bluetooth lowenergy - Using BLE for indoor positioning

Question

I have a project that i need to know that if some smartphones are in the same room to implement that i checked several approaches but i found using BLE the best.

The algorithm is that i have a master smartphone that i know is in the room and i want to validate all other smartphones with RSSI that this smartphone get from them. I want to know that does any body have any experience about this approach like that how much the RSSI should be that i be sure that other smartphone is in the same room that master smartphone is?

Answer 1

Unfortunately, RSSI is not a perfect model for getting the distance, and in your use case this is highly dependent on the structure of the room and architecture of the building. There have been many attempts in the past to get distance data from RSSI and most of them have been fruitless. Please see the links below for more information:-

• https://stackoverflow.com/a/16927330/2215147
• https://stackoverflow.com/a/32900428/2215147
• https://stackoverflow.com/a/27943540/2215147

If you still want to use RSSI to get the distance data, the best mechanism would be a trial-and-error model. Basically, if your project is going to be carried out only in one room then you can run tests there on multiple devices from inside and outside the room, then collect the RSSI data that you get accordingly. You can then write an app that tells you whether the device is in the room or outside based on the data that you have already collected. Please see the links below that can help you get started:-

• https://stackoverflow.com/a/13724027/2215147
• https://developer.radiusnetworks.com/2014/12/04/fundamentals-of-beacon-ranging.html

I hope this helps.