Maximum troughput with 3 peripherals and one central

[Constantin]

Hi,

I am planning two have the following network:

1 central communicating with 3 peripherals

One of the peripherals will be a smart device (iOS or Android). What would be the maximum through put. From my understanding the minimum connection interval is 7.5 ms and the nRF52 is capable of sending 6 packages in between this interval. But does this mean for three peripherals that the central can send 2 packages two each peripheral in between one interval?

iOS only supports intervals down to 30 ms. This would mean that if an iOS device is inside the network the throughput will reduce by factor 4?

And last questions doe a package send always mean both ways? So the central sends one package and the peripheral answers?

Thanks for your help.

[endnode]

When you start to multiplex several ongoing links (whatever Peripheral or Central like in your case) the situation will stop being deterministic. You can run several Central connections with nRF5x each having different bandwidth and connection interval, it will just "collide" internally in Soft Device scheduler from time to time (no worry, it won't crash, just one of them will be served depending on priorities described in the documentation and the other will continue later when scheduling collision goes away) and you will suffer from scanning bandwidth (meaning that opening of every other Central connection will take more time as Scanner and Peripheral must meet with their intervals which have random shift). In general using Connection interval 15ms or higher should work with 3 Central connections and HIGH bandwidth on nRF52 and S132/S140. For more read...

[endnode]

... full Scheduling section from S132 Soft Device specification (especially last section 16.10). I would actually write the FW and do the test if you are really so much interested into detailed bandwidth.

To the BT5.0 remark: it sounds completely incorrect, at least in the way you wrote it ("The only change for BT 5.0 will be the amount of bytes per package which can be sent."). Already BT4.2 has various extensions like Connection Interval, PDU and ATT_MTU. The only added feature in BT5.0 is 2Mbps airspeed option, it gives you larger bandwidth if you can leverage it.