Hybrid Positioning Using Signal Power and Timing
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Solution Overview
Problem
Current cellular positioning methods, such as UE-assisted and UE-based approaches, face challenges in network congestion and battery life due to the need for frequent uplink transmissions and reliance on network-provided assistance data, which limits positioning accuracy and efficiency.
Innovation Solution
A hybrid method that utilizes both received signal power and timing measurements on mobile devices to estimate position using a power-time hybrid Gaussian maximum likelihood estimator, allowing for local generation of high-quality assistance data and reduced network interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UE-assisted positioning method is used, then network can provide assistance data to improve positioning capability, but frequent uplink transmissions cause network congestion and increased battery consumption
Solution Approach 1:
The patent inverts the traditional UE-assisted positioning architecture by implementing UE-based positioning where the mobile device independently performs positioning calculations locally. Instead of the network server computing position based on UE measurements, the UE now computes its own position using locally stored assistance data and received signals, eliminating the need for uplink measurement transmissions to the network.
Solution Approach 2:
The mobile device serves itself by performing autonomous positioning calculations using locally cached assistance data from the base station almanac. The UE independently measures signal parameters, computes position estimates, and determines when assistance data updates are needed, without requiring continuous network interaction or uplink transmissions for positioning purposes.
2Measurement precision
If frequent network interactions are performed for positioning updates, then positioning accuracy can be maintained, but network congestion increases and power consumption rises
Solution Approach 1:
The system performs preliminary actions by pre-downloading and caching the complete base station almanac containing assistance data for multiple base stations directly on the mobile device. This allows the UE to perform multiple positioning calculations locally without needing to frequently request updated assistance data from the network, reducing network interaction frequency while maintaining positioning capability.
Solution Approach 2:
The patent implements local quality by enabling the mobile device to independently process positioning data locally using cached assistance data specific to its geographic area. The UE can perform positioning calculations using locally stored base station information without requiring real-time network connectivity, thus improving network efficiency while maintaining positioning accuracy in the local context.
3Ease of operation
If assistance data is provided by network server, then positioning can be performed, but positioning accuracy is limited and network dependency increases
Solution Approach 1:
The patent adds another dimension to positioning accuracy by incorporating received signal power measurements in addition to traditional timing measurements. The UE-based processor performs positioning calculations using both time difference of arrival (TDOA) data and signal strength information from multiple base stations, creating a multi-dimensional positioning solution that improves accuracy beyond what network-provided assistance data alone can achieve.
Solution Approach 2:
The system replaces the network-centric positioning calculation mechanism with a device-based computational approach. Instead of relying on the network server to perform positioning computations based on UE measurements, the mobile device's local processor performs the positioning calculations using locally cached assistance data and received signals, substituting network-based computation with autonomous device-based computation.
4Measurement precision
If UE performs measurements and transmits to location server, then position can be estimated, but uplink transmissions increase battery life consumption
Solution Approach 1:
The patent extracts the positioning calculation function from the network server and relocates it to the mobile device. By taking out the computational burden from the network and placing it locally on the UE, the system eliminates the need for uplink transmission of measurement data, thereby removing the energy consumption associated with these transmissions while preserving positioning accuracy through local processing.
Data Source
AI summary
A hybrid method of estimating position of a mobile device which utilizes both received signal power and timing measurements. Received signal power of signals received by the mobile device from a plurality of cells are measured and corresponding received signal power measurements are stored. The method further includes measuring, at the mobile device, times of arrival of signals received from the plurality of cells. A plurality of time difference of arrival (TDOA) measurements are determined from the times of arrival. A power-time hybrid Gaussian maximum likelihood estimator and positioning assistance data for the plurality of cells are used to generate a maximum likelihood estimate of the position of the mobile device by evaluating a joint conditional probability of the received signal power measurements and the plurality of TDOA measurements. Gaussian random variables may be used to represent the received signal power measurements and the TDOA measurements.