I am currently developing an iOS app for a BLE device which will implement the Proximity Profile (which I currently don't have access to yet), but I am at a loss as to what that actually means.
I have read the pdf document from bluetooth, and know that the BLE device would be the proximity reporter and the application the proximity monitor, but what does that mean in terms of the CoreBluetooth framework?
After connecting to a BLE device, the method I am currently using to measure proximity is through calls to readRSSI on the peripheral device. Does a device which implements the proximity profile behave differently so that I don't need to make that call? There isn't much documentation around to give a better idea.
Here is a description of the GATT services related to the proximity profile: http://developer.bluetooth.org/gatt/profiles/Pages/ProfileViewer.aspx?u=org.bluetooth.profile.proximity.xml
It looks like it allows for an attribute to read the RSSI from (I think normally you can read that value from a lower level method directly from the transmitter/receiver). So you should be able to read the RSSI value on both ends of the connection.
The profile also allows for alerts to happen on both ends and you can control what level of alert occurs.
I think essentially, a "profile" is just a collection of attributes in GATT. If you have the required attributes you can state that you support that particular profile.
Here's a PDF with the little details if you want: https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=239392