# US 12,603,667 B2 · Method and apparatus for detecting and correcting passive intermodulation (PIM) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,603,667 B2 - Document ID: US12603667B2 - Status: Granted - Kind: B2 - Application number: 18/556,426 - Filed: 2021-05-04 - Published: 2025-03-13 - Granted: 2026-04-14 - Earliest claimed: 2021-05-04 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget Lm Ericsson (Publ) - Inventors: Zhongwen Zhu; Manoj Kopparambil Nambiar - Web page: https://patentgrep.com/patent/US12603667B2 ## CPC - H04B 1/1027: {assessing signal quality or detecting noise/interference for the received signal} - H04B: TRANSMISSION ## Abstract The disclosure relates to a method, apparatus and computer readable media, for detecting and correcting passive intermodulation (PIM). The method comprises receiving a radio frequency (RF) signal. The method comprises providing the RF signal to a first and a second PIM detectors. The method comprises, upon detection of PIM by at least one of the first and second PIM detectors, for which, based on a schedule, the detection of PIM is applicable at a time of detection of PIM, activating PIM correction. ## Claims ### Claim 1 A method for detecting and correcting passive intermodulation (PIM), comprising: receiving a radio frequency (RF) signal; providing the RF signal to a legacy PIM detector (PIMD) and a model-based PIM detector, wherein the model-based PIM detector comprises a features extractor which extracts features from the RF signal and feeds the features into a trained model for detection of PIM and wherein the features extracted from the RF signal comprise minimum, maximum, average, standard deviation of amplitude and frequency measurements of the RF signal, and corresponding PIM or NO-PIM expected outputs correspond to outputs from the model-based PIM detector or from the PIMD; and upon detection of PIM by at least one of the PIMD and the model-based PIM detector, for which, based on a schedule, the detection of PIM is applicable at a time of detection of PIM, activating PIM correction. ### Claim 2 (depends on 1) The method of claim 1, wherein the RF signal is received by a base station through an antenna. ### Claim 3 (depends on 2) The method of claim 2, wherein activating PIM correction comprises correcting a new RF signal to be transmitted from the base station through the antenna. ### Claim 4 (depends on 1) The method of claim 1, wherein the features extracted from the RF signal, and the corresponding PIM or NO-PIM expected outputs, are collected and labeled for training the model. ### Claim 5 (depends on 1) The method of claim 1, further comprising receiving a new model, updated via offline training, and updating the trained model-based PIM detector with the new model. ### Claim 6 (depends on 1) The method of claim 1, wherein activating PIM correction comprises sending a signal to a PIM Corrector (PIMC) Controller (PIMC-C) decoupled from a PIMC Processor (PIMC-P). ### Claim 7 (depends on 6) The method of claim 6, wherein the PIMC-C and the PIMC-P are not collocated in a same hardware and wherein PIM correction is effected by PIMC-C and PIMC-P collectively. ### Claim 8 (depends on 7) The method of claim 7, wherein one PIMC-C serves a plurality of base stations. ### Claim 9 (depends on 1) The method of claim 1, wherein the schedule defines at least one of: a time period when detection of PIM is applicable for the PIMD only, a time period when detection of PIM is applicable for the model-based PIM detector only, and a time period when detection of PIM is applicable for both the PIMD and the model-based PIM detector concurrently. ### Claim 10 An apparatus for detecting and correcting passive intermodulation (PIM) comprising processing circuits and a memory, the memory containing instructions executable by the processing circuits whereby the apparatus is operative to: receive a radio frequency (RF) signal; provide the RF signal to a legacy PIM detector (PIMD) and a model-based PIM detector, wherein the model-based PIM detector comprises a features extractor which extracts features from the RF signal and feeds the features into a trained model for detection of PIM and wherein the features extracted from the RF signal comprise minimum, maximum, average, standard deviation of amplitude and frequency measurements of the RF signal, and corresponding PIM or NO-PIM expected outputs correspond to outputs from the model-based PIM detector or from the PIMD; and upon detection of PIM by at least one of the PIMD and the model-based PIM detector, for which, based on a schedule, the detection of PIM is applicable at a time of detection of PIM, activate PIM correction. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the RF signal is received through an antenna. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein activating PIM correction comprises correcting a new RF signal to be transmitted through the antenna. ### Claim 13 (depends on 10) The apparatus of claim 10, wherein the features extracted from the RF signal, and the corresponding PIM or NO-PIM expected outputs, are collected and labeled for training the model. ### Claim 14 (depends on 10) The apparatus of claim 10, further operative to receive a new model, updated via offline training, and update the trained model-based PIM detector with the new model. ### Claim 15 (depends on 10) The apparatus of claim 10, wherein activating PIM correction comprises sending a signal to a PIM Corrector (PIMC) Controller (PIMC-C) decoupled from a PIMC Processor (PIMC-P). ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the PIMC-C and the PIMC-P are not collocated in a same hardware and wherein PIM correction is effected by PIMC-C and PIMC-P collectively. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein one PIMC-C serves a plurality of apparatuses. ### Claim 18 (depends on 10) The apparatus of claim 10, wherein the schedule defines at least one of: a time period when detection of PIM is applicable for the PIMD only, a time period when detection of PIM is applicable for the model-based PIM detector only, and a time period when detection of PIM is applicable for both the PIMD and the model-based PIM detector concurrently. ### Claim 19 (depends on 10) The apparatus of claim 10, wherein the apparatus is a radio base station. ### Claim 20 A non-transitory computer readable media having stored thereon instructions for detecting and correcting passive intermodulation (PIM), the instructions comprising: receiving a radio frequency (RF) signal; providing the RF signal to a legacy PIM detector (PIMD) and a model-based PIM detector, wherein the model-based PIM detector comprises a features extractor which extracts features from the RF signal and feeds the features into a trained model for detection of PIM and wherein the features extracted from the RF signal comprise minimum, maximum, average, standard deviation of amplitude and frequency measurements of the RF signal, and corresponding PIM or NO-PIM expected outputs correspond to outputs from the model-based PIM detector or from the PIMD; and upon detection of PIM by at least one of the PIMD and the model-based PIM detector, for which, based on a schedule, the detection of PIM is applicable at a time of detection of PIM, activating PIM correction.