SSB-Based Beam Failure Detection QCL Configuration
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Solution Overview
Problem
Current 5G and NR wireless communication systems face challenges in beam failure detection due to undefined quasi-co-location (QCL) transitions and implicit configuration of Synchronization Signal Blocks (SSBs) for Beam Failure Detection (BFD), leading to potential mismatches and inefficiencies in radio link monitoring and recovery procedures.
Innovation Solution
The enhancement of BFD procedures includes SSB-based BFD with QCL and use case restrictions for SSBs in Physical Downlink Control Channel (PDCCH), handling transition periods, and implicit configuration mechanisms for SSBs, ensuring accurate and efficient beam failure detection and recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If SSB is used for BFD without explicit configuration, then device complexity is reduced, but measurement precision deteriorates due to undefined QCL mismatch transition periods
Solution Approach 1:
The patent applies preliminary action by pre-configuring QCL relationships between SSB and PDCCH DMRS through RRC signaling before beam failure detection occurs. This establishes a known reference relationship in advance, eliminating the need for real-time QCL determination and avoiding measurement precision loss while maintaining low device complexity.
Solution Approach 2:
The patent introduces QCL Type D as an intermediary concept to bridge the relationship between SSB and PDCCH DMRS. By defining that SSB and PDCCH DMRS share the same spatial parameters through QCL Type D, the system enables implicit SSB-based BFD without direct configuration, resolving the contradiction between simplicity and precision.
2Adaptability or versatility
If TCI state is updated by MAC CE, then adaptability is improved, but reliability deteriorates due to QCL mismatch transition period
Solution Approach 1:
The patent applies preliminary action by pre-establishing QCL Type D relationships between multiple candidate SSBs and PDCCH DMRS through RRC configuration before MAC CE updates occur. This ensures that when TCI states are dynamically updated via MAC CE, the QCL relationships are already defined, eliminating transition period mismatches and maintaining reliability while preserving adaptability.
Solution Approach 2:
The patent enables dynamic TCI state updates via MAC CE while maintaining reliability by separating the static QCL relationship definition (done once via RRC) from the dynamic state selection (done via MAC CE). This allows the system to adapt quickly while the pre-defined QCL relationships ensure consistent beam failure detection throughout transitions.
3Reliability
If SSB configuration is updated by RRC signaling, then reliability is improved, but productivity deteriorates due to slow update speed
Solution Approach 1:
The patent segments the configuration process into two independent parts: QCL relationship definition (via RRC for reliability) and TCI state activation/selectivity (via MAC CE for speed). By separating these functions, the system achieves both high reliability through RRC-defined QCL relationships and high productivity through fast MAC CE-based state updates, eliminating the need to choose between the two.
Data Source
AI summary
Systems, apparatuses, methods, and computer-readable media are provided for performing Beam Failure Detection (BFD), and in particular, for performing Synchronization Signal Block (SSB) based BFD and/or Channel State Information Reference Signal (CSI-RS) based BFD. Disclosed embodiments include quasi co-location (QCL) and use case restrictions for SSB for BFD and Physical Downlink Control Channel (PDCCH), transition period handling for BFD, and implicit configuration SSB for BFD. Other embodiments may be described and/or claimed.