SYSTEM FOR SIMULTANEOUSLY IDENTIFYING MASSIVE RFID TAGS USING HF BAND

• US 20140111310A1
• Filed: 10/18/2013
• Published: 04/24/2014
• Est. Priority Date: 10/18/2012
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: BAE, Ji Hoon, CHO, Kwang Soo, PARK, Man Sik, CHOI, Won Kyu, YANG, Hoe Sung, PARK, Chan-Won, CHAE, Jong-Suk, PYO, Cheol Sig
• Granted Patent: US 9,256,771 B2
• Time in Patent Office: Days
• US Class Current: 340/10.3
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/10138 the step consisting of determining the type of record carrier, e.g. to determine if the record carrier is an RFID tag of the long or short range type, or to determine the preferred communication protocol of the RFID tag
• CPC Class Codes: G06K 7/10198 setting parameters for the interrogator, e.g. programming parameters and operating modes
• CPC Class Codes: G06K 7/10297 arrangements for handling protocols designed for non-contact record carriers such as RFIDs NFCs, e.g. ISO/IEC 14443 and 18092 cryptographic protocols H04L9/00; network security protocols H04L63/00; real-time communication protocols in data switching networks H04L65/00; network protocols for data switching network services H04L67/00
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A tag of an apparatus for simultaneously identifying massive tags according to the present invention may include an analog circuit unit to communicate with a reader through an analog signal and to receive energy via magnetic coupling with the reader. Further, the tag may include a digital circuit unit to be supplied with power from the analog circuit unit. The digital circuit unit may support a sleep mode for the tag to stand by in a low power state after transmitting an identifier (ID) to the reader and a wait mode for controlling random access to the reader.

Claims

1. A high-frequency (HF) tag comprising:

an analog circuit unit to communicate with a reader through an analog signal and to receive energy via magnetic coupling with a reader; and

a digital circuit unit to be supplied with power from the analog circuit unit,

wherein the digital circuit unit supports a sleep mode for the tag to stand by in a low power state after transmitting an identifier (ID) to the reader and a wait mode for controlling random access to the reader.

2. The HF tag of claim 1, wherein the analog circuit unit comprises:

a transmission unit to receive an input of an encoded signal from the digital circuit unit and to transmit the encoded signal to the reader via amplitude-shift keying (ASK) modulation using load modulation;

a rectifier and power supply unit to receive a carrier wave transmitted from the reader and to generate own power;

an initialization unit to initialize an internal operation of the tag in the wait mode of the tag; and

a reception unit to receive a command transmitted from the reader and to conduct ASK demodulation.

3. The HF tag of claim 1, wherein the digital circuit unit comprises:

an encoder to encode a reply message to a reader command;

a decoder to receive an input of the reader command from the analog circuit unit and to extract information;

a protocol processing unit to process inventory and access protocols;

a tag state controller to comprise a wait mode controller, a sleep mode controller, and a tag state transition unit; and

a memory to store the ID.

4. The HF tag of claim 3, wherein:

the sleep mode controller controls the tag to transition to the sleep mode when a reader command needed for the inventory protocol is received in an acknowledged mode, and

the wait mode controller controls the tag in the sleep mode to transition to the wait mode using a carrier wave.

5. The HF tag of claim 4, wherein the sleep mode controller blocks supply of power and a clock to all blocks, excluding the rectifier and power source unit and the initialization unit, in the sleep mode.

6. The HF tag of claim 4, wherein the wait mode controller initializes all operations of the tag using a reset signal in the wait mode.

7. The HF tag of claim 4, wherein:

the wait mode controller controls a first random access mode and a second random access mode using an internal parameter and a preset waiting time, and

the internal parameter and the preset waiting time are changed using a reserved reader command.

8. The HF tag of claim 7, wherein the wait mode controller generates a random sequence based on the internal parameter in the first random access mode, selects any one random value from the generated random sequence, and controls the tag to transition to a ready mode after discounting the random value to 0.

