Positioning Assistance Data Timing for Unknown Cells
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Solution Overview
Problem
Current positioning techniques in LTE networks face challenges when the serving cell is not included in assistance data, leading to uncertainties in timing information acquisition by mobile terminals, which can result in delayed or failed positioning measurements due to inadequate accounting for cell timing acquisition time.
Innovation Solution
Network nodes determine and account for the time required by mobile terminals to acquire timing information by transmitting assistance data ahead of the expected measurement start time, ensuring inclusion of cells with known timing or facilitating the acquisition of timing information for neighbor cells, and implementing signaling techniques to provide necessary timing information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If assistance data is transmitted without accounting for cell timing acquisition time, then positioning measurement speed is improved, but positioning accuracy deteriorates due to timing uncertainties
Solution Approach 1:
The network node transmits assistance data in advance before the positioning measurement time, allowing the mobile terminal to acquire cell timing information beforehand. This preliminary transmission ensures that timing information is available when needed without delaying the positioning measurement schedule.
Solution Approach 2:
The assistance data acts as an intermediary that carries timing information from the network to the mobile terminal. By including cell timing acquisition time in the assistance data, the system mediates the timing synchronization between network and terminal without requiring direct real-time interaction.
2Adaptability or versatility
If assistance data includes cells with unknown timing information, then positioning coverage is improved, but positioning reliability deteriorates due to acquisition failures
Solution Approach 1:
The mobile terminal feeds back information about its ability to acquire timing information for neighbor cells to the network node. This feedback mechanism allows the network to identify which cells have reliable timing information and include only those in the assistance data, ensuring both coverage and reliability.
Solution Approach 2:
The composition of assistance data is dynamically adjusted based on the mobile terminal's acquisition capability feedback. The network node adaptively selects which neighbor cells to include in assistance data, changing the data set according to real-time conditions rather than using a static configuration.
3Adaptability or versatility
If the serving cell is excluded from assistance data, then positioning flexibility is improved, but device complexity increases due to additional acquisition procedures
Solution Approach 1:
The mobile terminal autonomously determines which neighbor cells to measure and acquires their timing information independently based on assistance data from the network. This self-service approach eliminates the need for the network to manage detailed acquisition procedures for each cell, reducing overall system complexity while maintaining flexibility.
Data Source
AI summary
Methods and apparatus for determining an assistance data transmission time to account for cell timing acquisition are disclosed. In an example method, a network node determines whether a target wireless communication node (110) will need to obtain timing information for at least one cell to be included in the assistance data. The network node then estimates an acquisition time ΔT for the wireless communication node (110) to obtain timing information for at least a first cell. The network node then transmits the positioning assistance data to the wireless communication node (110) at least ΔT before an expected time for the wireless communication node (110) to begin performing positioning measurements. In some embodiments, the network node is configured to wait for a time period at least equal to an expected reporting delay that accounts for the acquisition time ΔT, before deciding that the positioning has failed.