In a tag identification system, active tags are configured to emulate at least one passive tag so that existing passive identifications systems, such as passive radio-frequency (RFID) systems or near field communication (NFC) systems, can be retrofitted to operate with the active tag without having
In a tag identification system, active tags are configured to emulate at least one passive tag so that existing passive identifications systems, such as passive radio-frequency (RFID) systems or near field communication (NFC) systems, can be retrofitted to operate with the active tag without having to make expensive hardware updates to the readers within the system. The active tag permits continuous monitoring of its movement or status, as may be desired, regardless of its proximity relative to the readers thereby allowing a system to capture more data regarding the tag's location and use. In addition, the active tag may be compatible with different passive identification systems thereby permitting it to operate with disparate passive identification systems and obviating the need of the user to carry multiple passive tags.
대표청구항▼
1. An active tag for emulating passive tags when communicating with readers of a passive-tag identification system, the readers configured to wirelessly transmit interrogation signals for interrogating passive tags within the passive-tag identification system, the passive tags configured to wireless
1. An active tag for emulating passive tags when communicating with readers of a passive-tag identification system, the readers configured to wirelessly transmit interrogation signals for interrogating passive tags within the passive-tag identification system, the passive tags configured to wirelessly transmit tag signals in response to the interrogation signals, the tag signals including tag identifiers for identifying the passive tags, the readers including at least a first reader and a second reader, the active tag comprising: a communication module for communicating with the readers, the communication module having a receiver and a transmitter, the receiver configured to receive a first interrogation signal from the first reader and a second interrogation signal from the second reader;a power supply for powering components of the active tag, including at least the transmitter; andlogic configured to control the transmitter such that the transmitter wirelessly transmits a first tag signal in response to the first interrogation signal, the logic configured to determine based on the first interrogation signal at least one of an identifier of the first reader and a frequency of the first interrogation signal, the logic configured to select a first frequency for the first tag signal based on the at least one of the identifier of the first reader and the frequency of the first interrogation signal, the logic further configured to control the transmitter such that the first tag signal is transmitted at the selected first frequency, wherein the first tag signal transmitted at the selected first frequency emulates a transmission from a passive tag for responding to the first interrogation signal,wherein the logic is configured to control the transmitter such that the transmitter wirelessly transmits a second tag signal in response to the second interrogation signal, wherein the logic is configured to determine based on the second interrogation signal at least one of an identifier of the second reader and a frequency of the second interrogation signal, wherein the logic is configured to select a second frequency for the second tag signal based on the at least one of the identifier of the second reader and the frequency of the second interrogation signal, wherein the logic is further configured to control the transmitter such that the second tag signal is transmitted at the selected second frequency, and wherein the second tag signal transmitted at the selected second frequency emulates a transmission from a passive tag for responding to the second interrogation signal. 2. The active tag of claim 1, wherein the logic is configured to communicate with a plurality of nodes of a wireless network of an asset tracking system for determining a location of the active tag. 3. The active tag of claim 2, wherein the logic is configured to determine whether to transmit the first tag signal in response to the first interrogation signal based on the determined location. 4. The active tag of claim 2, wherein the logic is further configured to select the first frequency for the first tag signal based on the determined location. 5. A method for emulating passive tags when communicating with readers of a passive-tag identification system, the readers configured to wirelessly transmit interrogation signals for interrogating passive tags within the passive-tag identification system, the passive tags configured to wirelessly transmit tag signals in response to the interrogation signals, the tag signals including tag identifiers for identifying the passive tags, the readers including at least a first reader and a second reader, the method comprising: receiving a first interrogation signal from the first reader at an active tag;receiving a second interrogation signal from the second reader at the active tag;determining with the active tag based on the first interrogation signal at least one of an identifier of the first reader and a frequency of the first interrogation signal;determining with the active tag based on the second interrogation signal at least one of an identifier of the second reader and a frequency of the second interrogation signal;selecting with the active tag a first frequency for a first tag signal based on the at least one of the identifier of the first reader and the frequency of the first interrogation signal;selecting with the active tag a second frequency for a second tag signal based on the at least one of the identifier of the second reader and the frequency of the second interrogation signal;transmitting the first tag signal from the active tag to the first reader at the selected first frequency in response to the first interrogation signal, wherein the first tag signal transmitted at the selected first frequency emulates a transmission from a passive tag for responding to the first interrogation signal; andtransmitting the second tag signal from the active tag to the second reader at the selected second frequency in response to the second interrogation signal, wherein the second tag signal transmitted at the selected second frequency emulates a transmission form a passive tag for responding to the second interrogation signal. 6. The method of claim 5, further comprising: wirelessly communicating between the active tag and a plurality of nodes of a wireless network; anddetermining a location of the active tag based on the communicating between the active tag and the plurality of nodes. 7. The method of claim 6, further comprising: storing, in memory, data indicating a plurality of interrogation-enabled zones for the active tag;determining, based on the data and the determining the location of the active tag, whether the active tag is within one of the interrogation-enabled zones; anddetermining whether to transmit the first tag signal from the active tag based on whether the active tag is determined to be within at least one of the interrogation-enabled zones. 