RIS-Reflected Sidelink Positioning Signals for Accurate UE Localization
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Solution Overview
Problem
The challenge in wireless communication systems, particularly in 5G networks, is to enhance spectral efficiency, support a large number of connections, and reduce latency while improving positioning accuracy for user equipment (UEs) using existing technologies.
Innovation Solution
The use of reconfigurable intelligent surfaces (RIS) to reflect sidelink reference signals (SL-RS-P) for positioning, enabling multiple reflections of SL-RS-P between a relay UE and a target UE, facilitating enhanced positioning measurements and accuracy through multiple reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sidelink reference signals are transmitted through different RIS elements, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The system segments the positioning function by dividing the RIS into multiple controllable elements, where each element can independently reflect a sidelink reference signal. This segmentation enables multiple measurement paths (direct signal, first reflection, second reflection) to be established simultaneously, improving positioning accuracy while distributing the complexity across multiple simple elements rather than requiring a complex single-unit system
Solution Approach 2:
The RIS acts as an intermediary device between the transmitting UE and the receiving UE for positioning measurements. By introducing this mediator, the system enables enhanced positioning through reflected signals without requiring direct complex interactions between the UEs themselves. The RIS intermediary handles the complexity of signal reflection and routing, simplifying the overall system architecture while improving measurement capabilities
2Productivity
If RIS is introduced for signal reflection, then spectral efficiency is enhanced, but system complexity increases
Solution Approach 1:
The RIS is designed with multi-functionality, serving both as a communication signal reflector and as a positioning measurement assistant. By integrating these functions into a single device, the system enhances spectral efficiency through improved signal propagation while avoiding the need for separate dedicated positioning infrastructure, thereby limiting the increase in overall system complexity
Solution Approach 2:
The RIS dynamically changes its reflection parameters (such as phase shift and amplitude) to optimize signal propagation for both communication and positioning functions. This parameter adjustment capability allows the same hardware infrastructure to serve multiple purposes efficiently, enhancing spectral efficiency without proportionally increasing system complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves positioning accuracy and enhances spectral efficiency by leveraging RIS to optimize signal reflections, addressing the limitations of existing 5G positioning methods.
Implementation Method 1
transmitting a second SL-RS-P to a first reconfigurable intelligent surface (RIS) that is configured to reflect the second SL-RS-P to the target UE
Data Source
AI summary
In an aspect, a relay UE transmits sidelink reference signals for positioning (SL-RS-P) off first and second reconfigurable intelligent surfaces (RISs). The target UE measures the reflected SL-RS-Ps. In an aspect, the SL-RS-Ps may be associated with configurations that are configured by a base station. In an aspect, a position estimation entity may obtain measurement information associated with the reflected SL-RS-Ps and determine a position estimate of the target UE based at least in part upon the measurement information.