Information access system and active-type contactless information storage device

• US 20070167139A1
• Filed: 01/12/2006
• Published: 07/19/2007
• Est. Priority Date: 09/07/2005
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yamada, Isamu, Shiotsu, Shinichi, Itasaki, Akira, Inano, Satoshi
• Granted Patent: US 7,536,152 B2
• Time in Patent Office: Days
• US Class Current: 455/88
• 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 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• CPC Class Codes: G06K 7/10128 the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

In an information access system, an active contactless information storage device senses a carrier of an RF signal at a first frequency in first predetermined periods occurring in a predetermined cycle and senses a carrier of an RF signal at a second frequency in second predetermined periods occurring in the predetermined cycle. When the storage device senses and detects a carrier of an RF signal at one of the first and second frequencies in a particular predetermined period, it receives further an ID request signal, and, in response to the ID request signal, transmits a response signal at a corresponding one of the third and fourth frequencies that carries an ID of the active contactless information storage device. This reduces possible interference between reader/writer devices for communicating with the information storage device.

Claims

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

an active contactless information storage device having a memory, a first control unit, a battery, a timer for measuring time, a receiver unit for sensing carriers of RF signals at first and second different frequencies for detection, and a transmitter unit for transmitting a response signal at a third or fourth frequency different from said first and second frequencies in response to reception of an ID request signal,

a first reader/writer device connected to an information processing apparatus, and having a second control unit, a second transmitter unit for cyclically transmitting an ID request signal at said first frequency under the control of said second control unit, and a second receiver unit adapted to be continuously ready to receive an RF signal at said third frequency, and

a second reader/writer device connected to an information processing apparatus, and having a third control unit, a third transmitter unit for cyclically transmitting an ID request signal at said second frequency under the control of said third control unit, and a third receiver unit adapted to be continuously ready to receive an RF signal at said fourth frequency, wherein

said first control unit controls said first receiver unit to sense a carrier of an RF signal at said first frequency in first predetermined periods occurring in a predetermined cycle and sense a carrier of an RF signal at said second frequency in second predetermined periods occurring in said predetermined cycle,

when said first receiver unit senses and detects a carrier of an RF signal at one of said first and second frequencies in a particular predetermined period, said first control unit causes said first receiver unit to receive further the ID request signal, and, in response to the ID request signal, causes said first transmitter unit to transmit a response signal at a corresponding one of said third and fourth frequencies that carries an ID of said active contactless information storage device stored in said memory;

in the carrier sensing, said first control unit causes said first receiver unit to be in an active state and said transmitter unit to be in an inactive state in the first and second predetermined periods; and

when said first receiver unit attempts to sense a carrier of an RF signal at said first frequency in the first predetermined period but detects no carrier, said first control unit controls said first receiver unit and said first transmitter unit to maintain the inactive state during a non-carrier sensing period between the first predetermined period for carrier sensing and the second predetermined period for subsequent carrier sensing.

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

an active contactless information storage device having a memory, a first control unit, a battery, a timer for measuring time, first and second receiver units for sensing carriers of RF signals at first and second different frequencies for detection, and first and second transmitter units for transmitting respective response signals at third and fourth frequencies different from said first and second frequencies in response to reception of ID request signals,

a first reader/writer device connected to an information processing apparatus, and having a second control unit, a third transmitter unit for cyclically transmitting an ID request signal at said first frequency under the control of said second control unit, and a third receiver unit adapted to be continuously ready to receive an RF signal at said third frequency, and

a second reader/writer device connected to an information processing apparatus, and having a third control unit, a fourth transmitter unit for cyclically transmitting an ID request signal at said second frequency under the control of said third control unit, and a fourth receiver unit adapted to be continuously ready to receive an RF signal at said fourth frequency, wherein

said first control unit controls said first and second receiver units to simultaneously sense carriers of RF signals at said first and second frequencies in predetermined periods occurring in a predetermined cycle,

when said first receiver unit senses and detects a carrier of an RF signal at said first frequency in a particular predetermined period, said first control unit causes said first receiver unit to receive further the ID request signal, and, in response to the ID request signal, causes said first transmitter unit to transmit a response signal at said third frequency corresponding to said first frequency that carries an ID of said active contactless information storage device stored in said memory;