9. The HF tag of claim 7, wherein the wait mode controller randomly selects one of 0 and 1 with the internal parameter fixed to 1, controls the tag to transition to a ready mode when 0 is selected, and reselects one of 0 and 1 after a wait for the preset waiting time when 1 is selected in the second random access mode.

10. The HF tag of claim 7, wherein the tag in a ready mode increases an error count by one when the reader command is not received for the preset waiting time or when a valid reader command is not received even after a plurality of rounds, and controls a tag state so as to transition to the wait mode when the error count is a preset value or higher.

11. A high-frequency (HF) reader comprising:

an analog circuit unit to receive a tag signal and to transmit a reader command in an analog form via amplitude-shift keying (ASK) modulation;

an analog-to-digital converter (ADC) to receive the modulated tag signal and to convert the tag signal into a digital signal; and

a digital circuit unit to receive the digital tag signal and to generate the reader command,

wherein the digital circuit unit adjusts a plurality of transmission output levels to conduct simultaneous identification of massive RFID tags.

12. The HF reader of claim 11, wherein the digital circuit unit comprises:

an encoder to encode and transmit the reader command to the analog circuit unit;

a subcarrier digital demodulator to receive an input of the tag signal received from the ADC to remove a subcarrier;

a decoder to receive an input of a basis signal with the subcarrier removed to extract tag information;

a protocol processing unit to process inventory and access protocols;

a transmission output level controller to control a transmission output level of a power amplifier of the analog circuit unit to switch between at least two transmission output levels; and

a carrier transmission controller to control an operation of a carrier output from a transmission unit of the analog circuit unit.

13. The HF reader of claim 12, wherein the subcarrier digital demodulator comprises:

a decimation filter to receive an input of the received tag signal and filter the tag signal;

a Miller subcarrier digital demodulator and a Manchester subcarrier digital demodulator to remove a subcarrier from the filtered tag signal; and

a multiplexer (Mux) to select one of the Miller subcarrier digital demodulator and the Manchester subcarrier digital demodulator.

14. The HF reader of claim 13, wherein the Miller subcarrier digital demodulator comprises:

a peak signal generator to generate a peak signal from the tag signal;

a peak extractor to extract a peak from the peak signal; and

a basis signal generator to generate the basis signal with the subcarrier removed from the extracted peak signal.

15. The HF reader of claim 12, wherein the transmission output level controller outputs a control signal of the power amplifier of the analog circuit unit to adjust the transmission output level and sets at least two transmission output levels to iteratively alternately switch between the levels in each round of a phase.

16. An operation method of a tag in a system for simultaneously identifying massive radio-frequency identification (RFID) tags using a high-frequency (HF) band, the operation method comprising:

receiving a carrier wave from a reader and waiting in a ready mode;

transitioning to an arbitrate mode and selecting one of a plurality of slots set by the reader when a BeginRound command is received in the ready mode; and

transitioning to a reply mode simultaneously with transmitting a stored Cyclic Redundancy Checking (CRC) packet using the selected slot.

17. The operation method of claim 16, wherein an internal parameter and a preset waiting time of the ready mode are determined on a reader command received from the reader.

18. An operation method of a reader in a system for simultaneously identifying massive radio-frequency identification (RFID) tags using a high-frequency (HF) band, the operation method comprising:

amplitude-shift keying (ASK) demodulating a received tag signal;

converting an analog signal into a digital signal for digital demodulation of the tag signal;

demodulating a subcarrier of the tag signal converted into the digital signal; and

decoding the demodulated tag signal to extract information,

wherein massive tag identification performance is improved by the ASK demodulating into the analog signal and the demodulating of the subcarrier into the digital signal.

19. The operation method of claim 18, wherein the demodulating of the subcarrier of the converted tag signal comprises Miller subcarrier digital demodulation, and the miller subcarrier digital demodulation comprises generating a peak signal from the tag signal;

extracting position information on the peak signal; and

generating a basis signal using the position information on the peak signal.

20. The operation method of claim 18, further comprising transmitting a reader command to a tag,

wherein the reader command comprises an R setting field to set an internal parameter for controlling a random access mode of the tag and a Twait setting field to set a preset waiting time for transition to a ready mode based on the internal parameter.