Wireless communication method between active NFC (Near Field Communication) equipment and plurality of passive NFC equipment

Abstract

The present disclosure relates to a near field communication (NFC) system for efficiently activating and reading a plurality of NFC tags by an NFC reader in the vicinity of the plurality of tags. Each NFC tag of the plurality of NFC tags includes the same identification data corresponding to the reference location.

Description

Technical Field

[0001] The present disclosure relates to a Near Field Communication (NFC) system. Background Art

[0002] Generally, a Near Field Communication (NFC) system includes a wireless communication link between two or more devices located within a limited distance from each other. Generally, based on device characteristics, the communication distance between NFC devices is less than 20 cm or less than 10 cm. For example, an NFC device with a power source can be active to form an active NFC system, which operates over a longer distance compared to a passive NFC system. In a passive NFC system, one or more devices can be passive without any power source. Although a passive NFC system can operate under a shorter distance limitation, it is more energy-efficient and cost-effective compared to an active NFC system. In a passive NFC system, an active device (e.g., an NFC reader or initiator) can wirelessly provide sufficient energy to a passive device (e.g., an NFC tag or listening device). In this case, the passive device operates in an energy harvesting mode, where the passive device is activated by receiving a wireless signal from the active device.

[0003] The passive device can include identification data readable by the active device, such as a unique identifier (UID). In some examples, the passive device can operate as a Radio Frequency Identification (RFID) tag within the radio frequency range. The active device can communicate with the passive device through different wireless communication methods, such as backscatter coupling, capacitive coupling, and inductive coupling. Generally, capacitive and inductive coupling are ideal for short-range communication (e.g., several centimeters), while backscatter coupling is used for long-range communication (e.g., hundreds of centimeters). In long-range communication, the active device can communicate with multiple passive devices simultaneously. Therefore, interference (collision) between multiple passive devices may affect data exchange through the wireless communication link. The collision may cause the loss of identification data of the passive device or result in a time delay for the active device to successfully read the identification data. Summary of the Invention

[0004] The present disclosure broadly relates to an active Near Field Communication (NFC) reader configured to interact with a plurality of passive NFC devices or tags that are very close to each other or otherwise near each other. The same or substantially similar data is stored in the memory of each NFC device or tag. This allows for a significant reduction in the processing time for reading and identifying multiple tags. The reading time is more efficient because the method avoids or greatly reduces the need for anti-collision detection of the tags.

[0005] In particular, the NFC reader is configured to interact with multiple tags, where the reader is configured to simultaneously activate multiple tags. This enables wireless communication between an active NFC reader or device and a number of passive NFC devices. The passive NFC devices are close to each other and store the same information in each different memory. The method is performed in the reader or device and includes detecting at least one of a number of passive NFC devices by sending a read command to all nearby passive NFC devices to obtain an information item of the number of passive NFC devices. The method includes receiving at least one response from one of the number of passive NFC devices and retrieving the information item from one of the number of passive NFC devices.

[0006] In one usage or implementation example, the present disclosure relates to an intelligent parking management system based on a Near Field Communication (NFC) link. The intelligent parking locations are equipped with multiple NFC tags. Each NFC tag includes identification data corresponding to the intelligent parking location. The identification data of the multiple NFC tags is the same or substantially the same. In a parking use case, a movable NFC reader is attached to a transport vehicle (e.g., an electric bicycle or scooter or other rentable vehicle) to park in an intelligent parking location. There are multiple different intelligent parking locations available, each with a specific parking location ID. The system is configured to quickly activate a subset of NFC tags when the transport vehicle is located in one of the intelligent parking locations, receive a specific parking location ID from one of the activated NFC tags, and notify the user of the validity of the intelligent parking location when the transport vehicle is located in an authorized location (i.e., an acceptable parking location for the transport vehicle).

[0007] The NFC reader of the present disclosure is designed to detect one of multiple NFC tags by transmitting a request signal and receiving one or more return signals from the NFC tags that are near each other. The NFC tag can be a passive tag activated by the request signal. The NFC reader includes a memory or is coupled to a remote server that stores identification data that identifies different authorized locations to be compared with a specific parking location ID read from the NFC tag. The NFC reader can simultaneously activate more than one tag. In known NFC systems, such interference (collision) may prevent the successful detection of NFC tags. Known NFC systems use time-consuming anti-collision processes to determine which NFC tag to read. Due to the multi-step matching identification process, this anti-collision process results in a delay in reading the NFC tag.

[0008] In contrast, in the present disclosure, the identification data of multiple NFC tags is substantially the same. Therefore, compared with known systems, the anti-collision process can be avoided or implemented less frequently. The anti-collision process is only implemented when NFC tags with different identification data are near the NFC reader. As an example in a parking use case, the anti-collision process is only activated when one of the NFC tags near the NFC reader does not have substantially the same identification data as the other NFC tags within the smart parking location. However, the NFC reader can handle the collision and focus on the NFC tags associated with the smart parking location. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Aspects of the present disclosure are best understood from the following detailed description when read in conjunction with the accompanying drawings. Note that the various features are not necessarily drawn to scale.

[0010] Figure 1 is a flowchart for activating and quickly identifying identification information of multiple NFC tags from near a near field communication (NFC) reader according to the present disclosure.

[0011] Figure 2 is an example NFC system of a reader and tags.

[0012] Figure 3 is a modulation scheme of an NFC system according to some embodiments.

[0013] Figure 4 is an example of a communication waveform in an NFC system according to some embodiments.

[0014] Figure 5 is a smart parking system for an electric bicycle including a near field communication (NFC) system according to some embodiments.

[0015] Figure 6 is Figure 5 an alternative configuration of the smart parking system.

[0016] Figure 7 is an alternative smart parking system for a driverless vehicle.

[0017] Figure 8A is an example of a communication waveform when a collision occurs in an NFC system according to some embodiments.

