Information access system, reader/writer device, and active-type contactless information storage device

• US 20080122584A1
• Filed: 11/09/2007
• Published: 05/29/2008
• Est. Priority Date: 11/24/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yamada, Isamu, Shiotsu, Shinichi, Itasaki, Akira, Inano, Satoshi
• Granted Patent: US 7,821,397 B2
• Time in Patent Office: Days
• US Class Current: 340/10.51
• 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: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/083 using passwords cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226

Abstract

In an information access system, an active-type contactless information storage device senses a carrier of an RF signal at a first frequency in time periods for carrier sensing occurring in a predetermined carrier sensing cycle period, and then in response to detection of a carrier of an RF signal at the first frequency, further receives the information request signal, while it also transmits the tag information signal at a second frequency carrying information in time periods for tag information transmission occurring in a predetermined tag information transmitting cycle period. A reader/writer device cyclically transmits an information request signal carrying values of the predetermined carrier sensing cycle period and the predetermined tag information transmitting cycle period, at a first frequency during a predetermined period of time for information request transmission, and in response to reception of a tag information signal at the second frequency, reproduces and compares received tag information with a list of tag information. In response to reception of the information request signal, the active-type contactless information storage device reproduces and sets the values of the two predetermined cycle periods into its respective timers. Thus the active-type contactless information storage device reduces its power consumption.

Claims

1. An information access system for accessing information stored in a contactless information storage device, said information access system comprising:

a reader/writer device connected to an information processing apparatus, said reader/writer device including;

a first timer,

a first memory,

a first transmitter unit which is capable of cyclically transmitting an information request signal at a first frequency during a predetermined time period for information request transmission,

a first receiver unit which is continuously ready to receive an RF signal at a second frequency different from the first frequency, and

a first controller which, in response to reception of a tag information signal at the second frequency, reproduces and compares received tag information carried by the tag information signal with a list of tag information in said first memory; and

an active-type contactless information storage device including;

a second memory,

a battery,

a second timer which measures a first predetermined cycle period for transmitting tag information,

a third timer which measures a second predetermined cycle period for sensing a carrier,

a second receiver unit which is capable of sensing a carrier of an RF signal at the first frequency for detection,

a second transmitter unit which is capable of transmitting a tag information signal at the second frequency, and

a second controller which controls said second receiver unit to sense a carrier of an RF signal at the first frequency in time periods for carrier sensing occurring in the second predetermined cycle period, then in response to detection of a carrier of an RF signal at the first frequency in said receiver unit, causes said receiver unit to further receive the information request signal, and also causes said second transmitter unit to transmit the tag information signal at the second frequency carrying information stored in the second memory in time periods for tag information transmission occurring in the first predetermined cycle period, and which, in response to reception of the information request signal in said second receiver unit, reproduces and processes received information carried by the information request signal, and which controls, in response to non-detection of an RF signal at the first frequency in a particular time period for carrier sensing in said second receiver unit, said second receiver unit to maintain an inactive state during a non-carrier sensing period before a subsequent time period for carrier sensing, and controls said second transmitter unit to maintain an inactive state during a non-transmission period between a particular time period for tag information transmission and a subsequent time period for tag information transmission.

2. An information access system according to claim 1, wherein, during the predetermined period of time for information request transmission which occurs temporarily, said first controller causes said first transmitter unit to cyclically transmit the information request signal at the first frequency carrying values of the first predetermined cycle period and the second predetermined cycle period, and wherein

when information carried by the information request signal received by said second receiver unit contains the values of the first and second predetermined cycle periods, said second controller sets the values of the first and second predetermined cycle periods into said second and third timers, respectively.

3. An information access system according to claim 1, wherein when said second receiver unit receives the information request signal at the first frequency, said second controller, in the subsequent tag information transmission period for transmitting the tag information, further causes the second transmitter unit to transmit the tag information signal at the second frequency carrying a response and information stored in said second memory.

4. An information access system according to claim 1, wherein, when the received tag information does not correspond to any tag information recorded in the list of tag information, said first controller causes said first transmitter unit to be in an active state and cyclically transmit the information request signal during the predetermined period of time for information request transmission which period occurs temporarily.

