SOLUTION
The problem (maybe) is that Windows 8.1 has HIDDEN THE SETTING you need to change! :(
Here's the solution I used for my Sony VAIO Touch Ultrabook.
Control Panel -> Device Manager.
View (menu) choose "Show Hidden Devices"
Network Adapters -> right-click Microsoft Wi-Fi Direct Virtual Adapter.
Properties-> Power Management
Unclick "Allow the computer to turn off this device to save power."
I tried everything else before doing this and it didn't work. I think that this HIDDEN Microsoft Virtual Wi-Fi Adapter was the problem. It appears in all my Windows 8 machines. I don't know yet if this is the absolute solution, but it has worked for me.
Please let me know if it works for you.
TSM