Beam Failure Recovery with BWP Timer Control on Secondary Cells
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Solution Overview
Problem
In wireless communications, beam failure recovery (BFR) procedures using bandwidth parts (BWPs) can lead to misalignment between a wireless device and a base station, increasing signaling overhead and decreasing spectral efficiency when the base station is unaware of the BFR procedure's outcome.
Innovation Solution
A wireless device initiates a random access procedure autonomously on a secondary cell, restarting the BWP inactivity timer of the secondary cell and potentially switching to a default BWP, while allowing the primary cell's timer to continue, thereby preventing timing misalignment and optimizing resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wireless device autonomously initiates a random access procedure for BFR on a secondary cell without base station awareness, then the device can perform beam failure recovery independently, but timing misalignment occurs between the device and base station, increasing signaling overhead and decreasing spectral efficiency
Solution Approach 1:
The wireless device performs the random access procedure for beam failure recovery before the base station is aware of the failure, enabling independent recovery action. The device proactively initiates the procedure using autonomous determination of beam failure conditions without waiting for base station detection or instruction.
Solution Approach 2:
The base station receives feedback information from the wireless device indicating the outcome of the autonomous random access procedure. This feedback mechanism allows the base station to learn about the BFR result and update its state, resolving the information asymmetry between device and network.
2Loss of time
If the wireless device restarts the BWP inactivity timer autonomously during BFR, then timing misalignment is prevented, but device complexity increases due to autonomous timer management
Solution Approach 1:
The wireless device autonomously manages its own BWP inactivity timer during the beam failure recovery procedure. The device independently determines when to restart the timer based on its own beam failure detection, without requiring base station intervention or coordination, enabling self-service timing management.
3Productivity
If the wireless device switches to a default BWP autonomously, then resource usage efficiency is improved, but signaling overhead increases due to base station unawareness of the switch
Solution Approach 1:
The wireless device performs the BWP switch to the default bandwidth part before the base station is aware of the beam failure recovery outcome. This preliminary action allows the device to optimize resource usage proactively while the base station remains unaware of the specific BWP configuration changes.
Solution Approach 2:
The base station receives feedback information about the BFR procedure outcome, which indirectly informs the network about the device's BWP state changes. This feedback mechanism allows the base station to update its understanding of the device's resource usage without requiring explicit BWP switch signaling.
Data Source
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.