I think the content of this forum shows that there is clearly a problem with iPhone 4S / IOS 5.1.1 and Wi-Fi. But I have a slight variation on the theme and would appreciate any help anyone can provide, please.
I live in an awful house for Wi-Fi - not only is it spread-out, but it also has metal sheets laid across every floor to reflect under floor heat upwards and, of course, to kill Wi-Fi signal dead. To get decent coverage I have 1 wireless router and 3 access points all using the same SSID and password, but using different channels (separated as much as possible physically and by frequency). The four units are connected by wire (over the power lines). This setup has worked fine for several years. It still works fine for my iPhone 3G, iPad 1, iPad 3, Squeezeboxes, MacBook Air, laptop PCs etc. (I program and use this kit for testing as well as playing).
The Saturday before last I bought an iPhone 4S to upgrade to (as my trusty iPhone 3G was broken (I dropped it :-( )). The iPhone 4 connects to the Wi-Fi nicely (so its not a security issue) but drops out after a few minutes and then refuses to re-connect. I am current still testing, but I believe it also drops out if I move in the house from one AP's strong area to another's. I suspect it hangs onto the weak channel and refuses to change. If I walk back to the AP that I originally connected to it re-connects.
I never had this problem with the iPhone 3G. I still don't (its repaired :-) ). And I am now testing by taking both phones with me as I roam about the house. Both phones are running IOS5.1.1 and the 3G works perfectly whilst the 4S drops out and throws a hissy fit.
The Apple Solution
The guys at the local Apple store are being sympathetic. So far I am onto my second phone, and I have a 'Genius' appointment in about an hour to switch to my third! Both the phones I have tried so far have behaved identically, so I am very skeptical that the third will solve the issue.
The good news, of course, is that after I've burnt through a couple of hundred iPhones all of which do the same thing, Apple might actually think its worth exploring the issue properly. (If you do read this Apple people I don't want to waste your iPhones/time/money any more than I do my own - I just want to be able to get to the internet on the 4S like I can on my 3G).
First question - does anyone know what's going on and can suggest a fix?
Second question - does anyone know how to tell which Wi-Fi channel your iPhone is connected to? If I could find that information I could test my theory about the roaming not working.
When making suggestions please remember that all my other devices work just fine, including my iPhone 3G which is physically touching the 4S that won't work. Therefore I may be a little sceptical if anyone suggests I upgrade the router (which I can't because its a Virgin one and updates automatically).
Thanks for any suggestions (including router upgrades).