Indoor Positioning via Base Station Signal Phase Sampling
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Solution Overview
Problem
Conventional mobile communications devices struggle to determine their location indoors where GPS signals are unavailable, as they rely on satellite signals that cannot penetrate buildings.
Innovation Solution
A communications device equipped with a receiver, antenna, and motion detector that interprets positioning reference signals from infrastructure equipment to estimate the direction of arrival, forming a synthetic antenna array to calculate its location, with the sampling rate adapted based on speed and motion detector accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS satellite signals are used for location determination, then location accuracy is improved, but the system fails to work indoors where satellite signals cannot penetrate
Solution Approach 1:
The patent introduces base station signals as an intermediary medium for location determination. Instead of relying directly on GPS satellite signals that cannot penetrate buildings, the system uses radio signals from base stations (which can penetrate buildings) as a mediator to enable indirect location determination through direction of arrival estimation and triangulation with other base stations.
Solution Approach 2:
The patent changes the fundamental parameter of signal source from GPS satellites (outdoor-only) to base station radio signals (indoor-capable). By transitioning to a different signal type that can penetrate buildings, the system maintains location determination functionality in indoor environments where GPS signals fail.
2Measurement precision
If sampling rate is increased to improve location accuracy, then measurement precision is improved, but energy consumption and processing complexity increase
Solution Approach 1:
The patent implements dynamic sampling rate adjustment based on the device's motion state. When the device is stationary or moving slowly, a lower sampling rate is used to conserve energy. When the device is moving quickly, the sampling rate is increased to maintain accurate location tracking. This dynamic adaptation optimizes the balance between measurement precision and energy consumption.
Solution Approach 2:
The system changes the sampling rate parameter dynamically based on motion detector input. By adjusting this critical measurement parameter according to actual operational conditions, the system achieves high precision when needed while minimizing energy consumption during stationary periods.
3Speed
If sampling rate is increased to track fast-moving devices, then location tracking accuracy is improved, but device complexity and processing requirements increase
Solution Approach 1:
The system uses the device's own motion detector to automatically determine the appropriate sampling rate. The motion detector provides feedback about the device's movement state, and this information is used to self-adjust the sampling rate without requiring external control or complex processing algorithms. This self-service approach simplifies the overall system architecture.
Solution Approach 2:
The patent implements a feedback loop where the motion detector continuously monitors device movement and feeds this information back to the controller, which then adjusts the sampling rate accordingly. This feedback mechanism enables automatic adaptation to changing motion conditions without increasing overall system complexity.
Data Source
AI summary
A communications device includes: a receiver configured to receive signals including at least one positioning reference signal transmitted in each of a plurality of time units, at least one antenna connected to the receiver; a motion detector configured to determine a relative local position of the communications device; and a controller configured to generate a measurement data set including plural measurement samples of at least a phase of the positioning reference signal according to a sampling rate, and a location of the communications device at which the phase of the positioning reference signal was determined. The controller is configured to estimate a relative angle of arrival of the received radio signals, used to determine an estimation of a location of the communications device, wherein the controller is configured to adapt at the rate of sampling to generate the measurement data set in accordance with predetermined conditions.