Radio interrogator system and radio communication method therefor

• US 20070057770A1
• Filed: 11/14/2006
• Published: 03/15/2007
• Est. Priority Date: 07/27/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tanaka, Yoshinori, Aoki, Nobuhisa, Ninomiya, Teruhisa
• Granted Patent: US 8,354,916 B2
• 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 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas

Abstract

There is provided a radio interrogator system which reduces the interference with a radio transponder and avoids the decrease in throughput of the entire system in a case in which a plurality of radio interrogators are disposed at positions brought relatively close to each other and are simultaneously placed into operation. The plurality of radio interrogators are classified into two groups and each of the radio interrogators has an operation mode setting unit capable of exclusively setting, for each of the classified groups, a transmission mode for transmitting a radio transmission signal to a radio transponder or a reception mode for receiving a radio response signal transmitted from the radio transponder as a response to a radio transmission signal from the radio interrogator.

Claims

1. A radio interrogator system, which includes a plurality of radio interrogators each made to transmit a radio transmission signal to a radio transponder and receive a radio response signal from said radio transponder, characterized in that said plurality of radio interrogators are classified into two groups and each of said radio interrogators has an operation mode setting unit to set a transmission mode for transmitting the radio transmission signal to said radio transponder or a reception mode for receiving the radio response signal transmitted from said radio transponder as a response to the radio transmission signal from said radio interrogator for each of the classified groups.

3. The radio interrogator system according to claim 1, characterized in that said operation mode setting unit of each of said radio interrogators sets said reception mode without transmitting the radio transmission signal to said radio transponder while said radio interrogators of the other group are in said transmission mode.

4. The radio interrogator system according to claim 3, characterized in that said operation mode setting unit of each of said radio interrogators set said transmission mode without receiving the radio response signal from said radio transponder while said radio interrogators of the other group are in said reception mode.

5. The radio interrogator system according to claim 1, characterized in that said operation mode setting unit of each of said radio interrogators has a switching setting unit to switch and set said operation mode of said radio interrogator, in which said operation mode setting unit resides, to one of said transmission mode and said reception mode on the basis of a transmission state of the radio transmission signal and a reception state of the radio response signal in the other radio interrogators and said radio interrogator in which said operation mode setting unit resides.

6. The radio interrogator system according to claim 5, characterized in that said operation mode setting unit of each of said radio interrogators includes a transmission state monitoring unit for monitoring a transmission state of a radio transmission signal to said radio transponder and a transmission busy state notifying unit for, on the basis of a result of the monitoring by said transmission state monitoring unit, making a notification to the effect of a transmission busy state to said switching setting units of the other radio interrogators during the transmission of the radio transmission signal and canceling the notification on the transmission busy state at the time that the transmission of the radio transmission signal comes to an end.

7. The radio interrogator system according to claim 6, characterized in that said operation mode setting unit of each of said radio interrogators includes a reception state monitoring unit for monitoring a reception state of a radio response signal from said radio transponder stemming from the radio transmission signal from said radio interrogator and a reception busy state notifying unit for, on the basis of a result of the monitoring by said reception state monitoring unit, making a notification to the effect of a reception busy state to said switching setting units of the other radio interrogators during the reception of the radio transmission signal and canceling the notification on the reception busy state at the time that the reception of the radio response signal comes to an end.

8. The radio interrogator system according to claim 7, characterized in that said switching setting unit of each of said radio interrogators includes a first transmission/reception busy cancellation judgment unit for, on the basis of notifications from said transmission busy state notifying units and said reception busy state notifying units in said radio interrogator, in which said switching setting unit resides, and in the other radio interrogators, canceling the reception busy states of all said radio interrogators pertaining to the group, to which said radio interrogator pertains, and making a judgment as to whether or not the transmission busy states of all said radio interrogators pertaining to the other group are canceled, and a first operation mode switching unit for, when said first transmission/reception busy cancellation judgment unit judges that the reception busy states and the transmission busy states are canceled, carrying out control to switch the operation mode from said reception mode to said transmission mode.

9. The radio interrogator system according to claim 6, characterized in that said radio interrogators are connected through a line to each other so as to notify, to the other radio interrogators, the reception busy state to be notified by said reception busy state notifying unit and the transmission busy state to be notified by said transmission busy state notifying unit.

10. The radio interrogator system according to claim 1, characterized by further comprising a control unit for outputting a control signal to switch and set the operation mode in each of said radio interrogators to one of said transmission mode said the reception mode,

said operation mode setting unit of each of said radio interrogators being made to set said transmission mode or said reception mode on the basis of the control signal from said control unit.

