Know Where You Are
Another example of a user aware system important ability is the knowledge of the location relative to other devices and relative to resources of the network. It is called location awareness . It is important that the system can use precision location in order to find those assets. You will probably think that a GPS could help, right? But GPS cannot give 100% reliable position especially indoors.
What are other options we could resort to trying to teach our system to determine the location? We could actually use Wi-Fi. We could locate the access points and then locate the assets from there. How do we do it? Very simple: by measuring the signal strength:
But as you can se from the graph the results of these calculations are not really accurate, the measuring error is a way to big.
Another approach is to use the time arrival of the signal to a location and then from there calculate the distance to it. The experimental results suggest that with this approach the accuracy is much better. Take a look yourself: we can get very high precision, so that the deviations get reduced down to 1meter.
The demonstration of the system location awareness was actually very illustrative. Say, you are watching a movie, and then you take your tablet, and go to another room. The system calculates your location and transfers the playback of the movie to a screen in another room. You keep moving, and when you get into the hallway, the only screen you have around is the one on your tablet, so the system continues the movie playback on your tablet screen. As soon as you get outside the house the movie is paused, which can also be a good protection technique, against unauthorized access into your home network from outside.