Full-Duplex Beam Training for Accurate CQI Feedback

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Solution Overview

Problem

Existing wireless communication systems, particularly in NR and LTE, face challenges in improving channel state feedback and beam training due to self-interference during simultaneous CSI-RS and SRS transmissions, which hampers accurate CQI computation and beam selection.

Innovation Solution

Implementing full-duplex communication to enable simultaneous CSI-RS and SRS transmissions, allowing UEs to measure CQI despite self-interference and enabling gNBs to compute CSI information based on SRS in the uplink, with techniques for beam sweeping and interference reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If simultaneous CSI-RS and SRS transmissions are implemented to improve communication efficiency, then productivity is improved, but self-interference increases causing measurement precision to deteriorate

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidCQI computation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful self-interference effect into a beneficial measurement opportunity. By having the UE measure the interfered CSI-RS signal during simultaneous SRS transmission, the system directly measures the actual received signal quality including self-interference, thereby obtaining accurate CQI that reflects real communication conditions. This resolves the contradiction by making the interference itself useful for accurate channel quality assessment.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Loss of time

If simultaneous CSI-RS and SRS transmissions are implemented, then loss of time is reduced, but reliability deteriorates due to self-interference

Engineering Contradiction:
Improvebeam training timeVSAvoidbeam selection accuracy
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies the same principle here: the self-interference during simultaneous transmission is converted into a useful indicator for beam selection. The UE measures channel quality on interfered signals and provides feedback that reflects actual communication conditions, enabling reliable beam selection despite the presence of self-interference. This achieves both time efficiency and reliability by measuring under realistic operating conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If full-duplex communication is implemented to enable simultaneous DL and UL signaling, then productivity is improved, but object-generated harmful factors increase

Engineering Contradiction:
Improvenetwork throughputVSAvoidself-interference
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent transforms the self-interference generated by full-duplex operation from a harmful factor into a useful measurement tool. By having UEs measure and report channel quality on signals received during simultaneous transmission, the system obtains accurate feedback that accounts for self-interference. This enables the network to optimize transmissions under actual full-duplex conditions, thereby maintaining high productivity while managing the harmful interference effect constructively.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a feedback mechanism where UEs measure channel quality on CSI-RS signals received during simultaneous SRS transmission and report CQI feedback to the gNB. This feedback loop allows the network to adapt transmissions based on actual channel conditions including self-interference, thereby managing the harmful effects of full-duplex operation while maintaining high throughput.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3909184B1Channel state feedback computation and beam training for full-duplex communication
Publication Date: 2025.11.26 QUALCOMM INC
  • EP3909184B1 patent drawingFigure 1
  • EP3909184B1 patent drawingFigure 2
  • EP3909184B1 patent drawingFigure 3

AI summary

Aspects of the present disclosure relate to wireless communications, and more particularly, to channel state operations using full-duplex communication. One example method generally includes receiving at least one channel state information-reference signal (CSI-RS) from a base station, transmitting at least one sounding reference signal (SRS) to the base station, wherein the CSI-RS is received simultaneously with the transmission of the at least one SRS, and transmitting, to the base station, at least one channel state feedback message comprising channel state information based on the at least one CSI-RS.