RSTD Measurement Using Assistant Data in Wireless Positioning
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Solution Overview
Problem
In wireless communication systems, determining a user equipment's location using reference signals is challenging due to the complexity of multi-node systems, where nodes are spaced apart and use different antenna configurations, leading to variations in cyclic prefix lengths and antenna port numbers, which can affect the accuracy of reference signal time difference measurements.
Innovation Solution
A method for measuring a reference signal time difference (RSTD) in a wireless communication system involves receiving assistant data related to reference and neighbor cells, including information on CRS antenna ports, cyclic prefix lengths, and MBSFN subframe configurations, to accurately calculate and report RSTD measurements to a location server, ensuring accurate location determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-node systems use different antenna configurations and cyclic prefix lengths, then system adaptability is improved, but measurement precision of reference signal time difference deteriorates
Solution Approach 1:
The patent applies local quality by configuring different cyclic prefix lengths and antenna port numbers for different cells based on their specific characteristics. Each cell can have optimized local parameters (normal or extended CP, different antenna port configurations) while the UE is instructed to use specific parameter combinations when measuring RSTD for particular neighbor cells, ensuring measurement accuracy despite system-wide diversity.
2Measurement precision
If assistant data includes detailed information on CRS antenna ports and cyclic prefix lengths, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary action by having the network pre-configure and provide assistant data to the UE before RSTD measurement. The assistant data includes pre-determined parameters such as CRS antenna port numbers, cyclic prefix lengths, and MBSFN subframe configurations for reference and neighbor cells. This allows the UE to perform measurements with high precision without needing to process complex real-time decisions about parameter selection.
3Object-generated harmful factors
If nodes are spaced apart by predetermined distance, then signal interference is reduced, but location determination accuracy deteriorates due to configuration variations
Solution Approach 1:
The patent applies parameter changes by systematically varying key parameters (cyclic prefix length, antenna port number, frequency shift) across different cells in the multi-node system. Each cell is configured with specific parameter combinations, and the assistant data provides the UE with the exact parameter sets needed for measuring RSTD to specific neighbor cells. This controlled parameter diversity allows nodes to be spaced apart for interference reduction while maintaining measurement accuracy through precise parameter matching.
Data Source
AI summary
A method of reporting information for positioning by a user equipment (UE) in a wireless communication system, includes receiving, from a location server, assistant data related to plurality of cells including a reference cell and one or more neighbor cells; receiving, from the location server, quasi-co-location (QCL) information on the PRS of the plurality of cells and the CRS of the plurality of cells; calculating a reference signal time difference (RSTD) measurement value using a positioning reference signal (PRS) of the plurality of cells and a cell-specific reference signal (CRS) of the plurality of cells based on the assistant data; and reporting the RSTD measurement value to the location server, wherein the assistant data includes information on a cyclic prefix (CP) length of the PRS of the plurality of cells, a CP length of the CRS of the plurality of cells, and a multicast broadcast single frequency network (MBSFN) subframe configuration of the plurality of cells.