Spoiler: Until enlightenmet age, we are not going to be able to deal with the nomads, period. The only possible hope is to delay the inevitable raids, but 'semi-permanently deal with' is bullshit, and 'we'll always be fighting off raids' is exactly what is going to happen, because that's how nomads roll.
We can't stop the raids, period. That's nomads for you.
EDIT: Like, if nomads were possible to actually deal with, things would be much easier for us. But noo, we have blob of angry dicks to the north, and organized smaller blob of dicks to the south because lol fuck us in the prehistory everyone is a warmonger.