Synchronous WWAN and WLAN Scanning for Indoor Positioning
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Solution Overview
Problem
Existing positioning systems for mobile devices, particularly indoors, face inaccuracies due to the unavailability or inaccuracy of satellite positioning systems, leading to compromised database growth and maintenance in terrestrial-based positioning, which relies on satellite fixes.
Innovation Solution
Mobile devices synchronize scans from both wireless wide area networks (WWAN) and local area wireless networks (WLAN/WPAN) to align positioning measurements in time, ensuring accurate and coordinated data collection for crowdsourcing and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If satellite positioning systems (SPS) are used for positioning, then positioning accuracy is improved, but availability deteriorates in indoor locations
Solution Approach 1:
The patent combines satellite positioning system (SPS) measurements with terrestrial network measurements (WWAN and WLAN) into a unified positioning solution. By merging multiple positioning sources, the system achieves reliable indoor positioning where SPS alone fails, while maintaining outdoor accuracy through SPS data when available.
2Reliability
If terrestrial based positioning is used when SPS is unavailable, then availability is improved, but measurement precision deteriorates due to lack of synchronized measurements
Solution Approach 1:
The system performs preliminary synchronization of scan timing between WWAN and WLAN networks before taking measurements. By pre-aligning the scan schedules and using synchronization signals from the networks, measurements are captured at effectively the same position, eliminating the precision loss that would otherwise occur during device movement between scans.
3Adaptability or versatility
If scans for WWAN and WLAN are performed separately, then adaptability is improved, but time consumption increases due to multiple separate scanning operations
Solution Approach 1:
The patent merges the scanning operations for WWAN and WLAN into a coordinated, simultaneous process. The mobile device scans both networks at the same time using synchronized timing, reducing the total time required compared to performing separate scan operations while maintaining the ability to adapt to different network conditions and types.
4Measurement precision
If database growth depends on SPS fixes through crowdsourcing, then database accuracy is improved, but productivity deteriorates in indoor locations where SPS is unavailable
Solution Approach 1:
The system enables mobile devices to self-determine their positions using terrestrial network measurements without requiring SPS fixes. Devices autonomously perform synchronized scans of WWAN and WLAN networks, calculate positions using time-based measurements (TOA, TDOA, RTT), and contribute this data to the database, allowing database growth to continue in indoor locations where SPS is unavailable.
Data Source
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AI summary
A mobile device synchronously scans different terrestrial networks for positioning measurements to align the scans in time. With minimal time difference between the scans, the positioning measurements from the different terrestrial networks may be used for crowdsourcing or position determination. The mobile device may synchronously scan a wireless wide area network (WWAN) and a local area wireless network so that positioning measurement derived from the scans are aligned in time. A local area wireless network is, e.g., a wireless local area networks (WLANs) or wireless personal area network (WPANs) but does not include cellular networks or satellite networks. The scans may be scheduled at a hardware level to ensure tight synchronization with near-zero time difference between the scans. Alternatively, the scans may be synchronized at a software level with only scans that occur within a time difference threshold from each other are used for crowdsourcing or positioning.