Default Beam Switching for Multi-PDSCH Repetition Timing
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Solution Overview
Problem
Existing wireless communication systems fail to address how a UE determines the use of default or indicated TCI states for multi-PDSCH repetitions, leading to unclear which TCI states or indicated TCI states for receiving the respective PDSCH repetitions should be received using the indicated or default TCI states.
Innovation Solution
The described techniques provide methods, systems, and apparatuses that support techniques for using default beams for multi-physical downlink shared channel (PDSCH) repetitions by defining various rules and conditions to determine default TCI states for receiving sets of repetitions of multiple PDSCH messages, including configurations and rules for a UE to determine which PDSCH repetitions should be received using the indicated or default TCI states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network transmits DCI messages indicating TCI states for PDSCH repetitions, then the UE can receive PDSCH repetitions with appropriate beam configurations, but it becomes unclear which TCI state the UE should use when multiple repetitions are scheduled
Solution Approach 1:
The patent introduces a time threshold parameter (threshold time duration) to determine whether to apply indicated TCI states or default TCI states. When the time interval between DCI and PDSCH is below the threshold, default TCI states are used; when above, indicated TCI states are used. This parameter-based decision rule resolves the ambiguity in TCI state selection.
Solution Approach 2:
The patent pre-configures default TCI states at the UE before PDSCH reception. These default TCI states are prepared in advance and can be immediately applied when the time threshold condition is met, eliminating the need for real-time TCI state determination and reducing complexity.
2Measurement precision
If the UE uses indicated TCI states for all PDSCH repetitions, then beam accuracy is maintained, but processing time may be insufficient for decoding TCI states in time-critical scenarios
Solution Approach 1:
The patent uses the time interval parameter to dynamically switch between indicated TCI states and default TCI states. When time is sufficient (above threshold), accurate indicated TCI states are used; when time is critical (below threshold), pre-configured default TCI states are used immediately, trading some beam accuracy for time efficiency.
Solution Approach 2:
The patent prepares default TCI states in advance as a backup mechanism. When time is insufficient to decode indicated TCI states, these pre-configured default states provide a reliable fallback, ensuring PDSCH reception can proceed without delay.
3Productivity
If default TCI states are used for time-critical PDSCH repetitions, then processing time is reduced, but beam accuracy may be compromised compared to using indicated TCI states
Solution Approach 1:
The patent dynamically changes the TCI state selection based on the time interval parameter. For time-critical repetitions (below threshold), default TCI states are applied to enable faster processing; for non-time-critical repetitions (above threshold), indicated TCI states are used to maintain higher beam accuracy.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to receive a downlink control message scheduling multiple downlink transmission repetitions of multiple transport blocks (TBs), the downlink control message indicating a specified transmission configuration indicator (TCI) state for receiving the multiple downlink transmission repetitions according to the scheduling, the multiple downlink transmission repetitions including a first set of downlink transmission repetitions and a second set of downlink transmission repetitions. The UE may be configured to receive, via a default TCI state different from the specified TCI state, a first subset of downlink transmission repetitions from the first set of downlink transmission repetitions, the second set of downlink transmission repetitions, or both, based on a first time interval between a receipt of the downlink control message and a receipt of at least one downlink transmission repetition failing to satisfy a time duration.