Reader, tags, radio frequency identification (RFID) system, and method thereof

• US 20060290508A1
• Filed: 06/23/2006
• Published: 12/28/2006
• Est. Priority Date: 06/23/2005
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Kyung-ho, Moutchkaev, Artem, Kang, Woo-shik
• Application Number:
  US11/473,031
• Publication Number:
  US 20060290508A1
• Time in Patent Office: Days
• US Class Current: 340/572.1
• 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
• CPC Class Codes: G06K 7/10019 resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. collision between the communication channels used by wireless communication devices, where the solution is not particularly adapted for RFIDs or the like, H04W74/08
• CPC Class Codes: H04B 2201/70715 with application-specific features
• CPC Class Codes: H04J 13/004 Orthogonal

Abstract

A reader, tags, an RFID system, and a method of simultaneously identifying a plurality of tags having colliding reply signals and reducing the reading time. In the RFID system including a reader and plural tags assigned unique IDs, the reader stores a comparison code which identifies ID codes generated based on the unique IDs of the tags, and issues a query signal to the tags to inquire into the presence of the tags. In response to the received query signal, the tags generate the ID) codes based on their unique IDs and sends the ID codes to the reader. The reader stores the received ID codes and identifies the responding tags by comparing the stored comparison code with the ID codes. When the ID codes are orthogonal, colliding reply signals can be resolved through a correlation technique.

Claims

1. A reader in a radio frequency identification (RFID) system which includes the reader and more than two tags assigned unique IDs, the reader comprising:

a storage which stores a comparison code for identifying each ID code generated based on each unique ID;

a transmitter which generates and transmits a query signal to the tags to inquire into the presence of the tags; and

a comparator which receives the ID codes from the tags, compares the ID codes with the comparison code stored in the storage, and identifies replying tags.

2. The reader of claim 1, wherein the ID codes are mutually orthogonal, the comparison code is a set of orthogonal codes including the ID codes, and the comparator identifies the replying tags by correlating the ID codes with the comparison code.

3. A tag in a radio frequency identification (RFID) system which includes a reader and more than one tag assigned a unique ID, the tag comprising:

a receiver which receives from the reader a query signal which is transmitted to inquire into the presence of the tag;

a ID code generator which generates an ID code for identifying the tag, based on the unique ID; and

a transmitter which sends the ID code to the reader in response to the query signal.

4. The tag of claim 3, wherein the ID code generator comprises:

a random number generator which generates random numbers based on the unique ID; and

a linear feedback shift register (LFSR) which receives the generated random numbers as an initial state value and generates the ID code.

5. The tag of claim 3, wherein the transmitter modulates the ID code according to a binary phase shift keying (BPSK) scheme and sends the modulated ID code.

6. A radio frequency identification (RFID) system comprising:

a reader; and

more than two tags which are assigned unique IDs, respectively,

wherein each of the tags comprises;

a receiver which receives from the reader a query signal which is transmitted to inquire into the presence of the tag;

a ID code generator which generates an ID code for identifying the tags based on their unique IDs; and

a transmitter which sends the ID code to the reader in response to the query signal, and

the reader comprises;

a storage which stores a comparison code for identifying the ID codes;

a transmitter which generates and transmits a query signal to the tags; and

a comparator which receives the ID codes from the tags, compares the ID codes with the comparison code stored in the storage, and identifies replying tags.

7. The RFID system of claim 6, wherein the ID codes are mutually orthogonal, the comparison code is a set of orthogonal codes including the ID codes, the ID code generator comprises:

a random number generator which generates random numbers based on the unique IDs; and

a linear feedback shift register (LFSR) which receives the generated random numbers as an initial state value and generates the ID code, and

the comparator identifies the replying tags by correlating the ID codes with the comparison code and obtains the random numbers.

8. A method of identifying tags in a radio frequency identification (RFID) system which includes a reader and more than two tags assigned unique IDs, the method comprising:

storing, by the reader, a comparison code for identifying ID codes, which is generated based on the unique IDs of the tags;

generating, by the reader, a query signal to inquire into the presence of the tags and transmitting the query signal to the tags;

receiving, by the tags, the query signal from the reader, generating ID codes based on the IDs in response to the query signal, and transmitting the ID codes to the reader; and

receiving, by the reader, the ID codes and identifying replying tags by comparing the stored comparison code with the ID codes.

9. The method of claim 8, wherein the ID codes are mutually orthogonal, the comparison code is a set of orthogonal codes including the ID codes, and the comparison identifies the replying tags by correlating the ID codes with the comparison code.

10. The method of claim 8, wherein the ID codes are generated by generating random numbers based on the unique IDs and receiving the generated random numbers as an initial state value.