RIS-Aided PRS Signaling for Asymmetric Uplink-Downlink Positioning
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Solution Overview
Problem
Existing wireless communication systems, particularly 5G networks, face challenges in enhancing spectral efficiency and reducing latency, especially in determining the location of mobile devices with accuracy using positioning reference signals (PRS) due to asymmetric uplink and downlink signal transfer via reconfigurable intelligent surfaces (RIS).
Innovation Solution
The use of uplink and downlink PRSs reflected by separate RISes to determine the range and direction between a mobile device and the RIS, enabling precise location estimation by analyzing time differences and angles of departure/arrival of these signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single RIS is used for both uplink and downlink PRS transmission, then device complexity is reduced, but location determination accuracy deteriorates due to asymmetric signal transfer
Solution Approach 1:
The patent divides the single RIS function into two separate RIS instances: a first RIS dedicated to downlink PRS transmission and a second RIS dedicated to uplink PRS reception. This segmentation allows each RIS to be optimized for its specific direction of signal transfer, improving location determination accuracy by accounting for asymmetric signal characteristics while maintaining manageable complexity through specialized functional division
Solution Approach 2:
The patent introduces separate RISes as intermediary devices between the wireless communication device and the network infrastructure. These intermediary RISes enable independent optimization of downlink and uplink signal paths, allowing the system to handle asymmetric signal transfer characteristics more effectively and improve positioning accuracy without requiring complex full-duplex operation from a single RIS
2Measurement precision
If separate RISes are used for uplink and downlink PRS, then location determination accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines the functionality of multiple specialized RISes into a coordinated system managed by a single processor at the wireless communication device. This merging approach allows the device to handle multiple RIS interactions through unified processing logic, reducing the effective complexity burden on individual components while maintaining the accuracy benefits of separate RISes for uplink and downlink signals
Solution Approach 2:
The wireless communication device is designed with universal processing capabilities that can handle both downlink PRS reception and uplink PRS transmission through a single processor. This multi-functionality allows the device to work with multiple separate RISes without requiring separate processing hardware for each direction, thereby improving location accuracy while controlling overall system complexity
3Adaptability or versatility
If PRS transmission timing is not synchronized, then system operation flexibility is maintained, but location determination accuracy deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the wireless communication device measures the time difference between downlink and uplink PRS transmission and feeds this information back to the processor. The processor uses this feedback to calculate and compensate for timing offsets, enabling accurate location determination even when the RISes operate with inherent timing differences, thus maintaining both flexibility and accuracy
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
Enhances location determination accuracy for mobile devices by leveraging separate RISes to account for asymmetric signal transfer, improving the precision of positioning in 5G networks.
Implementation Method 1
transmit, via the transceiver at a first time, a first PRS (positioning reference signal) to a second wireless signaling device via a first RIS (reconfigurable intelligent surface)
Data Source
AI summary
A signal reporting method includes: transmitting, from a first wireless signaling device at a first time, a first PRS (positioning reference signal) to a second wireless signaling device via a first RIS (reconfigurable intelligent surface); receiving, at the first wireless signaling device at a second time, a second PRS from the second wireless signaling device via a second RIS that is physically separate from the first RIS; and providing a signal report including at least one time value corresponding to the first time and the second time, and indicative of the first PRS and the second PRS.