Bluetooth Low Energy Packet Phase Measurement for Device Location
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing device location systems face challenges in determining the location of devices lacking hardware capabilities to transmit continuous wave tones, particularly with Bluetooth or BLE signals, due to unpredictable phase modulation and regulatory compliance issues.
Innovation Solution
A method using packet signals transmitted according to Bluetooth or BLE protocols, where the packet signal is specially configured with a known data sequence, allowing for phase determination through in-phase and quadrature component filtering, enabling accurate phase measurement and device location calculation without requiring continuous wave tone transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous wave tone transmission is used to determine device location, then measurement precision is improved, but device complexity increases due to hardware modifications
Solution Approach 1:
The patent creates a virtual continuous wave tone by processing standard Bluetooth packet signals through correlation detection. Instead of requiring the device to actually transmit a continuous wave tone, the system copies the essential characteristics of such a signal through mathematical processing of the packet's known data sequence, thereby achieving continuous wave-like measurement properties using existing hardware
Solution Approach 2:
The patent introduces correlation detection as an intermediary process between the packet signal and phase measurement. This intermediary technique extracts continuous wave tone characteristics from the packet signal by correlating the received signal with a local copy of the known data sequence, enabling accurate phase determination without modifying the device hardware
2Ease of operation
If Bluetooth or BLE packet signals are used for location determination, then ease of operation is improved by using existing protocols, but measurement precision deteriorates due to unpredictable phase modulation
Solution Approach 1:
The patent extracts the known data sequence from the Bluetooth packet structure and uses it as a reference for correlation detection. By isolating and utilizing this predictable portion of the signal, the system can determine phase information accurately despite the unpredictable phase modulation caused by frequency modulation and whitening processes
Solution Approach 2:
The patent replaces direct phase measurement methods with correlation detection. Instead of attempting to measure phase directly from the frequency-modulated packet signal (which has unpredictable phase), the system substitutes correlation-based processing that can extract phase information through the known data sequence, effectively replacing a direct measurement approach with a computational method
3Object-generated harmful factors
If continuous wave tone transmission is modified to comply with FCC regulations, then object-generated harmful factors are reduced, but productivity decreases due to hardware and software upgrades
Solution Approach 1:
The patent makes the standard Bluetooth packet signal serve multiple functions: both communication (advertising packets) and location determination. By designing the packet with a known data sequence that can be used for correlation detection, the same signal structure achieves both regulatory compliance and enables accurate phase measurement for location tracking without requiring separate continuous wave transmission hardware
Data Source
Figure 1
Figure 2
AI summary
Methods and systems for determining the location of a Bluetooth device using a standard broadcast packet containing known data. Multiple antennas are used to take measurements of the packet are converted into in-phase and quadrature components, then a low-pass filter is applied. The known data presents an in-phase and quadrature spectrum that is a continuous wave-tone representation of the packet signal in the passband of the low-pass filter. Multiple measurements are used to determine the phase difference of the filtered measurements at the different antenna locations. Phase difference is used to determine the location of the device.