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Frequency hopping with S132 v3

AmiguelS

Hello! I'd like to know if S132 v3 implements the frequency hopping scheme defined by BLE.

I've read some documentation on Gazell, but from what I understood, that is a completely different protocol, not a superset of BLE. I require BLE communication, so If my understanding is correct, Gazell is not an option.

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    Of course it does implement frequency hopping. You don't have to think about such a low layers - this (among other features) is what softdevice is written for. You can however control which channels are used for advertisements.

    Yes, Gazell is something completely different.

  • 0 in reply to Wojtek

    Well frequency hopping is kind of "dumb" property of BLE link layer on up to 37 channels used for PDU exchange during connection. You have right to exclude some channels if you suspect some interference there but this is not done automatically. Moreover embedded chips such as nRF5x don't have any specific indication of noisy channels so you can only try to observe and then use channel map functions of stack (SD) API... so you see initial channel map and hopping pattern in CONNECT_REQ (from GAP Central = master) and then only channel map can change. In the worst case you leave all 37 channels and during hopping patter some packets will drop but that's nothing serious until this will happen systematically on most of the channels for longer time. More about BLE frequency hopping (and BLE overall) here (slides 65-70 and 126-145).

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  • 0 in reply to Wojtek

    Well frequency hopping is kind of "dumb" property of BLE link layer on up to 37 channels used for PDU exchange during connection. You have right to exclude some channels if you suspect some interference there but this is not done automatically. Moreover embedded chips such as nRF5x don't have any specific indication of noisy channels so you can only try to observe and then use channel map functions of stack (SD) API... so you see initial channel map and hopping pattern in CONNECT_REQ (from GAP Central = master) and then only channel map can change. In the worst case you leave all 37 channels and during hopping patter some packets will drop but that's nothing serious until this will happen systematically on most of the channels for longer time. More about BLE frequency hopping (and BLE overall) here (slides 65-70 and 126-145).

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