The tethering function found on Android devices lets you create portable hotspots on your device, so you can wirelessly connect several devices with your hotspot and share data. Also, if your Internet connection is particularly zippy, you can share it also with other people by creating your own hotspot. Unfortunately, on some devices Tethering option is hidden, or only works if you have a SIM inserted. Here is how to fix this issue.
Hotspot Control is a little app for Android Phone running ICS or above (Android 4.0.3 and up) that lets you enable Portable Hotspot functionality that is usually hidden on some Android devices.
It’s quite simple to setup and no root access is required for normal uses. Install the app from Play Store, just enable Wi-Fi option, input a name and password (for security purposes), and then enable the access point.
However, note that Hotspot Control is designed for establishing local connections only and not with the internet (though that also works on several devices).
If you’re interested, you’ll get more details, suggestions, discussion, etc. at this XDA Developers forum thread.