Terminal PDCCH TCI Coordination for SFN and Search Space Linking
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Solution Overview
Problem
Existing communication systems in cellular mobile communications, such as LTE and NR, face challenges in efficiently managing and applying TCI states and search space linking for PDCCH and PUSCH transmissions, leading to suboptimal communication performance.
Innovation Solution
A terminal apparatus and base station apparatus are designed to apply an SFN scheme and search space linking for PDCCH, with TCI states determined by higher layer parameters, ensuring efficient communication by configuring TCI states based on specific indications, and managing DMRS ports' quasi-co-location with DL-RS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple TCI states are applied to a CORESET with SFN scheme, then communication reliability is improved through diverse beam transmission, but device complexity increases due to multiple QCL relationships
Solution Approach 1:
The patent segments the TCI state application by introducing a higher layer parameter that independently controls whether first or second TCI states are applied to the CORESET. This segmentation allows the system to activate only the necessary TCI states based on SFN configuration, reducing unnecessary complexity while maintaining reliability when needed.
Solution Approach 2:
The patent implements dynamic TCI state selection where the application of first or second TCI states to the CORESET is determined dynamically based on the higher layer parameter configuration. This dynamic approach enables the system to adapt the number of active TCI states to the actual SFN scheme requirements, optimizing the balance between reliability and complexity.
2Device complexity
If search space linking is applied with single TCI state, then device complexity is reduced, but communication performance deteriorates due to limited beam diversity
Solution Approach 1:
The patent applies local quality by differentiating the TCI state configuration based on the specific SFN scheme activation. When SFN is configured, the system locally applies both first and second TCI states to the CORESET through higher layer parameter control, providing beam diversity exactly where needed (in SFN scenarios) while maintaining simplicity in non-SFN scenarios.
3Adaptability or versatility
If higher layer parameter controls TCI state application, then adaptability is improved for different SFN configurations, but ease of operation decreases due to additional configuration parameters
Solution Approach 1:
The higher layer parameter serves multiple functions: it controls TCI state selection, adapts to different SFN configurations, and manages the relationship between first and second TCI states. This multi-functionality consolidates what would otherwise require multiple separate parameters into a single universal control mechanism, improving adaptability without proportionally increasing operational complexity.
Data Source
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AI summary
A terminal apparatus including a receiver configured to receive a first PDCCH to which first DCI is mapped and a second PDCCH in at least one CORESET, and a transmitter configured to transmit a PUSCH scheduled by second DCI mapped to the second PDCCH, wherein an SFN scheme is configured to be applied for the second PDCCH, search space linking is configured to be applied for the second PDCCH, the first DCI indicates a first TCI state and a second TCI state, in a case that one of the first TCI state and the second TCI state is applied to the one CORESET, the search space linking is applied and the SFN scheme is not applied, and in a case that both of the first TCI state and the second TCI state are applied to the one CORESET, the SFN scheme is applied and the search space linking is not applied.