Detecting passive RF components using radio frequency identification tags
Systems and methods are provided for automatically detecting passive components in communications systems using radio frequency identification (“RFID”) tags. A coupling circuit is provided in a system between a communications network and an RFID tag. The RFID tag is associated with a passive element of a distributed antenna system (“DAS”). The coupling circuit can allow an RFID signal received from an RFID transmitter over the communications network to be transported to the RFID tag. The coupling circuit can substantially prevent mobile communication signals on the communications network from being transported to the RFID tag.
1. A system comprising:
a coupling circuit between a communications network and a radio frequency identification (RFID) tag associated with a passive element of a distributed antenna system, the distributed antenna system comprising at least one master unit communicatively coupled to one or more remote antenna units, wherein the at least one master unit is configured to communicate uplink and downlink telecommunications signals between a base stations and the one or more remote antenna units over the communications network; and
an attenuation circuit between the coupling circuit and the RFID tag, wherein the attenuation circuit is configured for coupling the RFID tag to ground;
wherein the coupling circuit comprises a physical coupling between the RFID tag and the communications network, the physical coupling having a resonant frequency that allows an RFID signal received from the RFID transmitter over the communications network to be transported to the RFID tag and impedes one or more non-RFID communication signals from the communications network from being transported to the RFID tag, wherein the RFID signal and the one or more non-RFID communication signals are carried on the communications network over at least one shared conductor.
2. The system of claim 1 , further comprising:
the RFID transmitter in a fixed location in the distributed antenna system, wherein the fixed location is remote to the passive element, and
wherein the passive element is a non-powered element.
3. The system of claim 1 , wherein the communications network comprises a coaxial cable.
4. The system of claim 1 , wherein the physical coupling comprises at least one of a directional coupler or a non-directional coupler.
5. The system of claim 1 , wherein the coupling circuit further comprises an air coupling between the RFID tag and the communications network.
6. The system of claim 5 , wherein the air coupling comprises an RFID antenna communicatively coupled to the RFID tag and configured to receive the RFID signal from an antenna of the distributed antenna system.
7. The system of claim 5 , wherein the coupling circuit further comprises a power divider between the RFID tag and each of the physical coupling and the air coupling.
8. The system of claim 1 , wherein the coupling circuit comprises a signal path from a point on the communications network to the RFID tag, the signal path having a resistor connected in series with an inductor and a capacitor.
9. A distributed antenna system comprising:
at least one master unit communicatively coupled to one or more remote antenna units, wherein the at least one master unit is configured to communicate uplink and downlink telecommunications signals between a base stations and the one or more remote antenna units over a communications network;
a radio frequency identification (RFID) transmitter positioned in a remote antenna unit of the one or more remote antenna units;
an RFID tag associated with a passive element remote from a position of the RFID transmitter over the communications network;
a coupling circuit providing a physical coupling between the RFID tag and the communications network, wherein RFID signals received from the RFID transmitter and non-RFID signals are carried on the communications network over at least one same conductor;
wherein the coupling circuit has a resonant frequency that allows the RFID signals received from the RFID transmitter over the communications network through the coupling circuit and inhibits the non-RFID signals from being transported to the RFID tag through the coupling circuit; and
an attenuation circuit between the coupling circuit and the RFID tag, wherein the RFID tag is configured to be coupled to ground via the attenuation circuit.
10. The distributed antenna system of claim 9 , wherein the communications network comprises a coaxial cable.
11. The distributed antenna system of claim 9 , further comprising:
an air coupling between the RFID tag and communications network, wherein the air coupling is configured for coupling a first RFID signal to the RFID tag via a first signal path and the coupling circuit is configured for coupling a second RFID signal to the RFID tag via a second signal path that is different from the first signal path; and
a power divider between the RFID tag and each of the first signal path and the second signal path, wherein the power divider is configured for communicating at least one of the first RFID signal and the second RFID signal to the RFID tag.
12. The distributed antenna system of claim 11 , wherein the air coupling comprises an RFID antenna communicatively coupled to the RFID tag and configured to receive an RFID signal from an antenna of the distributed antenna system, the RFID signal transmitted by the RFID transmitter.
13. A method comprising:
providing a coupling circuit between a communications network and a radio frequency identification (RFID) tag associated with a passive element of a distributed antenna system, the distributed antenna system comprising at least one master unit communicatively coupled to one or more remote antenna units, wherein the at least one master unit is configured to communicate uplink and downlink telecommunications signals between a base stations and the one or more remote antenna units over the communications network; and
transmitting an RFID signal received from an RFID transmitter to the RFID tag via the communications network and coupling circuit, wherein the RFID tag is coupled to ground via an attenuation circuit between the RFID tag and the coupling circuit, wherein the RFID signal and mobile communication signals are carried on the communications network over at least one same conductor;
wherein the coupling circuit inhibits the mobile communication signals on the communications network from being communicated to the RFID tag;
wherein providing the coupling circuit comprises providing a coupling circuit configured with a resonant frequency for allowing the RFID signal received from the RFID transmitter over the communications network to the transported to the RFID tag and for inhibiting the mobile communications signals on the communications network from being transported to the RFID tag.
14. The method of claim 13 , further comprising:
providing the RFID transmitter in a fixed location in the distributed antenna system, wherein the fixed location is remote to the passive element.
15. The method of claim 13 , wherein the communications network comprises a coaxial cable.
16. The method claim 13 , wherein the coupling circuit further comprises an air coupling between the RFID tag and the communications network.
17. The method of claim 16 ,
wherein providing the coupling circuit that includes the air coupling comprises providing an RFID antenna communicatively coupled to the RFID tag; and
further comprising receiving an additional RFID signal from an antenna of the distributed antenna system via the air coupling.