- Joined Aug 27, 2009
THE INVENTORS OF BLUETOOTH SAY THERE COULD BE PROBLEMS USING THEIR TECH FOR CORONAVIRUS CONTACT TRACING
I asked Jaap Haartsen and Sven Mattisson, who invented Bluetooth together while working at the Swedish telecom Ericsson, whether their tech was up to the task. While both expressed hope that Bluetooth could be used to save lives, they also noted that problems of accuracy are very real. Bluetooth Low Energy, or BLE, a more modern iteration of the tech that’s a great deal more efficient and accurate, and which is used in the Apple/Google contact tracing system, is still subject to finicky physics.
“One issue that comes to mind at the physical layer is the uncertainty in the detection range,” explained Mattisson, “i.e. how well can you assess the distance to another BLE device. … The radio signal’s path loss will vary significantly depending on conditions (i.e. free space or obscured). Whether knowing the distance only within a factor of, say, ten is a problem or not, depends on the application. E.g. do we get too many or too few contacts…? Temporal aspects can be used to reduce this uncertainty but it is easy to forget about the coarse range resolution of a single radio link.”