How to estimate distance between two android devices through wifi-direct?

Question

I am reading about Received Signal Strength Indicator(RSSI) . This could be used for our particular case, a rough estimation of distance between devices . But maybe there could be something to combine in order to improve the accuracy.

Answer 1

There are too many variables at play to accurately determine such data. It's completely impractical to obtain a reliable distance figure just looking at the RSSI. It may give you an order of magnitude but nothing remotely accurate.

Most notable is the variety of devices and underlying hardware used. But take into account this simple example: you have 2 pairs of devices, 1 pair has good signal for a range of 30m without obstacles within and another pair has the same value for what would be considered a good signal but they are within 1m but with an obstacle which causes heavy interefernce. Any interpretation from empirical data would be awfully inaccurate.

The best change you have is to pinpoint each device's location by GPS and communicate&compare coordinates. But again, the underlying hardware comes at play. Also the length of time it takes to pinpoint with a better accuracy. We're talking about 5-50 meters. So it's basically mostly noise.

Go beyond that and you go out of wi-fi direct / peer-to-peer range.

As such, trying to estimate distances begtween 2 android devices at this time would be in my view an utter waste of time. (unless you are building a huge network of interconnected wi-fi direct devices in which case you could come up with some cool applications, or at least visualisation stuff - that's a bit of a stretch considering one-to-many limitations).