Base Station Passive Intermodulation Detection Using TDR

Solution Overview

Problem

Current methods for detecting passive intermodulation (PIM) in broadband communication networks are resource-intensive and time-consuming, requiring expensive equipment and labor, and are ineffective in identifying the root causes of receiver degradation due to PIM issues, especially in aging networks.

Innovation Solution

Utilizing BTS radio resources for direct measurement of passive intermodulation using time-domain reflectometry (TDR) and cross-correlation (CCR) methods to identify the location and strength of PIM signals, enabling remote detection and correction of faults without external equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external PIM testers and manual field measurements are used to detect passive intermodulation, then measurement precision is improved, but device complexity and loss of time increase

Engineering Contradiction:

ImprovePIM detection precisionVSAvoidtime for field measurement

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The base station performs self-diagnosis by using its own transmission signals to generate and detect passive intermodulation products. The processor identifies PIM sources by analyzing signals already present in the system, eliminating the need for external testers and field measurements while maintaining detection precision.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The processor acts as an intermediary that uses the base station's existing transmission signals as a mediator to indirectly detect PIM sources. By analyzing the interaction between transmission signals and potential PIM sources, the system identifies faults without requiring physical access to remote antenna components.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If external PIM testers are deployed for PIM detection, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

ImprovePIM detection precisionVSAvoidequipment complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The base station performs self-diagnosis by using its own transmission signals to generate and detect passive intermodulation products. The processor identifies PIM sources by analyzing signals already present in the system, eliminating the need for external testers and field measurements while maintaining detection precision.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The base station's existing processor and signal transmission capabilities are made multi-functional by enabling them to perform PIM detection in addition to their primary communication functions. This eliminates the need for separate specialized PIM testing equipment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If statistical KPI methods are used to indirectly measure PIM, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:

Improvemeasurement system complexityVSAvoidPIM measurement precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The processor acts as an intermediary that uses the base station's existing transmission signals as a mediator to indirectly detect PIM sources. By analyzing the interaction between transmission signals and potential PIM sources, the system identifies faults without requiring physical access to remote antenna components.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical field measurement systems with signal processing-based detection. Instead of physically accessing antenna components with external testers, the system uses electronic signal analysis to identify PIM sources, reducing complexity while improving precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables precise identification and correction of PIM sources within the antenna network, reducing the need for external testers and manual labor, while supporting multiple standards and bandwidths, and allowing simultaneous detection of multiple PIM sources.

Implementation Method 1

Utilizing BTS radio resources for direct measurement of passive intermodulation using time-domain reflectometry (TDR) and cross-correlation (CCR) methods to identify the location and strength of PIM signals

Methodology Applied

Scientific EffectTime-domain reflectometry:

Implementation Method 2

Utilizing BTS radio resources for direct measurement of passive intermodulation using time-domain reflectometry (TDR) and cross-correlation (CCR) methods to identify the location and strength of PIM signals

Methodology Applied

Scientific EffectCross-correlation:

Data Source

PatentEP2875600B1Detecting intermodulation in broadband communication affecting receiver sensitivity

Publication Date: 2025.04.02 NOKIA SOLUTIONS & NETWORKS OY

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AI summary

The present invention provides methods, apparatuses and a program relating to detecting passive intermodulation in broadband communication. The present invention includes transmitting, at a base station, a first signal at a first centre frequency and a second signal at a second centre frequency with a predetermined transmit power, capturing, at the base station, received signal at a reception frequency, obtaining, at the base station, a delay between the transmitted signal and a passive intermodulation caused received signal.