Rooting is not required. With USB cable connected, port 5555 opened across all involved firewalls and debug mode enabled
`adb tcpip 5555`
then look into wireless properties of your device and the network you use, to see which IP address have been granted to device (or configure your DHCP always to use the same for the device mac address). Then
`adb connect 192.168.1.133`
(were 192.168.1.133 is a sample IP address).
This is all. You can now use adb shell or adb install or adb upload or the like with USB cable plugged out.
To switch back to USB mode,
`adb usb`
The device may also revert back to USB mode after reboot.
This mode is needed for development of applications that use attached USB devices directly (USB port is used by device so cannot be used by ADB). It is briefly covered in the USB debugging section of the Android website.