PRS Transmission Selection in Combined Cell Positioning
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Solution Overview
Problem
In wireless communication systems, particularly in LTE networks with heterogeneous deployments, the use of multiple transmission points per cell leads to ambiguous positioning estimates due to inconsistent Reference Signal Time Difference (RSTD) measurements, causing positioning coverage problems and inaccurate user equipment (UE) location determination.
Innovation Solution
Configuring cells with multiple transmission points to transmit Positioning Reference Signals (PRS) only from selected or all transmission points, based on attributes indicating whether PRS transmission is enabled for each point, thereby ensuring unambiguous PRS-based positioning without altering the OTDOA positioning method principles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple transmission points transmit PRS in a combined cell, then coverage and data transmission capability are improved, but positioning accuracy deteriorates due to ambiguous RSTD measurements
Solution Approach 1:
The patent extracts the PRS transmission function from all transmission points and assigns it to only one selected transmission point. This separation allows the cell to maintain multiple transmission points for data communication while designating a specific transmission point for positioning reference signals, thereby eliminating measurement ambiguity and improving positioning accuracy without sacrificing coverage.
Solution Approach 2:
The patent applies different transmission characteristics to different transmission points within the same cell. While all transmission points provide data transmission services, only the selected transmission point transmits PRS with specific characteristics (e.g., higher power, dedicated time resources). This local differentiation ensures that positioning functionality is maintained with high accuracy while other transmission points focus on data communication.
2Area of stationary object
If all transmission points transmit PRS, then positioning coverage is extended, but positioning performance degrades due to inconsistent RSTD measurements
Solution Approach 1:
The patent extracts the unreliable PRS transmission function from multiple transmission points and consolidates it to a single selected transmission point. This extraction eliminates the source of measurement inconsistency while maintaining positioning coverage through the strategic selection of transmission points that can reliably transmit positioning signals.
Solution Approach 2:
The patent segments the transmission points into two functional groups: those that transmit data and those that transmit positioning reference signals. This segmentation allows the system to maintain positioning coverage by having multiple transmission points while ensuring reliability by assigning PRS transmission to only the selected points with appropriate characteristics.
3Productivity
If PRS transmission is enabled at all transmission points, then system capacity is increased, but positioning accuracy is reduced due to multiple signal sources
Solution Approach 1:
The patent extracts the positioning reference signal transmission function from the general data transmission function at all transmission points. By selecting only specific transmission points for PRS transmission, the system maintains high system capacity through data transmission at multiple points while ensuring positioning precision through consistent reference signals from selected points only.
Data Source
AI summary
A method in a first radio base station of a wireless communication system, for transmitting a reference signal for positioning in a cell. The cell is hosted by the first radio base station and served by a plurality of transmission points. Each transmission point is associated with a value of a first attribute indicating whether transmission of the reference signal for positioning is enabled for the associated transmission point. The method comprises selecting at least one transmission point among the plurality of transmission points based on the values of the first attribute, and transmitting the reference signal for positioning in the cell from the selected at least one transmission point only.