Wideband remote unit for distributed antenna system

• US 10,009,120 B2
• Filed: 06/23/2017
• Issued: 06/26/2018
• Est. Priority Date: 04/15/2014
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Inventors: Ranson, Christopher Goodman, Kummetz, Thomas, Hanson, Van E., Lange, Keld Knut
• Primary Examiner(s): Moutaouakil, Mounir
• Application Number:
  US15/631,798
• Publication Number:
  US 20180048397A1
• Time in Patent Office: 368 Days
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Certain aspects involve a wideband remote unit. The wideband remote unit can include one or more antennas and an analog-to-digital converter (“ADC”). The antenna can receive wideband signals. The wideband signals can include an uplink RF signal and a leaked downlink RF signal. The uplink RF signal can have an uplink signal power at or near a noise level. The leaked downlink RF signal can have a downlink signal power greater than the uplink signal power. The ADC can convert the received wideband signals to digital RF signals representing the uplink signal and the downlink signal. The wideband remote unit can transmit the digital RF signals to a unit of a DAS that is in communication with a base station.

Claims

1. A wideband remote unit of a digital antenna system that includes a unit in communication with a base station, the remote unit comprising:

a downlink path, wherein the wideband remote unit is configured to wirelessly transmit a downlink RF signal from the downlink path; and

an uplink path, wherein the wideband remote unit is configured to process a wideband composite uplink signal comprising an uplink RF signal wirelessly received from a user by the wideband remote unit and a leaked downlink RF signal, wherein the leaked downlink RF signal is a signal component of the downlink RF signal wirelessly transmitted by the wideband remote unit and leaked into the uplink path;

a converter associated with uplink path and configured with a dynamic range suitable to digitize both the uplink RF signal and the leaked downlink RF signal of the wideband composite uplink signal, the converter further configured to convert the composite uplink signal to a digital representation of the uplink RF signal and to a digital representation of the leaked downlink RF signal; and

wherein the uplink path is further configured to transmit to the unit of the distributed antenna system in communication with the base station both the representation of the uplink RF signal and the representation of the leaked downlink RF signal.

2. The remote unit of claim 1, further comprising a splitter-combiner configured to couple to an antenna;

wherein an output of the downlink path is coupled to the splitter-combiner;

wherein an input of the uplink path is coupled to the splitter-combiner; and

wherein the leaked downlink RF signal is leaked into the uplink path via the splitter-combiner.

3. The remote unit of claim 1, wherein an uplink signal power of the uplink RF signal has a thermal noise level associated with the wideband remote unit, wherein the converter comprises an analog-to-digital converter, wherein the dynamic range of the converter is a function of a dynamic range of the analog-to-digital converter, wherein the minimum value of the dynamic range of the converter corresponds to the thermal noise level and the maximum value of the dynamic range of the converter corresponds to a downlink signal power of the downlink RF signal.

4. The remote unit of claim 1, wherein the dynamic range of the converter is based on a data rate for a digital communication link between the wideband remote unit and the unit.

5. The remote unit of claim 4, wherein the converter comprises at least one analog-to-digital converter configured with a sampling rate corresponding to a maximum RF frequency of the composite uplink signal and the data rate for the digital communication link.

6. The remote unit of claim 1, wherein the downlink RF signal comprises a first multiple-input, multiple-output data stream received from the unit.

7. A distributed antenna system comprising:

a first unit of the distributed antenna system in communication with a base station;

a second unit of the distributed antenna system in communication with the first unit, the second unit comprising;

a downlink path, wherein the second remote unit is configured to wirelessly transmit a downlink RF signal from the downlink path; and

an uplink path, wherein the second unit is configured to process a wideband composite uplink signal comprising an uplink RF signal wirelessly received from a user by the second unit and a leaked downlink RF signal, wherein the leaked downlink RF signal is a signal component of the downlink RF signal wirelessly transmitted by the second unit that is leaked received into the uplink path;

a converter associated with uplink path and configured with a dynamic range suitable to digitize both the uplink RF signal and the leaked downlink RF signal of the wideband composite uplink signal, the converter further configured to convert the composite uplink signal to a digital representation of the uplink RF signal and to a digital representation of the leaked downlink RF signal; and

wherein the uplink path is further configured to transmit to the unit of the distributed antenna system in communication with the base station both the representation of the uplink RF signal and the representation of the leaked downlink RF signal.

8. The distributed antenna system of claim 7, wherein the second unit further comprises a splitter-combiner configured to couple to an antenna;

wherein an output of the downlink path is coupled to the splitter-combiner;

wherein an input of the uplink path is coupled to the splitter-combiner; and

wherein the leaked downlink RF signal enters the uplink path via the splitter-combiner.

