Uplink Beam Control via DCI Spatial Relation Mapping
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Solution Overview
Problem
In future radio communication systems, the number of candidates for configuring spatial relations for uplink transmission is limited, leading to potential delays and resource consumption when reconfiguration is performed using higher layer signaling.
Innovation Solution
A user terminal assumes that the spatial relation of specific uplink transmission is the same as the transmission control indication (TCI) state of a specific downlink channel or quasi-co-location (QCL) assumption, allowing for efficient control of uplink beams without the need for RRC reconfiguration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If reconfiguration using higher layer signaling is performed to use a large number of spatial relation candidates, then the number of configurable candidates increases, but delay occurs and resources are consumed
Solution Approach 1:
The patent pre-configures spatial relation information in downlink control information (DCI) before uplink transmission is needed. The base station includes spatial relation indicators in DCI messages, allowing the user terminal to have beam configuration information ready in advance, eliminating the need for time-consuming higher layer reconfiguration when beam changes are required.
Solution Approach 2:
The patent extracts the spatial relation configuration from higher layer signaling and places it directly into downlink control information (DCI) at the physical layer. This separation allows beam configuration to be handled independently and rapidly through physical layer signaling rather than being tied to slower higher layer reconfiguration procedures.
2Adaptability or versatility
If reconfiguration using higher layer signaling is performed to use a large number of spatial relation candidates, then the number of configurable candidates increases, but signaling overhead and resource consumption increase
Solution Approach 1:
The patent combines spatial relation configuration information with downlink control information (DCI) that is already being transmitted for uplink scheduling. By merging beam configuration into existing DCI structures, the patent avoids separate higher layer signaling messages, thereby reducing overall signaling overhead while maintaining the ability to configure multiple spatial relations.
Solution Approach 2:
The patent makes the downlink control information serve multiple functions: both uplink scheduling and spatial relation configuration. The DCI structure is designed to carry both resource allocation information and beam configuration information, eliminating the need for dedicated higher layer signaling for spatial relations and reducing total signaling overhead.
3Speed
If rapid beam switching is implemented without higher layer reconfiguration, then response speed increases, but configuration accuracy may be compromised
Solution Approach 1:
The patent introduces downlink control information (DCI) as an intermediary carrier that transmits spatial relation configuration from the base station to the user terminal. This intermediary structure allows rapid beam switching by physical layer signaling while maintaining configuration accuracy through standardized DCI formats that ensure proper interpretation and application of beam parameters.
Data Source
AI summary
A user terminal according to one aspect of the present disclosure includes a control section that assumes that a first reference signal of spatial relation of specific uplink transmission is a second reference signal of QCL type D in a transmission control indication (TCI) state of a specific downlink channel or quasi-co-location (QCL) assumption, and a transmitting section that performs the specific uplink transmission by using the spatial relation. According to one aspect of the present disclosure, control of a UL beam can be appropriately performed.