Time-division duplexing (TDD) in distributed communications systems, including distributed antenna systems (DASs)
First Claim
1. A control circuit for controlling switching between a time-division duplexing (TDD) transmit mode and a TDD receive mode in a system supporting TDD, the control circuit comprising:
- a first power detector configured to determine a first power level from a radio source in a downlink direction on a downlink path;
a second power detector configured to determine a second power level in an uplink direction on an uplink path;
a receive/transmit comparator coupled to the first power detector and to the second power detector, wherein the receive/transmit comparator compares the first power level to the second power level to provide a first indication that the system should be switched to TDD transmit mode when the first power level exceeds the second power level;
a second power comparator configured to determine a second indication indicative of whether the first power level exceeds a value of a transmit power reference; and
a logic circuit coupled to the receive/transmit comparator for receiving the first indication, the logic circuit coupled to the second power comparator for receiving the second indication, wherein the logic circuit is configured to determine if the system should be switched to TDD transmit mode or TDD receive mode based at least in part on the received first indication from the receive/transmit comparator and the received second indication from the second power comparator.
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Accused Products
Abstract
Time-division duplexing (TDD) in distributed communications systems, including distributed antenna systems (DASs) is disclosed. In one embodiment, a control circuit is provided and configured to control the TDD transmit mode of a DAS to control the allocation of time slots for uplink and downlink communications signal distribution in respective uplink path(s) and downlink path(s). The control circuit includes separate power detectors configured to detect either a transmit power level in a downlink path or a receive power level in an uplink path. If the transmit power detected in the downlink path is greater than receive power detected in the uplink path, the control circuit switches the TDD transmit mode to the downlink direction. In this manner, the control circuit does not have to control the TDD transmit mode based solely on detected power in the downlink path, where a directional coupler may leak uplink power in the downlink path.
813 Citations
23 Claims
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1. A control circuit for controlling switching between a time-division duplexing (TDD) transmit mode and a TDD receive mode in a system supporting TDD, the control circuit comprising:
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a first power detector configured to determine a first power level from a radio source in a downlink direction on a downlink path; a second power detector configured to determine a second power level in an uplink direction on an uplink path; a receive/transmit comparator coupled to the first power detector and to the second power detector, wherein the receive/transmit comparator compares the first power level to the second power level to provide a first indication that the system should be switched to TDD transmit mode when the first power level exceeds the second power level; a second power comparator configured to determine a second indication indicative of whether the first power level exceeds a value of a transmit power reference; and a logic circuit coupled to the receive/transmit comparator for receiving the first indication, the logic circuit coupled to the second power comparator for receiving the second indication, wherein the logic circuit is configured to determine if the system should be switched to TDD transmit mode or TDD receive mode based at least in part on the received first indication from the receive/transmit comparator and the received second indication from the second power comparator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A distributed communication system capable of supporting time-division duplexing (TDD), the distributed communication system comprising:
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a central unit configured to receive a plurality of downlink signals from at least one radio source; a plurality of remote units each configured to receive downlink signals from the central unit, and to return uplink signals to the central unit; and a control circuit for controlling TDD switching in the distributed communication system, the control circuit comprising; a first power detector configured to determine a first power level from the at least one radio source; a second power detector configured to determine a second power level from an uplink path; a receive/transmit comparator coupled to the first power detector and to the second power detector, wherein the receive/transmit comparator compares the first power level to the second power level to provide an indication indicating when the first power level exceeds the second power level; and a transmit power comparator configured to determine whether the first power level exceeds a reference value and provide an indication indicative of whether the first power level exceeds the reference value, wherein the control circuit is configured to determine if the distributed communication system should be switched to TDD transmit mode or TDD receive mode based at least in part on the received indication from the receive/transmit comparator and the received indication from the transmit power comparator. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification