Uplink path integrity detection in distributed antenna systems

• US 9,894,623 B2
• Filed: 09/14/2012
• Issued: 02/13/2018
• Est. Priority Date: 09/14/2012
• Status: Active Grant

• Current Assignee: Andrew Wireless Systems GmbH (CommScope Holding Company, Inc.)
• Original Assignee: Andrew Wireless Systems GmbH (CommScope Holding Company, Inc.)
• Inventors: Dussmann, Alfons, Brighenti, Samuele
• Primary Examiner(s): REGO, DOMINIC E
• Application Number:
  US14/428,254
• Publication Number:
  US 20150249965A1
• Time in Patent Office: 1,978 Days
• Field of Search: 455522, 455 68, 455 69
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Aspects and features are directed to an uplink integrity detection sub-system. In one aspect, a distributed antenna system is provided that includes a remote antenna unit that communicates with wireless devices in a coverage area, additional remote antenna units that communicate with wireless devices in additional coverage areas, and a unit that communicates with the remote antenna unit and the additional remote antenna units. The unit includes a distributed antenna system controller. The distributed antenna system controller can determine that an undesirable signal component having a power level exceeding a threshold power is communicated via an uplink path from the remote antenna unit. The distributed antenna system controller can also minimize an impact of the undesirable signal component on the additional coverage areas of the additional remote antenna units. Minimizing the impact can include modifying the gain of the uplink path over which the undesirable signal component is communicated.

Claims

1. A distributed antenna system comprising:

a remote antenna unit configured to communicate with wireless devices in a coverage area;

one or more additional remote antenna units configured to communicate with wireless devices in one or more additional coverage areas; and

a unit configured for communicating with the remote antenna unit and the one or more additional remote antenna units, the unit comprising a distributed antenna system controller that is configured to;

determine that an undesirable signal component having a signal power exceeding a threshold power is communicated via an uplink path from the remote antenna unit; and

minimize an impact of the undesirable signal component on the additional coverage areas of the one or more additional remote antenna units, wherein minimizing the impact comprises modifying the gain of the uplink path over which the undesirable signal component is communicated as a function of a measured signal power of the undesirable signal component in the uplink path from the remote antenna unit.

2. The distributed antenna system of claim 1,

wherein the distributed antenna system controller is configured to determine that the undesirable signal component having the signal power exceeding the threshold power is communicated via the uplink path from the remote antenna unit by:

determining, based on an output power of a test signal traversing the uplink path, a noise figure of the remote antenna unit, and

determining that the noise figure of the remote antenna unit exceeds a threshold noise figure; and

wherein the distributed antenna system controller is configured to minimize the undesirable signal component by minimizing a noise contribution of the remote antenna unit.

3. The distributed antenna system of claim 2, wherein the distributed antenna system controller is configured to determine the noise figure based on the output power, a measurement bandwidth, and an input power of the test signal.

4. The distributed antenna system of claim 2, wherein the distributed antenna system controller is configured to minimize the noise contribution of the remote antenna unit by reducing the gain of the uplink path over which the undesirable signal component is communicated.

5. The distributed antenna system of claim 2, wherein the unit is one of a master unit, a zone combiner, or a base station router.

6. The distributed antenna system of claim 2, further comprising a test signal generator disposed in the remote antenna unit, wherein the test signal generator is configured to provide the test signal.

7. The distributed antenna system of claim 6,

further comprising a frequency scanner, wherein the frequency scanner is configured to determine respective frequencies of one or more extraneous signals in the coverage area of the remote antenna unit;

and

wherein the test signal generator is configured to provide the test signal at a test frequency such that a measurement bandwidth does not include the respective frequencies of the one or more extraneous signals.

8. The distributed antenna system of claim 2, further comprising a power detector disposed in the unit, wherein the power detector is configured to measure the output power at an input to a combiner module of a master unit.

9. The distributed antenna system of claim 2, further comprising a narrow-band filter disposed in the unit, the narrow-band filter configured to attenuate extraneous signals interfering with the test signal.

10. The distributed antenna system of claim 1, wherein the undesirable signal component comprises an interfering signal received by the remote antenna unit and wherein the remote antenna unit comprises:

a measurement receiver configured to measure the signal power of the interfering signal;

a controller configured to;

determine that the signal power of the interfering signal exceeds a threshold signal power;

configure an attenuator disposed in the remote antenna unit to attenuate the interfering signal based on the signal power of the interfering signal; and

generate a control message for the distributed antenna system controller, the control message identifying an amount of gain adjustment of the uplink path over which the interfering signal is communicated based on the signal power of the interfering signal; and

wherein the distributed antenna system controller is configured to minimize the undesirable signal component by providing a control signal to a gain adjustment device of the unit, the control signal configuring the gain adjustment device to adjust the gain of the uplink path over which the interfering signal is communicated by the amount of gain adjustment.

