Terminal TCI State Control for Multi-TRP Downlink Throughput
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Solution Overview
Problem
Current Next-Generation Mobile Communication Systems, specifically 5G NR, face challenges in controlling Quasi-Co-Location (QCL) assumptions when multiple transmission/reception points (TRPs) and panels are used, leading to inadequate spatial diversity gain and suppressed communication throughput.
Innovation Solution
A terminal and radio communication method that receives downlink shared channels based on a single piece of downlink control information, with a control section determining the default transmission configuration indication state (TCI state) for multiple Physical Downlink Shared Channels (PDSCHs), allowing for effective QCL assumption and improved communication even with multiple TRPs/panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing NR specifications are followed without considering multiple panels/TRPs, then system complexity is maintained at current levels, but spatial diversity gain and communication throughput are suppressed
Solution Approach 1:
The patent segments the TCI state configuration into multiple codepoints within the DCI format, allowing different TCI states to be indicated for different TRPs/panels. This segmentation enables independent control of QCL assumptions for each transmission point while maintaining a unified DCI structure, thus improving throughput without excessive complexity increase.
Solution Approach 2:
The patent introduces dynamic TCI state indication through the TCI field in DCI, allowing the network to flexibly switch between different TCI states and codepoints based on channel conditions and TRP configurations. This dynamic adaptation enables the system to optimize spatial diversity gain and throughput while managing complexity through standardized procedures.
2Reliability
If multiple panels/TRPs are used without appropriate QCL assumption control, then spatial diversity gain and high rank transmission cannot be achieved, but adding QCL control mechanisms increases system complexity
Solution Approach 1:
The patent performs preliminary configuration of TCI states through higher layer signaling (RRC/MAC CE) before actual data transmission. This preliminary action establishes the mapping between codepoints and TCI states in advance, allowing the DCI to simply indicate the appropriate codepoint without carrying full TCI state information, thereby achieving reliable QCL control with minimal runtime complexity.
Solution Approach 2:
The patent introduces codepoints as intermediaries between the DCI and TCI states. The codepoint mapping serves as a mediator that translates between the compact DCI indication and the detailed TCI state configurations, enabling efficient QCL assumption control for multiple TRPs/panels without directly increasing DCI complexity.
3Productivity
If a single TCI state is applied to multiple PDSCHs, then control signaling is simplified, but spatial diversity and communication throughput are limited
Solution Approach 1:
The patent applies local quality by associating different TCI states with different TRPs/panels through codepoint mapping. Each codepoint can represent a specific TCI state or combination of TCI states appropriate for local transmission conditions at each TRP, enabling differentiated QCL assumptions while maintaining unified DCI-based control for multiple PDSCHs.
Data Source
AI summary
A terminal according to one aspect of the present disclosure includes a receiving section that receives a plurality of downlink shared channels (Physical Downlink Shared Channels (PDSCHs)) on the basis of one piece of downlink control information, and a control section that judges that a default transmission configuration indication state (TCI state) applied to the plurality of the PDSCHs corresponds to a TCI state corresponding to a code point in a TCI field for the downlink control information. According to one aspect of the present disclosure, it is possible to perform DL communication preferably even when multiple panels/TRPs are used.