9. The distributed antenna system of claim 7, wherein the first unit comprises a non-duplexer isolation sub-system configured to mitigate the representation of the leaked downlink RF signal.

10. The distributed antenna system of claim 7, wherein an uplink signal power of the uplink RF signal has a thermal noise level associated with the wideband remote unit, wherein the converter comprises an analog-to-digital converter, wherein the dynamic range of the converter is a function of a dynamic range of the analog-to-digital converter, wherein the minimum value of the dynamic range of the converter corresponds to the thermal noise level and the maximum value of the dynamic range of the converter corresponds to a downlink signal power of the downlink RF signal.

11. The distributed antenna system of claim 10, wherein the dynamic range of the converter is based on a data rate for a digital communication link between the first unit and the second unit.

12. The distributed antenna system of claim 11, wherein the analog-to-digital converter has a sampling rate corresponding to a maximum RF frequency of the wideband composite uplink signal and the data rate for the digital communication link.

13. The distributed antenna system of claim 7, wherein the first unit is configured to mitigate representation of the leaked downlink RF signal by at least one of:

filtering the representation of the leaked downlink RF signal from the wideband composite uplink signal;

cancelling the representation of the leaked downlink RF signal from the wideband composite uplink signal;

or attenuating the representation of the leaked downlink RF signal.

14. The distributed antenna system of claim 7, wherein the first unit is configured to mitigate the representation of the leaked downlink RF signal by:

correlating a downlink signal traversing the downlink path with a signal component traversing the uplink path;

generating a cancellation signal corresponding to the representation of the leaked downlink RF signal based on correlating the downlink signal traversing the downlink path with the signal component traversing the uplink path; and

combining the cancellation signal with a combined uplink signal generated from the representation of the uplink RF signal.

15. The distributed antenna system of claim 7, wherein the downlink RF signal comprises a first multiple-input, multiple-output data stream received from the first unit, wherein the distributed antenna system further comprises:

a third unit configured to;

wirelessly transmit an additional downlink RF signal comprising a second multiple-input, multiple-output data stream, wherein an additional leaked downlink RF signal is obtained from the additional downlink RF signal wirelessly transmitted by the third unit, and transmit a third digital RF signal to the first unit, wherein the third digital RF signal is generated from the additional leaked downlink RF signal, wherein the first unit is further configured to mitigate the third digital RF signal.

16. A method for a wideband remote unit of a digital antenna system that includes a unit in communication with a base station, the method comprising:

wirelessly transmitting a downlink RF signal from a downlink path of a remote antenna unit;

receiving a wideband composite uplink signal at an uplink path of the remote antenna unit, the wideband composite uplink signal comprising an uplink RF signal wirelessly received from a user by the wideband remote unit and a leaked downlink RF signal, wherein the leaked downlink RF signal is a signal component of the downlink RF signal wirelessly transmitted by the wideband remote unit and leaked into the uplink path;

converting the composite uplink signal to a digital representation of the uplink RF signal and to a digital representation of the leaked downlink RF signal, wherein the uplink path is configured with a dynamic range suitable to digitize both the uplink RF signal and the leaked downlink RF signal of the wideband composite uplink signal;

transmitting to the unit of the distributed antenna system in communication with the base station both the representation of the uplink RF signal and the representation of the leaked downlink RF signal.

17. The method of claim 16, the remote antenna unit further comprising a splitter-combiner configured to couple to an antenna;

wherein an output of the downlink path is coupled to the splitter-combiner;

wherein an input of the uplink path is coupled to the splitter-combiner; and

wherein the leaked downlink RF signal is leaked into the uplink path via the splitter-combiner.

18. The method of claim 16, further comprising:

mitigating the representation of the leaked downlink RF signal at the unit.

19. The method of claim 18, wherein mitigating the representation of the leaked downlink RF signal comprises at least one of:

filtering the representation of the leaked downlink RF signal from the wideband composite uplink signal;

cancelling the representation of the leaked downlink RF signal from the wideband composite uplink signal;

or attenuating the representation of the leaked downlink RF signal.

20. The method of claim 18, wherein mitigating the representation of the leaked downlink RF signal comprises:

correlating a downlink signal traversing the downlink path with a signal component traversing the uplink path;

generating a cancellation signal corresponding to the representation of the leaked downlink RF signal based on correlating the downlink signal traversing the downlink path with the signal component traversing the uplink path; and

combining the cancellation signal with a combined uplink signal generated from the representation of the uplink RF signal.