Uplink Beam Spatial Relation Control via Downlink TCI States

Solution Overview

Problem

In future radio communication systems like NR, the number of candidates for configuring uplink beams is limited, leading to delays and resource consumption during reconfiguration.

Innovation Solution

A user terminal determines the uplink beam control based on time offset thresholds and the usage of sounding reference signals, using transmission control indications and quasi-co-location assumptions for downlink transmission to establish appropriate spatial relations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If reconfiguration is performed by higher layer signaling to increase the number of beam candidates, then the adaptability of uplink beam configuration is improved, but delay and resource consumption increase

Engineering Contradiction:

Improvenumber of beam candidatesVSAvoidreconfiguration delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent pre-configures a limited set of beam candidates through higher layer signaling before transmission. The user terminal determines spatial relations by selecting from these pre-configured candidates based on downlink beam information, avoiding the need for real-time reconfiguration and reducing delay.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent copies spatial relation information from downlink beams to uplink beams. The user terminal determines uplink spatial relations by referencing downlink beam information (such as TCI states or QCL assumptions), thereby reusing existing beam configurations rather than creating new ones, which reduces signaling overhead and reconfiguration delay.

Inventive Principle:

Principle #26Copying

2Adaptability or versatility

If reconfiguration is performed by higher layer signaling to increase the number of beam candidates, then the adaptability of uplink beam configuration is improved, but resource consumption increases

Engineering Contradiction:

Improvenumber of beam candidatesVSAvoidresource consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent makes downlink beam information serve multiple purposes: it is used for downlink reception and also for determining uplink spatial relations. By reusing the same beam information for both downlink and uplink, the system reduces the need for separate uplink beam configuration resources, thereby reducing overall resource consumption while maintaining adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent copies spatial relation information from downlink beams to uplink beams. The user terminal determines uplink spatial relations by referencing downlink beam information (such as TCI states or QCL assumptions), thereby reusing existing beam configurations rather than creating new ones, which reduces signaling overhead and resource consumption.

Inventive Principle:

Principle #26Copying

3Loss of time

If a limited number of beam candidates are configured, then reconfiguration delay and resource consumption are reduced, but the adaptability of uplink beam control deteriorates

Engineering Contradiction:

Improvereconfiguration delayVSAvoiduplink beam control flexibility

Core Design Contradiction:

Loss of timeVSAdaptability or versatility

Solution Approach 1:

The patent copies spatial relation information from downlink beams to uplink beams. The user terminal determines uplink spatial relations by referencing downlink beam information (such as TCI states or QCL assumptions), thereby reusing existing beam configurations rather than creating new ones, which reduces signaling overhead and reconfiguration delay.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The user terminal autonomously determines uplink spatial relations by selecting from pre-configured beam candidates based on downlink beam information. This self-service mechanism allows the terminal to adaptively choose appropriate beams without requiring explicit reconfiguration signaling, maintaining flexibility while reducing delay.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11943157B2User terminal and radio communication method

Publication Date: 2024.03.26 NTT DOCOMO INC

AI summary

A user terminal includes a control unit that determines, based on at least one of comparison of a time offset with a threshold value between a timing related to a spatial relation of uplink transmission and the uplink transmission and that usage of a sounding reference signal (SRS) resource set for the uplink transmission is a specific usage, one of a transmission control indication (TCI) state or a quasi-co-location (QCL) assumption for downlink transmission and indicated spatial relation information as the spatial relation, and a transmitting unit that performs the uplink transmission by using the spatial relation.