MAC-CE Implicit TCI Update Rule for Wireless Signaling Overhead

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Solution Overview

Problem

Current wireless communication systems face inefficiencies in managing transmission configuration indicators (TCI) due to the need for explicit downlink control information (DCI) updates, which can increase signaling overhead and complexity, especially when multiple TCI codepoints are involved.

Innovation Solution

Implementing a MAC-CE-based implicit TCI update rule that allows a single activated TCI codepoint to be applied to multiple channels or reference signals, reducing the need for additional DCI transmissions by enabling the UE to automatically apply predetermined TCI states based on an indication from the base station.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If explicit DCI updates are used to manage TCI codepoints, then TCI states can be updated accurately, but signaling overhead and system complexity increase

Engineering Contradiction:

ImproveTCI state update accuracyVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring TCI codepoints and their associated TCI states through RRC signaling before actual transmission. The MAC-CE activation command then simply activates pre-configured codepoints rather than updating full TCI state information, significantly reducing signaling overhead while maintaining update accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces MAC-CE activation commands as an intermediary mechanism between RRC-configured TCI codepoints and actual TCI state application. This intermediary layer allows efficient activation/deactivation of pre-configured codepoints without requiring full DCI updates, reducing signaling overhead while preserving update precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple TCI codepoints are activated for different channels, then beam diversity is improved, but management complexity and signaling overhead increase

Engineering Contradiction:

Improvebeam diversityVSAvoidTCI management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments TCI management into distinct layers: RRC configuration of multiple TCI codepoints with their associated states, and MAC-CE activation of specific codepoints for specific channels. This segmentation allows beam diversity through multiple codepoints while simplifying management by separating configuration from activation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates universal TCI codepoints that can be applied across multiple channels and signal types (PDSCH, PDCCH, CSI-RS, etc.). A single MAC-CE activation command can activate a TCI codepoint that then serves multiple functions across different channels, reducing overall management complexity while maintaining beam diversity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20240251469A1Activating transmission configuration indicator codepoints

Publication Date: 2024.07.25 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a base station, an indication that indicates whether a medium access control control element (MAC-CE)-based implicit transmission configuration indicator (TCI) update rule is enabled. The UE may receive, from the base station, a MAC-CE that activates one or more TCI codepoints based at least in part on the indication. Numerous other aspects are described.