RFID system

• US 20070279191A1
• Filed: 05/18/2007
• Published: 12/06/2007
• Est. Priority Date: 05/19/2006
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Masaaki, Yamazoe, Takanori, Kuwana, Toshiyuki
• Application Number:
  US11/802,018
• Publication Number:
  US 20070279191A1
• Time in Patent Office: Days
• US Class Current: 340/10.100
• 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 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06K 7/10435 the interrogation device being positioned close to a conveyor belt or the like on which moving record carriers are passing conveying in accordance with bodily destination marks, see B65G47/46, sorting of objects carrying identity markings, see B07C5/34
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A technique of reducing the interference wave occurred between a plurality of reader/writers in an environment in which a plurality of RFID systems are operating. An RFID system includes a plurality of reader/writers and a controller for controlling the plurality of reader/writers. Each reader/writer includes a body, antennas, and a distributor for selecting one antenna from the antennas. The controller selects an antenna having a positional relationship in which the interference wave is small from the antennas of each reader/writer, and giving a command for the antenna to the body of each reader/writer. Each reader/writer selects one antenna from the antennas based on the command from the controller and transmits a command to the RFID.

Claims

1. An RFID system comprising a plurality of reader/writers for transmitting an interrogation signal to an RFID and receiving a response signal, and a controller for controlling the plurality of reader/writers;

wherein the plurality of reader/writers each includes;

a body;

a plurality of antennas; and

a distributor for selecting one antenna from the plurality of antennas;

the controller has a function of giving a command to each body of the plurality of reader/writers which antenna to select from the plurality of antennas of the plurality of reader/writers;

the controller selects an antenna having a positional relationship in which an interference wave is small, and giving a command for the antenna to each body of the plurality of reader/writers; and

the plurality of reader/writers each selects one antenna from the plurality of antennas based on the command from the controller and transmits the interrogation signal via the distributor.

2. The RFID system according to claim 1,

wherein the respective antennas have a directivity property in which its gain become strong in one direction and weak in another direction.

3. The RFID system according to claim 2,

wherein the controller selects antennas of respective reader/writers according to an antenna arrangement of each arranged reader/writer and the directivity property.

4. The RFID system according to claim 2,

wherein the controller selects antennas having the same orientation from the plurality of antennas of the plurality of reader/writers as the antenna having a positional relationship in which the interference wave is small.

5. The RFID system according to claim 3,

wherein the controller further has a function of:

selecting a carrier wave frequency to be used for transmitting and receiving the interrogation signal and a response signal; and

giving a command for the carrier wave frequency to each body of the plurality of reader/writers.

6. The RFID system according to claim 5,

wherein the controller selects a carrier wave frequency to be used by each reader/writer in transmission and reception with a frequency interval set apart, and giving a command for the carrier wave frequency to the body of each reader/writer.

7. The RFID system according to claim 3,

wherein the controller further has a function of:

monitoring transmission and reception states of the interrogation signal and the response signal in the respective plurality of reader/writers; and

giving a command for the transmission and reception timings of each reader/writer to the body of each reader/writer.

8. The RFID system according to claim 7,

wherein the controller monitors the transmission and reception state of the each reader/writer to match the transmission and reception timings of each reader/writer;

stops and stands by the radio communication other than that of a specific reader/writer if a time width of the transmission signal of each reader/writer differs;

selects the carrier wave frequency to be used in transmission and reception; and

gives a command for a carrier wave frequency to the body of each reader/writer.