Terminal Beam Failure Detection in Deactivated SCG
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Solution Overview
Problem
In dual connectivity technology for 5G NR, terminal apparatuses face challenges in efficiently managing communication with multiple cell groups, leading to high power consumption due to continuous monitoring. Additionally, existing solutions do not properly handle beam failure detection in deactivated cell groups.
Innovation Solution
A terminal apparatus is designed to include a processing unit and a transmitter that communicate with a base station using Multiple Cell Groups (MCG) and Secondary Cell Groups (SCG). The SCG includes at least a Primary Secondary Cell (PSCell). The processing unit provides indications of beam failure to the Radio Resource Control (RRC) entity, and based on a configured threshold, initiates signaling for SCG failure information when beam failure is detected multiple times after SCG deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the terminal apparatus continuously monitors multiple cell groups to enable low latency communication, then communication latency is reduced, but power consumption increases
Solution Approach 1:
The patent implements dynamic monitoring behavior where the terminal adapts its monitoring frequency based on the activation state of cell groups. When a cell group is deactivated, the terminal stops or reduces monitoring of that cell group, while maintaining full monitoring capability when activated. This dynamic adjustment resolves the contradiction by making monitoring intensity variable rather than fixed, allowing low latency when needed while reducing power consumption during normal operation.
2Use of energy by moving object
If the terminal apparatus deactivates cell groups to reduce power consumption, then power consumption is reduced, but beam failure detection becomes problematic
Solution Approach 1:
The patent segments the detection function by introducing a dedicated beam failure detection reference signal (BFD-RS) that operates independently from regular data transmission. This BFD-RS is specifically configured for failure detection purposes and can be monitored even when the cell group is in a deactivated state. The segmentation allows the terminal to maintain reliable beam failure detection capability while keeping the cell group deactivated for power saving, thus resolving the contradiction between power consumption and reliability.
3Reliability
If the terminal monitors deactivated cell groups to detect beam failure, then beam failure detection reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies local quality by making the monitoring behavior cell-group-specific rather than uniform across all cell groups. When a cell group is deactivated, the terminal selectively stops monitoring regular data channels for that cell group to save power, while maintaining monitoring of the dedicated BFD-RS for beam failure detection. This localized differentiation in monitoring strategy allows the terminal to achieve reliable beam failure detection in deactivated cell groups without incurring the full power cost of continuous monitoring, thus resolving the contradiction.
Data Source
AI summary
A MAC entity of a terminal apparatus provides an indication indicating a beam failure in the PSCell to an RRC entity of the terminal apparatus, in a case that a value of BFI_COUNTER of a PSCell is equal to or greater than a first parameter and an SCG is deactivated, based on a determination of whether the beam failure in the PSCell has been indicated to the RRC entity since a last reconfiguration of a BFD-RS of the PSCell by the RRC entity, and a determination that the beam failure in the PSCell has not been indicated to the RRC entity since the last reconfiguration of the BFD-RS of the PSCell by the RRC entity, and the first parameter is a threshold configured by a base station apparatus and used in beam failure detection.