Radio Unit Interference Reduction via Dynamic Downlink Power Control

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Solution Overview

Problem

Radio devices, especially those with multiple antenna branches, face interference issues due to self-generated intermodulation distortion, which can desensitize uplink channels and impact performance.

Innovation Solution

A method is implemented in radio units to detect interference levels in antenna branches, select affected branches, identify impacted uplink channels, and reduce downlink power on associated carriers to mitigate interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If downlink power is reduced to mitigate intermodulation distortion, then interference in uplink channels is reduced, but downlink transmission power and coverage are degraded

Engineering Contradiction:

Improveinterference in uplink channelsVSAvoiddownlink transmission power

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The system dynamically adjusts the downlink power parameter based on detected interference conditions. When intermodulation distortion is detected in uplink channels, the downlink power on affected carriers is reduced to a lower level, and when interference subsides, power is restored. This dynamic parameter adjustment resolves the contradiction by adapting power levels to actual interference conditions rather than maintaining fixed high power.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If downlink power is reduced to mitigate intermodulation distortion, then interference in uplink channels is reduced, but overall system capacity and throughput are degraded

Engineering Contradiction:

Improveinterference in uplink channelsVSAvoidsystem capacity and throughput

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

Instead of reducing downlink power across all carriers and antenna branches, the system applies power reduction only to specific carriers and branches where intermodulation distortion is detected. This localized mitigation preserves system capacity on unaffected carriers while reducing interference on affected ones, resolving the contradiction between interference reduction and maintaining overall system productivity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system applies partial power reduction rather than complete shutdown of affected downlink carriers. By reducing power to a moderate level rather than eliminating it entirely, the system achieves sufficient interference mitigation while maintaining some downlink capacity, thus balancing interference reduction with preservation of system throughput.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If multiple antenna branches are monitored for interference, then interference detection accuracy is improved, but device complexity and processing overhead increase

Engineering Contradiction:

Improveinterference detection accuracyVSAvoidprocessing overhead

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides the antenna array into multiple independent branches and monitors each branch separately for interference. By segmenting the monitoring process across branches, the system achieves comprehensive interference detection accuracy while distributing the processing load, preventing any single processing unit from becoming overwhelmed by analyzing all antenna signals simultaneously.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250030489A1Reduction of interference caused by downlink aggressors

Publication Date: 2025.01.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Methods and systems are described for reducing interference on radio units from passive intermodulation (PIM) distortion. Base station radio units can have multiple antennas, each receiving and sending communications over various frequencies. Embodiments under the present disclosure can identify the source of PIM and then reduce power of the aggressor downlink carriers on the impacted antennas. This can reduce the PIM that desensitizes the uplink receivers.