Reader/writer and data communication method

• US 20080001721A1
• Filed: 10/31/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tanaka, Yoshinori
• Granted Patent: US 7,940,161 B2
• Time in Patent Office: Days
• US Class Current: 340/10.31
• 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 7/10039 interrogator driven, i.e. synchronous

Abstract

A reader/writer transmitting and receiving data, through wireless communications, to and from a passive type wireless tag having a nonvolatile storage unit, includes a tag selection unit selecting a target wireless tag performing the wireless communications with the reader/writer, a data transmitting/receiving unit executing data transmission/reception between the selected target wireless tag and the reader/writer, and a time information writing unit writing, when completing the data transmission/reception by the data transmitting/receiving unit, the time information on completion time of the data transmission/reception to the nonvolatile storage unit, wherein the tag selection unit selects the target wireless tag from within one or the plurality of wireless tags on the basis of the time information already written by the time information writing unit through the previous data communications with the reader/writer.

Claims

1. A reader/writer transmitting and receiving data, through wireless communications, to and from a wireless tag having a storage unit, comprising:

a tag selection unit selecting a target wireless tag performing the wireless communications with the reader/writer from within one or a plurality of wireless tags;

a data transmitting/receiving unit executing data transmission/reception between the target wireless tag selected by the tag selection unit and the reader/writer; and

a time information writing unit writing, when completing the data transmission/reception by the data transmitting/receiving unit, the time information on completion time of the data transmission/reception to the storage unit provided in the target wireless tag,

wherein the tag selection unit selects the target wireless tag from within one or the plurality of wireless tags on the basis of the time information written through the previous data communications with the reader/writer.

2. A reader/writer according to claim 1, wherein the wireless tag further includes a temporary storage unit enabled to temporarily store the data by its being supplied with electric power from the reader/writer,

the reader/writer further includes a completion flag writing unit writing, when completing the data transmission/reception by the data transmitting/receiving unit, a completion flag representing completion of the data transmission/reception to the temporary storage unit provided in the target wireless tag, and

the tag selection unit selects the target wireless tag on the basis of any one of the time information written and the completion flag written in accordance with a content of the data transmission/reception.

3. A reader/writer according to claim 2, wherein the tag selection unit estimates time required for the data transmission/reception in accordance with the content of the data transmission/reception executed by the data transmitting/receiving unit, selects the target wireless tag on the basis of the time information written when the estimated time is equal to or longer than a predetermined period of time, and selects the target wireless tag on the basis of the completion flag written when the estimated time is less than the predetermined period of time.

4. A reader/writer according to claim 1, wherein the tag selection unit selects, as the target wireless tag, the wireless tag about which the time information already written is information registered earlier by the predetermined period of time than when being selected by the tag selection unit.

5. A reader/writer according to claim 1, wherein the selection of the target wireless tag, the data transmission/reception and the writing of the time information are sequentially conducted for every single wireless tag.

6. A reader/writer according to claim 1, wherein the time information writing unit writes, to the storage unit, the time information on the data transmission/reception in the data communications performed before a plurality of times with the reader/writer, and

the tag selection unit selects the target wireless tag from within one or the plurality of wireless tags on the basis of a history of plural pieces of time information written by the time information writing unit.

7. A data communication method based on wireless communications performed between a wireless tag having a storage unit and a reader/writer, comprising:

a tag selection step of selecting a target wireless tag performing the wireless communications with the reader/writer from within one or a plurality of wireless tags;

a data transmitting/receiving step of executing data transmission/reception between the target wireless tag selected in the tag selection step and the reader/writer; and

a time information writing step of writing, when completing the data transmission/reception in the data transmitting/receiving step, the time information on completion time of the data transmission/reception to the storage unit provided in the target wireless tag,

wherein the tag selection step includes selecting the target wireless tag from within one or the plurality of wireless tags on the basis of the time information written through the previous data communications with the reader/writer.

8. A data communication method according to claim 7, wherein the wireless tag further includes a temporary storage unit enabled to temporarily store the data by its being supplied with electric power from the reader/writer,

the data communication method further comprises a completion flag writing step of writing, when completing the data transmission/reception in the data transmitting/receiving step, a completion flag representing completion of the data transmission/reception to the temporary storage unit provided in the target wireless tag, and

the tag selection step includes selecting the target wireless tag on the basis of any one of the time information written and the completion flag written in accordance with a content of the data transmission/reception.

9. A data communication method according to claim 8, wherein the tag selection step includes estimating time required for the data transmission/reception in accordance with the content of the data transmission/reception executed in the data transmitting/receiving step, selects the target wireless tag on the basis of the time information written when the estimated time is equal to or longer than a predetermined period of time, and selects the target wireless tag on the basis of the completion flag written when the estimated time is less than the predetermined period of time.

10. A data communication method according to claim 7, wherein the tag selection step includes selecting, as the target wireless tag, the wireless tag about which the time information already written is information registered earlier by the predetermined period of time than when being selected in the tag selection step.

11. A data communication method according to claim 7, wherein the selection of the target wireless tag, the data transmission/reception and the writing of the time information are sequentially conducted for every single wireless tag.

12. A data communication method according to claim 7, wherein the time information writing step includes writing, to the storage unit, the time information on the data transmission/reception in the data communications performed before a plurality of times with the reader/writer, and

the tag selection step includes selecting the target wireless tag from within one or the plurality of wireless tags on the basis of a history of plural pieces of time information written in the time information writing step.