Closed-Loop Interference Feedback for TDD Remote Mitigation

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Solution Overview

Problem

Current remote interference mitigation schemes are inadequate in environments with atmospheric ducting or high interference levels, leading to degraded uplink performance due to downlink-to-uplink interference in TDD networks.

Innovation Solution

Implementing a closed-loop feedback mechanism using reference signals (RS-1 and RS-2) for remote interference mitigation, where RS-1 indicates interference detection and RS-2 confirms the persistence of atmospheric ducting, allowing aggressor nodes to adjust their transmission patterns, power, and guard periods accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If synchronized TDD UL/DL patterns are used across all cells, then cross-link interference between network nodes is reduced, but remote interference from atmospheric ducting cannot be mitigated

Engineering Contradiction:
Improvecross-link interferenceVSAvoidinterference mitigation adaptability
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent implements a feedback mechanism where victim network nodes detect remote interference from atmospheric ducting and send reference signals (RS-1, RS-2) to aggressor network nodes. The aggressor nodes receive these feedback signals and adjust their transmission parameters accordingly, enabling adaptive mitigation of remote interference while maintaining synchronized TDD patterns for cross-link interference protection

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static synchronized TDD patterns to dynamic interference mitigation by allowing aggressor nodes to adjust transmission power, antenna downtilt, and guard period lengths based on real-time feedback from victim nodes, enabling the system to adapt to changing atmospheric ducting conditions

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If aggressive remote interference mitigation techniques are applied, then interference levels are reduced, but system complexity and coordination overhead increase

Engineering Contradiction:
Improveremote interference levelVSAvoidinterference mitigation system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses a feedback-based approach where victim nodes send reference signals indicating interference detection and persistence. This structured feedback mechanism enables coordinated mitigation actions without requiring complex real-time calculations or extensive coordination overhead between all network nodes

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The mitigation actions are applied locally at the aggressor node level based on specific feedback received from affected victim nodes. Each aggressor node independently adjusts its transmission parameters (power, antenna tilt, guard periods) based on local interference conditions, avoiding the need for centralized complex coordination

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If guard period length is increased to prevent DL-to-UL interference, then interference protection is improved, but uplink transmission efficiency decreases

Engineering Contradiction:
ImproveDL-to-UL interference protectionVSAvoiduplink transmission efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system dynamically adjusts guard period lengths based on detected atmospheric ducting conditions. During normal conditions, standard guard periods are used to maintain uplink efficiency. When remote interference is detected through the feedback mechanism, guard periods are selectively extended only in affected cells and time periods, minimizing the impact on overall uplink transmission efficiency while providing necessary interference protection

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4120771B1Closed loop remote interference management
Publication Date: 2025.12.10 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4120771B1 patent drawingFigure 1
  • EP4120771B1 patent drawingFigure 2
  • EP4120771B1 patent drawingFigure 3A~3B

AI summary

Methods and apparatuses are disclosed for a closed-loop remote interference management framework. In one embodiment for a victim node, a method includes determining one of at least two messages corresponding to a closed-loop feedback for remote interference mitigation, the at least two messages comprising a first message and a second message, the first message providing a positive mitigation indication and the second message providing a negative mitigation indication; and transmitting the determined one of the at least two messages to another network node. In another embodiment for an aggressor node, a method includes receiving one of at least two messages corresponding to a closed-loop feedback for remote interference mitigation; and taking a remote interference mitigation action based on the received one of at least two messages.