I have the same experience. I am from Purdue University and we have wifi all over the campus. My friends and I owned 1 iphone3gs and 2 iphone4 collectively. Whenever we are at our office, the iphone3gs will be connected to wifi just fine. The iphone4s, however, will either stay connected for a short time and then get disconnected, or will not connect at all. I thought iphone4 should have improvements or at least stay as good as the 3gs. Its very discouraging to know if iphone4 design is compromised even for the wifi.
My iphone4 does not connect to an ibook in ad-hoc modus. Hardware is like this
lspci -vnn | grep 14e4
0001:10:12.0 Network controller : Broadcom Corporation BCM4306 802.11b/g Wireless LAN Controller [14e4:4320] (rev 03)
see table on:
my iphone3G was able to do this, so I am thinking about buying a router ....
So I was scarred there was something wrong with my phone since this was happening on multiple networks, and brought it to the genius bar today. After doing some checks the genius at the Apple Store (he was a pretty cool guy) couldn't replicate the problem (as this only happens randomly) and didn't know if it was an hardware issue, but agreed to swap the phone. Anyways, came home and still have the issue. To me this indicates this is not a hardware issue, but based on it happening on other networks may be a software issue. Like I said, it happens on multiple networks, so it's not just my router. Kind of too bad that I got a new phone even though nothing was likely wrong with the old one (I hate wasting an iPhone), but good to know it wasn't the phone and will make for a good refurb.
Anyways heres the info you guys probably want- a fix:
To fix this issue (at least on your home network) do the follow:
1. Go to your router's wireless network page.
2. Near the bottom of your DCHP server settings (Under Wireless/Network Settings-depends on router)you will see your devices with the option to add a reservation. Add a reservation for the iPhone. This will reserve an IP address specifically for your device and not change it or assign it to other devices.
3. Go to your WiFi settings on the phone and click on your network. Copy down the information under DCHP. Then switch to static and manually input this information. This will ensure your iPhone always knows what its IP is while using your network and won't look for a new one assigned by DCHP.
Note this isn't a true "fix", since DCHP is still having issues, but it will stop your WiFi drops (at least if we have the same issue as I did there may be other issues). DCHP is a system used by routers to make adding new devices easy, by automatically assigning IP address. However, there seems to be an issue using DCHP and the iPhone.
Sorry to revive an old thread, but I may have found the issue. Just to clarify my problem was I could connect to the wifi, but it would drop constantly.
I decided to check to see what was connected to my network in my router settings. I found Three items and only 2 were connected at the time. My iPhone wirelessly and computer hardwired. It showed an extra wired connection with the name #D&@ or something close to that effect.
I deleted that and hit refresh. Now it showed I had two iPhones connected wirelessly, so I deleted the one with the wrong IP address, the problem has not happened since. I hope this helps atleast some of you out there.
sorry to revive such an old thread, but i've been dealing with this exact issue for quite some time and i can't seem to find a solution. i've read through this entire thread and have followed the advice in each post but nothing seems to work for me.
my specific problem is that each time i come out of standby, my iphone 4 says it is connected to 3G then switches to wifi shortly thereafter (its really annoying to wait for wifi to kick in). sometimes, after it switches to wifi, it quickly goes back to 3G and doesnt switch back for quite some time. all the while, in the settings/wifi section, it says that im connected to my wifi network.
switching wifi on and off helps it to come back sometimes. i've reinstalled my router dozens of times (DLINK DIR 615 - latest firmware), reset the network settings on my phone dozens of times, but to no avail.
i hope someone can help me out!
So, I am having the same problem, but under different circumstances. First off, I have had this 3GS for a year with no wifi issue like this.
It unlocks and connects to wifi fine.
After a few minutes or even up to an hour, safari no longer loads pages, itunes remote loses it's connection to iTunes; airmouse no longer connects to computer, but I still have wifi signal indicator in the menu bar. What's extremely frustrating is that I paid $2.11 for airmouse, an amazing program, so I could use my comp from the other room on the big screen. Now when wifi dies, program crashes and I have to go into the other room to kill the desktop app. Bug is not apples fault, but the wifi is.
Here is my setup:
Same router password for 1.1+ years.
-no recent firmware updates, no changes made for months. ( i moved in june , got new cable modem, changed ssid, but kept all other things the same. It has been flawless since then and before that since I bought it new.
Here is the other weird thing, this started at work on a wrt54g (rev3 I believe) and that boots me off and the iPhone loses the password. My netgear here boots me off but the iPhone says it's connected.
I reset all network settings to no avail. I recently upgraded to 4.3.5
To fix it temporarily, I found that I can turn off wifi for 1-2 seconds, then turn it back on. It finds my network even!
wifi fine for one year, Same router, no changes. Upgrade to ios4.3.5 and all of a sudden won't connect.
On linksys wrt54g at work, same thing but loses password also.
Today I took my iphone to the genius in my local Apple Store, he hooked it up to test it and said it had all sorts of issues, his answer was a full reset. This didn't work, but funnily enough I had no problems connecting to wifi in the Apple Store, but it still wouldn't work on my home wifi.
I then started playing with the settings on my router. What fixed it was turning off the 20Mhz & 40Mhz bands, and just using 20MHz, the phone connected and has stayed connected.
It seems the Iphone 4 can't cope with a router using dual bands.
I can verify that this works. I have 6 iOS devices at my house, NONE of them would stay connected to my wireless router. I am a product reviewer by trade and every iOS device I've had is like this since iOS 4. The iOS has something going on with 20/40 dynamic channel width settings.
What you need to do is go into your wireless router's settings. You will see something called "Channel Width" if you have a Netgear Prosafe Dual Band Access Point. If you have something else it will be called something else more than likely. EASY FIX just look for an option that says "20/40" or "20mhz / 40mhz" or it may be set to "AUTO" and when you select it you have options for 20, 40, etc...
SELECT 20MHz. I also have Guard Interval set to LONG (800ms) which helps it stay connected to legacy devices. In addition I also turned RIFS transmission ON. It allows transmission of successive frames at different transmission powers. It has increased my network performance quite a bit.
So Thank Snapper70 he/she came up with the solution and it does work.