11. The radio interrogator system according to claim 10, characterized in that said operation mode setting unit of each of said radio interrogators includes a transmission state monitoring unit for monitoring a transmission state of a radio transmission signal to said radio transponder and a transmission busy state notifying unit for, on the basis of a result of the monitoring by said transmission state monitoring unit, making a notification to the effect of a transmission busy state to said control unit during the transmission of the radio transmission signal and canceling the notification on the transmission busy state at the time that the transmission of the radio transmission signal comes to an end.

12. The radio interrogator system according to claim 10, characterized in that said control unit and each of said radio interrogators are connected through a line to each other so that said reception busy state notifying unit notifies the reception busy state to said control unit and said transmission busy state notifying unit notifies the transmission busy state to said control unit and said control unit outputs the control signal to each of said radio interrogators.

13. The radio interrogator system according to claim 1, characterized in that said plurality of radio interrogators are classified into two groups so that a minimum distance between the individual radio interrogators pertaining to the same group becomes relatively long.

14. The radio interrogator system according to claim 1, characterized in that said plurality of radio interrogators are classified into two groups according to frequency channel.

2. A radio interrogator system, which includes a plurality of radio interrogators each made to transmit a radio transmission signal to a radio transponder and receive a radio response signal from said radio transponder, characterized in that each of said radio interrogators has an operation mode setting unit made to set one of a first group which transmits the radio transmission signal to said radio transponder, a second group which receives the radio response signal transmitted from said radio transponder as a response to the radio transmission signal from said radio interrogator and a third group which carries out neither the transmission to said radio transponder nor the reception of the radio response signal transmitted from said radio transponder.

15. A radio communication method for a radio interrogator system including a plurality of radio interrogators each made to interchange a radio signal with respect to a radio transponder, characterized in that said plurality of radio interrogators are classified into two groups according to two types of communication channels and said radio interrogator pertaining to one group is set in a reception mode for receiving, from said radio transponder, a radio response signal stemming from a radio transmission signal from said radio interrogator pertaining to the one group without transmitting a radio transmission signal to said radio transponder while the radio interrogators pertaining to the other group are in a transmission mode for transmitting a radio transmission signal to said radio transponder, and said radio interrogator pertaining to the one group is set in a transmission mode for transmitting a radio transmission signal to said radio transponder without receiving a radio response signal from said radio transponder while the radio interrogators pertaining to the other group is in a reception mode for receiving, from said radio transponder, a radio response signal stemming from a radio transmission signal from said radio interrogator pertaining to the other group.

16. The radio communication method for a radio interrogator system according to claim 15, characterized in that said plurality of radio interrogators are classified into the two groups so that a minimum distance between the individual radio interrogators pertaining to the same group becomes relatively long.

17. The radio communication method for a radio interrogator system according to claim 15, characterized in that said plurality of radio interrogators are classified into the two groups according to a frequency channel set in each of said radio interrogators for interchanging a radio signal with respect to said radio transponder.

18. The radio communication method for a radio interrogator system according to claim 15, characterized in that, for setting the operation mode, said radio interrogator in said transmission mode monitors a transmission state of the radio transmission signal and outputs a transmission busy state during the transmission of the radio transmission signal and cancels the output of the transmission busy state at the time that the transmission of the radio transmission signal comes to an end, and said radio interrogator in said reception mode monitors a reception state of the radio response signal and outputs a reception busy state during the reception of the radio response signal and cancels the output of the reception busy state at the time that the reception of the radio response signal comes to an end.

19. The radio communication method for a radio interrogator system according to claim 18, characterized in that, for setting the operation mode, each of said radio interrogators in said reception mode makes a judgment, on the basis of the transmission busy states and reception busy states outputted from this radio interrogator and the other radio interrogators, as to whether or not the reception busy states of all said radio interrogators pertaining to the group including this radio interrogator are canceled and the transmission busy states of all said radio interrogators pertaining to the other group are canceled and, when the judgment shows the cancellation of the reception busy states and the transmission busy states, carries out control for switching the operation mode from said reception mode to said transmission mode, while each of said radio interrogators in said transmission mode makes a judgment, on the basis of the transmission busy states and reception busy states outputted from this radio interrogator and the other radio interrogators, as to whether or not the transmission busy states of all said radio interrogators pertaining to the group including this radio interrogator are canceled and the reception busy states of all said radio interrogators pertaining to the other group are canceled and, when the judgment shows the cancellation of the transmission busy states and the reception busy states, carries out control for switching the operation mode from said transmission mode to said reception mode.

20. The radio communication method for a radio interrogator system according to claim 18, characterized in that each of said radio interrogators transmits dummy data from when the transmission of the radio transmission signal to said radio transponder comes to an end until the transmission busy states of all said radio interrogators pertaining to the group including this radio interrogator are canceled and the reception busy states of all said radio interrogators pertaining to the other group are canceled.