[0018] Figure 8B is an example of a communication waveform when reading multiple tags in an NFC system according to some embodiments. DETAILED DESCRIPTION

[0019] The present disclosure relates to a system and method for more efficiently processing a set of NFC tags, all of which are in the vicinity or activation area of an NFC reader. The method of the present disclosure is configured to quickly activate and identify authorized NFC tags by eliminating or significantly reducing the need for an anti-collision process. This is achieved by each NFC tag having the same or substantially the same item of information stored in its memory.

[0020] In known systems, each NFC tag includes a unique ID. Each tag includes a memory, such as an EEPROM that can store user data. In order to access the user data in the EEPROM, the NFC reader must obtain the unique ID and then use the unique ID as a filter to select or address the target tag. This is to avoid cross-reading. This uses an anti-collision process to first identify the correct unique ID, then select the target tag, and then read the user data. The anti-collision process can take a long time.

[0021] The method and system of the present disclosure address the challenges of known systems. For example, Figure 1 is a flowchart 500 of a process for efficiently detecting one or more tags of an NFC system. NFC readers (such as readers 108, 308, and 430 in the figures below) are configured to quickly detect authorized tags in the vicinity of the area of the NFC reader. Each authorized tag includes the same or substantially the same user data in each of its memories. By including the same or substantially the same (such as within a few bit differences) user data, the need for an anti-collision process that takes a long time to implement is reduced. The method includes an anti-collision process to eliminate collisions when unauthorized tags are near the reader. Therefore, the anti-collision process is selectively applied only when there is a collision. As a result, the total time of the reading process is reduced from approximately 500 milliseconds (ms) to less than 10 ms.

[0022] Note that the unique ID of each tag is unique. The user data stored in tags near each other (as determined by the end use) is the same or substantially the same, such as information about parking location. The read command initiated by the NFC reader is used to read the user data, not necessarily the unique ID. This method allows "read" commands to be sent out periodically, removing other commands to check for the presence of the unique ID or other tags.

[0023] At 502, the NFC reader transmits a request signal (based on the NFC communication range) to a plurality of tags within the communicable distance or vicinity. The NFC reader includes a process or control unit configured to generate the request signal. The process is configured to modulate and encode the signal to be transmitted by the reader's antenna. The request signal includes a command from the reader received by the control module of each tag in the vicinity. The signal activates the tags to provide access to the unique ID and user data from each activated tag.

[0024] At 504, the reader detects a response or received signal from one or more tags. At 506, the processor of the reader analyzes the received signal after demodulation and decoding to detect or determine the user data stored in the activated tag. If the received signal does not return authorized user data, the process ends at 512, or the reader can return to step 502 and send another request signal with a different time slot. In some embodiments, the reader repeats the transmission of the request signal in different time slots (corresponding to the number of tags assigned to the NFC system) and waits for a period of time to receive a signal from the tags. In the case where no tags are in the vicinity, the reader can repeat the transmission of the request signal until a return signal is received from the tags.

[0025] At 506, the processor compares the received user data with an accessed inventory stored in the memory of the processor or in a remote server, such as via a wireless communication channel. The inventory includes one or more authorized locations or identifiers for comparison with the user data collected from one or more tags. Note that each tag includes a unique ID and the same or substantially the same user data in the tag memory.

[0026] After the reader determines or otherwise detects one or more tags, the reader detects at 508 whether a conflict exists. If there is no conflict between the detected tags, the processor retrieves the user data stored in one or more tags in the vicinity. This communication method is used to accelerate the retrieval of user data stored in multiple NFC tags. The process bypasses the anti-collision process by sending a read command to all NFC tags. Since all NFC tags share the same information in the memory, when all responses are received, the information related to the parking area can be retrieved from all the received responses. In this case, there is no interference problem because all tags respond with the same user data.

[0027] By assigning substantially the same user data to multiple tags, such as tag 110, the inventory can include only substantially the same user data (or, in the use case of a parking system, multiple authorization options). Thus, after the reader detects that the user data of one or more tags matches the substantially the same user data in the inventory, the processor confirms the detection and ends the process. Additionally, when multiple tags are detected in the same time slot and the processor detects a collision, the time required to perform the anti-collision process is shorter compared to conventional methods. For example, during the anti-collision process, the processor compares all tags in the vicinity of the reader with the user data in the inventory within one timing cycle. Thus, over many timing cycles, the anti-collision process is not repeated for all detected tags. The anti-collision process is repeated only when the detected tags have user data that does not match the user data in the reader's inventory (e.g., unauthorized tags, tags of different brands, and illegal or fraudulent tags).

[0028] Figure 2 is a circuit diagram of a passive tag 400 configured to interact with an active reader 430 via a wireless network 460 (e.g., via a magnetic field). The passive tag 400 can be used as a tag in the system described in this disclosure. The tag 400 includes an antenna 402 coupled to a rectifier 404. The rectifier 404 is coupled to a control module 406. A load or resistor 408 is coupled between the rectifier 404 and the control module 406. The control module 406 is coupled to a memory 410. In some examples, the memory can be a non-volatile memory, such as an electrically erasable programmable read-only memory (EEPROM), which stores a unique ID of the tag 400 and stores user data, such as location information. The control module 406 can be a digital access control that analyzes the signal received by the antenna 402 and retrieves the unique ID and user data of the tag 400 from the memory 410.

[0029] Rectifier 404 receives an RF signal from antenna 402 and converts a portion of the RF signal into a direct current (DC) voltage to power on control module 406. In some examples, rectifier 404 includes two diodes 412, 414 (D1 and D2) and a Zener diode 416. Two capacitors 418, 420 (C1 and C2) store enough charge to power on Zener diode 416, which provides a constant voltage to control module 406. Diodes 412, 414 can be low-barrier Schottky diodes with a low threshold that are capable of turning on under the low-energy RF signal received by antenna 402. Additionally, rectifier 404 is coupled to control module 406 through a transistor 422 (e.g., a field-effect transistor) controlled by load 408. Transistor 422 and load 408 can modulate the impedance of antenna 402 to backscatter a portion of the RF signal including the UID of tag 400. The received RF signal can include a command for enabling control module 406 to retrieve the UID of tag 400 stored in memory 410. In some examples, the retrieved UID can be modulated on a portion of the RF signal to be backscattered by antenna 402 to reader 430.

