Default Spatial Relation Determination for 5G NR PUSCH Transmission
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Solution Overview
Problem
Current 5G NR systems lack efficient methods for determining default spatial relation information for PUCCH and SRS resources, leading to suboptimal UL beam management and increased signaling overhead, particularly in scenarios without explicit spatial relation information configuration.
Innovation Solution
The implementation of a method where a UE receives configuration signaling for PUCCH resources without PUCCH-SpatialRelationInfo, enabling a default spatial relation behavior for PUSCH transmission based on a pre-determined QCL-TypeD RS corresponding to a CORESET on the active DL BWP, allowing for spatial relation determination even without explicit signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If explicit spatial relation information is configured for PUCCH resources, then spatial relation accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts the spatial relation information determination from explicit configuration by deriving it from implicit QCL assumptions associated with CORESETs. When PUCCH-SpatialRelationInfo is not configured, the UE automatically determines spatial relation based on the QCL-TypeD RS of the CORESET, eliminating the need for redundant explicit signaling while maintaining spatial relation accuracy.
Solution Approach 2:
The UE performs self-service by autonomously determining spatial relation information using pre-configured QCL assumptions without requiring additional explicit configuration. The UE uses its own received configuration signaling and internal QCL tables to derive the necessary spatial relation parameters, reducing dependency on continuous network signaling.
2Loss of information
If default spatial relation behavior is enabled for PUSCH transmission, then signaling overhead is reduced, but spatial relation precision may deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-configuring QCL assumptions for CORESETs before PUSCH transmission occurs. The UE stores these pre-determined QCL-TypeD RS associations in its internal tables, enabling rapid retrieval and application of spatial relation information without requiring real-time explicit configuration during transmission, thus reducing signaling overhead while maintaining precision through pre-established accurate QCL mappings.
3Device complexity
If PUCCH resources are configured without PUCCH-SpatialRelationInfo, then device complexity is reduced, but spatial relation determination capability is limited
Solution Approach 1:
The patent implements universality by making the QCL assumption mechanism serve multiple functions: it provides spatial relation information for PUCCH transmission, serves as a reference for PUSCH spatial relation determination, and acts as a fallback mechanism when explicit configuration is absent. This multi-functional QCL framework eliminates the need for separate configuration mechanisms, reducing complexity while enhancing versatility.
Data Source
AI summary
A method, performed by a User Equipment (UE), includes receiving, from a cell, configuration signaling configuring the UE with one or more PUCCH resources on an active UL BWP, the one or more PUCCH resources not being configured with PUCCH-SpatialRelationInfo, and the configuration signaling indicating that a default spatial relation behavior for PUSCH transmission scheduled by a DCI format 0_0 is enabled; receiving, from the cell, the DCI format 0_0 on an active DL BWP, the DCI format 0_0 providing scheduling information for a PUSCH; and transmitting the PUSCH according to the default spatial relation behavior which determines a spatial relation with reference to a QCL-TypeD RS corresponding to a QCL assumption of a pre-determined CORESET on the active DL BWP of the cell.