RFID tag device, tag identification device and radio communication system

• US 7,365,636 B2
• Filed: 08/24/2005
• Issued: 04/29/2008
• Est. Priority Date: 08/25/2004
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ozaki, Satoshi, Wakayama, Shirou, Ishiyama, Masahiro, Doi, Yusuke
• Primary Examiner(s): Hofsass; Jeffery
• Assistant Examiner(s): SYED, NABIL H
• Application Number:
  US11/209,754
• Publication Number:
  US 20060044115A1
• Time in Patent Office: 979 Days
• Field of Search: 340/10.4, 340/5.26, 340/5.61, 340/572.1, 340/825.69, 380/270, 380/268
• US Class Current: 340/10.4
• 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 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Abstract

An RFID tag device has a random number generator which generates a random number or a pseudo-random number, an identification information holding unit which holds identification information having a plurality of bits, a noise addition processing unit which generates noise-added identification information by conducting either of reversal from “0” of a bit decided based on the random number generated by the random number generator to “1” or reversal from “1” of the bit to “0”, among a plurality of bits included in the identification information, and a radio communication unit which transmits the noise-added identification information by radio.

Claims

1. An RFID tag device, comprising:

a random number generator which generates a random number or a pseudo-random number;

an identification information holding unit which holds identification information having a plurality of bits;

a noise addition processing unit which generates noise-added identification information by conducting either of reversal from “

0”

of a bit decided based on the random number generated by the random number generator to “

1”

or reversal from “

1”

of the bit to “

0”

, among a plurality of bits included in the identification information; and

a radio communication unit which transmits the noise-added identification information by radio.

2. An RFID tag device according to claim 1, further comprising a temporary storage unit which stores the random number generated by the random number generator,

wherein the radio communication unit transmits the random number stored in the temporary storage unit with the noise-added identification information by radio.

3. An RFID tag device according to claim 1, further comprising a time measuring unit which measures a time after transmitting the noise-added identification information from the radio communication unit,

wherein the radio communication unit transmits a subsequent noise-added identification information when the time measured by the time measuring unit is a predetermined time or more.

4. An RFID tag device according to claim 1, further comprising a noise generator which generates a noise relating to a noise included in the noise-added identification information,

wherein the radio communication unit transmits the noise generated by the noise generator with the noise-added identification information by radio.

5. An RFID tag device, comprising:

a filter holding unit which holds a filter having a plurality of bits capable of probabilistically detecting whether or not a certain bit string is included in a group of bit strings;

a random number generator which generates a random number or a pseudo-random number;

a noise addition processing unit which generates a noise-added filter obtained by either of reversal from “

0”

of a bit decided based on the random number generated by the random number generator or reversal from “

1”

of a bit decided based on the random number generated by the random number generator among a plurality of bits included in the filter; and

a radio communication unit which transmits the noise-added filter by radio.

6. An RFID tag device according to claim 5, wherein the filter held by the filter holding unit is generated by using the identification information having a plurality of bits and a Hash function.

7. An RFID tag device according to claim 5, wherein the filter held by the filter holding unit is a fixed bloom filter.

8. An RFID tag device according to claim 5, wherein the noise addition processing unit generates the noise-added filter obtained by reversing “

0”

of a bit decided based on the random number generated by the random number generator to “

1”

, among the plurality of bits included in the filter held by the filter holding unit.

9. An RFID tag device according to claim 5, further comprising a filter selector which selects any of a plurality of filters held by the filter holding part,

wherein the noise-added processing unit generates the noise-added filter corresponding to the filter selected by the filter selector.

10. An RFID tag device according to claim 5, further comprising a temporary storage unit which stores the random number generated by the random number generator,

wherein the radio communication unit transmits the random number stored in the temporary storage unit with the noise-added filter by radio.

11. An RFID tag device according to claim 5, further comprising a time measuring unit which measures a time after transmitting the noise-added filter from the radio communication unit,

wherein the radio communication unit transmits a subsequent noise-added filter when the time measured by the time measuring unit is a predetermined time or more.

12. An RFID tag device according to claim 5, further comprising a noise generator which generates a noise relating to a noise added to the noise-added filter,

wherein the radio communication unit transmits the noise generated by the noise generated by the noise generator with the noise-added filter by radio.

13. A tag identification device, comprising:

a tag information storage unit which stores identification information of a known radio tag device;

a radio communication unit which receives noise-added identification information or a noise-added filter having a plurality of bits with a noise bit, transmitted from a certain RFID tag device;

a bit comparison unit which compares a bit having a certain bit value among a plurality of bits included in the received noise-added identification information or the received noise-added filter with corresponding bit of the identification information stored in the tag information storage unit, based on a ratio of bit “

0”

to bit “

1”

included in the plurality of bits; and

a determination unit which determines whether or not the identification information corresponding to the noise-added identification or the noise-added filter received by the radio communication unit is stored in the tag information storage unit based on a result compared by the bit comparison unit.

14. A tag identification device according to claim 13, wherein the filter is generated by using the identification information having a plurality of bits and a Hash function.

15. A tag identification device according to claim 14, wherein the filter is a fixed bloom filter.

16. A tag identification device according to claim 13, wherein the noise-added filter is generated by reversing a bit having “

0”

to “

1”

decided by a random number, among the plurality of bits including in the filter before adding the noise.

17. A tag identification device according to claim 13, wherein the radio communication unit receives a random number used for generating the noise which is added to the noise-added identification information or the noise-added filter, and is included in the noise-added identification information or the noise-added filter.

18. A tag identification device according to claim 13, wherein the radio communication unit receives a noise relating to a noise which is added to the noise-added identification information or the noise-added filter, and is included in the noise-added identification information or the noise-added filter.