TDOA Positioning Reference Signals for Sync Error Compensation
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Solution Overview
Problem
Existing positioning technologies in wireless networks suffer from network synchronization errors that limit the accuracy of Time Difference of Arrival (TDOA) measurements, such as Reference Signal Time Difference (RSTD), which affect the precision of user equipment (UE) location estimation.
Innovation Solution
The method and apparatus mitigate network synchronization errors by configuring and managing the transmission of positioning reference signals (PRS) between base stations and user equipment (UE) to account for propagation and processing delays, enabling accurate determination of RSTD through Observed Time Difference of Arrival (OTDOA) and Uplink Time Difference of Arrival (UTDOA) positioning methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional TDOA positioning is used, then positioning can be performed, but network synchronization errors limit positioning accuracy
Solution Approach 1:
The patent applies preliminary action by having the reference base station transmit a reference signal before the neighboring base station transmits its positioning reference signal. The UE measures the time difference between receiving the reference signal from the reference base station and the positioning reference signal from the neighboring base station, and subtracts the known processing delay of the reference base station. This preliminary timing arrangement allows the system to compensate for synchronization errors between base stations, thereby improving positioning accuracy while accounting for reliability concerns.
2Measurement precision
If PRS transmission is configured with processing delay compensation, then positioning accuracy is improved, but system complexity increases
Solution Approach 1:
The patent applies self-service by having the reference base station automatically transmit the reference signal at a predetermined time before the neighboring base station's positioning reference signal, without requiring complex manual configuration. The UE automatically measures the time difference and subtracts the known processing delay parameter. This self-organizing mechanism improves RSTD measurement accuracy while minimizing the operational complexity that would otherwise be required to coordinate between multiple base stations.
Data Source
AI summary
Downlink and uplink Time Difference of Arrival (TDOA) is performed using Reference Signal Time Difference (RSTD) measurements. The transmissions and measurements of positioning reference signals (PRS) are configured to mitigate or eliminate network synchronization errors which conventionally limit positioning accuracy of TDOA. The synchronization errors are mitigated using inter-base station PRS, and transmission of the PRS in response to receipt of the initial reference signal. For DL TDOA, a reference base station may transmit PRS to the user equipment (UE) and neighboring base station. In response, the neighboring base station transmits PRS to the UE. The RSTD may be determined as the difference in the time of reception of the PRS signals received at the UE after removal of the total delay for transmitting the PRS by the neighboring base station, including propagation time and processing time. The RSTD for UL TDOA may be determined in a similar manner.