I had my laptop wireless card changed a month ago, after that I noticed that the wifi led keep blinking on transmitting data and after a while the OS logged off and started a new session, and kept logging itself off after a while of logging again.
I've tried to use some distros. Like manjaro, fedora and Ubuntu and I faced the same problem.
By the way, I have Windows 10 installed alongside with Linux and this problem is not found, but I hate Windows and want to install Linux again but I cannot fix this problem.
/var/log/syslog
and/var/log/messages
it will tell you what happened last. – JoKeR Mar 21 '18 at 23:22