Interference Detection, Identification, Extraction and Reporting

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.

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.