NFC device 102 or NFC device 104 to provide some examples. The NFC device 1000 includes an antenna module 1001, a demodulator module 1003, a controller module 1005, and a power acquisition module 1007. NFC device 1000 may represent an exemplary embodiment of NFC device 102.

The antenna module 1001 inductively receives a communication signal 1051 from another NFC-enabled device to provide a recovered communication signal 1053. Typically, the received communication signal 1051 includes a polling command that it has modulated in another NFC-enabled device.

Demodulator module 1003 demodulates recovered communication signal 1053 using any suitable analog or digital modulation technique to provide recovered command 1055. The resume command 1055 may be a polling command. Suitable analog or digital modulation techniques may include Amplitude Modulation (AM), Frequency Modulation (FM), Phase Modulation (PM), Phase Shift Keying (PSK), Frequency Shift Keying (FSK), Amplitude Shift Keying (ASK), Quadrature Amplitude Modulation (QAM), and/or any other suitable modulation technique apparent to one skilled in the relevant art.

When the demodulator module 1003 is within a type a NFC technology tag, it detects a polling command based on 100% ASK modulation. The voltage amplitude must drop to zero sufficiently for the demodulator module 1003 to function as a spacing detector for a type a technology tag. In this case, any modulation based on another modulation scheme that does not drop below the threshold required by the type a NFC technology tag may be assigned a digital value of 1. When the amplitude drops low enough, the demodulator module 1003 gives a digital value of 0 according to the modified miller coding scheme.

When the demodulator module 1003 is within a type B NFC technology tag, it detects a polling command based on 10% ASK modulation. The demodulator module 1003 has a voltage threshold equal to 90% of the total modulation amplitude. If the modulation of the polling command falls below the threshold, the demodulator module 1003 gives it a digital value of 0 according to the NRZ-L coding scheme. In this case, any modulation based on another protocol falls below the threshold required by the type B NFC technology tag and is therefore given a digital value of 0. Any modulation that remains above the threshold will be assigned a digital value of 1.

When the demodulator module 1003 is within a type F NFC technology tag, it detects the polling command based on using a manchester encoding scheme for the modulation threshold between the type a NFC technology tag and the type B NFC technology tag. If the modulation of the polling command falls below the threshold, it will be assigned a digital value of 0. Any modulation that remains above the threshold is assigned a digital value of 1.

As can be seen from the above, a type a NFC technology tag does not assign a digital value of 0 to any modulation based on a type B or type F NFC technology tag because the modulation amplitude does not drop below the threshold required for 100% ASK modulation. Thus, the demodulator module 1003 in a type a NFC technology tag does not detect the polling command sent to detect a type B or type F NFC technology tag.

Continuing into other aspects of the NFC device 1000, the controller module 1005 controls the overall operation and/or configuration of the NFC device 1000. The controller module 1005 provides a response 1057 to the command 1055 to resume.

Typically, after another NFC enabled device transmits a polling command and/or a read command to the NFC device 1000, it inductively couples a carrier to the antenna module 1001 as a received communication signal 1051. Controller module 1005 modulates the carrier wave in response 1057 to provide transmitted communication signal 1061. For example, the impedance of the antenna module 1001 changes based on the response 1057 to change the load of another NFC-enabled device.

Power harvesting module 1007 can harvest power for NFC device 1000 from recovered communication signal 1053. The power coupling of the power harvesting module 1007 that supplies power to other modules of the NFC device 1000, such as the antenna module 1001, the demodulator module 1003, and/or the controller module 1005, is not shown in fig. 10.

Conclusion

It is to be understood that the detailed description section, and not the abstract section, is intended to be used to interpret the claims. The abstract section may set forth one or more, but not all exemplary embodiments of the invention, and is therefore not intended to limit the invention and the appended claims in any way.

The invention has been described above with the aid of functional building blocks illustrating the implementation of specific functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Accordingly, the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims (10)

1. A method for detecting a Near Field Communication (NFC) device, comprising:

polling with a first polling command using a first modulation on a carrier field after a first guard time;

maintaining the carrier field unmodulated for a first reply period to detect a response from the NFC device to the first polling command;

polling the carrier field with a second polling command using a second modulation without waiting for a second guard time, the second modulation having an amplitude greater than the first modulation; and

maintaining the carrier field unmodulated for a second reply period to detect a response from the NFC device to the second polling command.

2. The method of claim 1, further comprising:

activating the carrier field;

during the first guard time, keeping the carrier field unmodulated; and

communicating with the NFC device if a response is received from the NFC device while waiting during the first reply period.

3. The method of claim 2, further comprising:

polling with a third polling command using a third modulation on the carrier field;

maintaining the carrier field unmodulated for a third reply period to detect a response from the NFC device to the third polling command; and

communicate with the NFC device if a response is received from the NFC device while waiting during the third reply period,

wherein the third polling command is in accordance with a proprietary standard.

4. The method of claim 2, wherein the first polling command relates to a type B NFC technology tag, and wherein the second polling command relates to a type a NFC technology tag.

5. The method of claim 2, wherein the first polling command relates to a type F NFC technology tag, and wherein the second polling command relates to a type a NFC technology tag.

6. The method of claim 4, wherein the first modulation is a 10% amplitude modulation, and wherein the second modulation is a 100% amplitude modulation.

7. The method of claim 5, wherein the first modulation is less than 100% amplitude modulation, and wherein the second modulation is 100% amplitude modulation.

8. A method for detecting a Near Field Communication (NFC) device, comprising:

receiving, from the NFC reader, a first polling command using a first modulation on a carrier field after a first guard time;

acknowledging the first polling command from the NFC reader for a first acknowledgement period if the NFC device is configured for the first modulation;

receiving, from the NFC reader, a second polling command that uses a second modulation on the carrier field without a second guard time, the second modulation having an amplitude greater than the amplitude of the first modulation; and

acknowledging the second poll command from the NFC reader for a second acknowledgement period if the NFC device is configured for a second modulation.

9. The method of claim 8, further comprising:

during the first guard time, extracting power from the carrier field without modulation.

10. An apparatus for detecting a Near Field Communication (NFC) device, comprising:

a first NFC device configured to:

polling with a first polling command using a first modulation on a carrier field after a first guard time;

maintaining the carrier field unmodulated for a first reply period to detect a response from the NFC device to the first polling command;

polling a carrier field with a second polling command using a second modulation without waiting for a second guard time, the second modulation having an amplitude greater than the first modulation; and

leaving the carrier field unmodulated for a second acknowledgement period to detect a response from the NFC device to the second polling command.