TDD Interference Mitigation via Dynamic Configuration

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Solution Overview

Problem

In mobile networks using time division duplex (TDD) configurations, interference issues arise due to differing uplink and downlink configurations between neighboring cells, leading to eNB-to-eNB and UE-to-UE interferences, which degrade system performance, especially near cell edges, and current systems' slow configuration changes fail to adapt quickly to varying traffic patterns.

Innovation Solution

The method involves an evolved Node B (eNB) identifying potential eNB-to-eNB and UE-to-UE interferences by correlating received signals with locally generated reference signals and determining interference thresholds, and performing interference mitigation by adjusting transmit powers and scheduling to minimize interference, using an additional interference type field in the interference overload indicator (IOI) information element and dynamic TDD UL/DL configuration changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If TDD configurations are used to separate uplink and downlink transmissions, then spectrum efficiency is improved, but inter-cell interference occurs when neighboring cells have different TDD configurations

Engineering Contradiction:
Improvespectrum efficiencyVSAvoidinter-cell interference
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic TDD configuration changes where the eNB can switch between different TDD configurations (0-6) based on real-time traffic conditions and interference levels. This allows the system to adaptively adjust the uplink-downlink subframe allocation ratio, transforming from static to dynamic configuration to optimize both spectrum efficiency and interference management

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the TDD configuration parameters (configuration index 0-6, each with different UL-DL subframe patterns) to mitigate interference. By switching between predefined TDD configurations, the system alters the temporal allocation parameters of uplink and downlink transmissions to avoid simultaneous opposite-direction transmissions in neighboring cells

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If static TDD configurations are used, then system complexity is reduced, but the system cannot adapt quickly to varying traffic patterns

Engineering Contradiction:
Improveconfiguration complexityVSAvoidtraffic pattern adaptation
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system transitions from static to dynamic TDD configuration by implementing real-time monitoring of traffic conditions and automatic switching between predefined configurations. The eNB dynamically adjusts the TDD configuration index based on current uplink-downlink traffic ratios, enabling quick adaptation to varying traffic patterns while maintaining manageable complexity through a finite set of predefined configurations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements periodic reevaluation of traffic conditions and periodic switching between TDD configurations. The system monitors traffic patterns at regular intervals and adjusts configurations periodically, creating a rhythmic adaptation cycle that balances responsiveness with system stability

Inventive Principle:
Principle #19Periodic action

3Reliability

If interference mitigation through configuration changes is implemented, then system performance is improved, but detection and measurement complexity increases

Engineering Contradiction:
Improvesystem performanceVSAvoidinterference detection complexity
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements feedback mechanisms where the eNB monitors interference conditions and system performance, then uses this feedback to automatically adjust TDD configurations. The feedback loop includes measuring interference levels, evaluating current configuration effectiveness, and triggering configuration changes when performance thresholds are violated, creating a self-optimizing system

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2936740B1Method and evolved node b for interference mitigation in time division duplex systems
Publication Date: 2018.02.28 BLACKBERRY LTD
  • EP2936740B1 patent drawingFigure 1~2
  • EP2936740B1 patent drawingFigure 3
  • EP2936740B1 patent drawingFigure 4

AI summary

Methods and apparatus at an evolved Node B (eNB) and user equipment (UE) in cells operating in time division duplex with a first configuration and having a neighbor cell eNB operating in time division duplex with a second configuration, the methods and apparatus: identifying potential eNB-to-eNB; UE-to-UE; eNB-to-UE; and UE-to-eNB interference. Further methods and apparatus to report interference including enumerated interference types to neighbor cell eNBs. Further, methods and apparatus for interference mitigation.