when said second receiver unit senses and detects a carrier of an RF signal at said second frequency in the particular predetermined period, said first control unit causes said second receiver unit to receive further the ID request signal, and, in response to the ID request signal, causes said second transmitter unit to transmit a response signal at said fourth frequency corresponding to said second frequency that carries an ID of said active contactless information storage device stored in said memory;

in the carrier sensing, said first control unit causes said first and second receiver units to be in an active state and said first and second transmitter units to be in an inactive state in the particular predetermined period and a subsequent predetermined period;

when said first receiver unit attempts to sense a carrier of an RF signal at said first frequency in the particular predetermined period but detects no carrier, said first control unit controls said first receiver unit and said first transmitter unit to maintain the inactive state during a non-carrier sensing period between the particular predetermined period for carrier sensing and the subsequent predetermined period for subsequent carrier sensing; and

when said second receiver unit attempts to sense a carrier of an RF signal at said second frequency in the particular predetermined period but detects no carrier, said first control unit controls said second receiver unit and said second transmitter unit to maintain the inactive state during a non-carrier sensing period between the particular predetermined period for carrier sensing and the subsequent predetermined period for subsequent carrier sensing.

3. An active contactless information storage device comprising:

a memory,

a battery,

a timer for measuring time,

a receiver unit for sensing and detecting carriers of RF signals at first and second different frequencies from a first or second reader/writer device in respective predetermined periods, when said active contactless information storage device is in a communication range of said first or second reader/writer device,

a transmitter unit for transmitting a response signal at a third or fourth frequency different from said first and second frequencies, when said receiver unit receives an ID request signal, and

a control unit for controlling said receiver unit and said transmitter unit, wherein

said control unit controls said receiver unit to sense a carrier of an RF signal at said first frequency in first predetermined periods occurring in a predetermined cycle and sense a carrier of an RF signal at said second frequency in second predetermined periods occurring in said predetermined cycle;

when said receiver unit senses and detects a carrier of an RF signal at one of said first and second frequencies in a particular predetermined period, said control unit causes said receiver unit to receive further the ID request signal, and, in response to the ID request signal, causes said transmitter unit to transmit a response signal at a corresponding one of said third and fourth frequencies that carries an ID of said active contactless information storage device stored in said memory;

in the carrier sensing, said control unit causes said receiver unit to be in an active state and said transmitter unit to be in an inactive state in the first and second predetermined periods; and

when said receiver unit attempts to sense a carrier of an RF signal at said first frequency in the first predetermined period but detects no carrier, said control unit controls said receiver unit and said transmitter unit to maintain the inactive state during a non-carrier sensing period between the first predetermined period for carrier sensing and the second predetermined period for subsequent carrier sensing.

4. An active contactless information storage device according to claim 3, wherein when said receiver unit receives RF signals carrying IDs of said first and second reader/writer devices substantially simultaneously, said control unit causes said transmitter unit to transmit a response signal correspondingly at said fourth frequency that carries the ID of said active contactless information storage device stored in said memory.

5. An active contactless information storage device according to claim 3, wherein when said receiver unit receives a first RF signal carrying an ID of said first reader/writer device and then receives a second RF signal carrying an ID of said second reader/writer device within a subsequent predetermined period of time after the reception of said first RF signal, said control unit causes said transmitter unit to transmit a response signal correspondingly at said fourth frequency that carries the ID of said active contactless information storage device stored in said memory.

10. An active contactless information storage device according to claim 3, further comprising:

a decoding unit for decoding an encoded ID request and reproducing the decoded ID request, and

an encoding unit for retrieving an ID from said memory, and encoding the ID to generate encoded data, wherein

the ID request carried by the ID request signal is encrypted together with the ID of said first or second reader/writer device;

said decoding unit decrypts, together with the ID request, the ID of said first or second reader/writer device;

only when the decrypted ID of said first or second reader/writer device matches with an ID of said first or second reader/writer device stored in said memory, said transmitter unit transmits said response signal; and

the ID of said contactless information storage device carried by the response signal is encrypted by said encoding unit.

