We are creating an Android App together with a piece of hardware where we have a Wifi Direct (Wifi Peer to Peer) cabable Wifi Chip built on. Our hardware controls sensors and an actuator. Lets call this hardware with its embedded software SmartController.
From the Android App, we connect to this SmartController using Wifi Direct. We test with a wide range of Android Devices, from some running 5.1 to some running 9.0. When trying to establish a connection from App to SmartController, we see very inconsistent behavior. On some Android devices it works almost everytime, on some almost never, on some it is completly unpredictable.
This behavior has also been verfied in an EMC lab, which was clean of incluences on the air (like interferences or managed WLAN).
It does not seem to relate to Android versions, best devices run 5.1, 6.0 and 8.0. It seems Samsung S7 and Samsung Activity Tab works best.
What can be reasons for the inconsistent behavior on Android devices?