Uplink Transmission Management with CORESET-Based Spatial Filtering
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Solution Overview
Problem
The existing 5G NR system lacks efficient methods for managing uplink transmission, particularly in scenarios where spatial domain transmission information is not received from the base station, leading to suboptimal use of default spatial domain transmission filters, which can result in inefficiencies and increased signaling overhead.
Innovation Solution
The proposed solution involves configuring UEs with spatial relation information for PUCCH and SRS resources using RRC signaling and MAC-CE activation, allowing for default spatial domain transmission filters to be determined based on QCL parameters of CORESETs, pathloss reference RSs, and CORESET groups, thereby optimizing UL transmission management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If default spatial domain transmission filters are used when spatial domain transmission information is not received from the base station, then uplink transmission can proceed without explicit signaling, but transmission efficiency deteriorates and signaling overhead increases
Solution Approach 1:
The UE autonomously determines the spatial domain transmission filter by self-service mechanisms: it identifies a QCL source reference signal (CSI-RS or SSB) associated with the CORESET, obtains QCL parameters from RRC configuration, and applies the default spatial domain transmission filter without requiring explicit base station signaling. This self-service approach resolves the contradiction by enabling transmission operation while maintaining efficiency through autonomous QCL-based determination.
Solution Approach 2:
The base station performs preliminary action by pre-configuring QCL parameters and source reference signals through RRC signaling before the UE needs to transmit uplink signals. The QCL relationships between CORESETs and source RSs are established in advance, allowing the UE to efficiently determine spatial domain transmission filters without real-time signaling overhead, thus improving both ease of operation and transmission efficiency.
2Adaptability or versatility
If multiple PUCCH-SpatialRelationInfo IEs are configured via RRC signaling, then spatial relation information is provided for flexibility, but signaling overhead increases during MAC-CE activation
Solution Approach 1:
The patent extracts the essential QCL parameters from the complete spatial relation information configuration. Instead of signaling full spatial relation details through MAC-CE activation, only the necessary QCL parameters and source reference signal identifiers are signaled through efficient RRC configuration. This extraction approach maintains adaptability for multiple spatial relations while reducing MAC-CE signaling overhead by transmitting only the critical parameters needed for UE determination.
Solution Approach 2:
The QCL parameter configuration serves multiple functions: it provides spatial domain transmission filter information, establishes QCL relationships between CORESETs and reference signals, and enables default spatial relation determination. This multi-functionality allows a single RRC configuration to replace multiple separate signaling messages, reducing overall signaling overhead while maintaining the flexibility to support multiple PUCCH spatial relations through unified QCL parameter management.
Data Source
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AI summary
A method, performed by a User Equipment (UE), for Uplink (UL) transmission management includes the UE determining a default spatial domain transmission filter for an UL resource according to at least one Quasi Co-Location (QCL) parameter of a Control Resource Set (CORESET) after determining that the UL resource is not configured with a spatial domain transmission filter and a pathloss reference Reference Signal (RS) resource, and transmitting the UL resource by applying the default spatial domain transmission filter.