TAG READING DEVICE
First Claim
1. A tag reading apparatus that reads a plurality of tags which are in a predetermined area, comprising:
- a transmission section that transmits reading signals for reading the tags to the plurality of tags;
a reception section that receives response signals from tags that have received the reading signals; and
a control section that controls the transmission section such that, when an idle time period out of a reception period during which the reception section receives the response signals exceeds a predetermined time period, output power of the transmission section is increased and the transmission section retransmits the reading signals.
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Accused Products
Abstract
A tag reading device can effectively read a plurality of tags. The tag reading device includes a power control unit (109) for controlling an output power of a transmission unit (101) by a control signal so as to transmit transmission data with an output power set by an output power setting unit (108). When a plenty of tags exist in a readable area and identifiers of the gags frequently make collisions, firstly, the output power of the transmission unit (101) is reduced so as to narrow the readable area and suppress generation of collisions. When the number of tags existing in the readable area of a reader (100) and not yet read has become small, the output power of the transmission unit (101) during retransmission is increased and the readable area of the reader (100) is increased and the remaining tags are effectively read.
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Citations
6 Claims
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1. A tag reading apparatus that reads a plurality of tags which are in a predetermined area, comprising:
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a transmission section that transmits reading signals for reading the tags to the plurality of tags; a reception section that receives response signals from tags that have received the reading signals; and a control section that controls the transmission section such that, when an idle time period out of a reception period during which the reception section receives the response signals exceeds a predetermined time period, output power of the transmission section is increased and the transmission section retransmits the reading signals. - View Dependent Claims (2, 4, 5)
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3. (canceled)
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6. A tag reading method for reading a plurality of tags in a predetermined area, comprising:
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a transmission step of transmitting reading signals for reading the tags to the plurality of tags; a reception step of receiving response signals from tags that have received the reading signals; a decision step of deciding whether the response signals have been successfully received in the reception step, a collision has occurred in the response signals or no response signal has been received from the tags; a data measuring step of measuring a number of read tags where the response signals have been successfully received within a reception period in the reception step, and an idle time period during which the response signals have not been received, based on the decision result in the decision step; an output power setting step of comparing the measurement result in the data measuring step with a predetermined threshold and setting output power in the transmission step when the reading signals are retransmitted in the transmission step; and an output power control step of controlling output power in the transmission step such that the reading signals are transmitted with the output power set in the output power setting step.
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Specification