[0030] Reader 430 includes an antenna 432 coupled to a directional coupler 434. Directional coupler 434 is coupled to a modulator 436 and a demodulator 438. Modulator 436 and demodulator 438 are coupled to a processor 444 through an encoder 440 and a decoder 442, respectively. Modulator 436 includes an oscillator 446 that generates a signal having a frequency (e.g., 13.56 MHz) consistent with the NFC communication protocol. Directional coupler 434 can direct the signal from modulator 436 to antenna 432 in the transmit mode and direct the received signal from antenna 432 to demodulator 438 in the receive mode (e.g., by disconnecting the path to modulator 436). Reader 430 can receive power from the vehicle's battery or can have an independent power source.

[0031] In operation, processor 444 generates a request signal to detect NFC tags that may be within communicable range. The request signal is encoded by encoder 440 and modulated by modulator 436 for transmission via antenna 432. If a portion of the request signal is backscattered by one or more tags within the communicable range of reader 430, antenna 432 receives the backscattered signal. When reader 430 is in receive mode, the backscattered signal received by antenna 432 is directed by directional coupler 434 to demodulator 438. Demodulator 438 demodulates the backscattered signal, and decoder 442 decodes the demodulated signal for processing by processor 444. Processor 444 may compare the received user data with an inventory to detect tag 400. In some examples, the processor may send the detected, authorized, and confirmed user data to a remote server to confirm the detection process.

[0032] Figure 2 is an example of circuitry that may be included in a tag or reader of the present disclosure. Figure 3 is an example of a waveform that may be implemented in the present disclosure. Other implementation options are conceivable.

[0033] Figure 3 is an example of different waveforms in modulation system 600 for establishing a communication link (e.g., communication link 106) in an NFC system. Modulation system 600 utilizes a subcarrier signal 602 having a lower frequency compared to carrier signal 604 to transmit data. In such an NFC system, the carrier signal is typically 13.56 MHz. The frequency of subcarrier signal 602 may be obtained based on the number of binary bits of data to be transmitted by carrier signal 604. For example, to transmit 16-bit data, the frequency of subcarrier signal 602 is calculated as 13.56 MHz / 16 (approximately 847 KHz). The higher frequency of carrier signal 604, compared to subcarrier signal 602, is represented by a more dense waveform within the same time period. In various embodiments, the shape of the waveform may be the same for both carrier signal 604 and subcarrier signal 602.

[0034] The sub - carrier signal 602 is modulated by the base - band encoded signal 606 (based on the data stream to be transmitted by the NFC system). The base - band encoded signal 606 carries data bits (e.g., the UID of the tag), and modulates the sub - carrier signal 602 to generate a modulated sub - carrier signal 608. For example, the data bits 605 in the base - band encoded signal 606 modulate the waveform of the sub - carrier signal 602 to generate modulated sub - carrier data bits 607. Thus, for data bits at a high logic level, such as data bit 605, the waveform of the modulated sub - carrier signal 608 is the same as the sub - carrier signal 602. While the waveform of the modulated sub - carrier signal 608 is flat for data bits at a low logic level, such as the low - logic - level data bit 615, which generates a flat waveform 617 corresponding to zero data.

[0035] Compared with the carrier signal 604, the lower frequency of the sub - carrier signal 602 is beneficial for generating the modulated sub - carrier signal 608 in a spectrum different from the operating frequency of the carrier signal 604. Thus, the modulated sub - carrier signal 608 is coupled to a switch of the tag (e.g., Figure 4 the transistor 422 in Figure 4 to modulate a load (e.g.,

[0036] the load 408 of

[0036] based on the data from the base - band encoded signal 606. Thus, the modulated sub - carrier signal 608 provides load modulation for the tag in the NFC system at a frequency different from the operating frequency of the carrier signal 604. In the spectrum, data is transmitted in the sidebands of the sub - carrier signal 602 instead of occupying the sidebands of the carrier signal 604. To transmit data with the carrier signal 604 at the operating frequency (13.56 MHz) of the NFC system, the modulated sub - carrier signal 608 modulates the carrier signal 604 through load modulation (turning the switch of the tag on and off) to generate a load - modulated signal 610. The load - modulated signal includes data from the base - band encoded signal 606, which is modulated on the sub - carrier signal 602. For example, the modulated sub - carrier data bits 607 modulate the carrier signal 604 with a waveform such as a part 609 of the load - modulated signal 610. While the flat waveform 617 of the modulated sub - carrier signal 608 generates a flat amplitude 619 of the load - modulated signal 610.

[0037] In various embodiments, the wireless network of the NFC system operates within the frequency range of the carrier signal 604 to exchange data between the reader and the tag. The reader receives the load - modulated signal 610 (which is modulated at the operating frequency of the carrier signal 604) from the tag, and extracts data from the load - modulated signal 610 through a demodulator and / or decoder. The extracted data is analyzed by a processor to complete the reading process based on the data received from the tag.

[0038] Figure 4is an example of the modulation system 700 during the reading of one or more tags corresponding to the NFC system of the present disclosure. In this embodiment, the baseband encoded signal 702 is an indication signal of the unique ID or user data of each tag in the NFC system. The baseband encoded signal 702 is generated based on the data stored in the EEPROM of each tag. Then, the baseband encoded signal 702 modulates the subcarrier signal to generate a modulated subcarrier signal 704. The modulated subcarrier signal 704 can turn on and off the transistors of the tag to generate a load modulation signal 706 on the carrier signal at the operating frequency (13.56 MHz) of the NFC system. The load modulation signal 706 has the waveform of the signal received by the antenna of the reader (e.g., antenna 432). The amplitude of the load modulation signal 706 is modulated by the modulated subcarrier signal 704, and this modulated subcarrier signal will be extracted as the read data by the processor in the reader. Under the same conditions, the processor of the reader generates commands through signals such as the baseband encoded signal 702, and modulates the subcarrier and carrier signals through the encoder and modulator of the reader (e.g., modulator 436 and encoder 440). The modulator may include an oscillator (e.g., oscillator 446) to generate the operating frequency (13.56 MHz) of the carrier signal. In this case, the modulation scheme is a digital modulation such as amplitude shift keying (ASK). In various embodiments, different modulation schemes such as phase shift keying (PSK) and frequency shift keying may be used.

