Beam Failure Recovery Using BWPs to Prevent Timing Misalignment

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Solution Overview

Problem

In wireless communication systems, beam failure recovery (BFR) procedures using bandwidth parts (BWPs) can be misaligned due to the base station's unawareness of unsuccessful BFR procedures, leading to increased signaling overhead and decreased spectral efficiency.

Innovation Solution

A wireless device initiates a random access procedure autonomously for BFR on a secondary cell with a first BWP, and based on unsuccessful completion, it restarts the BWP inactivity timer of the secondary cell, the primary cell, or switches to a default BWP of the secondary cell, thereby preventing timing misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the wireless device autonomously initiates random access procedure for BFR without base station awareness, then the device can perform beam failure recovery independently, but timing misalignment occurs between the device and base station

Engineering Contradiction:

Improveautonomous BFR capabilityVSAvoidtiming alignment

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The base station is configured to provide feedback to the wireless device regarding the outcome of the BFR procedure. When the base station detects an unsuccessful BFR, it sends a indication to the device, enabling the device to restart the BWP inactivity timer and maintain proper timing alignment, thus resolving the contradiction between autonomous operation and timing synchronization.

Inventive Principle:

Principle #23Feedback

2Reliability

If the base station is made aware of the BFR procedure through additional signaling, then timing alignment can be maintained, but signaling overhead increases

Engineering Contradiction:

Improvetiming alignmentVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The wireless device autonomously monitors the outcome of its own BFR procedure by detecting whether the base station successfully recovered the beam. Based on this self-monitoring, the device independently decides whether to restart the BWP inactivity timer, eliminating the need for additional base station feedback signaling while maintaining timing alignment.

Inventive Principle:

Principle #25Self-service

3Reliability

If the BWP inactivity timer is restarted upon unsuccessful BFR, then timing misalignment is prevented, but device complexity increases

Engineering Contradiction:

Improvetiming alignmentVSAvoidtimer management logic

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The BFR outcome detection function is merged with the existing BWP inactivity timer management logic. The same timer that tracks BWP inactivity is also used to maintain timing alignment during BFR, combining two functions into a single mechanism and reducing overall device complexity despite the added BFR monitoring capability.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12335975B2Beam failure recovery procedures using bandwidth parts

Publication Date: 2025.06.17 COMCAST CABLE COMM LLC

AI summary

Systems, apparatuses, and methods are described for wireless communications. A wireless device may initiate a beam failure recovery (BFR) procedure using a bandwidth part (BWP) on a secondary cell. Based on initiating a random access procedure for the BFR procedure and/or based on unsuccessfully completing the BFR procedure, the wireless device may perform one or more operations to prevent and/or reduce misalignment between the wireless device and a base station.