Full-Duplex Beam Failure Recovery via Self-Interference Detection

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Solution Overview

Problem

In wireless communication systems, full-duplex operations often experience self-interference issues due to simultaneous transmission and reception in the same frequency band, leading to beam failures that can incorrectly trigger radio link failures (RLFs), disrupting ongoing communications.

Innovation Solution

A method where user equipment (UE) detects beam failures in full-duplex mode and determines if they are caused by self-interference, refraining from declaring RLFs and instead performing beam failure recovery procedures using existing beams, and switching to half-duplex mode if necessary, to minimize disruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full-duplex mode is used for simultaneous uplink and downlink communication, then spectral efficiency and throughput are improved, but self-interference causes beam failures that incorrectly trigger radio link failures

Engineering Contradiction:

Improvespectral efficiencyVSAvoidcommunication reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent converts the harmful self-interference effect into a useful diagnostic tool by measuring reference signal received power (RSRP) and comparing it against threshold values. The self-interference that causes beam failure is transformed into an identifiable condition that triggers alternative recovery procedures rather than radio link failure, thereby maintaining full-duplex operation while handling the interference constructively

Inventive Principle:

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

Solution Approach 2:

The patent introduces dynamic parameter changes by adjusting RSRP thresholds based on full-duplex operating conditions. Different threshold values are applied depending on whether the system is in full-duplex or half-duplex mode, allowing the beam failure detection mechanism to adapt to the specific interference characteristics of each operating mode and prevent false radio link failure declarations

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If beam failure recovery procedures are performed using existing beams in full-duplex mode, then communication continuity is maintained, but self-interference may prevent successful recovery

Engineering Contradiction:

Improvecommunication continuityVSAvoidrecovery success rate

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent implements dynamic behavior by making the beam failure recovery procedure adaptive to full-duplex conditions. When self-interference is detected through RSRP measurement, the system dynamically switches from standard recovery procedures to alternative procedures that may involve beam switching or parameter adjustments, allowing the recovery mechanism to respond appropriately to the specific interference conditions rather than following a fixed procedure

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent introduces RSRP measurement as an intermediary diagnostic step between beam failure detection and recovery execution. This intermediary measurement allows the system to determine the cause of beam failure (self-interference versus other issues) and select the appropriate recovery path, acting as a mediator that prevents inappropriate recovery attempts and guides the system toward successful recovery actions

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If RLF declaration thresholds are lowered to detect beam failures earlier, then link quality is maintained, but false RLF declarations increase due to self-interference

Engineering Contradiction:

Improvelink qualityVSAvoidfalse RLF declarations

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent implements feedback mechanisms where RSRP measurements continuously monitor the impact of self-interference on downlink reception. This feedback loop allows the system to distinguish between beam failures caused by self-interference (which should not trigger RLF) and those caused by actual link degradation (which should trigger RLF), preventing false declarations while maintaining sensitive detection of genuine problems

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary RSRP measurement and analysis before declaring radio link failure. By measuring the reference signal received power in advance and comparing it against appropriate thresholds, the system identifies self-interference conditions early and takes preventive action to avoid false RLF declarations, ensuring that RLF is only declared when truly warranted by link quality degradation

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11546045B2Radio link failure declaration for full-duplex

Publication Date: 2023.01.03 QUALCOMM INC

AI summary

Wireless communication systems and methods related radio link failure monitoring and handling in full-duplex communications are provided. A user equipment communicates, with a base station, in a full-duplex mode using a first uplink beam and a first downlink beam. The user equipment detects a beam failure of at least one of the first uplink beam or the first downlink beam. The user equipment determines whether the beam failure is associated with self-interference in the full-duplex mode. The user equipment determines, based at least in part on the determination that the beam failure is associated with the self-interference in the full-duplex mode, to refrain from declaring a radio link failure.