Positioning via Phase and Time Differences of Polyphase Signals
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Solution Overview
Problem
Current wireless geolocation techniques, such as OTDOA and U-TDOA, rely on time difference of arrival measurements, which can increase power consumption and compromise accuracy due to environmental factors affecting received signal strength indicator (RSSI) values.
Innovation Solution
A positioning service that utilizes both time and phase differences of signals, where a network device transmits a position reference signal encoded with a perfect polyphase sequence, and the end device responds with a modified signal, allowing the network to calculate accurate distance and location using phase and time differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time difference of arrival measurements are used for positioning, then positioning can be achieved, but power consumption increases and accuracy is compromised
Solution Approach 1:
The patent changes the measurement parameters from time difference of arrival (OTDOA) to phase difference of arrival (PDOA) and time difference of arrival (TDOA). By measuring phase differences of reference signals at multiple frequencies and combining with time difference measurements, the system achieves higher positioning accuracy without significantly increasing power consumption, as the end device only needs to measure phase and time differences rather than performing complex time difference calculations
2Measurement precision
If RSSI values are used for position calculation, then positioning can be performed, but accuracy is compromised due to environmental factors
Solution Approach 1:
The patent replaces the RSSI-based positioning mechanism with a phase and time difference-based mechanism. Instead of using signal strength (RSSI) which is susceptible to environmental factors like multipath effects and shadowing, the system uses phase differences of reference signals and time differences of arrival, which are less sensitive to environmental variations. This substitution fundamentally changes how positioning is achieved, moving from signal strength-based to geometric-based positioning
3Manufacturing precision
If traditional positioning methods are used, then existing infrastructure can be utilized, but manufacturing precision and measurement accuracy are limited
Solution Approach 1:
The patent makes the existing wireless communication infrastructure universal for positioning by utilizing reference signals that are already transmitted for other network functions. The end device uses its existing receiver to measure phase and time differences of these multi-purpose reference signals, eliminating the need for dedicated positioning hardware. This approach achieves high measurement precision while maintaining device simplicity and avoiding additional hardware requirements
Data Source
AI summary
A method, a device, and a non-transitory storage medium provide to generate a first signal that includes a perfect polyphase-encoding of an identifier of the wireless station; transmit the first signal; receive from an end device, a second signal that is responsive to the first signal and includes a perfect polyphase-encoding of the identifier of the wireless station and an identifier of the end device; autocorrelate the first signal and the second signal; calculate in response to the autocorrelation, a time difference between the first signal and the second signal; calculate in response to the calculation, a phase difference between the first signal and the second signal; and calculate in response to the calculation of the phase difference, a distance between the wireless station and the end device based on the time difference, the phase difference, the identifier of the wireless station, and the identifier of the end device.