Uplink Beam Switching via TCI State Mapping in 5G Terminals

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Solution Overview

Problem

In future radio communication systems, dynamically switching uplink beams for UL transmission by a UE is not fully studied, leading to potential deterioration of communication quality.

Innovation Solution

A method is introduced to dynamically control the spatial relation/TCI state for uplink channels based on the transmission configuration indication state, allowing flexible and dynamic switching of UL beams similar to DL beams, using DCI-level signaling for both downlink and uplink channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a terminal transmits multiple types of information (buffer status, power headroom, scheduling request) simultaneously using different MAC CE formats, then communication efficiency is improved, but the size of the MAC layer control element increases and message structure complexity increases

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidmessage structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple MAC CE formats (Buffer Status Report, Power Headroom Report, and Scheduling Request) into a single unified MAC CE structure. This allows the terminal to transmit all three types of information simultaneously in one uplink transmission, improving communication efficiency while the unified structure manages complexity through standardized formatting and bit field organization.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If a terminal frequently updates buffer status and power headroom information, then network resource allocation accuracy is improved, but uplink signaling overhead increases

Engineering Contradiction:
Improveresource allocation accuracyVSAvoiduplink signaling overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

By merging Buffer Status Reports, Power Headroom Reports, and Scheduling Requests into a single MAC CE, the patent reduces the total number of separate uplink transmissions required. This maintains accurate resource allocation information while reducing signaling overhead compared to sending each report type separately.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the MAC CE includes detailed buffer status for multiple logical channels and power headroom for multiple uplink carriers, then network scheduling accuracy is improved, but the MAC CE size increases

Engineering Contradiction:
Improvescheduling accuracyVSAvoidMAC CE size
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent applies local quality by including detailed buffer status information only for active logical channels and power headroom information only for active uplink carriers. This selective inclusion maintains high scheduling accuracy for relevant channels while reducing MAC CE size by excluding unnecessary information from inactive channels and carriers.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4132216B1Terminal, wireless communication method and base station
Publication Date: 2026.04.29 NTT DOCOMO INC
  • EP4132216B1 patent drawingFigure 1
  • EP4132216B1 patent drawingFigure 2
  • EP4132216B1 patent drawingFigure 3

AI summary

A terminal according to one aspect of the present disclosure includes a receiving section that receives a downlink shared channel scheduled by downlink control information, and a control section that determines, on the basis of at least one of a TCI state (Transmission Configuration Indication state) applied to the downlink shared channel and information notified by the downlink control information, a spatial relation or TCI state applied to an uplink channel corresponding to the downlink control information.