I have a dell Latitude E5450 that had windows installed. I erased the hard drive and put installed Ubuntu 18.04. The wifi stays connected for a few minutes and then goes out. I have to go to settings and click the network, and it will connect again for a few minutes. The wifi is Qualcomm Atheros QCA 95665/ AR9565 wireless network adapter[168c:0036] (rev 01). Am I missing drivers? How do I install them?