RE: BLE Multi-Role Multi-Link intervals for reliable connections

David — Wed, 12 Dec 2018 02:32:55 GMT

Edvin,

I have set the following parameters:

Advertising Interval to 5000
Scan interval to 160
Scan Window to 80
Min Connection interval to 100
Max Connection interval to 200
MTU is set to 100

and it seems to be working quite well with 7 devices connected.
i am going to add another 7 devices and see how it behaves

I realized i had a memory leak which was causing the application to get stuck.
Thank you for your help 🙂

Regards,

David Hutchinson

RE: BLE Multi-Role Multi-Link intervals for reliable connections

Edvin — Tue, 11 Dec 2018 14:50:35 GMT

Hello David,

I believe that the first thing you should check is the disconnect reason in your disconnected events. Check on both sides of the connection, peripheral and the central.

You are closing in on the limit of possible connections when you have 15 connections. Is there a reason for why 7 are central and 7 peripheral? Do want all devices to be connected to all other devices?

100 bytes every 5 seconds is not a lot of payload data, but depending on the connection, you must either use a long MTU and enable Data Length Extension (DLE), or you can split the 100 byte packets into 5 20 byte packets.

If you want a lot of connections, in the range of 15, I would suggest that you start with using 100ms connection interval. If everything is OK, and you for some reason want a shorter interval, you can try to decrease it.

If you don't want to reduce the packet payload to below 100bytes, I suggest you use an even larger connection interval. A longer payload takes longer time on air, and increases the chances for event collisions.

Best regards,

Edvin