[0039] Figure 8A is an example of the waveform generated by the demodulation system 800 in response to reading two different tags. To read multiple tags, the reader generates a request signal with a plurality of time slots corresponding to the number of tags in the NFC system. In normal operation, for an NFC system with 16 tags, the reader generates a request signal with 16 consecutive time slots. Each tag randomly selects a time slot to respond to the reader. If the time slots selected for two or more tags overlap in the same time slot and the user data in all the activated tags is the same, the user data is confirmed. Otherwise, if one or more user data is different from the other user data in the same time slot, it will cause a conflict during the reading process. The demodulation system 800 shows the case of detecting two tags with different user data. In this example, the user data of the two tags has only a one-bit difference. In response to detecting different user data, the controller (e.g., Figure 2 the processor 444 in) detects a one-bit conflict and executes a program for the anti-collision process (e.g., Figure 1 the step 510 in). In various embodiments, the different user data may indicate unauthorized tags in the system, and the anti-collision process is performed as an anti-spoofing process to prevent fraud or subversion behavior.

[0040] Demodulation system 800 includes a baseband coded signal 802, a subcarrier demodulated signal 804, and a load demodulated signal 806. Two tags are detected in the same time slot 808. In this embodiment, the timing period 810 shows an example of a conflict between the two detected tags, where the two tags have only one bit of different data. In response to detecting a one-bit difference (in the timing period 810) between the user data of the two detected tags, the controller (e.g., Figure 2 the processor 444 therein) executes a program for the anti-collision process (e.g., Figure 1 step 510 therein). In various embodiments, the two detected tags may have more than one bit difference in the user data. In the examples described herein, only a one-bit difference is considered to test the accuracy of unauthorized tag detection, where the minimum possible difference between the user data of the tags is one bit.

[0041] Figure 8B is an enlarged view of the baseband coded signal 802 and the load demodulated signal 806 described in the case where the user data of the detected tags are the same and there is no conflict in the demodulation system 800 Figure 8A The duty cycle (i.e., the timing ratio between the on state 812 and the load demodulated signal 806 (the accumulation of the on state 812 and the off state 814)) shows an acceptable quality due to the time interval between the time slots for reading multiple tags. The waveform of the load demodulated signal 806 confirms that the on state 812 and the off state 814 can be detected when multiple tags are detected in different time slots with the same user data.

[0042] Returning to Figure 1 , at 508, if the processor detects that there is only one unique ID in each time slot and there is no conflict, the processor ends collecting user data and ends the read / activate process at 512. In some embodiments, if the processor detects multiple unique IDs with substantially the same user data in the same time slot, the processor may not detect a conflict and ends the process at 512.

[0043] If there are multiple unique IDs with different user data, the processor executes the anti-collision program at 510. During the anti-collision process, the processor compares all the unique IDs detected in all time slots with the inventory. The inventory includes a single user data reference or multiple authorized user data references (such as multiple authorized parking locations). Thus, the processor compares all the different user data from the detected tags with the inventory within one timing period to identify the authorized tags. In some examples, substantially the same user data may be the SID corresponding to the parking location. If there is other detected user data that does not match the inventory, the processor blocks or filters these tags from the communication network and ends the process at 512.

[0044] At 512, in an alternative embodiment, if the processor detects a first tag that matches the user data and then detects any second tag that also matches the same user data, the processor places the second tag in a sleep mode. The processor may generate a sleep mode command and transmit it to the second tag to activate it in the sleep mode (non-responsive) for a period of time to avoid additional conflicts in the time slots during the process. When the processor detects that any tag has authorized user data, the processor transmits an acknowledgement signal. In some embodiments, such as in a parking example use case, the acknowledgement signal may communicate with a remote server, such as the server of an e-bike service provider for parking and payment confirmation. In some examples, the remote server may complete a rental transaction (e.g., for renting an e-bike) in response to receiving the acknowledgement signal from the reader.

[0045] The present disclosure may be integrated in various use cases. Several smart parking examples are described below. These examples are not exhaustive.

[0046] Figure 5 There is provided a smart parking system 100 for an e-bike 102 or other vehicle, such as a rentable scooter, bicycle, or other mobility option. The e-bike 102 is configured to automatically detect and identify whether a parking location 104 is an acceptable location for parking the e-bike 102 by activating a plurality of tags 110 in the vicinity of a reader 108 coupled to the bike. The reader (or initiator) 108 is positioned or otherwise coupled to the bottom surface of the e-bike 102, which is configured to wirelessly communicate with a plurality of tags (or listening devices) 110 fixed to the parking location 104 via a near field communication (NFC) system. The NFC system allows a communication link 106 to be established between the two wireless components only when the two wireless components (the reader 108 and each tag of the plurality of tags 110) are within a communicable distance. The communicable distance of the NFC system is less than about 20 - 30 cm, where the reader 108 is configured to activate passive radio frequency identification (RFID) tags (e.g., the plurality of tags 110). The passive tags are activated by the signal transmitted by the reader. The passive RFID tags may not include a battery but are only activated or powered on when within a specific distance of the NFC reader.

[0047] By utilizing the NFC system to manage the smart parking system 100, the distance between the e-bike 102 and the parking location 104 can be less than one meter (e.g., 20 - 30 cm) to sufficiently establish the communication link 106 (e.g., via a magnetic field).

[0048] Reader 108 is attached to the electric bicycle 102 and faces the ground. A plurality of tags 110 are arranged in fixed positions along the parking location 104. For example, the plurality of tags 110 can be attached as different tags of a strip to a hard surface such as a road or asphalt. In some embodiments, the plurality of tags are equally spaced apart. Reader 108 is configured to activate one of the plurality of tags 110 when the operator moves the electric bicycle 102 over a portion of the plurality of tags 110. Reader 108 provides sufficient energy to the subset of tags to be activated.

