Sidelink Synchronization Source Selection for C-V2X Positioning
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Solution Overview
Problem
Existing wireless communication systems, particularly in C-V2X, face challenges in achieving stringent synchronization for accurate positioning, especially in GNSS-challenged environments, which is crucial for meeting sub-lane level accuracy requirements.
Innovation Solution
The system employs sidelink PRS-driven synchronization source selection to determine optimal synchronization sources for vehicles, enabling tight synchronization between vehicles for both communication and positioning purposes, using PRS or SRS signals, and negotiating synchronization sources during pre-PRS handshakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS is used for synchronization, then positioning accuracy is improved, but reliability deteriorates in GNSS-challenged environments
Solution Approach 1:
The patent introduces sidelink synchronization signals (SLSS) and positioning reference signals (PRS) as intermediary synchronization sources when GNSS is unavailable. These signals enable vehicles to synchronize with each other directly, bypassing the need for GNSS infrastructure and maintaining reliability in challenging environments while achieving sub-lane level positioning accuracy.
Solution Approach 2:
The system dynamically changes synchronization source parameters by selecting between GNSS, SLSS, and PRS based on availability and accuracy requirements. When GNSS is challenged, the system transitions to using SLSS/PRS with adjusted timing and frequency parameters to maintain synchronization quality and positioning accuracy without GNSS dependency.
2Measurement precision
If sidelink PRS-driven synchronization is implemented, then synchronization accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary synchronization establishment through pre-PRS handshakes and synchronization source selection before actual positioning operations. This preliminary action prepares the synchronization state in advance, reducing the complexity of real-time synchronization adjustments and enabling accurate positioning without requiring complex dynamic synchronization algorithms during operation.
Data Source
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AI summary
Systems and techniques are described for sidelink synchronization source selection. For example, a method for wireless communications at a user equipment (UE) may include transmitting, from the UE to a target UE, a message including information associated with a first synchronization reference source associated with the UE. The method may include receiving, at the UE from the target UE in response to the message, a response message including an indication of whether the target UE can use the first synchronization reference source for sidelink positioning. The method can further include determining, at the UE based on the response message, whether to use the first synchronization reference source or a different synchronization reference source as a master synchronization reference source for the sidelink positioning.