Multi-Cell TCI State Mapping for Multi-TRP NR Terminals
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Solution Overview
Problem
The challenge in future radio communication systems, such as NR, lies in the unclear method for simultaneously updating transmission control indication (TCI) states across multiple component carriers (CCs), particularly when at least one CC uses multiple transmission/reception points (TRPs), which can lead to reduced throughput and communication quality.
Innovation Solution
A terminal and radio communication method that includes a receiving section to handle a list of serving cells and a control section for mapping TCI state IDs, allowing appropriate updating of TCI states across multiple serving cells, even when different TRPs are involved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous TCI state update is applied to multiple CCs including those with multi-TRP, then update efficiency is improved, but ambiguity in update method causes reduced throughput and communication quality
Solution Approach 1:
The patent segments the update method by distinguishing between single-TRP CCs and multi-TRP CCs. For multi-TRP CCs, it further segments the TCI code points to individually manage those mapped to one TCI state versus those mapped to two TCI states, allowing precise control over which code points receive updates based on the MAC CE received on the trigger CC.
Solution Approach 2:
The patent applies different update rules to different TCI code points based on their local characteristics. Specifically, only TCI code points mapped to two TCI states in multi-TRP CCs are updated when triggered by a MAC CE on a single-TRP CC, while other code points maintain their existing mappings. This localized differentiation resolves the ambiguity while maintaining overall system efficiency.
2Reliability
If TCI states are updated across all serving cells, then communication quality is improved, but overhead increases due to unclear update rules
Solution Approach 1:
The patent extracts and applies the TCI state update mechanism selectively rather than universally. By identifying and updating only the specific TCI code points in multi-TRP CCs that are mapped to two TCI states, it avoids the overhead of updating all TCI states across all serving cells while still improving communication quality where needed.
Solution Approach 2:
The patent establishes preliminary rules for determining which TCI code points should be updated before the actual update occurs. The terminal预先 identifies TCI code points mapped to two TCI states in multi-TRP CCs, so when a MAC CE is received, the update can be applied immediately without additional overhead for determining which code points to update.
Data Source
AI summary
A terminal according to an aspect of the present disclosure includes a receiving section that receives a list of a plurality of serving cells, and receives, for one serving cell of the plurality of serving cells, a medium access control-control element (MAC CE) used for activation of a TCI state for a physical downlink shared channel, and a control section that, when the plurality of serving cells include one or more specific serving cells in which at least one transmission configuration indication (TCI) code point is mapped to two transmission configuration indication (TCI) states, maps one or more TCI state IDs indicated by the MAC CE to a TCI code point of one or more serving cells of the plurality of serving cells. According to an aspect of the present disclosure, TCI states can be appropriately updated.