BLE throughput with iOS connection parameters

[Aymen Rejeb]

Hello Nordic Team,

After setting connection parameters in accordance with Apple BLE design guidelines the BLE throughput has been significantly decreased.

My parameters are as following:

Interval Max * (Slave Latency + 1) ≤ 2 seconds ==> 40ms

Interval Min ≥ 20 ms ==> 20ms

Interval Min + 20 ms ≤ Interval Max ==> 20 + 20 ≤ 40

Slave Latency ≤ 4 ==> 0

connSupervisionTimeout ≤ 6 seconds ==> 4s

Interval Max * (Slave Latency + 1) * 3 < connSupervisionTimeout ==> 120

I'm on nRF51822 (32KB RAM/ 256KB Flash) using SDK10 and s130_nrf51_1.0.0_softdevice

What should I do to get the maximum throughput?

Many thanks in advance,

Kind Regards, Ayman.

[run_ar]

Since you are using the nRF51 this post will explain how his works. (for newer chips/stack combination DLE and 2Mbit could be used to increase the throughput). Note that it is possible to get faster intervals with iOS if you don't follow the guidelines. e.g. min 12.5 and max 22.5 might work. I would also recommend that you use another softdevice e.g. 130 v2 which is capable of sending up to 6 packets per interval.