Sidelink Positioning Accuracy via Synchronization Feedback

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Solution Overview

Problem

Sidelink time difference of arrival (SL-TDOA) positioning accuracy is compromised by synchronization errors and clock drift in wireless communication systems, particularly when user equipment (UE) lacks direct access to a network node or global navigation satellite system (GNSS), leading to reduced positioning precision.

Innovation Solution

The method involves exchanging synchronization status data between UEs and a location management function (LMF) server to mitigate synchronization errors, using multiple antennas from a single target UE, and employing a positioning reference unit (PRU) to improve SL-TDOA accuracy by reducing the impact of clock drift and synchronization errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If SL-TDOA positioning is performed using neighboring UEs as anchor UEs, then positioning can be achieved without direct access to network nodes or GNSS, but positioning accuracy deteriorates due to synchronization errors and clock drift

Engineering Contradiction:

Improvepositioning capability without network node or GNSS accessVSAvoidpositioning accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system implements feedback mechanisms where UEs exchange synchronization status information and measurement data. The LMF server processes this feedback to determine clock drift and generate compensation values, which are then applied to improve positioning accuracy in subsequent measurements.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The LMF server acts as an intermediary that collects synchronization status from multiple UEs, processes the data to determine clock drift, and provides compensation values to the target UE. This intermediary function enables accurate positioning without requiring direct network node or GNSS access at the UE level.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If multiple measurements are performed to determine clock drift, then positioning accuracy can be improved, but measurement time and processing complexity increase

Engineering Contradiction:

Improvepositioning accuracyVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary synchronization status exchanges and measurements before the actual positioning calculation. By pre-collecting RSTD measurements and synchronization status information from multiple UEs, the system prepares compensation values in advance, reducing the time required during the actual positioning operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes measurement parameters dynamically based on synchronization status. When synchronization quality is high, fewer measurements are required. When clock drift is detected, the system adjusts the number and type of measurements needed, optimizing the balance between accuracy and time consumption.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20240373394A1Systems and methods for sidelink positioning accuracy

Publication Date: 2024.11.07 SAMSUNG ELECTRONICS CO LTD

AI summary

A system and a method are disclosed. The method includes performing, by a first user equipment (UE), a first measurement between a second UE and a third UE, receiving status data from the third UE, the status data including synchronization information associated with the third UE, based on the status data, selecting the third UE for determining the first measurement, and performing a positioning determination based on the first measurement.