Sidelink Ranging with Reconfigurable Intelligent Surface
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face inefficiencies and high latency in sidelink ranging and positioning due to high signaling overhead and reliance on round-trip time (RTT) calculations for distance determination, especially in non-line-of-sight (NLOS) conditions.
Innovation Solution
The implementation of a method that utilizes a reconfigurable intelligent surface (RIS) for reflecting reference signals, allowing for single-sided PRS transmission and reception, which reduces signaling overhead and latency by calculating the RTT between transmitted and reflected signals, thereby determining the distance between devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional round-trip time (RTT) calculations are used for sidelink ranging, then distance determination can be achieved, but signaling overhead and latency increase significantly
Solution Approach 1:
The patent extracts the ranging function from the traditional bidirectional RTT measurement process and implements it through unidirectional reference signal transmission. The first wireless device transmits reference signals that are reflected by the RIS associated with the second device, eliminating the need for the second device to transmit separate measurement signals back, thus reducing signaling overhead and latency while maintaining distance measurement capability
Solution Approach 2:
The patent introduces a reconfigurable intelligent surface (RIS) as an intermediary element between the two wireless devices. The RIS reflects the reference signals from the first device back to it, enabling the first device to calculate RTT based on the time difference between transmission and reception of reflected signals. This intermediary approach reduces the complexity of direct bidirectional communication while achieving accurate ranging
2Measurement precision
If traditional RTT calculations are used for sidelink ranging, then distance can be determined, but signaling overhead increases
Solution Approach 1:
The patent extracts the ranging function from the traditional bidirectional RTT measurement process and implements it through unidirectional reference signal transmission. The first wireless device transmits reference signals that are reflected by the RIS associated with the second device, eliminating the need for the second device to transmit separate measurement signals back, thus reducing signaling overhead and latency while maintaining distance measurement capability
Solution Approach 2:
The patent makes the reference signal serve multiple functions: it acts as both the transmission signal from the first device and the reflected signal for RTT calculation. The same reference signal sequence is used for both outbound and return path measurement, eliminating the need for separate signaling channels and reducing overall signaling overhead
3Productivity
If reconfigurable intelligent surface is used for signal reflection, then signaling overhead and latency are reduced, but system complexity increases
Solution Approach 1:
The patent implements self-service by having the RIS automatically reflect the reference signals without requiring active participation or control from the second wireless device. The RIS operates autonomously to bounce signals back to the first device, reducing the processing burden on the wireless devices while enabling efficient ranging through passive signal reflection
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 enhances the efficiency and accuracy of sidelink-based ranging and positioning by reducing latency and signaling overhead, improving performance in both line-of-sight (LOS) and NLOS conditions, and is applicable to various wireless communication standards.
Implementation Method 1
The apparatus receives one or more reflected reference signals reflected from the at least one RIS
Data Source
AI summary
Aspects presented herein may enable a wireless device to perform an SL ranging based on a single-sided PRS transmission. In one aspect, a first wireless device transmits one or more reference signals to at least one RIS associated with a second wireless device. The first wireless device receives one or more reflected reference signals reflected from the at least one RIS. The first wireless device calculates a signal RTT based on the one or more reference signals and the one or more reflected reference signals. In another aspect, a second wireless device transmits, to a first wireless device, information indicating a time, a duration, or a periodicity in which at least one RIS associated with the second wireless device is to be activated. The second wireless device activate the at least one RIS based on the information.