6. An active contactless information storage device comprising:

a memory,

a battery,

a timer for measuring time,

first and second receiver units for sensing and detecting, in the same predetermined period, carriers of RF signals at first and second different frequencies from a first or second reader/writer device, when said active contactless information storage device is in a communication range of said first or second reader/writer device,

first and second transmitter units for transmitting respective response signals at respective third and fourth frequencies different from said first and second frequencies, when said first and second receiver units receive ID request signals, and

a control unit for controlling said first and second receiver units and said first and second transmitter units, wherein

said control unit controls said first and second receiver units to simultaneously sense carriers of RF signals at said first and second frequencies in predetermined periods occurring in a predetermined cycle;

when said first receiver unit senses and detects a carrier of an RF signal at said first frequency in a particular predetermined period, said control unit causes said first receiver unit to receive further the ID request signal, and, in response to the ID request signal, causes said first transmitter unit to transmit a response signal correspondingly at said third frequency that carries the ID of said active contactless information storage device stored in said memory;

when said second receiver unit senses and detects a carrier of an RF signal at said second frequency in the particular predetermined period, said control unit causes said second receiver unit to receive further the ID request signal, and, in response to the ID request signal, causes said second transmitter unit to transmit a response signal correspondingly at said fourth frequency that carries the ID of said active contactless information storage device stored in said memory;

in the carrier sensing, said control unit causes said first and second receiver units to be in an active state and said first and second transmitter units to be in an inactive state in the particular predetermined period and a subsequent predetermined period;

when said first receiver unit attempts to sense a carrier of an RF signal at said first frequency in the particular predetermined period but detected no carrier, said control unit controls said first receiver unit and said first transmitter unit to maintain the inactive state during a non-carrier sensing period between the particular predetermined period for carrier sensing and the subsequent predetermined period for subsequent carrier sensing; and

when said second receiver unit attempts to sense a carrier of an RF signal at said second frequency in the particular predetermined period but detected no carrier, said control unit controls said second receiver unit and said second transmitter unit to maintain the inactive state during a non-carrier sensing period between the particular predetermined period for carrier sensing and the subsequent predetermined period for subsequent carrier sensing.

7. An active contactless information storage device according to claim 6, wherein when said first and second receiver units receive RF signals carrying IDs of said first and second reader/writer devices substantially simultaneously, said control unit causes said second transmitter unit to transmit a response signal correspondingly at said fourth frequency that carries the ID of said active contactless information storage device stored in said memory.

8. An active contactless information storage device according to claim 6, wherein when said first receiver unit receives a first RF signal carrying an ID of said first reader/writer device and then receives a second RF signal carrying an ID of said second reader/writer device within a subsequent predetermined period of time after the reception of said first RF signal, said control unit causes said second transmitter unit to transmit a response signal at corresponding said fourth frequency that carries the ID of said active contactless information storage device stored in said memory.

9. An active contactless information storage device according to claim 6, wherein

said first receiver unit is operative to sense and detect further, in another predetermined period, a carrier of an RF signal at a fifth frequency different from said first, second, third and fourth frequencies;

said first transmitter unit is operative to transmit further an RF response signal at a sixth frequency different from said first, second, third, fourth and fifth frequencies;

said control unit controls said first receiver unit to sense a carrier of an RF signal at said first frequency in first predetermined periods occurring in said predetermined cycle and sense a carrier of an RF signal at said fifth frequency in second predetermined periods occurring in said predetermined cycle;

when said first receiver unit senses and detects a carrier of an RF signal at said fifth frequency in the second predetermined period, said control unit causes said first receiver unit to receive further the ID request signal, and, in response to the ID request signal, causes said first transmitter unit to transmit a response signal correspondingly at said sixth frequency that carries the ID of said active contactless information storage device stored in said memory;

in the carrier sensing, said control unit causes said first receiver unit to be in an active state and said first transmitter unit to be in an inactive state in the second predetermined period; and

when said first receiver unit attempts to sense a carrier of an RF signal at said fifth frequency in the second predetermined period but detects no carrier, said control unit controls said first receiver unit and said first transmitter unit to maintain the inactive state during a non-carrier sensing period between the second predetermined period for carrier sensing and a further predetermined period for subsequent carrier sensing.

11. An active contactless information storage device according to claim 6, further comprising:

a decoding unit for decoding an encoded ID request and reproducing the decoded ID request, and

an encoding unit for retrieving an ID from said memory, and encoding the ID to generate encoded data, wherein

the ID request carried by the ID request signal is encrypted together with the ID of said first or second reader/writer device;

said decoding unit decrypts, together with the ID request, the ID of said first or second reader/writer device;

only when the decrypted ID of said first or second reader/writer device matches with an ID of said first or second reader/writer device stored in said memory, said transmitter unit transmits said response signal; and

the ID of said contactless information storage device carried by the response signal is encrypted by said encoding unit.