[0049] In some examples, the NFC system can operate in an RF backscatter mode, where reader 108 transmits an RF signal to a subset of tags within region 103 corresponding to the coverage area of the RF signal of reader 108 among the plurality of tags 110. In this example, there are three tags 110a - 110c within region 103, and when the operator moves the electric bicycle 102 to overlap with the parking location 104, reader 108 will activate these tags. The backscattered signal includes user data. The plurality of tags can be spaced 1 inch to 12 inches or more from adjacent tags. The spacing of the tags is determined by the end use of these methods and systems. For example, the width of a scooter is smaller than that of some electric bicycles, which can benefit from tags being closer to each other compared to an electric bicycle system. Alternatively, each tag can be spaced from an adjacent tag by an amount equal to the distance of the tag. The system is configured to address the situation where the NFC reader detects at least two tags during a scan or activation process.

[0050] In some embodiments, region 103 can be approximately 30 centimeters (diameter). When reader 108 is placed close enough to the plurality of tags 110, the reader communicates with the plurality of tags within the communicable distance to establish an NFC communication link 106. Reader 108 will receive identification or user data from all tags activated within region 103. Reader 108 communicates with a remote server and ultimately with the operator to provide an indication of the adequacy of the parking location 104. The remote server can communicate directly with the reader or can be coupled to the reader through an application on the user's mobile communication device (such as a phone). In response to the determination of an acceptable parking location 104, the operator can receive a notification "Yes, this is an OK parking space" or "No, a parking space is detected" through the application. Additionally, the parking location can be stored at the server level to help obtain a complete picture of the location of parked vehicles in a shared vehicle system.

[0051] If the operator places the electric bicycle 102 in an unauthorized location, such as a parking location with multiple fixed tags for different rental companies, the reader 108 will be able to activate the passive tags at that parking location (except for parking location 104), but will not receive acceptable identification data from the tags. There can be multiple strips of tags in the parking area, one area associated with the rental company used by the operator and other areas associated with other rental companies. If the operator moves the electric bicycle 102 to an unauthorized parking area, the reader 108 and the NFC system will notify the operator that the location is not a proper location.

[0052] Each NFC tag among the multiple tags 110 includes a unique identifier (UID) readable by the reader 108. When the reader 108 receives backscattered signals from multiple tags simultaneously (cross-reading of multiple tags), it may cause interference (collision) between the tags. Polling by the NFC reader will only perform an anti-collision process when the user data in the simultaneously activated tags is different. If the user data in the activated tags is the same, the user data is confirmed and the processor performs the next step in the final process.

[0053] The unique ID of each tag is unique. The user data stored in tags near each other (as determined by the end use) is the same or substantially the same, such as information regarding parking location. The read command initiated by the NFC reader is used to read the user data, not necessarily the unique ID. This method allows the "read" command to be sent out periodically, removing other commands to check for the presence of the unique ID or other tags.

[0054] Even in the case of cross-reading between multiple tags with substantially the same identification (e.g., tags 110a - 110c), this feature provides the reader 108 with the opportunity to identify acceptable locations of the parking positions 104. In the case of performing an anti-collision process, since all detected tags are confirmed with substantially the same identification within a single timing period, it takes a shorter time compared to traditional methods. The memory bits of the user data in each of the multiple tags are within 1 - 4 bits of each other, and in some embodiments, these improvements are achieved by each tag in the parking position having the same or substantially the same identification data (within one or two different bits). Each tag includes information for identifying the parking position, such as by a station identification (SID). Thus, when multiple tags are detected in the area of the reader, i.e., within the same time slot, the NFC system avoids applying or performing an anti-collision process because each tag stores substantially the same data (parking position information). Therefore, the processor only detects a conflict when an unauthorized tag (e.g., a tag not assigned to a specific rental company's parking position) is within the communicable distance from the reader. Unauthorized tags have different identification data from each other or from authorized tags in the same area.

[0055] Typically, the anti-collision process includes an inventory of authorized NFC tags of the system (e.g., the smart parking system 100). The inventory can include a list of authorized parking positions for comparison with user data from the authorized NFC tags, and the inventory is stored in the memory of the reader's processor or in a remote server.

[0056] The present disclosure broadly relates to an active near field communication (NFC) reader configured to interact with multiple passive NFC devices or tags that are very close to each other or otherwise near each other. Each NFC device or tag has the same identification or a similar identification reference in its memory.

[0057] In various embodiments, the NFC reader can detect multiple NFC tags by transmitting a request signal and receiving one or more return signals from the multiple NFC tags. In some examples, the multiple NFC tags can be passive and capable of being activated by harvesting energy from the request signal transmitted by the NFC reader.

[0058] Typically, if an NFC reader receives backscatter signals from multiple NFC tags simultaneously, interference (collision) may prevent successful detection of the NFC tags in the NFC system. Typically, by matching the detected identification data with an inventory mask (e.g., the inventory of authorized NFC tags) to identify each NFC tag among the multiple NFC tags, the anti-collision process can provide the desired resolution for NFC tag detection. However, due to the multi-step matching of the identification data with the inventory mask, this anti-collision process results in a delay in the readout process of the NFC tags.

[0059] In the present disclosure, the identification data of multiple NFC tags that are very close to each other are substantially the same. Thus, the anti-collision process can be avoided unless an NFC tag having identification data different from the multiple NFC tags is within the range of the active NFC reader. In such a case, the anti-collision process is activated only when the NFC reader detects identification data that is substantially different from the other NFC tags within the range of the NFC reader.

[0060] Figure 6 An example of a smart parking system 100 is shown, where multiple electric bicycles 202 are parked at a designated parking location 104. As Figure 5 shown, each of the multiple electric bicycles 202 can be represented by an electric bicycle 102 with a reader 108. When the operator of each electric bicycle 202 moves the electric bicycle over a portion of the multiple tags 110, the reader 108 on the electric bicycle detects one or more of the multiple tags 110 and, in response, notifies the operator of the electric bicycle parked at the authorized parking location 104. In some examples, the parking notification can complete the rental transaction of the electric bicycle. The system can also be configured to notify the operator if the bicycle is not at an authorized parking location, such as a location owned or managed by a different company or provider.