5. An information access system according to claim 1, wherein, when the received tag information carried by the tag information signal contains a response to the tag information request signal, said first controller records, into the list of tag information, the received tag information and time of day in association with the received tag information, without further causing said first transmitter unit to transmit the information request signal.

6. An information access system according to claim 1, wherein, when the received tag information corresponds to tag information recorded in the list of tag information, said first controller records, into the list of tag information, time of day in association with the tag information in the list of tag information, without causing said first transmitter unit to transmit the information request signal.

7. An information access system according to claim 5, wherein said first controller deletes tag information in the list of tag information, when tag information corresponding to the tag information in the list of tag information has not been received for an elapse of a predetermined time since previous reception of the tag information in the list of tag information.

8. The information access system according to claim 1, wherein said first controller causes said first transmitter unit to continue to cyclically transmit the information request signal.

9. A contactless reader/writer device connected to an information processing apparatus and capable of accessing information stored in a contactless information storage device, said contactless reader/writer device comprising:

a memory;

a transmitter unit which is capable of transmitting cyclically an information request signal at a first frequency during a predetermined period of time for information request transmission;

a receiver unit which is continuously ready to receive an RF signal at a second frequency different from the first frequency; and

a controller which, in response to reception of a tag information signal at the second frequency in said receiver unit, reproduces and compares received tag information carried by the tag information signal with a list of tag information in said memory, and then causes said transmitter unit to cyclically transmit the information request signal at the first frequency during the predetermined period of time for information request transmission which period occurs temporarily when the received tag information does not correspond to any tag information recorded in the list of tag information.

10. A contactless reader/writer device according to claim 9, wherein, during the predetermined period of time for information request transmission which occurs temporarily, said controller causes said transmitter unit to cyclically transmit the information request signal at the first frequency carrying values of the first predetermined cycle period and the second predetermined cycle period.

11. A contactless reader/writer device according to claim 9, wherein, when the received tag information carried by the tag information signal contains a response to the tag information request signal, said controller records, into the list of tag information, the received tag information and time of day in association with the received tag information, without further causing said first transmitter unit to transmit the information request signal.

12. A contactless reader/writer device according to claim 9, wherein, when the received tag information corresponds to tag information recorded in the list of tag information, said controller records, into the list of tag information, time of day in association with the tag information in the list of tag information, without further causing said transmitter unit to transmit the information request signal.

13. A contactless reader/writer device according to claim 11, wherein said controller deletes tag information in the list of tag information, when tag information corresponding to the tag information in the list of tag information has not been received for an elapse of a predetermined time since previous reception of the tag information in the list of tag information.

14. An active-type contactless information storage device which is accessible by a reader/writer device, said active-type contactless information storage device comprising:

a memory;

a battery;

a first timer which measures a first predetermined cycle period for transmitting tag information;

a second timer which measures a second predetermined cycle period for sensing a carrier;

a receiver unit which is capable of sensing a carrier of an RF signal at a first frequency for detection;

a transmitter unit which is capable of transmitting a tag information signal at a second frequency different from the first frequency; and

a controller which controls said receiver unit to sense a carrier of an RF signal at the first frequency in time periods for carrier sensing occurring in the second predetermined cycle period, then in response to detection of a carrier of an RF signal at the first frequency in said receiver unit, causes said receiver unit to further receive the information request signal, and also causes said second transmitter unit to transmit the tag information signal at the second frequency carrying information stored in said memory in time periods for tag information transmission occurring in the first predetermined cycle period, and which, in response to reception of the information request signal in said receiver unit, reproduces and processes received information carried by the information request signal and further causes said transmitter unit to transmit the tag information signal at the second frequency carrying a response and information stored in said memory in a subsequent time period for tag information transmission, and which controls, in response to non-detection of an RF signal at the first frequency in a particular time period for carrier sensing in said receiver unit, said receiver unit to maintain an inactive state during a non-carrier sensing period before a subsequent time period for carrier sensing, and controls said transmitter unit to maintain an inactive state during a non-transmission period between a particular time period for tag information transmission and a subsequent time period for tag information transmission.

