US 12,267,705 B2
Method and apparatus for detecting and mitigating passive intermodulation interference in a communication system
Amr Abdelmonem, Northbrook, IL (US); Pablo Tacconi, Arlington, TX (US); and Igor Goodman, Buffalo Grove, IL (US)
Assigned to ISCO International, LLC, Schaumburg, IL (US)
Filed by ISCO International, LLC, Schaumburg, IL (US)
Filed on Oct. 22, 2020, as Appl. No. 17/076,930.
Claims priority of provisional application 62/925,891, filed on Oct. 25, 2019.
Prior Publication US 2021/0127284 A1, Apr. 29, 2021
Int. Cl. H04W 24/08 (2009.01); H04L 27/00 (2006.01)
CPC H04W 24/08 (2013.01) [H04L 27/0008 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method, comprising:
receiving, by a circuit, a first uplink signal generated by a communication device without passive modulation interference;
measuring, by the circuit, a time-domain profile and a frequency-domain profile of the first uplink signal to generate pre-determined profile thresholds;
comparing, by the circuit, a second time-domain profile of a second uplink signal and a second frequency-domain profile of the second uplink signal with the pre-determined profile thresholds to detect a passive intermodulation interference in the second uplink signal, wherein the passive intermodulation interference is caused by one or more unknown downlink signals generated by one or more transmitters, wherein the one or more transmitters are unassociated with the communication device generating the first uplink signal; and
performing, by the circuit, signal conditioning on the second uplink signal to reduce the passive intermodulation interference, wherein the signal conditioning is based on a profile of the passive modulation interference that the circuit calculates by mathematically solving a system of equations comprising coefficients for a known downlink signal from a transmitter associated with the communication device and unknown coefficients for the one or more unknown downlink signals.