Spatial QCL Conflict Handling in Carrier Aggregation
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Solution Overview
Problem
Wireless communication systems face challenges in supporting multiple spatial quasi co-location (QCL) relationships simultaneously, particularly in intra-band carrier aggregation configurations, due to hardware cost constraints and assumptions about QCL relationships between synchronization signal blocks (SSBs) and reference signals.
Innovation Solution
Implementing a predetermined relationship rule that allows user equipment (UE) to assume a single spatial QCL relationship across multiple cells based on shared SSB indices, cross-carrier indications, or specific cell characteristics, enabling the UE to receive signals as if they are spatially quasi co-located, even when actual QCL may not be present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE supports multiple spatial QCL relationships simultaneously across multiple cells, then the communication reliability and throughput are improved, but the hardware cost and device complexity increase
Solution Approach 1:
The patent merges multiple spatial QCL relationships into a single unified spatial QCL relationship by establishing a predetermined relationship among SSBs across different cells. The UE determines a single spatial QCL relationship based on SSB indices and predetermined rules, allowing the UE to treat multiple cells as if they share the same spatial QCL properties, thereby reducing hardware requirements while maintaining communication reliability.
Solution Approach 2:
The patent makes the single spatial QCL relationship universal across multiple cells by using predetermined relationship rules that apply to all cells in the carrier aggregation configuration. This allows the UE to use the same spatial QCL assumptions for receiving signals from different cells, eliminating the need for cell-specific spatial QCL handling and reducing device complexity.
2Device complexity
If the UE assumes a single spatial QCL relationship across multiple cells, then the device complexity is reduced, but the accuracy of QCL parameter inference may deteriorate
Solution Approach 1:
The patent applies local quality by making the spatial QCL relationship determination cell-specific through predetermined rules that consider SSB indices and cell characteristics. Each cell's SSB is evaluated against the predetermined relationship rule to determine whether it shares the same spatial QCL relationship, allowing localized accuracy while maintaining overall system simplicity.
Solution Approach 2:
The patent uses preliminary action by pre-establishing the predetermined relationship rule that defines when SSBs across different cells are considered to have the same spatial QCL relationship. This pre-defined framework allows the UE to quickly determine spatial QCL relationships without complex real-time analysis, maintaining measurement precision while reducing device complexity.
3Loss of time
If the UE determines spatial QCL relationships based on predetermined relationship rules, then the processing time is reduced, but the flexibility in handling actual QCL variations is limited
Solution Approach 1:
The patent introduces dynamics by allowing the predetermined relationship rule to be configured based on network conditions and cell characteristics. The rule can adapt to different scenarios such as intra-band or inter-band carrier aggregation, different SSB configurations, and varying spatial QCL conditions, providing flexibility while maintaining efficient processing through pre-defined logic.
Solution Approach 2:
The patent uses parameter changes by allowing the predetermined relationship rule to consider multiple parameters including SSB indices, frequency bands, cell types, and spatial QCL types. By changing and evaluating these parameters against the rule, the system can adapt to different QCL variations while maintaining fast processing through efficient parameter comparison rather than full analysis.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a carrier aggregation (CA) configuration for communications on a set of cells. The UE may determine that signals transmitted on the set of cells may be spatially quasi co-located based on the CA configuration and a predetermined relationship rule. For example, the UE may determine that the signals are spatially co-located based on receiving multiple synchronization signal blocks (SSBs) that have a same SSB index, receiving a common SSB, assuming that an SSB and reference signals sourced by the SSB are spatially quasi co-located, receiving a signal from a particular cell of the set of cells, or receiving a common spatial QCL relationship during a configured period of time. Once the spatial QCL relationship is determined, the UE may receive the signals transmitted on the set of cells based on the spatial QCL relationship.