In-Coverage Sidelink Positioning With Coordinated PRS
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Solution Overview
Problem
Existing 5G NR sidelink communication systems face inefficiencies in positioning UEs both in and out of network coverage, particularly in the absence of tight network timing synchronization, limiting the flexibility and efficiency of positioning techniques like TDOA.
Innovation Solution
Implementing sidelink positioning techniques that utilize positioning reference signals (PRS) through sidelink transmissions, supported by RRC signaling and NR Positioning Protocol A (NRPPa) messages, enabling centralized coordination via a gNB and location management function (LMF) for UEs in coverage, with enhanced LPP and NRPPa messages for configuration and activation/deactivation of SL PRS and SRS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If centralized coordination via gNB and LMF is implemented for UEs in coverage, then positioning efficiency and accuracy are improved, but device complexity and network configuration requirements increase
Solution Approach 1:
The patent segments the positioning system into two distinct modes: in-coverage mode with centralized gNB/LMF coordination for high-accuracy positioning, and out-of-coverage mode with UE-autonomous operations for simplicity. This segmentation allows the system to achieve high positioning accuracy when needed without permanently increasing complexity across all operating conditions.
Solution Approach 2:
The system dynamically adapts its operation mode based on network coverage status. UEs transition between centralized coordination mode (when in coverage) and autonomous mode (when out of coverage), allowing the system to optimize positioning accuracy when possible while maintaining simplicity when centralized coordination is unavailable.
2Adaptability or versatility
If RTT-based positioning is used without tight network timing synchronization, then adaptability and deployment flexibility are improved, but measurement precision may be compromised
Solution Approach 1:
The patent introduces the concept of a reference UE that acts as an intermediary to facilitate RTT-based positioning without requiring tight network synchronization. The reference UE provides timing reference information that enables other UEs to perform relative positioning measurements, thereby achieving positioning functionality with relaxed synchronization requirements.
Solution Approach 2:
The system changes the timing parameter approach from absolute network-synchronized timing to relative UE-based timing measurements. By using RTT measurements and reference UE timing information, the system achieves positioning accuracy through parameter transformations that do not require tight network synchronization, thereby improving deployment flexibility.
3Adaptability or versatility
If out-of-coverage positioning is supported with generic PC5-RRC interface, then adaptability is improved, but positioning efficiency decreases
Solution Approach 1:
The patent segments positioning operations into two distinct scenarios: in-coverage operations utilizing efficient centralized gNB/LMF coordination for high-speed positioning, and out-of-coverage operations using generic PC5-RRC interface for coverage flexibility. This segmentation allows the system to optimize for efficiency when possible while maintaining adaptability when needed.
Solution Approach 2:
The system implements partial centralized coordination functionality even in out-of-coverage scenarios where UEs can establish PC5-RRC connections and perform positioning operations with limited network assistance. This partial action approach maintains positioning efficiency to the extent possible while achieving the adaptability of out-of-coverage operation.
Data Source
AI summary
A method performed for side-link (SL) configuration of a plurality of user equipment (UEs), the method comprising: sending, to a transmitting UE (Tx UE) and a receiving UE (Rx UE), a request for sidelink (SL) positioning reference signal (PRS) capabilities data; receiving, from each of the Tx UE and the Rx UE, respective SL PRS capabilities data; configuring a SL positioning reference signal (PRS) that is based on the SL PRS capabilities data for each of the Tx UE and the Rx UE; sending data specifying a selected SL PRS configuration to the Tx UE; receiving an acknowledgement signal from the Tx UE indicating a Tx UE SL PRS configuration that is based on the selected SL PRS configuration; and providing, to the Rx UE, the Tx UE SL PRS configuration.