Candidate Frequency Blanking for Dynamic PIM Interference Isolation

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Solution Overview

Problem

Existing methods assume predictable and static interference like PIM can be reliably compensated for, but in reality, PIM can be transient or caused by environmental unknowns, leading to ineffective mitigation strategies.

Innovation Solution

A method involving a binary search approach to divide candidate frequencies into subsets, blank one subset, and determine interference causation based on interference reduction, allowing for real-time identification and mitigation of PIM caused by known or unknown factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If simulation and/or ML models are used to predict and compensate for PIM, then interference mitigation is improved, but reliability deteriorates because PIM may be transient or changeable

Engineering Contradiction:
Improveinterference mitigation reliabilityVSAvoidmodel adaptability to transient PIM
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from static simulation/ML models to a dynamic binary search approach that adapts to changing PIM conditions. The system continuously divides candidate frequencies into subsets and tests them in real-time, allowing the interference mitigation strategy to evolve as PIM sources change or disappear, thereby maintaining reliability in transient environments.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs self-diagnosis by autonomously identifying PIM-causing frequencies through the binary search method. It automatically divides candidate frequencies, blanks subsets, measures interference reduction, and determines causation without external intervention, enabling the network to self-correct against transient PIM interference.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If all candidate frequencies are continuously monitored to identify PIM sources, then measurement precision is improved, but productivity deteriorates due to increased processing time

Engineering Contradiction:
Improveinterference source identification accuracyVSAvoidfrequency identification speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the set of candidate frequencies into smaller subsets through the binary search process. Instead of monitoring all candidate frequencies simultaneously, the system divides them into first and second subsets, blanks one subset at a time, and identifies PIM sources by measuring interference reduction in each segment, thereby achieving precise identification with reduced processing time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The binary search methodology enables continuous interference identification without exhaustive testing. By systematically dividing candidate frequencies and testing subsets in sequence, the system maintains continuous useful action of identifying PIM sources efficiently, avoiding the productivity loss associated with monitoring all frequencies simultaneously while preserving measurement precision.

Inventive Principle:
Principle #20Continuity of useful action

3Object-affected harmful factors

If candidate frequencies are blanked to identify PIM sources, then harmful factors are reduced, but loss of information occurs about potential interference sources

Engineering Contradiction:
ImprovePIM interference levelVSAvoidinterference source data
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The system implements feedback by measuring uplink noise levels before and after blanking candidate frequency subsets. This feedback mechanism allows the system to determine whether a blanked subset contained PIM-causing frequencies based on interference reduction, thereby reducing harmful PIM effects while preserving information about which frequencies are actual interference sources through the measurement results.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4331295B1Reducing interference in a communications network
Publication Date: 2026.02.25 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4331295B1 patent drawingFigure 1
  • EP4331295B1 patent drawingFigure 2
  • EP4331295B1 patent drawingFigure 3

AI summary

A computer implemented method (200) for reducing interference experienced at a first frequency due to transmissions made at one or more of a plurality of candidate frequencies. The method comprises i) dividing (202) the candidate frequencies into a first subset of candidate frequencies and a second subset of candidate frequencies; ii) blanking (204) the first subset of candidate frequencies; and iii) determining (206) whether the interference experienced at the first frequency is due to transmissions made on the first subset of candidate frequencies, dependent on whether said interference is reduced as a result of blanking the first subset of candidate frequencies.