Positioning Reference Signal Beamforming Using Expected AoD
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Solution Overview
Problem
In new radio (NR) positioning, uplink beam management towards serving and neighbor cells faces challenges with large resource overhead and UE power consumption due to the need for beam sweeping without pre-knowledge, especially for UL positioning-only RPs that lack transmit capability.
Innovation Solution
A location management device estimates an expected angle of departure (AoD) for reference signal transmission and communicates this to the transmitting device, facilitating targeted beamforming to reduce unnecessary sweeping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam sweeping is used for transmitting SRS towards UL positioning-only RP, then the UE can transmit reference signals, but the resource overhead and UE power consumption increase significantly
Solution Approach 1:
The network performs preliminary actions by calculating and providing expected angle of departure (AoD) information to the UE before the actual SRS transmission. This allows the UE to pre-determine the optimal beam direction based on network-provided spatial relation information, eliminating the need for exhaustive beam sweeping and significantly reducing power consumption while maintaining positioning reliability.
Solution Approach 2:
The system establishes a feedback mechanism where the network provides spatial relation information (expected AoD) to the UE, which then uses this feedback to determine the appropriate beam direction for SRS transmission. This closed-loop approach ensures the UE transmits signals in the correct direction without needing to sweep all possible beams, thereby reducing energy consumption while maintaining positioning accuracy.
2Reliability
If beam sweeping is used for transmitting SRS towards UL positioning-only RP, then the UE can transmit reference signals, but the resource overhead increases
Solution Approach 1:
The network performs preliminary calculations to determine the expected AoD and provides this information to the UE in advance. This preliminary action allows the UE to directly transmit SRS in the correct beam direction without needing to perform exhaustive beam sweeping, thereby reducing the resource overhead required for positioning while maintaining positioning reliability.
Solution Approach 2:
The system extracts and utilizes only the necessary beam direction information (expected AoD) from the full set of possible beam configurations. By taking out just the essential spatial relation information provided by the network, the UE can achieve accurate positioning without needing to sweep through all possible beams, thus reducing resource overhead while maintaining positioning capability.
3Reliability
If the UE transmits SRS to all directions without pre-knowledge, then positioning can be attempted, but the positioning accuracy is compromised due to unnecessary sweeping
Solution Approach 1:
The network performs preliminary calculation of the expected AoD based on the UE's location and transmission target, then provides this information to the UE. This preliminary action enables the UE to transmit SRS in the precisely correct beam direction from the outset, achieving high positioning accuracy without the need for exhaustive beam sweeping that would degrade measurement precision.
Solution Approach 2:
The network provides feedback in the form of expected AoD information to the UE, which the UE uses to determine the optimal beam direction for SRS transmission. This feedback mechanism ensures that the UE transmits signals in the correct direction with high precision, avoiding the accuracy degradation that would result from unnecessary beam sweeping across all possible directions.
Data Source
AI summary
Embodiments of the present disclosure relate to a transmit beamforming for positioning. A location management device generates information regarding an angle of departure, the angle of departure being expected for transmission of reference signals for positioning and transmits the information to a device transmitting the reference signals. The device may determine a transmit beamforming solution for transmitting the reference signals based on the angle of departure. In this way, power savings can be achieved due to decreased reference signal overhead. Further, positioning accuracy can be improved through appropriately beamformed reference signal transmissions.