iPhone 4 WiFi Problem - Keeps disconnecting

Hi I FINALLY found the solution and it was posted on the apple website. You need to access your routers settings and enable the WMM (Wi-fi multimedia) setting. I tried everyone suggestions and could never figure out why nothing was working. Apparently the phone has to have it. So just google your router and include WMM in the search. Here is the article on apple.

http://support.apple.com/kb/TS3727

i came to know that discconecting from WiFi to 3G is a built-in feature in IOS 5 that enable battery save! your phone will keep listings to incoming connections from 3G (if it is enabled) and will turn to WiFi once needed, or when you unlock the screen manually to use your phone!

However, i did find a fix (at least works for me at the moment)

Connect your iPhone to your Mac/PC and launch iTunes (if it is not already launched, make sure you run latest iTunes version), once your phone is visible in the left hand side column, click on it, then in the right window you will see tabs on top (summary, info, apps, tones, etc....), click on summary and scroll to the bottom of the page until you reach options box, tick the box that says (Sync with this iPhone over wifi) and then hit apply in the bottom right corner (check any warranging message if they show up).

now you can disconnect your iPhone and close/quit iTunes.

Now your phone will have WiFi on all the time, and will be automatically discovered in iTunes once you launch it (if you want)

This is working for me. and i hope it will help you

To all having problems with their iPhone keeps disconnecting on their wifi at home, try to change your Wifi Channel Settings on your router, usually its on automatic change it to channel 9, this is what I did to fix my iPhone wifi disconnecting problem.

I think that's done it for me. THANK YOU! :-D

Thanks for this post. My router was set to "Auto" channel. I changed it to "1" and now my iphone stays on Wi-fi even when locked. Pity I didn't discover this before choosing to update my 46 apps!!

Actually this alone did not work. From other posts I tried changing network name, changing security level on router. Everything is now back the way it was except that the lease duration on the routers was only 15 seconds which probably didn't help, now set to 1 day. I can now see on my router status that the wi-fi connection is retained when the iphone is locked.