Femtocell Transmission Power Adaptation for Uplink Interference Mitigation

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Solution Overview

Problem

In wireless communication networks, especially in areas with high building penetration loss, small-coverage base stations like femtocells face interference issues due to uplink transmissions from nearby UEs, leading to degraded signal quality and service reliability.

Innovation Solution

Femtocells adapt their transmission power to mitigate interference by either short-term or long-term adjustments, either by redirecting interfering UEs to other cells or absorbing them, using methods that involve detecting interference, assessing quality of service, and making incremental or permanent power adjustments based on interference thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If small-coverage base stations (femtocells) are deployed to provide indoor services and improve signal quality in areas with high building penetration loss, then coverage and signal quality are improved, but uplink interference from nearby UEs increases

Engineering Contradiction:
Improvesignal qualityVSAvoiduplink interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic transmission power adjustment where the femtocell base station continuously monitors uplink interference levels and adapts its downlink transmission power accordingly. When uplink interference from nearby UEs exceeds a threshold, the system dynamically reduces downlink power to mitigate the interference, and increases power when interference subsides, creating a responsive adaptive system that balances coverage and interference management

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the transmission power parameter based on detected interference conditions. By monitoring uplink signal quality and interference levels, the femtocell adjusts its downlink transmission power parameter to optimize performance, transforming a static power configuration into a dynamically adjustable parameter that responds to real-time channel conditions

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If transmission power is increased to improve coverage area, then coverage is extended, but interference to other cells increases

Engineering Contradiction:
Improvecoverage areaVSAvoidinterference to other cells
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies different transmission power levels to different spatial locations and time periods. Instead of using a uniform high power level across the entire coverage area, the system implements localized power adjustment where power is increased only in directions and areas where interference is not problematic, while reducing power in directions where nearby UEs cause uplink interference, creating a spatially differentiated transmission strategy

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2965575B1Uplink interference mitigation by adapting open cell transmission power
Publication Date: 2017.04.19 QUALCOMM INC
  • EP2965575B1 patent drawingFigure 1
  • EP2965575B1 patent drawingFigure 2
  • EP2965575B1 patent drawingFigure 3

AI summary

Methods and apparatus are disclosed for interference mitigation of an open-access node. The method includes determining, at the open-access node, whether uplink interference from a mobile entity is above a threshold. The method includes adjusting a transmission power to trigger a hand-in of the mobile entity in response to determining the uplink interference is above the threshold. The method includes handing-in the mobile entity from a first cell in response to adjusting the transmission power. The method includes redirecting the mobile entity to a second cell different from the first cell.