11. The distributed antenna system of claim 10, wherein the gain adjustment device of the unit comprises an amplifier configured to increase the gain of the uplink path over which the interfering signal is communicated in response to the control signal.

12. The distributed antenna system of claim 10, wherein the gain adjustment device of the unit comprises an attenuator configured to attenuate the gain of the uplink path over which the interfering signal is communicated in response to the control signal.

13. An uplink integrity detection sub-system, comprising:

a test signal generator disposed in a remote antenna unit of a distributed antenna system, wherein the test signal generator is configured to provide a test signal to an uplink path of the distributed antenna system;

a power detector disposed in a unit, the unit in communication with a plurality of remote antenna units of the distributed antenna system, wherein the power detector is configured to measure at a measurement point an output power of the test signal, wherein the output power of the test signal comprises a function of an input power of the test signal as modified by the test signal traversing the uplink path from the remote antenna unit; and

a distributed antenna system controller disposed in the unit, wherein the distributed antenna system controller is configured to determine a noise figure of the remote antenna unit based on the output power of the test signal and the input power of the test signal.

14. The uplink integrity detection sub-system of claim 13, wherein the distributed antenna system controller is further configured to:

determine that the noise figure of the remote antenna unit exceeds a threshold noise figure; and

minimize a noise contribution of the remote antenna unit.

15. The uplink integrity detection sub-system of claim 14, wherein the distributed antenna system controller is configured to minimize the noise contribution of the remote antenna unit by reducing the gain of the uplink path from the remote antenna unit.

16. The uplink integrity detection sub-system of claim 15, wherein the distributed antenna system controller is configured to determine the noise figure based on the output power, a measurement bandwidth, and the input power of the test signal provided by the test signal generator.

17. The uplink integrity detection sub-system of claim 13, further comprising:

a measurement receiver disposed in the remote antenna unit, the measurement receiver configured to measure the signal power of an interfering signal communicated via the uplink path from the remote antenna unit;

a controller disposed in the remote antenna unit, the controller configured to;

determine that the signal power of the interfering signal exceeds a threshold signal power; and

configure an attenuator disposed in the remote antenna unit to attenuate an uplink signal including the interfering signal based on the signal power of the interfering signal.

18. An uplink integrity detection sub-system, comprising:

a remote antenna unit of a distributed antenna system;

wherein the remote antenna unit comprises;

a measurement receiver configured to measure the signal power of an undesirable signal component having a frequency in an uplink frequency band used by the remote antenna unit for communicating uplink signals;

a controller configured to;

determine that the signal power of the undesirable signal component exceeds a threshold signal power; and

configure an attenuator disposed in the remote antenna unit to attenuate an uplink signal including the undesirable signal component based on the signal power of the undesirable signal component.

19. The uplink integrity detection sub-system of claim 18,

wherein the remote antenna unit is in communication with a unit, the unit in communication with a plurality of remote antenna units of the distributed antenna system,

wherein the controller is further configured to generate a control message for the unit, the control message identifying an amount of gain adjustment by the unit of an uplink path from the remote antenna unit,

wherein the uplink integrity detection sub-system further comprises a distributed antenna system controller disposed in the unit, wherein the distributed antenna system controller is configured to provide a control signal to a gain adjustment device of the unit, the control signal configuring the gain adjustment device to adjust the gain of the uplink path by the amount of gain adjustment.

20. The uplink integrity detection sub-system of claim 19, wherein the gain adjustment device of the unit comprises an amplifier configured to increase the gain of the uplink signal in response to the control signal.

21. The uplink integrity detection sub-system of claim 19, wherein the gain adjustment device of the unit comprises an attenuator configured to attenuate the uplink signal in response to the control signal.

22. The uplink integrity detection sub-system of claim 18,

wherein the remote antenna unit is in communication with a unit, the unit in communication with a plurality of remote antenna units of the distributed antenna system;

wherein the undesirable signal component comprises a noise contribution of the remote antenna unit; and

wherein the uplink integrity detection sub-system further comprises;

a test signal generator disposed in the remote antenna unit, wherein the test signal generator is configured to provide a test signal to an uplink path from the remote antenna unit to the unit;

a power detector disposed in the unit, wherein the power detector is configured to measure at a measurement point an output power of the test signal, wherein the output power of the test signal comprises a function of an input power of the test signal as modified by the test signal traversing the uplink path; and

a distributed antenna system controller disposed in the unit, wherein the distributed antenna system controller is configured to;

determine a noise figure of the remote antenna unit based on the output power of the test signal and the input power of the test signal;

determine that the noise figure of the remote antenna unit exceeds a threshold noise figure; and

minimize the noise contribution of the remote antenna unit based on the noise figure of the remote antenna unit.

23. The uplink integrity detection sub-system of claim 18, wherein the undesirable signal component comprises an intermodulation product having a frequency within the uplink frequency band, wherein the intermodulation product is generated by extraneous signals received by the remote antenna unit.