[Galaxy S III Q&A, (US Carriers)] stan.s:
Update, I've had my phone replaced by Samsung tech in Plano TX, that doesn't help, but updating my router to the Apr 2012 eko dd-wrt did make some differences. Also the ota update from att has a new modem apk and that also chg'd the phone functionality. One thing that I have seen is that the phone reports the wifi network signal as being lower than before, and the output signal is slightly higher. I find that I have to occasionally turn the wifi on and off to reset it.

Short list of fixes and things to try:

1 update routers firmware

2 no dual encryption

3 some routers with 300 or greater Mbps settings need to be toned down to 150 or less

4 phone likes mixed protocol network over N only.

5 turn off phone power save

6 un check the carrier hot spot notify.

7 un check open wifi notify

8 pick a single band 2.4 or 5ghz. Note that updates with this can temporarily lock in to that frequency and not allow changes.

9. Dial *#0011# menu button, wifi and turn off the power save setting. This has to be done on every boot, and may cancel the display timeout.

10 On 5Ghz don't use DFS channels

Incorrect since people who have installed some roms and cm 10 are saying that they don't have any problems: I am almost certain now, that the wifi disconnect/connect issue is hardware incompatibility.

I have Linksys wrt-610 v2 -- which has problems

I have Netgear WHR3500L which has problems

I have Linksys wrt-54GL v1.1 which has NO problems (had to dig this out of storage)

If YOURS works or YOURS doesn't work pls visit this thread and post your info so we can find out what routers do and don't: http://xdaforums.com/show....php?t=1752356

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I've posted this and then the mod's moved the thread http://xdaforums.com/showthread.php?t=1722363&goto=newpost to the Sprint version of the forum.

Here's a recap since the guy has a sprint phone and won't recognize my issue there.

Here's the issue I've been having. I'm in a very active 2.4 wifi neighborhood. Even though I had the advanced wifi set to 'Always on' it kept disconnecting (and instantly reconnecting) to my network. The phone is scanning the neighborhood almost every 15 seconds. It's simply WPA-2 with just AES (and I'm not changing to TKIP)

This is a problem for me as I use "Unlock wtih WiFi" to keep from having to enter my PIN when I'm at work/home and "Home Sweet Home" which uploads any photos I have taken to my server when it detects the home wifi network (and deletes them from my phone after 3 months).

Anyway, I was just on the chat with Samsung and in the end we did this,

1. disable the ATT WIFI auto login function (seems there's something similar on the Sprint phones that's a issue).

2. soft reboot the phone (turn off, pull battery, count to 30, boot up)

However this suggested solution doesn't work.

The wifi isn't staying connected though the breaks are very very temporary, but long enough for those apps to kick in.

Update additional things tried:

3. Turned off WiFi power save in the *#0011# service menu

4. Turned off Open WiFi notifications, ATT Autologon.

5. Selected a single wifi band (5Ghz) where there is ONLY one network, mine

FWIW, I like that it connects to my 5Ghz wifi at 150 mbps, the speed is great.

6. I've disabled the Unlock with WiFi and it still occurred.

Here's a video of the issue showing the phone:

http://youtu.be/FBo3NFdcMhs

Here's a videoe of the issue showing the router: http://youtu.be/rRALDc8LZOk

and for those technically inclined here's a dump of the logs which clearly shows the drop and reconnect: https://dl.dropbox.com/u/38266113/SendLog.txt

FWIW. I just got off a 45 minute call with Samsung Help Support, went to level 3 support in Texas. This is newly documented, I've referenced this forum for additional reports of the dual encryption and the wifi connnect/reconnect issue I'm having. My ticket # 2113584507 (just for disconnect/reconnect) which you can mention at level 1 as having the same disconnect/connect issue. I specifically asked if I could post the ticket # so anyone could reference it at Level 1, but they will still take your own experience down.

Level 3 said they expect that they will be getting calls today since it's the first full day after the release. So if you want it fixed, CALL SAMSUNG, they're collecting bug reports.