WL-500g, IBM a/b/g Wireless Mini PCI, GSM Phones = permanent disconnections

[J.B.]

Hi guys,

I am having this really weird disconnection problem with my wireless set-up at home. I'd really appreciate someone here could help me to solve it.

The set-up is quite simple - WL-500g acting as an access point, IBM ThinkPad laptop with built-in IBM a/b/g dual-band wireless Mini-PCI card. Now, without GSM phones around, the wireless connection would go flawlessly with signal strength about 60%, as shown in Windows XP. However, whenever a GSM phone is nearby and is having continuous activities (e.g. during a call or SMS received or sent..etc), the wireless would just disconnect immediately. In that case, trying to search for available APs again would end up none, no matter how many time I tried or how long I waited. In order to get it work again, I'd have to shut down the client PC completely (power off) and after restart the laptop's wireless would be able to find the WL-500g and connect to it.

I have tried different firmware versions for the WL-500g and Windows XP drivers for the laptop's wireless hardware, all with no vail. The interesting thing is that this problem happens on the laptop running either Windows XP or Fedora Core 2 (Linux). That leads me think it could be simply WL-500g is somehow incompatible with IBM's a/b/g dual-band card (it uses Atheros chipset). Is it possible?

P.S. This "interefence" problem seems very odd to me because 802.11 a/b/g and GSM are operating at very different frequencies?!

Any suggestion on how I should go about finding out the exact problem could be? Thanks!

[J.B.]

Just a bit more findings.

If I move the laptop closer to WL-500g so the signal strength is strong (90~100%), the GSM phone activities won't disconnect the wireless, as if it is able to withstand the interference. GSM and 802.11 inteference?! Very odd.

[wiz]

If I work from home I use an IBM laptop as well, and I never suffered from disconnects while using the cellphone. Never got disconnected because I was calling on my mobile.

Did you try this with different cell phones, or just one phone?

[J.B.]

Thanks for helping wiz,

yes, with the laptop (IBM ThinkPad 41p) sitting at the exact same location, my friend who has Nokia 8810 receiving a call, which then caused the same immediate disconnection. Had the calls twice, disconnection happened twice.

I wouldn't be so annoyed if the connection could come back on itself. But I have to shut down the laptop and power it back on to get the connection working - EVERYTIME :mad:

wiz, is your IBM laptop also with built-in IBM a/b/g dual-band card? If so, which version of the driver you are currently using? The WL-500g firmware version and wireless settings?

Thanks.

[wiz]

I use a R50p, I think it has the same lan card build in.

If it happens and you press fn+F5 can't you switch the wireless off and back on and let it discover your wan again?

My asus runs Olegs 1.9.2.7-3a firmware at the moment. I don't know the version of the drivers of the wireless because I haven't installed the laptop myself (yet) :D , I haven't had time yet.

[Technik]

...I wouldn't be so annoyed if the connection could come back on itself. But I have to shut down the laptop and power it back on to get the connection working - EVERYTIME :mad:
...

So it looks like your Atheros MiniPCI hangs - not Asus. Make sure you have updated the system BIOS and embedded controller firmware to the latest version as well > http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-50275
If this update does not help I would recommend to get the Atheros card replaced in warranty.

[J.B.]

To Technik,
Yup, I have the lastest system BIOS and embedded controller firmware updated. Maybe you are right, I should bring the laptop to IBM service and have them checked.

To wiz,
I tried to turn off and on the wireless by using Fn+F5 key, from Windows XP's Network Connections, as well as the Device Manager, it would find zero Wireless APs. The only way is still to power off the laptop completely and turn it back on (Restarting will not work either).

[Ifaistos]

It's not your wifi cards "fault", neither the pc's
GSM phones so close to a device will produce EMI (Electro Magnetic Interfearence) that will make the device(s) perform erraticly and even hang-up.
(Most gsm phones have a power output of approx 2 Watts when in operation)
Devices that are also transmiters/receives (like the wifi cards) are even more prone to EMI.

I have seen similar results with a lot of devices from notebooks to gps when phone is active close to them.
It all comes down to how well the system is designed and shealded against EMI.

IMHO the best way to avoid problems is to have the phone situated as far as possible

[J.B.]

Thanks Ifaistos,

your explaination sounds very logical to me. However, I am not exactly sure how EMI that is produced at the GSM frequencies could affect so badly on the devices that are in 802.11 (2.5 or 5 GHz) frequencies.

It's just so frustrating to find these problems because I "upgraded" my wireless gears hoping for a better performance (from 802.11b to g). Will try some other wireless cards and routers combination if I can.

[wiz]

Still think you should have the wireless card replaced. I never suffered disconnects with my laptop yet.