Energy detection in BLE advertisement channel

[Ali]

Hi

I have a project to model the RSSI based indoor location using Bluetooth beacons. However, in order to do the basic distance and RSSI relation, I want to sense the channel 37,38,39 before sending any packets to have an index of energy detection (CCA) or RSSI of the environment including Wi-Fi, background noise or any other operating devices without receiving any packet. I also need to mention that I found these links but it is not for the latest softdevice.

devzone.nordicsemi.com/.../

I would really appreciate if you could kindly help me about it.

Regards

Ali

[Roger Clark]

What difference does background RSSI make to the RSSI of the beacons you are receiving

RF transmissions are not additive.

[ovrebekk]

Hi Ali

If you configure the radio to the channel you want to sense on, and enable it in RX mode, you can trigger the RSSI freely and sample the RSSI level of the receiver even if no valid address is detected.

If you want to sense on multiple channels you have to disable the radio, change the frequency, and re-enable it, before sensing on the next channel.

Please be aware that this method might not be quick enough to pick up small bursts of energy on a particular channel. BLE systems in particular send very short packets that are hard to isolate.

Best regards
Torbjørn