RIS-Assisted Sidelink Ranging for NLOS RTT Accuracy
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately determining the range between devices using sidelink communication, especially in non-line-of-sight (NLOS) conditions, due to increased signal round-trip time (RTT) and potential blockages.
Innovation Solution
The use of reconfigurable intelligent surfaces (RIS) to relay reference signals between wireless devices, allowing for improved accuracy in sidelink ranging by creating a path closer to line-of-sight (LOS), thereby reducing RTT and enhancing signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sidelink communication is used for range determination in NLOS conditions, then wireless communication capability is maintained, but measurement precision deteriorates due to increased signal RTT and blockages
Solution Approach 1:
The patent introduces a gNB (base station) as an intermediary node to facilitate range determination between wireless devices in NLOS conditions. The gNB transmits reference signals to both devices and calculates the range based on RTT measurements, eliminating the need for direct device-to-device signal propagation that is blocked in NLOS conditions. This mediator approach maintains communication reliability while restoring measurement precision.
2Ease of operation
If direct sidelink signal transmission is used for ranging, then device autonomy is improved, but measurement precision deteriorates due to signal blockages in NLOS conditions
Solution Approach 1:
The gNB acts as a mediator that enables autonomous ranging operations without requiring direct signal paths between devices. The base station manages the reference signal transmission and RTT calculation, allowing devices to perform ranging autonomously even when direct communication paths are blocked by buildings or other obstacles.
3Measurement precision
If RIS is deployed to improve signal propagation, then measurement precision is improved by creating LOS-like paths, but device complexity increases
Solution Approach 1:
The RIS functions as a passive intermediary surface that reflects and redirects electromagnetic waves to create artificial line-of-sight paths between the gNB and wireless devices. By controlling the phase and amplitude of reflected signals, the RIS improves measurement precision without requiring active processing or power consumption at the device level, thus limiting the increase in system complexity.
Solution Approach 2:
The RIS introduces a new spatial dimension for signal propagation by utilizing reflective surfaces positioned in three-dimensional space. This allows signals to reach devices through indirect paths that mimic direct LOS propagation, improving ranging accuracy without requiring complex multi-antenna systems or sophisticated signal processing at the devices.
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
The implementation of RIS in sidelink communication systems enhances the accuracy of range determination by mitigating NLOS issues, improving signal propagation, and reducing power consumption.
Implementation Method 1
The use of reconfigurable intelligent surfaces (RIS) to relay reference signals between wireless devices, allowing for improved accuracy in sidelink ranging by creating a path closer to line-of-sight (LOS)
Data Source
AI summary
Aspects presented herein may enable one or more wireless devices to perform a sidelink-based ranging and/or positioning with an assistance of an RIS. In one aspect, a first wireless device receives an information indicating at least a time in which at least one RIS is to be activated. The first wireless device transmits a first set of reference signals to a second wireless device via the at least one RIS. The first wireless device receives a second set of reference signals transmitted from the second wireless device via the at least one RIS. The first wireless device calculates a first signal RTT based on the first set of reference signals and the second set of reference signals.