There is an issue with the current Kernel that Ubuntu is using with all distro's based off of it, with the 15.04 series that is an odd release before the next LTS, which will be 16.04. The issue is with WiFi not staying connected. The suggested fix right now is to use NDiswrapper and use the Windows drivers instead of the ones that the Ubuntu distro's are using for the Intel adapters.

This has been an ongoing issue with not only the Intel adapters, but also with the RaLink ones. There is an open Bug report that dates back to when this problem was found with the 13.10 release.

Anyone planning on using a Ubuntu based distro for a NAS, Gateway, experiment with. Just be cautious that when your WiFi disconnects, it is not a problem with the hardware.