Interference detection and identification in wireless network from RF or digitized signal

Patent metadata

Field	Value
Publication number	US-10609582-B2
Application number	US-201715691615-A
Country	US
Kind code	B2
Filing date	Aug 30, 2017
Priority date	Sep 8, 2016
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

A method for detecting interference in a wireless system is disclosed. The method includes receiving an uplink signal at a remote radio head in a distributed base station, passing the uplink signal from the remote radio head to a baseband unit over a front-haul communication link as baseband IQ data, and intercepting the baseband IQ data at a tester coupled between the remote radio head and the baseband unit. Processing of the IQ data is performed to determine whether an interfering signal is present in the uplink signal.

First claim

The invention claimed is:

1. A method for detecting interference in a wireless system, the method comprising:
receiving an uplink signal at a remote radio head in a distributed base station;
passing the uplink signal from the remote radio head to a baseband unit over a front-haul communication link as baseband IQ data;
intercepting the baseband IQ data at a tester coupled between the remote radio head and the baseband unit;
calculating a signal statistic for the uplink signal from the baseband IQ data;
determining whether an interfering signal is present based on the signal statistic;
wherein calculating a signal statistic comprises calculating a peak-to-average power ratio;
and further de-noising the baseband IQ data prior to calculating the peak-to-average power ratio; and
wherein the de-noising comprises applying a wavelet packet decomposition to the baseband IQ data.

2. The method of claim 1 , wherein calculating a signal statistic comprises calculating a kurtosis value from the baseband IQ data.

3. The method of claim 2 , wherein calculating the kurtosis value comprises calculating the Kurtosis value on an entire signal bandwidth.

4. The method of claim 2 , wherein calculating the kurtosis value comprises calculating the Kurtosis value on a partial signal bandwidth.

5. The method of claim 2 and further comprising comparing the calculated kurtosis value with an expected value to determine whether an interfering signal is present.

6. A method for detecting interference in a wireless system, the method comprising:
receiving an uplink signal at a remote radio head in a distributed base station;
passing the uplink signal from the remote radio head to a baseband unit over a front-haul communication link as baseband IQ data;
intercepting the baseband IQ data at a tester coupled between the remote radio head and the baseband unit;
calculating a signal statistic for the uplink signal from the baseband IQ data;
determining whether an interfering signal is present based on the signal statistic;
wherein calculating a signal statistic comprises calculating a peak-to-average power ratio; and further comprising:
determining if there is signal activity present in the baseband IQ data;
determining whether the determined signal activity corresponds to a transition in signal energy; and
when the determined signal activity corresponds to a transition, omitting the calculation of peak to average power ratio for the baseband IQ data.

7. A method for detecting interference in a wireless system, the method comprising:
receiving an uplink signal at a remote radio head in a distributed base station;
passing the uplink signal from the remote radio head to a baseband unit over a front-haul communication link as baseband IQ data;
intercepting the baseband IQ data at a tester coupled between the remote radio head and the baseband unit;
applying a non-linear transformation to the baseband IQ data;
determining whether an interfering signal is present based on the results of the non-linear transformation of the baseband IQ data;
wherein applying a non-linear transformation comprises applying one or more of a cyclic autocorrelation function to the baseband IQ data and calculating the spectral correlation density for the baseband IQ data.

8. A method for detecting passive intermodulation (PIM) interference in a wireless system, the method comprising:
transmitting tones in a downlink channel at a remote radio head of a distributed base station;
receiving an uplink signal at the remote radio head in the distributed base station;
passing the uplink signal from the remote radio head to a baseband unit over a front-haul communication link as baseband IQ data;
intercepting the baseband IQ data at a tester coupled between the remote radio head and the baseband unit;
applying spectral estimation to the baseband IQ data around an expected PIM interferer;
determining whether the expected PIM interferer is present based on the spectral estimation for the baseband IQ data;
further comprising establishing a noise floor of the distributed base station; and
wherein applying spectral estimation comprises gathering a set of an analysis metrics including power in the expected PIM interferer, a standard deviation and mean of the noise floor, and a bandwidth of the expected PIM interferer.

9. The method of claim 8 , and further comprises testing the distributed base station by repeating the sending the tones in the downlink channel of the remote radio head, the receiving the uplink signals and saving a history of the tests.

10. The method of claim 9 , and further comprises inserting a random delay between sequential tests of the testing of the distributed base station.

11. The method of claim 9 , and further comprising:
comparing at least one of the analysis metrics to an associated threshold; and
updating one or more counters, each counter is correlated with a possible outcome of a test.

12. A tester, comprising:
at least one interface to communicatively couple the tester unit to a front-haul communication link used for communicating front-haul data to a remote radio head (RRH) having one or more antenna ports;
a programmable processor, coupled to the interface, configured to execute software, wherein the software is operable to cause the tester to do the following:
intercept baseband IQ data received from the remote radio head on the front-haul communication link;
calculate a signal statistic for the uplink signal from the baseband IQ data;
determine whether an interfering signal is present based on the signal statistic;
wherein calculating a signal statistic comprises calculating a peak-to-average power ratio;
and further de-noising the baseband IQ data prior to calculating the peak-to-average power ratio; and
wherein the de-noising comprises applying a wavelet packet decomposition to the baseband IQ data.

13. The tester of claim 12 , wherein calculate a signal statistic comprises calculating a kurtosis value.

Assignees

• Commscope Technologies Llc

Inventors

• Hannan Ariful
• Al-Mufti Khalid W
• Gravely Thomas B
• Beck Andrew E

Classifications

• H04B17/26

  using historical data, averaging values or statistics · CPC title

• H04W24/08 Primary

  Testing, {supervising or monitoring} using real traffic · CPC title

• H04W52/24

  using SIR [Signal to Interference Ratio] or other wireless path parameters · CPC title

• H04B17/345

  Interference values ({signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]} H04B17/336) · CPC title

• H04W72/082

  Electricity · mapped topic