PIM Finder System Using AoA for Base Station Interference Location

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Solution Overview

Problem

Current methods for locating external sources of passive intermodulation (PIM) interference on rooftops are difficult, expensive, and often ineffective, requiring manual testing and equipment that is bulky and requires access to rooftops.

Innovation Solution

A PIM finder system that utilizes the base station's own transmission and reception components to locate PIM sources by modifying the downlink data stream, injecting specific signals, and using angle of arrival (AoA) and beamforming techniques to identify the location of PIM sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual testing methods are used to locate PIM sources, then equipment can identify interference sources, but the process becomes difficult, expensive, and time-consuming requiring access to rooftops and bulky equipment

Engineering Contradiction:

ImprovePIM source location accuracyVSAvoidtesting equipment complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The base station uses its own transmission and reception components to locate PIM sources, eliminating the need for external bulky testing equipment. The system performs self-diagnosis by injecting test signals through its existing antenna and analyzing the returned interference patterns, thereby serving itself rather than requiring separate specialized equipment

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces manual physical testing methods with automated signal processing techniques. Instead of technicians physically accessing rooftops with bulky equipment, the system uses electronic signal injection and AoA computation to automatically locate PIM sources, substituting mechanical/physical processes with electronic/digital ones

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If manual rooftop access methods are used, then PIM sources can be located, but the process requires difficult access to rooftops and manual intervention

Engineering Contradiction:

ImprovePIM source location accuracyVSAvoidoperational simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The base station autonomously performs PIM source location without requiring technician intervention or rooftop access. The system automatically injects test signals, receives interference patterns, computes AoA, and identifies PIM sources, eliminating the need for manual operations and difficult physical access

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent introduces signal processing algorithms and AoA computation as intermediaries between the base station and PIM sources. Instead of direct physical inspection requiring rooftop access, the system uses electromagnetic signal analysis as an intermediary mechanism to indirectly locate PIM sources from a remote location

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If conventional PIM hunting processes are used, then interference sources can be identified, but the process is slow and requires extensive manual testing

Engineering Contradiction:

ImprovePIM source identification reliabilityVSAvoidPIM locating speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system periodically injects test signals at different frequencies and computes AoA measurements systematically. This structured periodic approach ensures reliable detection of PIM sources while automating the process to increase speed, replacing ad-hoc manual hunting with methodical automated cycles

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The base station analyzes the received interference patterns and uses AoA computation feedback to iteratively refine PIM source location estimates. This feedback mechanism improves identification reliability by confirming detections through multiple measurements while automating the process to reduce time compared to manual methods

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The PIM finder system simplifies, speeds up, and makes the PIM locating process more reliable by reducing the need for manual testing and enabling the use of existing base station components, thereby improving the efficiency of PIM source identification and mitigation.

Implementation Method 1

computing an angle of arrival (AoA) of the interference signal to obtain an estimated location of the interference source

Methodology Applied

Scientific EffectAngle of Arrival (AoA):

Implementation Method 2

causing one or more radio frequency (RF) signals corresponding to the one or more modified signals to be transmitted by the base station; responsive to transmission of the one or more RF signals, monitoring uplink (UL) signals received by the base station to detect interference

Methodology Applied

Scientific EffectElectromagnetic radiation:

Data Source

PatentUS12301298B1Methods and systems for locating interference sources via angle of arrival (AoA)

Publication Date: 2025.05.13 ISCO INTERNATIONAL LLC

AI summary

Aspects of the subject disclosure may include, for example, identifying an interference signal in one or more radio frequency (RF) signals received by an antenna system, the interference signal originating from an interference source, and computing an angle of arrival (AoA) of the interference signal to obtain an estimated location of the interference source. Other embodiments are disclosed.