Complementary Assistance Data for LTE Positioning Handovers
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Solution Overview
Problem
Current positioning systems in LTE networks face performance degradation during cell handovers or carrier switching, leading to reduced accuracy and increased positioning time, especially in multi-carrier systems where assistance data is not adequately provided for new frequency or primary component carriers.
Innovation Solution
The system proactively generates and sends complementary assistance data to user equipment before a cell change, adapting to the new cell configuration, including neighbor cells, primary cells, and timing information, to ensure continuous and accurate positioning sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If assistance data is provided only for the current serving cell, then the positioning system works correctly during stable cell conditions, but positioning accuracy and continuity degrade during cell handovers or carrier switching
Solution Approach 1:
The positioning node proactively generates and provides complementary assistance data for the second cell (target cell) before the cell change occurs. This preliminary action ensures that the user equipment already has the necessary assistance data for the new cell when handover occurs, preventing positioning session interruption and maintaining continuous positioning accuracy during cell transitions
Solution Approach 2:
The system dynamically adapts the assistance data provision to match the dynamic cell change conditions. By detecting that a cell change is occurring and automatically providing complementary assistance data for the new cell, the system makes the positioning assistance dynamic and adaptable to changing radio conditions, rather than using a static assistance data approach
2Measurement precision
If complementary assistance data for the second cell is provided in advance, then positioning accuracy and session continuity improve during handover, but signaling overhead and processing complexity increase
Solution Approach 1:
The positioning node applies local quality by providing assistance data specifically tailored to the local condition of the second cell. The complementary assistance data includes cell-specific parameters such as physical cell identity, carrier frequency, and positioning reference signal configuration that are locally relevant to the target cell, rather than using generic or overly comprehensive data sets
Solution Approach 2:
The system uses partial action by providing only the necessary complementary assistance data for the second cell rather than complete re-provisioning of all assistance data. This selective provision includes only the specific parameters needed for positioning in the new cell, reducing processing complexity while maintaining positioning accuracy
3Loss of time
If assistance data is updated after cell change occurs, then signaling complexity is reduced, but positioning session interruption and latency increase
Solution Approach 1:
The positioning node performs preliminary action by providing the complementary assistance data for the second cell before the cell change occurs. This ensures that when the user equipment hands over to the new cell, the assistance data is already available, preventing positioning session interruption and eliminating the time loss that would occur if data had to be provided after handover
Solution Approach 2:
The system maintains continuity of useful action by ensuring that assistance data remains available and valid across the cell transition. By providing complementary assistance data in advance, the positioning functionality continues uninterrupted during handover, maintaining measurement quality and positioning session continuity without gaps or interruptions
Data Source
AI summary
A positioning node (110), a user equipment (120), a radio network node (130) and methods therein for providing complementary assistance data to be used by a user equipment (120) during a positioning session for determining a position of the user equipment (120) and for enabling continuation of the positioning session are provided. A change from a first cell to a second cell occurs during the positioning session. The user equipment (120) receives control information from the first cell before the change and from the second cell after the change. The positioning node obtains information identifying the second cell. Next, the positioning node generates the complementary assistance data relating to the second cell in advance of the change. The complementary assistance data comprises assistance data adapted to the second cell when the second cell is configured to provide control information to the user equipment (120). The positioning node sends the complementary assistance data relating to the second cell to the user equipment (120) via the radio network node (130) in advance of the change. Next, the user equipment (120) processes the complementary assistance data, thereby enabling continuation of the positioning session.