I’ve already found the solution.
I’ll keep the thread alive so people with similar problems can see my solution.
The problem was not caused by my DWM1001 Dev-Kit but by my mobile phone which runs Android. Android OS by default has a Bluetooth Low Energy MTU of 20 bytes. Once someone wants to establish a connection to a remote Bluetooth device, one can call BluetoothGatt.requestMtu(MTU) and receive a callback with onMtuChanged(). I simply set the MTU for my case to 33 and now I am able to receive 30 bytes per packet.
For some reason, setting the MTU to 30 is not enough. Then I only receive 27 bytes per packet. It seems like 3 bytes are reserved for headers or something similar.
Follow these links for further information:
requestMtu() Doc
onMtuChanged() Doc
Regards,
Max