PDSCH QCL Determination Under Multi-TCI Codepoint Scheduling
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Solution Overview
Problem
The existing methods for determining the QCL relationship of PDSCH transmission are not optimized when multiple TCI codepoints are activated by the MAC CE, leading to poor performance in various scenarios.
Innovation Solution
A QCL determining method that identifies the QCL relationship of PDSCH transmission by pre-dividing DCI into different cases based on high-layer parameter configuration and DCI indication, allowing terminals to determine the appropriate QCL relationship for each case and improve reception performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all TCI codepoints activated by MAC CE are mapped to one TCI state, then the QCL determination is simplified, but the performance of PDSCH transmission deteriorates when time offset is less than threshold
Solution Approach 1:
The patent segments the QCL determination process into different cases based on the number of TCI states per codepoint. When all codepoints map to one TCI state, simplified determination is used. When at least one codepoint maps to multiple TCI states, the patent applies different determination rules for different PDSCH transmission occasions, thus segmenting the problem into manageable scenarios that balance complexity and performance.
Solution Approach 2:
The patent introduces dynamic selection of QCL determination methods based on the time offset between PDCCH and PDSCH. When the time offset is less than the threshold, the system dynamically switches to a more sophisticated determination method that considers multiple TCI states, while allowing simpler methods when the threshold is met, thus adapting the complexity to the actual transmission conditions.
2Adaptability or versatility
If multiple TCI codepoints are mapped to multiple TCI states, then the adaptability of PDSCH transmission is improved, but the difficulty of determining QCL relationship increases
Solution Approach 1:
The patent performs preliminary classification of DCI into different cases based on high-layer parameter configuration and DCI indication before QCL determination. This preliminary action organizes the complex multi-TCI-state scenario into structured cases, making the subsequent QCL determination more systematic and less difficult despite the increased adaptability requirements.
Solution Approach 2:
The patent applies different QCL determination rules to different local scenarios (different cases of DCI, different PDSCH transmission occasions). Instead of using a single uniform method for all situations, the system applies locally optimized determination rules that match the specific scenario, thus managing complexity while maintaining adaptability.
3Speed
If default reception beams are used for PDSCH with small time offset, then the reception speed is improved, but the reception performance deteriorates
Solution Approach 1:
The patent dynamically adjusts the QCL determination method based on the time offset condition. When the time offset is less than the threshold, the system maintains fast reception by using predetermined rules while incorporating multiple TCI state considerations to preserve performance. This dynamic adjustment allows the system to optimize for both speed and reliability based on actual transmission conditions.
Data Source
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AI summary
The present invention provides a QCL determining method, a terminal, and a network side device. The method applied to the terminal includes: in a case that there are L first transmission configuration indication TCI codepoints in TCI codepoints activated by a medium access control MAC control element CE, determining, according to detected downlink control information DCI, a quasi co-located QCL relationship of M times of physical downlink shared channel PDSCH transmission scheduled by the DCI, where both L and M are positive integers; each first TCI codepoint indicates P TCI states, and P is an integer greater than 1.