Wireless Location Using Power and Timing Measurements
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Solution Overview
Problem
Current wireless location technologies, such as Enhanced Cell-ID (ECID), face limitations in accuracy due to RF multipath, mobile receiver quality, and the need for calibration, especially in GSM, UMTS, and LTE networks, where the number of neighbor cell measurements is limited, leading to reduced location accuracy and increased latency.
Innovation Solution
The method involves using power and timing measurements from sibling pairs of cell site antennas to determine the location of a mobile device with higher accuracy, employing power-difference-of-arrival (PDOA) and power-angle-of-arrival (AoA) techniques, which do not require extensive calibration and can operate with fewer neighbor cell measurements, improving location accuracy and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ECID technique is used to refine location estimate using power levels from neighboring cells, then location accuracy is improved, but the number of required neighbor cell measurements increases, leading to reduced location yield and increased latency
Solution Approach 1:
The patent extracts the location estimation problem from the traditional multi-cell ECID approach and focuses specifically on utilizing measurements from the serving cell and a limited set of neighboring cells. By taking out the requirement for extensive neighbor cell measurements and focusing on essential measurements, the system achieves good location accuracy without the penalty of reduced location yield.
Solution Approach 2:
Instead of requiring complete measurement sets from all potential neighboring cells (excessive action), the patent applies partial action by using measurements from a subset of cells - specifically the serving cell and selected neighboring cells. This partial measurement approach achieves sufficient location accuracy while maintaining higher location yield and reducing latency.
2Measurement precision
If ECID technique is used to refine location estimate using power levels from neighboring cells, then location accuracy is improved, but measurement complexity and calibration requirements increase
Solution Approach 1:
The patent applies self-service by utilizing measurements that are already being collected by the mobile device for mobility management purposes (serving cell and neighboring cell power levels). These measurements are naturally available during normal network operation, eliminating the need for separate calibration procedures or additional measurement infrastructure.
Solution Approach 2:
The patent makes the location estimation system universal by using the same power level measurements that serve dual purposes: mobility management (handover decisions) and location estimation. This multi-functionality eliminates the need for separate calibration systems or additional measurement equipment, reducing overall system complexity.
3Measurement precision
If sibling pairs of cell site antennas are used with PDOA and power-AoA techniques, then location accuracy is significantly improved, but the requirement for specific antenna configurations increases system complexity
Solution Approach 1:
The patent applies preliminary action by pre-identifying and pre-configuring sibling pairs of cell site antennas before location estimation is performed. The system pre-establishes which antenna pairs form sibling relationships based on their spatial and functional characteristics, so that when location estimation is needed, the appropriate measurements are already available without complex real-time configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances location accuracy beyond traditional cell-ID methods, achieving medium to high accuracy without the need for calibration, and reduces latency by utilizing power and timing measurements from sibling pairs, effectively addressing the limitations of existing technologies.
Implementation Method 1
employing power-difference-of-arrival (PDOA) and power-angle-of-arrival (AoA) techniques
Implementation Method 2
employing power-difference-of-arrival (PDOA) and power-angle-of-arrival (AoA) techniques
Implementation Method 3
using power and timing measurements from sibling pairs of cell site antennas to determine the location of a mobile device
Data Source
AI summary
Disclosed is a method for processing readily available radio network, timing and power information about cellular networks and typical measurements made by the mobile device and network. A probabilistic method is disclosed that uses both time (i.e., range) and power differences with known downlink transmitter antenna characteristics to locate mobiles with accuracy better than cell-ID with ranging, with high capacity, and without the need for field calibration.