Read TX Power from Central Device

[scturner06]

Setup: Galaxy S3 (Android 5.1.1), nRF52 with S132

Basically I am trying to estimate distance from the phone on the nRF52 by measuring the RSSI and in order to do this to some level of accuracy I'll need to know the TX Power on the phone. Is there a way to do this without having to install an app on the phone to expose the TX Power? I have the HID service running on the nRF52 if that is at all helpful.

After some reading of the BLE Spec I came across TX Power Control in LMP with the functions LMP_max_power and LMP_min_power as well as being able to adjust the power in steps. However I think this is just for BR/EDR and will not help me. Can some one clarify this?

So, is the only solution to install an app onto the phone that will expose the TX Power? Or is there another way to get at it? I've considered taking an initial reading with the phone being very close to the nRF52 but if the power changes during use, it's useless.

[Susheel Nuguru]

1. the peer can place its TX power in the adv data. This will not be the case if it is phone and not advertising.

2. There is a service that can be used Transmit Power Service. It says that this is a mandatory service so i am guessing this should be implemented by the OS in your phone.