15. A program stored on a computer-readable recording medium for use in a contactless reader/writer device, said contactless reader/writer device being connected to an information processing apparatus and capable of accessing information stored in a contactless information storage device, said contactless reader/writer device comprising:

a memory, a controller, a transmitter unit which is capable of transmitting cyclically an information request signal at a first frequency during a predetermined period of time for information request transmission under the control of the controller, a receiver unit which is continuously ready to receive an RF signal at a second frequency different from the first frequency, said program causing the controller to execute the steps of;

in response to reception of a tag information signal at the second frequency in the receiver unit, reproducing and comparing received tag information carried by the tag information signal with a list of tag information in the memory, and

causing the transmitter unit to cyclically transmit the information request signal at the first frequency during the predetermined period of time for information request transmission which period occurs temporarily, when the received tag information does not correspond to any tag information recorded in the list of tag information.

16. A program according to claim 15, causing the controller to further execute the step of:

recording, into the list of tag information, the received tag information and time of day in association with the received tag information, without further causing the first transmitter unit to transmit the information request signal, when the received tag information carried by the tag information signal contains a response to the tag information request signal.

17. A program according to claim 15, causing the controller to further execute the step of:

recording, into the list of tag information, time of day in association with the tag information in the list of tag information, without further causing the transmitter unit to transmit the information request signal, when the received tag information corresponds to the tag information recorded in the list of tag information.

18. A program according to claim 16, causing the controller to further execute the step of:

deleting tag information in the list of tag information, when tag information corresponding to the tag information in the list of tag information has not been received for an elapse of a predetermined time since previous reception of the tag information in the list of tag information.

19. A program stored on a computer-readable recording medium for use in an active-type contactless information storage device which is accessible by a reader/writer device, said active-type contactless information storage device comprising:

a memory, a controller, a battery, a receiver unit which is capable of sensing a carrier of an RF signal at a first frequency for detection, and a transmitter unit which is capable of transmitting a tag information signal at a second frequency different from the first frequency, said program causing the controller to execute the steps of;

controlling the receiver unit to sense a carrier of an RF signal at the first frequency in time periods for carrier sensing occurring in a first predetermined cycle period for sensing a carrier,

in response to detection of an RF signal at the first frequency in the receiver unit, causing the receiver unit to further receive the information request signal,

causing the transmitter unit to transmit the tag information signal at the second frequency carrying information stored in the memory in time periods for tag information transmission occurring in a second predetermined cycle period for transmitting a tag information,

in response to reception of the information request signal in the receiver unit, reproducing and processing received information carried by the information request signal and further causing the transmitter unit to transmit the tag information signal at the second frequency carrying a response and information stored in the memory in a subsequent time period for tag information transmission,

controlling, in response to non-detection of an RF signal at the first frequency in a particular time period for carrier sensing in the receiver unit, the receiver unit to maintain an inactive state during a non-carrier sensing period before a subsequent time period for carrier sensing, and

controlling the transmitter unit to maintain an inactive state during a non-transmission period between a particular time period for tag information transmission and a subsequent time period for tag information transmission.

20. In a reader/writer device connected to an information processing apparatus and capable of accessing information stored in a contactless information storage device, a method of accessing information stored in a contactless information storage device, said reader/writer device comprising:

a memory, a controller, a transmitter unit which is capable of transmitting cyclically an information request signal at a first frequency during a predetermined period of time for information request transmission under the control of the controller, a receiver unit which is continuously ready to receive an RF signal at a second frequency different from the first frequency, said method comprising;

in response to reception of a tag information signal at the second frequency in the receiver unit, comparing received tag information carried by the tag information signal with a list of tag information in the memory, and

causing the transmitter unit to cyclically transmit the information request signal at the first frequency during the predetermined period of time for information request transmission which period occurs temporarily, when the received tag information does not correspond to any tag information recorded in the list of tag information.