Cross-Link Interference Mitigation in Wireless Networks

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Solution Overview

Problem

Current wireless communication systems face challenges in mitigating cross-link interference between different radio access technologies (RATs) such as LTE and NR, which affects communication performance and spectrum utilization.

Innovation Solution

The proposed solution involves techniques for aligning transmission directions between adjacent deployments to minimize cross-link interference, using guard bands, and implementing flexible scheduling to avoid interference while maintaining efficient spectrum use, specifically by aligning UL and DL transmissions and utilizing NR's capabilities to mitigate interference effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If large guard bands are used to mitigate cross-link interference between LTE and NR, then interference is reduced, but spectrum utilization efficiency deteriorates

Engineering Contradiction:
Improvecross-link interferenceVSAvoidspectrum utilization
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent implements dynamic TDD uplink-downlink configuration where the direction of transmission (uplink or downlink) can be flexibly changed based on traffic demands and interference conditions. This allows the system to adaptively adjust resource allocation in real-time, eliminating the need for static large guard bands while maintaining interference mitigation through coordinated scheduling between LTE and NR systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the configuration parameters of TDD frames dynamically, allowing different uplink-downlink configurations to be applied in different time periods. By adjusting the timing and direction parameters of transmissions, the system can mitigate cross-link interference without requiring fixed large guard bands, thus improving spectrum utilization while controlling interference.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If flexible scheduling is implemented to avoid interference, then communication performance is improved, but system complexity increases

Engineering Contradiction:
Improvecommunication performanceVSAvoidscheduling complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an interference coordination mechanism that acts as an intermediary between LTE and NR scheduling entities. This mediator coordinates the TDD configurations and resource allocations between the two systems, enabling flexible scheduling to avoid cross-link interference while distributing the complexity management across multiple coordinated entities rather than concentrating it in a single complex scheduler.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If transmission directions are aligned between adjacent deployments, then cross-link interference is minimized, but deployment flexibility is reduced

Engineering Contradiction:
Improvecross-link interferenceVSAvoiddeployment flexibility
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent employs periodic TDD frame structures where transmission directions are systematically alternated between uplink and downlink in a repeating pattern. This periodic alignment of transmission directions between adjacent LTE and NR deployments minimizes cross-link interference through predictable, coordinated timing while still allowing flexibility within each period to accommodate different traffic demands and deployment scenarios.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3701739B1Interference mitigation in wireless communications
Publication Date: 2022.04.27 QUALCOMM INC
  • EP3701739B1 patent drawingFigure 1
  • EP3701739B1 patent drawingFigure 2
  • EP3701739B1 patent drawingFigure 3

AI summary

Certain aspects of the present disclosure provide techniques for interference mitigation. Certain aspects provide a method for wireless communication. The method generally includes performing communications, in a first channel, on a first downlink in a first time period based on communications in a second channel adjacent to the first channel being performed on a second downlink in the first time period. Communications in the first channel on a first uplink are performed in a second time period based on communication in the second channel being performed on a second uplink in the second time period. The method further includes refraining from communicating in the first channel on one or more resources in the first time period or the second time period to mitigate cross-link interference with a third channel adjacent to the first channel.