Bluetooth BR Geo-location via Correlation RTT Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for active geo-location of Classic Bluetooth Basic Rate (BR) devices are limited in accuracy and sensitivity, particularly in noisy environments, due to the reliance on time-of-arrival measurements which are prone to errors and interference.
Innovation Solution
The method involves transmitting paging requests and synchronization packets to determine round trip times (RTTs) through correlation techniques, using a correlation threshold to filter noise and accurately measure RTTs, and sorting these measurements into bins to differentiate between true and noise-induced responses, thereby improving the sensitivity and accuracy of device location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time-of-arrival measurements are used for geo-location, then device location can be determined, but measurement accuracy deteriorates in noisy environments
Solution Approach 1:
The patent introduces correlation as an intermediary processing step between signal reception and time-of-arrival measurement. By correlating received signals with expected signaling patterns, the system filters out noise interference before determining RTT, thereby maintaining measurement accuracy in noisy environments
Solution Approach 2:
The patent replaces direct time-of-arrival measurement with a correlation-based measurement approach. Instead of directly measuring signal arrival time which is susceptible to noise, the system uses correlation analysis to indirectly determine RTT, substituting a more robust measurement mechanism
2Measurement precision
If correlation techniques are used to filter noise, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent segments the RTT measurement process into distinct phases: transmitting paging requests, receiving responses, performing correlation with expected patterns, and determining RTT from correlation results. This segmentation allows each step to be optimized independently and simplifies the overall complex process into manageable stages
3Reliability
If multiple paging requests are transmitted to improve measurement reliability, then geo-location accuracy improves, but time consumption increases
Solution Approach 1:
The patent implements continuous transmission of paging requests and continuous correlation processing, rather than discrete batch processing. This allows the system to maintain measurement operations without interruption, improving reliability while minimizing idle time between measurements
Data Source
AI summary
A method implemented in a first wireless device is described. The method includes transmitting a plurality of paging requests, receiving a first plurality of bit streams, and performing a first correlation, during a reception window, of each bit stream. When a correlation threshold is exceeded, a synchronization packet is transmitted, a bit stream received, and a second correlation performed. When a third time difference between a first time difference and a second time difference is within a predetermined time difference range, a plurality of poll packets is transmitted, a second plurality of bit streams received, and a third correlation is performed of each bit stream of the second plurality of bit streams with a second expected bit stream. The method further includes determining a correlation time of a maximum correlation value of each poll packet and determining the plurality of RTTs corresponding to the plurality of poll pockets.