random delay

RE: random delay

Marius Heil — Mon, 15 Dec 2014 13:02:42 GMT

Aw, thanks. I was hoping a PRNG was used so this would have been deterministic. I know about the timeslot API, but I need to understand the synchronization problematics at first, thanks :-)

RE: random delay

David Edwin — Fri, 12 Dec 2014 12:35:01 GMT

The softdevice generated advertisements are randomized with a 0 to 10ms using a hardware based random number generator. You can use the Timeslot API for directly generating the advertisements and then scanning for them. An example to do so is located in the NordicSemiconductor github repository.

RE: random delay

Marius Heil — Thu, 11 Dec 2014 09:54:45 GMT

Hello,

thanks, that's also on my list of possibilities. I know that the synchronization will be a hard thing to achieve but when using the Softdevice SD130, I am restricted to 3 central and one peripheral connection which might be too low. Is this restriction coming from the implementation or is it rather due to the BLE standard? I am writing on my master thesis on Bluetooth Low Energy mesh networks. I looked into CSRmesh, but they kinda use bruteforce with advertising packets as far as I could figure out, I looked into Wirepas, which is using a custom protocol to overcome the limitations posed by BLE in that respect, and I investigate if it is possible to marry some good features while being compatible to the BLE standard.

RE: random delay

Stefan Birnir Sverrisson — Wed, 10 Dec 2014 13:35:36 GMT

Why do you want to sync the advertiser and scanner? Why not connect and then you will get this synchronization for free. What are you actually trying to achieve?