8. An active tag for emulating passive tags when communicating with readers of a passive-tag identification system, the readers configured to wirelessly transmit interrogation signals for interrogating passive tags within the passive-tag identification system, the passive tags configured to wirelessly transmit tag signals in response to the interrogation signals, the tag signals including tag identifiers for identifying the passive tags, the active tag comprising: a communication module having a transmitter and a receiver for communicating with the readers, the receiver configured to receive an interrogation signal from one of the readers;a power supply for powering components of the active tag; andlogic configured to wirelessly transmit a tag signal via the communication module in response to the received interrogation signal, the logic configured to determine a first communication characteristic and a second communication characteristic of the tag signal based on at least one interrogation signal transmitted by the one of the readers such that the tag signal emulates a transmission from a passive tag for responding to the received interrogation signal, the logic further configured to control the tag signal according to the first communication characteristic and the second communication characteristic determined by the logic,wherein the first communication characteristic pertains to a timing of the tag signal, wherein the logic is configured to transmit the tag signal after a predefined delay from reception of the interrogation signal received from the one of the readers such that the one of the readers receives the tag signal within an expected time window for receiving a response to the received interrogation signal, wherein the second communication characteristic pertains to a frequency of the tag signal, and wherein the logic is configured to transmit the tag signal within an expected frequency window for the one of the readers to receive the response to the received interrogation signal. 9. A method for emulating passive tags when communicating with readers of a passive-tag identification system, the readers configured to wirelessly transmit interrogation signals for interrogating passive tags within the passive-tag identification system, the passive tags configured to wirelessly transmit tag signals in response to the interrogation signals, the tag signals including tag identifiers for identifying the passive tags, the method comprising: receiving an interrogation signal from one of the readers via an active tag;transmitting a tag signal from the active tag to the one of the readers in response to the received interrogation signal;automatically determining a first communication characteristic and a second communication characteristic of the tag signal with the active tag based on at least one interrogation signal transmitted by the one of the readers such that the tag signal emulates a transmission from a passive tag for responding to the received interrogation signal; andcontrolling the tag signal with the active tag according to the first communication characteristic and the second communication characteristic determined by the active tag,wherein the first communication characteristic pertains to a timing of the tag signal, wherein the transmitting the tag signal comprises transmitting the tag signal after a predefined delay from the receiving such that the one of the readers receives the tag signal within an expected time window for receiving a response to the received interrogation signal, wherein the second communication characteristic pertains to a frequency of the tag signal, and wherein the transmitting the tag signal comprises transmitting the tag signal within an expected frequency window for the one of the readers to receive the response to the received interrogation signal. 10. An asset tracking system, comprising: a first reader configured to wirelessly transmit interrogation signals for interrogating passive tags;a controller configured to control access to a first restricted area, the controller communicatively coupled to the first reader;a second reader configured to wirelessly transmit interrogation signals for interrogating passive tags;a network having a plurality of nodes;an active tag configured to wirelessly communicate with the nodes for determining a location of the active tag, the active tag configured to receive a first interrogation signal from the first reader and to wirelessly transmit a first tag signal in response to the first interrogation signal, the first tag signal having a tag identifier for identifying the active tag, the active tag configured to determine based on the first interrogation signal at least one of an identifier of the first reader and a frequency of the first interrogation signal, the active tag configured to select a first frequency for the first tag signal based on the at least one of the identifier of the first reader and the frequency of the first interrogation signal, the active tag further configured to control the first tag signal such that the first tag signal is transmitted at the selected first frequency, wherein the first tag signal transmitted at the selected first frequency emulates a transmission from a passive tag for responding to the first interrogation signal,wherein the active tag is configured to wirelessly transmit a second tag signal in response to the second interrogation signal, wherein the active tag is configured to determine based on the second interrogation signal at least one of an identifier of the second reader and a frequency of the second interrogation signal, wherein the active tag is configured to select a second frequency for the second tag signal based on the at least one of the identifier of the second reader and the frequency of the second interrogation signal, wherein the active tag is further configured to control the second tag signal such that the second tag signal is transmitted at the selected second frequency, and wherein the second tag signal transmitted at the selected second frequency emulates a transmission from a passive tag for responding to the second interrogation signal, andwherein the first reader is configured to receive the first tag signal and to provide the tag identifier to the controller for authorizing access to the first restricted area in response to the first tag signal. 11. The system of claim 10, wherein the active tag is configured to determine whether to transmit the first tag signal in response to the first interrogation signal based on the determined location. 12. The system of claim 10, further comprising a server configured to determine the location of the active tag and to control, based on the location, whether the active tag transmits the first tag signal in response to the first interrogation signal. 13. The system of claim 12, wherein the server is configured to store data in memory, the data indicating a plurality of interrogation-enabled zones for the active tag, wherein the server is configured to determine whether the active tag is in at least one of the interrogation-enabled zones based on the location, and wherein the server is configured to control whether the active tag transmits the first tag signal in response to the first interrogation signal based on the whether the active tag is determined to be within at least one of the interrogation-enabled zones.
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이 특허에 인용된 특허 (12)
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