PDCCH TCI Determination via CORESET for Multi-TRP Reliability
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Solution Overview
Problem
In multi-TRP transmission scenarios, terminal devices face challenges in accurately determining the Transmission Configuration Indicator (TCI) for downlink channels due to the lack of TCI indication fields in downlink control information, leading to unreliable downlink channel transmission.
Innovation Solution
A method where terminal devices receive multiple physical downlink control channels carrying the same downlink control information, and determine a target TCI based on specific rules or higher layer signaling, ensuring accurate transmission configuration even without explicit TCI indication, thereby improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple PDCCHs are transmitted by multiple TRPs without TCI indication field in DCI, then transmission diversity is improved, but terminal device cannot accurately determine TCI for PDSCH
Solution Approach 1:
The patent uses the CORESET as an intermediary to carry TCI indication information. When DCI does not include TCI indication field, the terminal device determines TCI for PDSCH based on the TCI indication in the CORESET where the PDCCH is located. This intermediary mechanism resolves the contradiction by providing TCI determination capability without requiring explicit TCI indication in DCI, thus maintaining both transmission diversity and TCI determination accuracy.
Solution Approach 2:
The patent applies preliminary action by pre-configuring TCI states in the CORESET before PDCCH transmission. The network device configures one or more TCI states for the CORESET using higher layer signaling, and the terminal device stores these TCI states for later use. This preliminary configuration enables the terminal device to determine TCI for PDSCH based on CORESET information without needing real-time TCI indication in DCI, thus resolving the contradiction between transmission diversity and TCI determination accuracy.
2Measurement precision
If TCI indication field is added to DCI, then TCI determination accuracy is improved, but control information overhead increases
Solution Approach 1:
The patent extracts the TCI indication function from the DCI by using the CORESET as the indication carrier. Instead of adding TCI indication field to DCI, the TCI indication is taken out and placed in the CORESET configuration. This extraction approach maintains TCI determination accuracy while avoiding the increase of control information overhead in DCI, thus resolving the contradiction between TCI determination accuracy and control information overhead.
3Device complexity
If TCI is assumed to be same as PDCCH TCI, then device complexity is reduced, but transmission reliability deteriorates in multi-TRP scenarios
Solution Approach 1:
The patent applies self-service by enabling the terminal device to autonomously determine TCI for PDSCH based on the CORESET where the PDCCH is located. The terminal device uses the TCI indication in the CORESET to determine the appropriate TCI without needing explicit TCI indication in DCI. This self-service mechanism maintains transmission reliability in multi-TRP scenarios while avoiding excessive terminal device processing complexity, thus resolving the contradiction between device complexity and transmission reliability.
Data Source
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AI summary
This application provides a downlink channel transmission method and apparatus, so that reliability of downlink channel transmission can be improved. The method includes: A terminal device receives at least two physical downlink control channels PDCCHs on at least two control information resources, where the at least two PDCCHs carry same downlink control information DCI, and the DCI is used to indicate a time-frequency resource corresponding to a first downlink channel. The terminal device obtains at least two transmission configuration indicators TCIs corresponding to the at least two control information resources. The terminal device determines a target TCI in the at least two TCIs, where the target TCI is a TCI corresponding to the first downlink channel. The terminal device receives the first downlink channel based on the DCI and the target TCI.