On my Acer Aspire V5 571 laptop, WiFi doesn't appear to work out of the box using ubuntu 14.04.
A list of PCI devices shows a Broadcom BCM43228 802.11a/b/g/n installed, but there is no drivers for this device.
# lspci 03:00.0 Network controller: Broadcom Corporation BCM43228 802.11a/b/g/n
To resolve this issue, very simply run:
sudo apt-get install linux-headers-generic sudo apt-get install --reinstall bcmwl-kernel-source
You should now have WiFi - You don't even need to reboot!