Mobile Device Localization via Selective Assistance Data
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Solution Overview
Problem
Device-centric localization systems require extensive assistance data storage on mobile devices, which is inefficient in terms of storage space and privacy, as they need to maintain up-to-date data for all reference nodes, and continuous requests to the location server can reveal the device's location, compromising privacy.
Innovation Solution
Implementing a controller that uses a coarse positioning system to select a subset of reference nodes based on an initial estimate, providing only necessary assistance data to the mobile device for a finer location calculation, reducing the need for full database storage and minimizing location inference by the server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If device-centric localization systems store extensive assistance data for all reference nodes on mobile devices, then location calculation can be performed independently, but storage space requirements increase significantly
Solution Approach 1:
The patent extracts only the necessary assistance data (for a subset of reference nodes within communication range) from the complete reference node database, storing only this extracted portion on the mobile device. This reduces storage requirements while maintaining the ability to perform independent location calculations using the extracted data subset.
Solution Approach 2:
The patent applies local quality by making the assistance data storage location-specific and context-dependent. Instead of uniformly storing all reference node data, the system stores assistance data selectively for reference nodes relevant to the device's current location and communication range, optimizing storage efficiency for each local context.
2Measurement precision
If mobile devices continuously request assistance data from the location server, then location accuracy is maintained, but privacy is compromised as the server can infer device location
Solution Approach 1:
The patent performs preliminary action by pre-storing assistance data for a subset of reference nodes on the mobile device before location calculation is needed. This allows the device to perform independent location calculations without continuous server communication, thereby maintaining location accuracy while protecting privacy through reduced interaction with the location server.
Solution Approach 2:
The patent introduces an intermediary mechanism where the mobile device maintains a local cache of assistance data that acts as a mediator between the location server and the device's localization function. This intermediary cache enables accurate location calculation without requiring direct, continuous communication with the server, thus protecting privacy while maintaining precision.
3Adaptability or versatility
If the location server maintains a complete database of all reference nodes, then comprehensive location coverage is achieved, but data transmission and processing overhead increases
Solution Approach 1:
The patent extracts and transmits only the necessary subset of assistance data from the complete reference node database to mobile devices based on their specific needs and communication range. This extraction approach reduces data transmission overhead and processing requirements while maintaining comprehensive location coverage through selective data delivery.
Solution Approach 2:
The patent segments the complete reference node database into smaller, device-specific subsets of assistance data. Each mobile device receives and stores only the segment relevant to its operational context, reducing overall system data transmission and processing overhead while maintaining comprehensive coverage across the network.
Data Source
AI summary
A method of determining a location of a mobile device based on a first location estimation performed using a first location system, the method comprising: obtaining an initial estimate of the mobile device's location based on a second location estimation that is coarser than the first location estimation; using the initial estimate to select a subset of the reference nodes of the first network that are within a defined vicinity of the mobile device's location; and from amongst a database of respective assistance data for each of the wireless reference nodes stored on a server of the first location system, selectively providing the respective assistance data for each of said subset of wireless reference nodes to a localization module on the mobile device, for the localization module of the mobile device to calculate a finer estimate of the mobile device's location.