Signalling Device Reference Signals for Positioning Accuracy
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Solution Overview
Problem
Current positioning methods in LTE wireless communications networks face challenges such as weak signal quality, high interference, poor cross-correlation properties, and limited flexibility, which affect positioning accuracy and service expansion, especially in environments with unfavorable conditions.
Innovation Solution
Deploying low-complexity signalling devices as limited-functionality cells (s-cells) that transmit pre-defined reference signals in a specific pattern, allowing user equipment to perform time measurements for positioning, while minimizing interference and maximizing signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional positioning methods are used in LTE networks, then positioning services can be provided, but signal quality is weak and interference is high in unfavorable environments
Solution Approach 1:
The patent introduces positioning reference signals (PRS) as intermediary signals specifically designed for positioning measurements. These PRS are transmitted by positioning reference signal transmitting points (which can be base stations or dedicated positioning devices) and serve as a mediator between the network and user equipment for accurate time-of-arrival measurements, thereby improving positioning accuracy while managing interference through dedicated signal design
Solution Approach 2:
The patent employs parameter changes by configuring positioning reference signals with specific physical layer parameters including frequency shifts, time delays, and resource element patterns. These parameter variations allow the PRS to be distinguished from other signals and enable accurate measurements even in challenging radio conditions, directly addressing the signal quality and interference issues
2Measurement precision
If more base stations are deployed to improve positioning coverage, then positioning accuracy improves, but network cost and complexity increase
Solution Approach 1:
The patent enables base stations to serve dual functions: traditional data transmission and positioning reference signal transmission. The positioning reference signal transmitting points can be existing base stations that already provide coverage, allowing them to additionally support positioning services without requiring separate dedicated infrastructure, thereby reducing network complexity while maintaining positioning precision
Solution Approach 2:
The patent creates positioning reference signals that are transmitted according to configured patterns and can be copied/repeated across multiple transmitting points. This allows the same positioning signal structure to be deployed throughout the network, enabling consistent positioning measurements without requiring complex unique signal designs for each base station
3Measurement precision
If positioning reference signals are transmitted frequently, then positioning accuracy improves, but interference and signal quality deteriorate
Solution Approach 1:
The patent implements periodic transmission of positioning reference signals according to configured patterns. The PRS are transmitted at specific time intervals and resource element positions rather than continuously, allowing for measurements to be taken periodically while reducing overall interference and signal quality degradation. This periodic action enables accurate time-of-arrival measurements without the harmful effects of continuous high-frequency transmission
Solution Approach 2:
The patent uses preliminary configuration of positioning reference signal parameters including frequency shifts, time delays, and resource element patterns before actual positioning measurements. This preliminary setup optimizes the PRS transmission characteristics in advance, ensuring that signals are transmitted at appropriate frequencies and times to maximize measurement accuracy while minimizing interference and signal quality issues
Data Source
AI summary
A method in a signalling device for assisting in positioning of user equipment based on time measurements is provided. The signalling device is associated with an s-cell, which is recognized by the first network node as having limited functionality and is, therefore, not considerable for the user equipment as a candidate cell for serving the user equipment (for data transmission. The signalling device associated s-cell is part of a positioning neighbor list of neighbor cells. The neighbor cells in the list are configured to have time measurements performed thereon by the user equipment for enabling positioning. The signalling device is configured to transmit predefined reference signals in predefined subframes and according to a predefined pattern relating to preselected subcarriers and preselected time slots within a subframe. The signalling device obtains synchronization information and transmits reference signals according to the configuration and synchronized according to the obtained synchronization information. This enables the user equipment to receive and perform time measurements on the transmitted reference signals for positioning when the signalling device associated s-cell is in the positioning neighbor list.