For standard run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tiwai:branches:Kernel:firmware/standard/home:tiwai:branches:Kernel:firmware.repo
zypper refresh
zypper install kernel-firmware-iwlwifi
For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tiwai:branches:Kernel:firmware/16.0/home:tiwai:branches:Kernel:firmware.repo
zypper refresh
zypper install kernel-firmware-iwlwifi
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tiwai:branches:Kernel:firmware/15.6/home:tiwai:branches:Kernel:firmware.repo
zypper refresh
zypper install kernel-firmware-iwlwifi