Reducing leaked downlink interference signals in a remote unit uplink path(s) in a distributed antenna system (DAS)
First Claim
1. A distributed antenna system (DAS), comprising:
- a head-end equipment (HEE) communicatively coupled to a plurality of remote antenna units (RAUs) over at least one downlink communications medium and at least one uplink communications medium;
wherein at least one RAU among the plurality of RAUs comprises a coupling device coupled to a downlink path configured to carry a downlink signal and an uplink path configured to carry an uplink signal, the coupling device configured to;
receive the downlink signal from the downlink path and provide the downlink signal to an antenna, wherein the downlink signal comprises at least one downlink communications signal and at least one downlink interference signal; and
provide the uplink signal to the uplink path, wherein the uplink signal comprises an uplink communications signal received from the antenna and the at least one downlink interference signal leaked from the downlink path to the uplink path; and
an interference control system communicatively coupled to the at least one RAU among the plurality of RAUs, the interference control system configured to;
provide the at least one downlink communications signal to the at least one RAU over the at least one downlink communications medium;
receive the uplink signal from the at least one RAU over the at least one uplink communications medium;
measure signal strength of the at least one downlink interference signal comprised in the uplink signal; and
generate and provide an adjustment control signal to an adjustment circuit in the at least one RAU to reduce the at least one downlink interference signal in the uplink signal to a minimal level based on the measured signal strength of the at least one downlink interference signal.
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Accused Products
Abstract
Methods and systems for reducing leaked downlink interference signals in a remote unit uplink path(s) in a distributed antenna system (DAS) are provided. In a remote antenna unit (RAU) disclosed herein, a downlink interference signal may be leaked from a downlink path to an uplink path in the RAU. In this regard, an adjustment circuit is provided in the downlink path of the RAU to suppress the downlink interference signal. A control system is provided in the DAS to monitor the leaked downlink interference signal and control the adjustment circuit in the RAU to minimize the leaked downlink interference signal in the uplink path. By providing the adjustment circuit in the RAU and the control system in the DAS to minimize the leaked downlink interference signal in the uplink path, it is possible to reduce interferences between downlink and uplink communications signals without increasing costs of the RAU.
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Citations
25 Claims
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1. A distributed antenna system (DAS), comprising:
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a head-end equipment (HEE) communicatively coupled to a plurality of remote antenna units (RAUs) over at least one downlink communications medium and at least one uplink communications medium; wherein at least one RAU among the plurality of RAUs comprises a coupling device coupled to a downlink path configured to carry a downlink signal and an uplink path configured to carry an uplink signal, the coupling device configured to; receive the downlink signal from the downlink path and provide the downlink signal to an antenna, wherein the downlink signal comprises at least one downlink communications signal and at least one downlink interference signal; and provide the uplink signal to the uplink path, wherein the uplink signal comprises an uplink communications signal received from the antenna and the at least one downlink interference signal leaked from the downlink path to the uplink path; and an interference control system communicatively coupled to the at least one RAU among the plurality of RAUs, the interference control system configured to; provide the at least one downlink communications signal to the at least one RAU over the at least one downlink communications medium; receive the uplink signal from the at least one RAU over the at least one uplink communications medium; measure signal strength of the at least one downlink interference signal comprised in the uplink signal; and generate and provide an adjustment control signal to an adjustment circuit in the at least one RAU to reduce the at least one downlink interference signal in the uplink signal to a minimal level based on the measured signal strength of the at least one downlink interference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A head-end equipment (HEE) in a distributed antenna system (DAS), comprising:
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a signal generator coupled to at least one remote antenna unit (RAU) among a plurality of RAUs in a DAS over at least one downlink communications medium, the signal generator configured to generate and distribute at least one downlink communications signal to a downlink path in the at least one RAU over the at least one downlink communications medium; and a spectrum analyzer coupled to the at least one RAU over at least one uplink communications medium, the spectrum analyzer configured to; receive an uplink signal from an uplink path in the at least one RAU over the at least one uplink communications medium, wherein the uplink signal comprises at least one downlink interference signal leaked from the downlink path to the uplink path in the at least one RAU; measure signal strength of the at least one downlink interference signal comprised in the uplink signal; and provide the measured signal strength of the at least one downlink interference signal to a process controller that is communicatively coupled to the spectrum analyzer and the signal generator; and wherein the process controller is configured to provide an adjustment control signal to the at least one RAU to minimize the at least one downlink interference signal in the uplink signal based on the measured signal strength of the at least one downlink interference signal. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A remote antenna unit (RAU) in a distributed antenna system (DAS), comprising:
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a coupling device coupled to a downlink path and an uplink path, the coupling device configured to; receive a downlink signal from the downlink path and provide the downlink signal to an antenna, wherein the downlink signal comprises at least one downlink communications signal and at least one downlink interference signal; provide an uplink signal to the uplink path, wherein the uplink signal comprises an uplink communications signal received from the antenna and the at least one downlink interference signal leaked from the downlink path to the uplink path; and an adjustment circuit comprising a local controller communicatively coupled to a process controller in an interference reduction control system, the local controller configured to suppress the at least one downlink interference signal in the downlink signal based on an adjustment control signal received from the interference reduction control system that is communicatively coupled to the adjustment circuit; and a first downlink signal amplifier and a second downlink signal amplifier disposed according to a serial arrangement in the downlink path before the coupling device, wherein the adjustment circuit comprises an adjustable matching circuit disposed between the first downlink signal amplifier and the second downlink signal amplifier, the adjustable matching circuit comprising; a capacitor circuit disposed between the first downlink signal amplifier and the second downlink signal amplifier, the capacitor circuit comprising a capacitor and an adjustable capacitor disposed in a parallel arrangement; and an inductor comprising a first end coupled to the first downlink signal amplifier before the capacitor circuit and a second end coupled to a ground. - View Dependent Claims (22, 23, 24, 25)
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Specification