Half-Duplex Carrier Aggregation Slot Conflict Resolution
Solution Overview
Problem
In carrier aggregation configurations, user equipment (UE) configured for half-duplex communications face challenges in managing conflicting slot format indicators (SFIs) from multiple cells, leading to simultaneous transmission and reception conflicts, which impact uplink and downlink communications.
Innovation Solution
The UE determines communication directions based on a set of rules, prioritizing the RRC-configured SFI of a reference cell and resolving conflicts by dropping assignments from secondary cells when dynamic SFIs contradict, ensuring compliance with the reference cell's direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple cells transmit slot format indicators (SFIs) in carrier aggregation configuration, then the UE can receive scheduling information from multiple cells, but conflicting SFIs indicate simultaneous transmission and reception directions that cannot be supported in half-duplex mode
Solution Approach 1:
The patent segments the conflicting SFI information from multiple cells by introducing a reference cell concept. The UE processes SFIs from the reference cell with higher priority and resolves conflicts by selectively applying or ignoring SFIs from non-reference cells based on directional compatibility, thereby enabling half-duplex operation while maintaining carrier aggregation functionality.
Solution Approach 2:
The patent introduces an intermediary resolution mechanism that mediates between conflicting SFI indications from multiple cells. The UE applies directional resolution rules that act as intermediaries to reconcile conflicting transmission and reception directions, allowing the system to handle multiple cell SFIs without violating half-duplex constraints.
2Productivity
If the UE follows SFIs from all cells in carrier aggregation, then scheduling information is maximized, but half-duplex UEs cannot simultaneously transmit and receive causing communication failures
Solution Approach 1:
The patent implements dynamic SFI application where the UE adaptively selects which cell's SFI to follow based on current operational state and conflict detection. The resolution mechanism dynamically adjusts between following reference cell SFI or non-reference cell SFI depending on whether conflicts arise, ensuring reliable half-duplex operation while maximizing scheduling information utilization.
3Ease of operation
If the UE resolves SFI conflicts by prioritizing reference cell configuration, then half-duplex operation is maintained, but assignments from secondary cells may be dropped
Solution Approach 1:
The patent applies partial action by selectively applying SFI assignments only from cells that do not create conflicts. Instead of completely ignoring non-reference cells, the UE processes and applies compatible assignments from secondary cells while dropping only those that would violate half-duplex constraints, thereby maintaining operation ease while preserving maximum possible productivity.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a first slot format configuration for a first serving cell for a set of transmission time intervals (TTIs) including a first TTI and receive a second slot format configuration for the first serving cell for the first TTI which is different from the first slot format configuration. The UE may determine, based on priorities of the slot format configurations, a first communication direction for the first serving cell for the first TTI. The UE may identify, for a second serving cell for the first TTI, a second communication direction indicated by one or more slot format configurations for the second serving cell. The UE may determine whether to communicate on the second serving cell for the first TTI according to the one or more slot format configurations for the second serving cell.