Low-layer DL Puncturing Indicator for PRS Positioning
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Solution Overview
Problem
In wireless communication systems, downlink positioning reference signals (PRS) can be preempted by higher priority transmissions like ultra-reliable low-latency traffic (URLLC), leading to positioning errors if not properly managed.
Innovation Solution
The system provides preemption information to user equipment (UE) about preempted DL PRS transmissions, allowing it to exclude affected signals from positioning measurements and ensuring accurate positioning by identifying preempted time and frequency domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If downlink positioning reference signals (PRS) are transmitted for positioning measurements, then positioning accuracy can be achieved, but the PRS transmissions may be preempted by higher priority transmissions (e.g., URLLC) causing positioning errors
Solution Approach 1:
The network pre-configures the UE with PRS preemption indication (PI) information before PRS transmissions occur. This includes configuring monitoring occasions, time domain parameters (offsets, durations), and frequency domain parameters (sub-band indications) in advance through RRC signaling, enabling the UE to proactively identify and exclude preempted PRS resources from positioning measurements
Solution Approach 2:
The system implements a feedback mechanism where the network provides PRS PI indications to the UE about which PRS transmissions are preempted. The UE uses this feedback information to adjust its positioning measurements by excluding affected PRS resources, thereby maintaining positioning accuracy despite preemption events
2Measurement precision
If PRS preemption indication information is provided to UE, then positioning measurement accuracy is maintained, but system complexity increases due to additional signaling and processing requirements
Solution Approach 1:
The PRS preemption indication information is segmented into distinct components: time domain parameters (offset, duration, monitoring occasion periodicity) and frequency domain parameters (sub-band indications). This segmentation allows the UE to process each component independently and efficiently, reducing overall processing complexity while maintaining measurement accuracy
Solution Approach 2:
The system provides PRS PI information at a granular level (per sub-band and per monitoring occasion) rather than blanket exclusions. This partial action approach allows the UE to selectively exclude only the preempted PRS resources while continuing to use non-preempted resources, optimizing the balance between measurement accuracy and processing complexity
Data Source
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AI summary
During positioning of a user equipment (UE), downlink (DL) positioning reference signals (PRS) transmitted by one or more transmission reception point (TRP) in a wireless communication system may be preempted or punctured by higher priority transmissions, such as ultra-reliable low-latency traffic (URLLC). A PRS preemption indication (PI) may be provided to a UE by a serving TRP identifying one or more TRPs affected by preemption. The PRS PI may further identify the time domain and frequency domain of the preempted DL PRS transmissions. The PRS PI may identify the time domain, e.g., based on a number of PRS symbols between two monitoring occasions, wherein only PRS symbols that contain downlink positioning reference signals associated with the group of TRPs are counted. The PRS PI may identify the frequency domain by identifying at least one of four or more frequency sub-bands of the preempted DL PRS transmissions.