Uplink SRS Spatial Relation Configuration for 5G Positioning
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Solution Overview
Problem
Current 5G positioning procedures for user equipment (UE) are inefficient due to the lack of optimized spatial filter configurations for uplink sounding reference signals (SRS), leading to excessive resource consumption and interference, especially in multi-TRP scenarios.
Innovation Solution
The UE is configured with higher layer parameters to determine reference spatial relations for SRS transmission, using DL-RS or UL-RS information to optimize beamforming and power control, thereby reducing unnecessary transmissions and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UE performs beam sweeping by transmitting SRS signals on different beams in different directions without spatialRelationInfo configuration, then the UE can establish spatial relationships with multiple TRPs, but the resource consumption and interference increase significantly
Solution Approach 1:
The network configures spatialRelationInfo parameters in advance for each SRS resource, specifying the spatial relationship between the SRS transmission and reference signals (DL-PRS, SSB, or CSI-RS). This preliminary configuration eliminates the need for UE to perform exhaustive beam sweeping, as the spatial filters are predetermined by the network based on downlink measurements and positioning requirements.
Solution Approach 2:
The patent introduces spatialRelationInfo as a configurable parameter that changes the transmission behavior of SRS. By setting spatialRelationInfo to reference specific downlink signals (DL-PRS, SSB, CSI-RS), the UE can derive appropriate spatial filters without exhaustive beam searching, thereby reducing the number of SRS transmissions while maintaining positioning accuracy.
2Measurement precision
If UE transmits SRS signals on multiple beams for positioning, then the positioning accuracy can be improved, but the power consumption and network resources are excessively consumed
Solution Approach 1:
The network performs downlink measurements and determines optimal spatial relationships in advance, then configures spatialRelationInfo parameters for UE. This preliminary action allows UE to use predetermined spatial filters for SRS transmission, eliminating the need for power-intensive beam sweeping while maintaining positioning accuracy through network-optimized beam selection.
Solution Approach 2:
UE derives spatial filters for SRS transmission by self-processing downlink reference signals (DL-PRS, SSB, or CSI-RS) that are already being received for positioning purposes. This self-service approach allows UE to generate appropriate spatial filters without additional network assistance or exhaustive beam searching, reducing power consumption while maintaining positioning performance.
3Device complexity
If UE uses fixed spatial domain transmission filter for SRS transmission across multiple SRS resources, then the implementation complexity is reduced, but the positioning efficiency and adaptability to different TRPs decrease
Solution Approach 1:
The patent segments the spatial filter configuration by assigning separate spatialRelationInfo parameters to each SRS resource. This allows different spatial filters to be applied to different SRS resources targeting different TRPs or positioning purposes, maintaining low UE implementation complexity through standardized configuration procedures while enabling high positioning efficiency through TRP-specific beam optimization.
Data Source
AI summary
A user equipment (UE) configured for operating in a wireless communication network that supports a plurality of reference signals (RS) such as sounding reference signals, comprises a wireless interface configured for transceiving signals, comprising receiving a configuration signal having a configuration information indicating a reference spatial relation. The UE further comprises a controller for evaluating the configuration information and to determine the reference spatial relation. The UE is configured for using the reference spatial relation as a reference for an uplink RS (UL-RS) in the wireless communication network.