Sidelink Multi-RTT Positioning with Parallel PRS Exchange
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Solution Overview
Problem
Existing wireless communication systems, particularly in 5G NR, face challenges in efficiently utilizing round trip time (RTT) for sidelink positioning, especially in supporting high-density mobile broadband users with low latency and flexible UE scheduling.
Innovation Solution
Implementing apparatuses and methods for RTT-based sidelink positioning, where UEs can transmit indications of their capabilities, determine supporting UEs, request sidelink positioning procedures, and schedule PRS sequence exchanges using sidelink control information to perform serial or parallel PRS sequence exchanges with multiple UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RTT-based sidelink positioning is implemented to support high-density mobile broadband users, then positioning precision and scheduling flexibility are improved, but system complexity and resource management difficulty increase
Solution Approach 1:
The positioning procedure is segmented into distinct phases: capability indication, supporting UE determination, resource determination, and PRS sequence exchange. Each phase is handled independently with specific messages and procedures, making the complex positioning process more manageable and implementable in high-density scenarios
Solution Approach 2:
UEs indicate their sidelink positioning capabilities (RTT measurement capability, PRS capability) in advance before the actual positioning procedure. This preliminary capability exchange allows the network to pre-configure appropriate positioning parameters and resources, reducing real-time complexity during the measurement phase
2Measurement precision
If multiple PRS sequence exchanges are performed with multiple supporting UEs, then positioning accuracy is improved, but latency and time consumption increase
Solution Approach 1:
The system enables continuous positioning measurements by maintaining active sidelink connections with multiple supporting UEs and performing sequential PRS sequence exchanges without full re-establishment of connections. This allows ongoing position updates with reduced latency compared to periodic re-initialization
Solution Approach 2:
PRS sequence exchanges are performed in structured periodic intervals with multiple supporting UEs, allowing the system to balance measurement accuracy (more UEs) against time consumption (measurement intervals) by adjusting the frequency and number of simultaneous exchanges
3Productivity
If RTT measurements are performed with multiple supporting UEs in parallel, then productivity and positioning speed are improved, but resource allocation complexity and interference risk increase
Solution Approach 1:
The system allocates PRS sequences across multiple dimensions: different time slots, frequency resources, and spatial directions (via beamforming). This multi-dimensional resource allocation allows parallel RTT measurements with multiple supporting UEs while minimizing interference and managing resource complexity through orthogonal resource assignment
Data Source
AI summary
Apparatuses, systems, and methods for RTT based sidelink positioning, e.g., in 5G NR systems and beyond. A UE may schedule a multi-RTT PRS sequence exchange with two or more supporting UEs using sidelink control information (SCI). The SCI may be the same as an SCI for a physical sidelink shared channel (PSSCH) or a dedicated SCI for RTT PRS sequence transmission. In addition, the UE may perform one of a serial or parallel PRS sequence exchange with the two or more supporting UEs.