[0061] The maximum number of multiple electric bicycles 202 that can be parked at the parking location 104 can depend on the number of authorized tags fixed at the parking location 104. For example, the multiple tags 110 can include 16 tags, which provide the capacity to park 16 electric bicycles at the parking location 104. Alternatively, the tags in the parking area can be much more numerous than the number of bicycles that can be accommodated in the parking area. For example, an area can be filled with tags in an array rather than just a strip of tags like the tags 110, so that electric bicycles can be parked in an area rather than in a line.

[0062] In Figure 2In it, multiple tags 110 are arranged in an I or H shape, having a central extension portion, a first side extension portion 113, and a second side extension portion 115. An electric bicycle is illustrated above the central extension portion. The first side extension portion 113 is separated from the second side extension portion 115 by the central extension portion 111, and the central extension portion is transverse or perpendicular to the first side extension portion and the second side extension portion. In some embodiments, an operator can park the electric bicycle on one of the first side extension portion or the second side extension portion. Various orientations of the multiple tags can be selected to meet the design parameters of the final system.

[0063] The multiple tags 110 are passive, so the parking location 104 can operate without any external energy source. Each of the multiple electric bicycles 202 provides sufficient energy for the reader 108 to communicate with one or more of the multiple tags 110 in the parking location 104. Each electric bicycle includes a main battery, which provides electrical energy for the operation of the electric bicycle in addition to the energy required by the reader 108. In some examples, the electric bicycle may include a backup battery different from the main battery, and the backup battery provides the required energy for the reader 108.

[0064] In some examples, each of the multiple electric bicycles 202 includes a communication interface or transceiver coupled to the reader 108. The communication interface communicates wirelessly with the server 204 via the network 206. The network 206 may include a wireless local area network (WLAN), such as Wi-Fi, a cellular network (e.g., 5G, 4G, LTE), or even a short-range communication network, such as Bluetooth. The reader 108 can transmit the detected user data from one of the multiple tags 110 to the server 204 to confirm the parking location 104 using the inventory stored in the server 204.

[0065] In one embodiment, the tags can be programmed by a rental company to change the unique identifier (UID) of each tag, so as to support efficient reading of multiple tags for parking. This application has focused on the unique ID with the same user data. Different combinations of programmable unique IDs and the same user data in the tags can be envisioned. For example, using a programmable unique ID, an NFC reader can be configured to read and efficiently process multiple tags with the same uniquely programmed ID.

[0066] In addition, the reader 108 can combine the identification data of the electric bicycle with the detected user data and transmit the combined data to the server 204. In this case, the server 204 can assign the detected user data to the identification data of the electric bicycle and send a notification to the operator of the electric bicycle through an application (e.g., installed on the operator's smart device). In addition, when the authorized parking location 104 is confirmed, the server 204 can retrieve the history of the identified electric bicycle and the operator of the identified electric bicycle to complete the rental transaction. The server 204 can send a confirmation signal to the reader 108 to notify the operator of the electric bicycle that the electric bicycle has been successfully located at the authorized parking location 104. In some examples, the notification can be displayed to the operator through a display screen on the electric bicycle or the user's mobile device (such as on a display). The remote server can be near the parking location, such as in an adjacent building, or can also be a remote cloud storage device.

[0067] The NFC system of the intelligent parking system 100 can be used in various automated management systems, such as factories or smart home applications, such as robotic vacuum cleaners. For example, as Figure 7 shown, the positioning management system 300 utilizes the NFC system to position the driverless vehicle 302 (e.g., a robot) at the authorized location 304. The reader 308 on the driverless vehicle 302 detects a subset of tags 310 arranged along the wall 312. When the driverless vehicle 302 is close enough to a portion of the plurality of tags 310, the reader 308 detects a subset of the plurality of tags 410. The reader 308 can activate the tags and collect user data to a server located within the same building to confirm the location 304 through the inventory stored in the server. The reader 308 can include an inventory to compare with the user data of the detected tags. By confirming the location of the driverless vehicle 302, the server or internal processor of the driverless vehicle 302 can execute a standby program to stop the driverless vehicle 302 at the authorized location 304. This can be used as a tracking system for different vehicles. In another example, the plurality of tags within the parking location (e.g., the plurality of tags 110) can include a read block in addition to the unique ID (UID). The read block includes the same identification data, such as SID, of the plurality of tags in the parking location. In this case, the command causes the read block of each tag to be retrieved and backscattered to the reader without retrieving the UID of each tag.

[0068] In another example, if the reader's command is to retrieve only the read block data, the processor analyzes the backscattered signal to detect whether there is a read block corresponding to the parking position. If the reader only detects the read block data instead of the UID, the processor compares the read block data with the inventory of the SID instead of the UID.

[0069] A method can be generally summarized as including transmitting a request signal including a read command by a removable near field communication (NFC) reader; receiving a first signal in a first time slot in response to activating a first NFC tag; receiving a second signal in a second time slot in response to activating a second NFC tag, the first NFC tag and the second NFC tag being located at fixed positions, the first signal including first identification data about the fixed position, and the second signal including second identification data about the fixed position; determining by the removable NFC reader whether the first identification data and the second identification data are substantially the same; and transmitting an acknowledgment signal in response to determining that the first identification data and the second identification data are substantially the same.

[0070] The determination can include comparing the first identification data and the second identification data with a station identification (SID) stored in the NFC reader, and substantially the same identification includes the SID.

[0071] The transmission can include a read command for retrieving two data blocks from the memory of each of the first NFC tag and the second NFC tag, and the memory of each of the first NFC tag and the second NFC tag includes four data blocks.

[0072] The method can also generate an acceptable position signal in response to the first identification data or the second identification data matching the SID; and can send the acceptable position signal to a remote server.

[0073] The SID can be stored in the removable NFC reader or the remote server.

