Full Duplex Relay Self-Interference Mitigation via Frequency Resource Segmentation

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Solution Overview

Problem

Full duplex relays in wireless communication systems face significant self-interference challenges, which current solutions like spatial separation and interference cancellation techniques are not always feasible or efficient, particularly in terms of cost and effectiveness.

Innovation Solution

The method involves a full duplex relay that selects and assigns specific resource sets to mitigate self-interference by influencing base station resource allocations, using techniques such as reporting low channel quality, negotiating resources, and managing reference signals to avoid collisions, thereby reducing the need for post-interference cancellation methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If spatial separation of backhaul link antennas and access link antennas is used to mitigate relay self-interference, then interference is reduced, but device complexity and cost increase

Engineering Contradiction:
Improverelay self-interferenceVSAvoidantenna configuration complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the frequency spectrum into different resource blocks for backhaul and access links. The relay node selectively receives or transmits on specific resource blocks to avoid self-interference, dividing the communication resources in frequency domain rather than using spatial separation of antennas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from spatial dimension (antenna separation) to frequency dimension (resource block allocation) for interference mitigation. By operating in the frequency domain, the relay can simultaneously maintain backhaul and access links without requiring physical antenna separation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If spatial separation of antennas is implemented to reduce self-interference, then interference mitigation is achieved, but implementation feasibility decreases for many relay deployments

Engineering Contradiction:
Improverelay self-interferenceVSAvoidrelay deployment flexibility
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent provides a universal interference mitigation mechanism that works for all relay deployments regardless of antenna configuration. The frequency-selective resource block allocation method can be applied universally without requiring specific antenna arrangements, making it adaptable to diverse deployment scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If interference cancellation techniques are used to cancel interference after-the-fact, then interference is reduced, but processing complexity and time increase

Engineering Contradiction:
Improverelay self-interferenceVSAvoidsignal processing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent prevents self-interference before it occurs by selectively allocating resource blocks for reception and transmission. The relay node determines which resource blocks to receive on from the base station and which to transmit on to user equipment, avoiding overlapping allocations that would cause interference, thereby eliminating the need for complex post-processing cancellation techniques.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If frequency band is used for both backhaul and access links simultaneously, then spectrum efficiency improves, but self-interference increases

Engineering Contradiction:
Improvespectrum efficiencyVSAvoidrelay self-interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by assigning different frequency characteristics (resource blocks) to different communication functions. Specific resource blocks are designated for backhaul reception while others are designated for access transmission, creating localized frequency allocation patterns that prevent self-interference while maintaining overall spectrum efficiency.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2617254B1Method and apparatus for mitigating relay interference
Publication Date: 2019.10.23 QUALCOMM INC
  • EP2617254B1 patent drawingFigure 1
  • EP2617254B1 patent drawingFigure 2
  • EP2617254B1 patent drawingFigure 3

AI summary

Methods and apparatuses are provided that include selecting resources for assigning to a device to mitigate relay self-interference when also communicating with a base station. The resources can be selected based on one or more factors, such as based on resources that are negotiated with the base station, or based on resources indicated as not desired for allocation from the base station, etc. In other examples, reference signals and control data can be communicated such as to mitigate relay self-interference as well.