Interference Detection, Identification, Extraction and Reporting

• US 20080160916A1
• Filed: 01/08/2008
• Published: 07/03/2008
• Est. Priority Date: 04/28/1999
• Status: Abandoned Application

• Current Assignee: ISCO International Inc.
• Original Assignee: ISCO International Inc.
• Inventors: Willetts, Mark N., Jagger, Charles E., Tobia, Micolino
• Application Number:
  US11/971,017
• Publication Number:
  US 20080160916A1
• Time in Patent Office: Days
• US Class Current: 455/63.1
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 1/71 the interference being narrowband interference
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 2001/1063 using a notch filter
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04B 2201/709718 Determine interference
• CPC Class Codes: H04B 7/005 Control of transmission; Equalising
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
• CPC Class Codes: H04W 28/20 Negotiating bandwidth
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/541 : using the level of interference
• CPC Class Codes: H04W 72/542 : using measured or perceived quality
• CPC Class Codes: H04W 88/02 : Terminal devices
• CPC Class Codes: H04W 88/08 : Access point devices

Abstract

An adaptive notch filter (ANF) module selectively filters a received wideband communication signal to eliminate narrowband interference that lies within the frequency spectrum of the wideband communication signal. To determine the presence of narrowband interference, the ANF module scans various known narrowband channels that lie within the frequency spectrum of the wideband communication signal and determines signal strengths for each of the narrowband channels. The signal strengths from the narrowband channels are compared to a threshold that is derived from the narrowband signal strengths. Narrowband channels having signal strengths that are greater than the threshold are determined to have interference.

Claims

1. A method of detecting and eliminating narrowband interference in a wideband communication signal having a frequency bandwidth with narrowband channels disposed therein, the method comprising:

scanning at least some of the narrowband channels to determine signal strengths in at least some of the narrowband channels;

determining a threshold based on the signal strengths in at least some of the narrowband channels;

identifying fading narrowband channels having signal strengths that do not exceed the threshold and that were previously identified as exceeding the threshold, based on how long the identified narrowband channels have not exceeded the threshold; and

filtering the wideband communication signal at a frequency corresponding to a fading narrowband channel.

2. The method of claim 1, comprising de-assigning filters from narrowband channels having signal strengths below the threshold that are not identified as having fading interference.

3. The method of claim 1, wherein a narrowband channel is identified as a fading narrowband channel when its signal strength is below the threshold for less than 20 milliseconds.

4. A system adapted to detect and eliminate narrowband interference in a wideband communication signal having a frequency bandwidth with narrowband channels disposed therein, the system comprising:

a scanner adapted to scan at least some of the narrowband channels to determine signal strengths in at least some of the narrowband channels in an order representative of a probability that the narrowband channels will have interference;

a notch module adapted to receive the wideband communication signal and to selectively remove narrowband interference from the wideband communication signal to produce a filtered wideband communication signal; and

a controller coupled to the scanner and to the notch module, wherein the controller is adapted to determining a threshold based on the signal strengths in at least some of the narrowband channels, to identify fading narrowband channels having signal strengths that do not exceed the threshold and that were previously identified as exceeding the threshold, based on how long the identified narrowband channels have not exceeded the threshold and to control the notch module to filter the wideband communication signal at a frequency corresponding to a fading narrowband channel.

5. The system of claim 4, wherein the controller is adapted to de-assigning notch modules from filtering narrowband channels having signal strengths below the threshold that are not identified as having fading interference.

6. The system of claim 4, wherein the controller is adapted to identify a narrowband channel as a fading narrowband channel when its signal strength is below the threshold for less than 20 milliseconds.