[0074] The method can also complete a rental transaction in response to the remote server receiving the acceptable position signal.

[0075] The NFC reader can be attached to an electric bicycle or a scooter.

[0076] The NFC reader can be attached to an unmanned movable device.

[0077] The method can also include activating an anti-collision process by determining that the first time slot overlaps with the second time slot; and determining by the removable NFC reader that the first identification data and the second identification data are different.

[0078] The timing from the transmission request signal to the transmission confirmation signal can be equal to or less than 100 milliseconds.

[0079] A near field communication (NFC) system can be generally summarized as including a plurality of NFC tags attached to a fixed position. Each NFC tag among the plurality of NFC tags includes: a first antenna configured to receive a request signal; a rectifier configured to rectify a part of the request signal, the rectifier being configured to activate the NFC tag; a memory configured to store identification data regarding the fixed position; and a processor configured to detect a command from the request signal, retrieve the identification data from the memory, and transmit the identification data, wherein the identification data is substantially the same for the plurality of NFC tags.

[0080] The memory can be a non-volatile memory.

[0081] The identification data of each NFC tag can include 8 bytes of data, and one bit in the 8 bytes of data is different for the plurality of NFC tags.

[0082] The substantially same identification data can be an indication data set corresponding to the fixed position.

[0083] The fixed position can be a parking position, and a movable reader can detect the parking position by detecting one or more NFC tags among the plurality of NFC tags.

[0084] The movable reader can include a processor configured to: extract the identification data of the detected NFC tag; compare the extracted identification data with a station identification (SID), the substantially same identification data including the SID; and perform an anti-collision process if two or more of the extracted identification data are in the same time slot and at least one of the extracted identification data is different from the SID.

[0085] A method can be generally summarized as including positioning a movable near field communication (NFC) reader at a fixed position; transmitting, by the movable NFC reader, a request signal for activating a plurality of NFC tags along the fixed position; reading out identification data from the plurality of NFC tags, the identification data being substantially the same for the plurality of NFC tags; indicating, by the movable NFC reader, the fixed position according to the identification data of the plurality of NFC tags; and notifying an operator of the fixed position.

[0086] The method can further include: activating an anti-collision process if the movable NFC determines that at least one of the identification data of the plurality of NFC tags is different from the substantially same identification data.

[0087] The time from positioning the movable NFC reader to notifying the operator can be equal to or less than 100 milliseconds.

[0088] The transmission request signal may include transmitting the request signal in a plurality of time slots, and the number of the plurality of time slots is the same as the number of the plurality of NFC tags.

[0089] The present disclosure relates to a method, which includes: within less than or equal to 100 milliseconds, reading a plurality of passive NFC devices near a near field communication (NFC) reader, and transmitting an acknowledgment signal by: simultaneously activating the plurality of passive NFC devices with the same signal; receiving user data from the plurality of activated passive NFC devices; comparing the received user data with each other; activating an anti-collision process only in response to the received user data differing from each other by at least one bit; and if the received user data is the same, processing the received user data without activating the anti-collision process. The processing is performed in a processor in the NFC reader, and the processing includes comparing the received user data from one of the plurality of passive NFC tags with reference data in a memory in the NFC reader. The acknowledgment signal is transmitted in response to when the received user data matches the reference data. The time from activation to transmission of the acknowledgment signal is less than or equal to 100 milliseconds.

[0090] The present disclosure relates to wireless communication between an active near field communication (NFC) reader and a plurality of first passive NFC devices near the NFC reader, and the plurality of first passive NFC devices include user data in a memory of each of the first passive NFC devices. The communication includes: transmitting an activation signal from the NFC reader to the plurality of first passive NFC devices; receiving responses from at least two of the first passive NFC devices; and activating an anti-collision process only in response to the user data from at least two of the first passive NFC devices differing from each other by more than one bit. The user data from the first of the first passive NFC devices is compared with authorized reference data without activating the anti-collision process. An authorization signal is transmitted in response to the user data matching the authorized reference data. An anti-collision process is activated only in response to the user data from at least two of the first passive NFC devices differing from each other by at least one bit. The user data is a parking station identifier, and the NFC reader is on a moving vehicle. The communication includes comparing the user data received from the first of the first passive NFC devices with authorized user data stored in the NFC reader.

[0091] The present disclosure relates to a near field communication (NFC) system having an NFC reader, the NFC reader including: a memory including authorized user data; a transmitter configured to output a read signal to a plurality of first passive NFC devices, each device having first user data in the memory; a receiver configured to receive the first user data from at least one of the first passive NFC devices; and a comparator configured to compare the authorized user data with the received first user data. The first user data is the same in each of the plurality of first passive NFC devices. The first user data is substantially the same in each of the plurality of first passive NFC devices, and the first user data differs by 1 to 4 bits in each of the first passive NFC devices. The receiver is configured to receive second user data from a second passive NFC device, the second user data being substantially different from the first user data; and the NFC reader includes a processor configured to initiate an anti-collision process only in response to the reception of the second user data.

[0092] The present disclosure relates to a method including positioning a near field communication (NFC) reader at a location; activating a plurality of NFC devices along the location by transmitting a request signal from the NFC reader; reading first identification data from a first NFC device among the plurality of activated NFC devices, the first identification data being substantially the same for the plurality of NFC devices; comparing, by the NFC reader, the first identification data with a reference location; and transmitting an authorization signal in response to a match between the first identification data and the reference location. The method includes activating an anti-collision process in response to reading second identification data from a second NFC device among the NFC devices, the second identification data being substantially different from the first identification data, the activating of the anti-collision process occurring before the comparison. Transmitting the authorization signal includes transmitting the authorization signal to a remote server. The time from positioning the NFC reader to transmitting the authorization signal is equal to or less than 10 milliseconds.

