Robust Downlink Positioning Using Displacement Sensors
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Solution Overview
Problem
Terrestrial positioning systems face challenges in determining the position of User Equipment (UE) in environments with poor signal hearability due to inter-cell interference and low Signal to Interference and Noise Ratio (SINR), leading to inadequate wireless signal measurements from base stations, which can result in positioning coverage holes, especially in indoor environments or when signals from neighbor cells become too weak.
Innovation Solution
A method and system that combine wireless signal measurements with displacement sensor measurements, such as those from Inertial Measurement Units (IMUs), Pedestrian Dead Reckoning (PDR), and Vehicular Dead Reckoning (VDR), to determine the position of UE, even when there are insufficient wireless signal measurements from base stations, by using a combination of sensor-based displacement measurements to bridge the gap and provide relative displacement and direction between locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DL positioning relies solely on wireless signal measurements from base stations, then positioning can be performed using standard cellular infrastructure, but positioning fails or becomes unreliable when signals from neighbor cells become too weak or unavailable
Solution Approach 1:
The patent combines wireless signal measurements with displacement sensor measurements (from IMUs, PDR, VDR) to determine UE position. This hybrid approach merges two different measurement systems to overcome the limitations of using either system alone, particularly in environments where wireless signals are weak or unavailable.
Solution Approach 2:
Displacement sensors serve as an intermediary measurement system that bridges gaps when primary wireless positioning fails. The displacement measurements act as a complementary data source that can be integrated with wireless signal measurements to maintain continuous positioning capability.
2Measurement precision
If the system requires measurements from 3 or more non-collocated base stations for positioning, then multilateration can be performed accurately, but positioning coverage holes occur when fewer base stations are available
Solution Approach 1:
The patent changes the parameters used for positioning by incorporating displacement sensor measurements alongside wireless signal measurements. This allows the system to maintain positioning capability even when the number of available base station measurements is insufficient for traditional multilateration.
Solution Approach 2:
The system accepts and processes positioning data even when fewer than the ideal number of base station measurements are available, using displacement sensors to compensate for the missing data and achieve sufficient positioning accuracy.
3Measurement precision
If PRS signals are used to improve hearability, then positioning reference signals can avoid collision with CRS and overlap with control channels, but positioning still fails when neighbor cell PRS become too weak to detect
Solution Approach 1:
Displacement sensors serve as an intermediary system that provides positioning capability when PRS signals from neighbor cells become too weak to detect due to inter-cell interference or distance, complementing the wireless measurement system.
Solution Approach 2:
The system prepares by integrating displacement sensor capabilities in advance, so when wireless signal conditions deteriorate due to inter-cell interference or low SINR, the positioning system can seamlessly rely on sensor-based measurements to maintain accuracy.
Data Source
AI summary
Disclosed embodiments facilitate combining a plurality of wireless signal measurement sets with displacement measurements within some time interval of a position request to determine a User Equipment (UE) position. A first set of wireless signal measurements may be obtained from a first set of base stations at a first time at a first location. Subsequently, a second set of wireless signal measurements from a second set of base stations may be obtained at a second time at a second location distinct from the first location. A displacement measurement (e.g. a displacement vector) between the first location and the second location may be obtained. The position of the UE at the second location may then be determined based on the first and second sets of wireless signal measurements and the displacement measurement. In some embodiments, the first and second sets of wireless signal measurements may each be deficient measurement sets.