UE Cross-Link Interference Control for Dynamic TDD

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Solution Overview

Problem

Existing wireless communication systems face significant challenges in measuring and mitigating cross-link interference (CLI) between devices, which is more severe and rapidly changing compared to same-link interference, with no satisfactory solutions in current technologies.

Innovation Solution

Implementing methods and devices for cross-link interference measurement and mitigation by receiving and transmitting wireless signals between nodes, using predetermined metrics to determine measurement values, and applying predetermined mitigation schemes based on detected events to control CLI.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If dynamic TDD operations are implemented to improve spectrum utilization efficiency, then spectrum utilization efficiency is improved, but cross-link interference becomes more serious and rapidly changing

Engineering Contradiction:
Improvespectrum utilization efficiencyVSAvoidcross-link interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing cross-link interference measurements before scheduling transmissions. The gNB measures CLI from neighboring cells using reference signals (SSB or CSI-RS) in advance, determines interference levels, and then makes informed scheduling decisions to avoid or mitigate interference, rather than reacting after interference occurs

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where measurement results of cross-link interference are reported back to the gNB, which then adjusts scheduling decisions, power levels, or resource allocations based on the feedback information about interference conditions from neighboring cells

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If flexible duplex operations are implemented to meet fast adaptive requirements, then adaptability is improved, but cross-link interference changes more rapidly

Engineering Contradiction:
Improveadaptive requirementsVSAvoidinterference direction stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by enabling the system to adaptively change transmission directions (uplink/downlink) on an unpaired spectrum based on traffic demands and interference conditions. The gNB can dynamically switch between different duplex modes and configurations, making the system flexible and adaptive to changing conditions rather than static

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary CLI measurements using reference signals before making dynamic scheduling decisions. By measuring interference levels in advance and having ready measurement results, the system can rapidly adapt to changing conditions without being overwhelmed by the speed of changes in interference directions

Inventive Principle:
Principle #10Preliminary action

3Reliability

If cross-link interference measurement is implemented to mitigate CLI, then CLI mitigation capability is improved, but device complexity increases

Engineering Contradiction:
ImproveCLI mitigation capabilityVSAvoidmeasurement and mitigation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses reference signals (SSB or CSI-RS) as intermediaries to enable CLI measurements. These reference signals are specifically designed and transmitted for measurement purposes, allowing the gNB to measure interference from neighboring cells without requiring direct data transmission measurements, thereby simplifying the overall measurement process

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs reference signals that are copies or representations of actual transmission signals. By measuring these reference signal copies instead of actual data transmissions, the system can assess interference conditions without the complexity of processing real traffic data, reducing computational and system complexity

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3636020B1Mitigating cross-link interference between a first UE and a second ue
Publication Date: 2025.07.09 ZTE CORP
  • EP3636020B1 patent drawingFigure 1A
  • EP3636020B1 patent drawingFigure 1B
  • EP3636020B1 patent drawingFigure 2

AI summary

A method and system for measuring and controlling cross-link interference (CLI) between two devices in a wireless communication network is disclosed herein. In one embodiment, a method implemented on a first node for mitigating CLI between the first node and a second node is disclosed. The method comprises: receiving a wireless signal from the second node; measuring the wireless signal to determine a measurement value according to a predetermined metric for measuring CLI; determining an event based on the measurement value; and mitigating the CLI in accordance with a predetermined mitigation scheme associated with the event.