[0093] The present disclosure relates to a Near Field Communication (NFC) system, the NFC system comprising: a plurality of first passive NFC devices, each first passive NFC device storing the same first user data in a memory; an NFC reader, the NFC reader comprising: a transmitter configured to output an activation signal to the plurality of first passive NFC devices; a receiver configured to receive a response from at least one of the first passive NFC devices; an anti-collision module configured to perform an anti-collision process in response to the receiver receiving a response from at least one of the first passive NFC devices and the second response including user data different from the first user data; a retrieval module configured to retrieve user data from at least one of the first passive NFC devices without activating the anti-collision module. The NFC reader comprises a processor, the processor comprising the anti-collision module and the retrieval module. The processor is configured to compare the retrieved user data with reference user data from a memory in the processor, and the processor is configured to transmit an authorization signal in response to the retrieved user data matching the reference user data. The NFC reader is configured to transmit the activation signal and transmit the authorization signal within less than or equal to 100 milliseconds.

[0094] The various embodiments described above may be combined to provide additional embodiments. If desired, aspects of the embodiments may be modified to incorporate concepts from various patents, applications, and publications to provide additional embodiments.

[0095] In light of the foregoing detailed description, these and other changes may be made to the embodiments. Generally, in the following claims, the terms used should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be understood to include all possible embodiments and the full scope of equivalents to such claims. Accordingly, the claims are not limited by the present disclosure.

Claims

1. A method, comprising: Reading a plurality of passive NFC devices in the vicinity of a Near Field Communication (NFC) reader, and transmitting an acknowledgement signal by: Simultaneously activating the plurality of passive NFC devices with the same signal; Receiving user data from the activated plurality of passive NFC devices; Comparing the received user data with each other; Activating an anti-collision process only in response to the received user data differing from each other by at least one bit; And If the received user data is the same, processing the received user data without activating the anti-collision process.

2. The method according to claim 1, wherein the reading and transmitting occur within less than or equal to 100 milliseconds, and the processing is performed in a processor in the NFC reader, the processing comprising comparing the received user data from one of the plurality of passive NFC tags with reference data in a memory in the NFC reader.

3. The method according to claim 2, wherein the transmitting of the acknowledgement signal is in response to a match between the received user data and the reference data.

4. The method according to claim 3, wherein the time from the activation to the transmitting of the acknowledgement signal is less than or equal to 100 milliseconds.

5. A method, comprising: Performing wireless communication between an active Near Field Communication (NFC) reader and a plurality of first passive NFC devices in the vicinity of the NFC reader, the plurality of first passive NFC devices including user data in a memory of each of the first passive NFC devices, the communication comprising: Transmitting an activation signal from the NFC reader to the plurality of first passive NFC devices; Receiving responses from at least two of the first passive NFC devices; and Activating an anti-collision process only in response to the user data from the at least two of the first passive NFC devices having data that differs from each other by more than one bit.

6. The method according to claim 5, wherein the communication comprises comparing the user data from a first one of the first passive NFC devices with authorized reference data stored in a memory of the NFC reader without activating the anti-collision process.

7. The method according to claim 6, wherein an authorization signal is transmitted in response to a match between the user data and the authorized reference data.

8. The method according to claim 6, wherein the anti-collision process is activated only in response to the user data from the at least two of the first passive NFC devices having data that differs from each other by at least one bit.

9. The method according to claim 6, wherein the user data is a parking station identifier and the NFC reader is on a moving vehicle.

10. The method according to claim 6, wherein the communication comprises comparing the user data received from a first one of the first passive NFC devices with stored authorized user data in the NFC reader.

11. A Near Field Communication (NFC) system, comprising: An NFC reader, comprising: A memory, comprising authorized user data; A transmitter, configured to output a read signal to a plurality of first passive NFC devices, each device having first user data in a memory; A receiver, configured to receive the first user data from at least one of the first passive NFC devices; and A comparator, configured to compare the authorized user data with the received first user data.

12. The system according to claim 11, wherein the first user data is the same in each of the plurality of first passive NFC devices.

13. The system according to claim 11, wherein the first user data is substantially the same in each of the plurality of first passive NFC devices, and the difference in the first user data in each of the first passive NFC devices is within 1 to 4 bits.

14. The system according to claim 11, wherein the receiver is configured to receive second user data from a second passive NFC device, the second user data being substantially different from the first user data; and the NFC reader includes a processor configured to initiate an anti-collision process only in response to the receipt of the second user data.

15. A method, comprising: Positioning a near field communication (NFC) reader in a location; Activating a plurality of NFC devices along the location by transmitting a request signal from the NFC reader; Reading first identification data from a first one of the activated plurality of NFC devices, the first identification data being substantially the same for the plurality of NFC devices; Comparing, by the NFC reader, the first identification data with a reference location; And Transmitting an authorization signal in response to a match of the first identification data with the reference location.

16. The method according to claim 15, comprising: Activating an anti-collision process in response to: reading second identification data from a second one of the NFC devices, the second identification data being substantially different from the first identification data, the activating of the anti-collision process being before the comparing.

17. The method according to claim 16, wherein transmitting the authorization signal includes transmitting the authorization signal to a remote server.

18. The method according to claim 17, wherein the timing from the positioning of the NFC reader to the transmitting of the authorization signal is equal to or less than 10 milliseconds.

19. A near field communication (NFC) system, comprising: A plurality of first passive NFC devices, each passive NFC device storing the same first user data in a memory; An NFC reader, comprising: A transmitter, configured to output an activation signal to the plurality of first passive NFC devices; A receiver, configured to receive a response from at least one of the first passive NFC devices; An anti-collision module, configured to: execute an anti-collision process in response to the receiver receiving the response from at least one of the first passive NFC devices and the second response including user data different from the first user data; A retrieval module, configured to: retrieve the user data from at least one of the first passive NFC devices without activating the anti-collision module.

20. The system according to claim 19, wherein the NFC reader includes a processor, the processor includes the anti-collision module and the retrieval module, the processor is configured to compare the retrieved user data with reference user data from a memory in the processor, and the processor is configured to transmit an authorization signal in response to a match between the retrieved user data and the reference user data.

21. The system according to claim 20, wherein the NFC reader is configured to transmit the activation signal and transmit the authorization signal within less than or equal to 100 milliseconds.

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