Dynamic PRS Group Formation for Interference-Aware LBT Positioning
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Solution Overview
Problem
In wireless communication systems, particularly in unlicensed spectrum, UEs experience varying channel access availability due to local interference, leading to increased PRS transmission latency and reduced reliability and accuracy of positioning reference signal (PRS) exchange procedures.
Innovation Solution
Dynamic group formation for group-based PRS listen before talk (LBT) procedures, where responder UEs can voluntarily opt out of the group based on local interference measurements during the LBT process, allowing the initiator UE to update the group membership list, thereby improving reliability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UEs participate in group-based PRS LBT procedures in unlicensed spectrum, then channel access is coordinated and positioning procedures can be executed, but local interference causes varying channel access availability leading to increased PRS transmission latency and reduced reliability
Solution Approach 1:
The patent implements dynamic group formation where UEs can join or leave the group dynamically based on real-time interference conditions. The group membership is not fixed but adapts to changing channel conditions, allowing UEs to opt out when interference is detected and rejoin when conditions improve, thereby maintaining reliable PRS exchange with minimal latency.
Solution Approach 2:
The patent employs feedback mechanisms where responder UEs provide feedback about their interference conditions and LBT outcomes to the initiator UE. This feedback loop enables the initiator to update the group membership list and adjust the PRS exchange procedure accordingly, ensuring that only UEs with favorable channel conditions participate, thus reducing transmission latency and improving reliability.
2Device complexity
If all UEs are included in the group for PRS LBT procedures, then group coordination is simplified, but interference-free UEs cannot be reliably identified leading to LBT failures
Solution Approach 1:
The patent segments the group of UEs into active participants and non-participants based on individual interference conditions. Instead of treating all UEs uniformly, the system identifies and separates interference-free UEs from those experiencing high interference, creating a segmented group structure that maintains coordination simplicity while ensuring LBT reliability.
Solution Approach 2:
The patent applies local quality by allowing each UE to have different participation status based on its local interference conditions. Each responder UE independently assesses its own interference level and determines whether to participate in the LBT procedure, creating a differentiated group where only UEs with favorable local conditions actively participate, thus maintaining high LBT reliability.
3Ease of operation
If the initiator UE maintains a fixed group membership list, then group coordination is straightforward, but the list does not reflect current interference conditions leading to suboptimal PRS exchange
Solution Approach 1:
The patent transforms the group membership list from a static fixed structure to a dynamic updated structure. The initiator UE continuously receives feedback from responder UEs about their interference conditions and LBT outcomes, and accordingly updates the group membership list in real-time. This dynamic approach maintains ease of coordination while significantly improving PRS exchange accuracy by ensuring the list reflects current channel conditions.
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from an initiator UE, a group formation communication indicating a group that the UE is associated with for a group positioning reference signal (PRS) Listen Before Talk (LBT) procedure. The UE may transmit, to the initiator UE, an indication that the UE should not be associated with the group based at least in part on performing the group PRS LBT procedure. Numerous other aspects are provided.