Wireless tag device, storage medium storing control program for wireless tag device, and control method for wireless tag device

• US 8,791,796 B2
• Filed: 03/29/2012
• Issued: 07/29/2014
• Est. Priority Date: 10/08/2009
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Shiotsu, Shinichi, Inano, Satoshi, Tanaka, Hideki
• Primary Examiner(s): Bugg, George
• Assistant Examiner(s): Afrifa-Kyei, Anthony D
• Application Number:
  US13/434,202
• Publication Number:
  US 20120182131A1
• Time in Patent Office: 852 Days
• Field of Search: 340 101- 106, 3405721-5729
• US Class Current: 340/10.4
• CPC Class Codes: G06K 19/0724 the arrangement being a circuit for communicating at a plurality of frequencies, e.g. for managing time multiplexed communication over at least two antennas of different types
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• 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

Abstract

A wireless tag device can communicate with an inquiry device includes: a local terminal storage unit storing local terminal identification information which can be discriminated from another wireless tag device; a reception detection unit detecting a signal transmitted from the inquiry device or another wireless tag device; an inquiry signal receiving unit receiving the detected inquiry signal if the inquiry signal is transmitted using a first frequency from the inquiry device; a reply signal transmitting unit transmitting a reply signal in response to the inquiry signal using a second frequency different from the first frequency; and a report signal transmitting unit transmitting a report signal including the local terminal identification information stored in the local terminal storage unit using a third frequency different from the second frequency if the inquiry signal transmitted from the inquiry device cannot be detected continuously in a specified time period in the reception detection unit.

Claims

1. A wireless tag device capable of communicating with an inquiry device, comprising:

a local terminal storage unit storing local terminal identification information which can be discriminated from another wireless tag device;

a reception detection unit detecting a signal transmitted from the inquiry device or another wireless tag device;

an inquiry signal receiving unit receiving the inquiry signal detected by the reception detection unit if the inquiry signal is transmitted using a first frequency from the inquiry device;

a reply signal transmitting unit transmitting a reply signal in response to the inquiry signal using a second frequency different from the first frequency; and

a report signal transmitting unit transmitting a report signal including the local terminal identification information stored in the local terminal storage unit using a third frequency different from the second frequency if the inquiry signal transmitted from the inquiry device cannot be detected continuously in a specified time period in the reception detection unit;

a report signal receiving unit receiving the report signal when a signal detected by the reception detection unit is transmitted using the second frequency from the other wireless tag device; and

another terminal storage unit storing terminal identification information included in the report signal received by the report signal receiving unit as other terminal identification information, wherein

the reply signal transmitting unit generates the reply signal according to local terminal identification information stored in the local terminal storage unit and other terminal identification information stored in the other terminal storage unit in response to the inquiry signal from the inquiry device, and transmits the generated signal to the inquiry device.

2. The device according to claim 1, wherein

the report signal transmitting unit transmits the report signal when the reception detection unit does not continuously detect an inquiry signal from the inquiry device for a specified time period, and detects that there is no reply signal transmitted by another wireless tag device.

3. The device according to claim 1, wherein

the first and third frequencies have a same frequency band.

4. The device according to claim 1, wherein

the report signal transmitting unit sets lower transmission power of the report signal than transmission power of the reply signal transmitted in the reply signal transmitting process.

5. A storage unit storing a control program used in a 25 wireless tag device which is provided with a local terminal storage unit storing local terminal identification information which can be identified from another wireless tag device and can communicate with an inquiry device, the control program operates a wireless tag device as:

a reception detection unit detecting a signal transmitted from the inquiry device or another wireless tag device;

an inquiry signal receiving unit receiving an inquiry signal detected by the reception detection unit if the inquiry signal is transmitted using a first frequency from the inquiry device;

a reply signal transmitting unit transmitting a reply signal in response to the inquiry signal using a second frequency different from the first frequency; and

a report signal transmitting unit transmitting a report signal including the local terminal identification information stored in the local terminal storage unit using a third frequency different from the second frequency if the inquiry signal transmitted from the inquiry device cannot be detected continuously in a specified time period in the reception detection unit;

a report signal receiving unit receiving the report signal when a signal detected by the reception detection unit is transmitted using the second frequency from the other wireless tag device; and

another terminal storage unit storing terminal identification information included in the report signal received by the report signal receiving unit as other terminal identification information, wherein

the reply signal transmitting unit generates the reply signal according to local terminal identification information stored in the local terminal storage unit and other terminal identification information stored in the other terminal storage unit in response to the inquiry signal from the inquiry device, and transmits the generated signal to the inquiry device.

6. A control method for a wireless tag device which is provided with a local terminal storage unit storing local terminal identification information which can be identified from another wireless tag device and can communicate with an inquiry device, comprising:

detecting a signal transmitted from the inquiry device or another wireless tag device;

receiving an inquiry signal detected by the reception detection unit if the detected signal is the inquiry signal which is transmitted using a first frequency from the inquiry device;

transmitting a reply signal in response to the inquiry signal using a second frequency different from the first frequency; and

transmitting a report signal including the local terminal identification information stored in the local terminal storage unit using a third frequency different from the second frequency if the inquiry signal transmitted from the inquiry device cannot be detected continuously in a specified time period;

a report signal receiving unit receiving the report signal when a signal detected by the reception detection unit is transmitted using the second frequency from the other wireless tag device; and

another terminal storage unit storing terminal identification information included in the report signal received by the report signal receiving unit as other terminal identification information, wherein

the reply signal transmitting unit generates the reply signal according to local terminal identification information stored in the local terminal storage unit and other terminal identification information stored in the other terminal storage unit in response to the inquiry signal from the inquiry device, and transmits the generated signal to the inquiry device.