Android bluetooth read rssi signal strength

Question

I need to measure bluetooth signal between two or more mobile phones and detect nearest phone in range. After a lot of researching I came to idea to do periodically discovering for new bluetooth devices and measure rssi via EXTRA_RSSI that returned by ACTION_FOUND. All devices must be always in discovery mode and also must periodically scan for other devices.

Is this approach good or there are some better solution? What problems I can expect with this approach?

This solution Android 2.1: How do I poll the RSSI value of an existing Bluetooth connection? doesn't work for me because need phones to be rooted.

Answer 1

RSSI is a bad indicator for distance under real world conditions.

It could work under ideal conditions (free space propagation) but in reality you always have obstacles like walls, trees, etc. that affect the propagation.

See this article for more detailed information on propagation models.

Answer 2

RSSI doesn't indicate which phone is nearest, only which phone has the strongest signal.