Bluetooth effect on WiFi

[WilsonF]

We are testing placement of new Cisco access points in our office and find that some of the TPs (T41s and T42s) close to the edge of the coverage area drop connections frequently if their bluetooth radios are on. Sniffing with NetStumbler, we find that bluetooth makes the signal to noise ratio worse. Anyone know anything about this?

[n3il]

I am sure I remember reading a page on the IBM site where they state that having both bluetooth and wifi active simultaneously could/would have a negative impact on their performance. I can't seem to find it - but I will post back if I do.

[n3il]

Found it:
http://www-1.ibm.com/support/docview.ws ... MIGR-39654
and
http://www-1.ibm.com/support/docview.ws ... IGR-4YTJQG
and
http://www-1.ibm.com/support/docview.ws ... MIGR-50066

Although none of these are for your specific machine(s) - I wouldn't have thought that this type of thing was machine-specific as they are mostly using the same technology.

[WilsonF]

Thanks.

The effect not limited just having the bluetooth on the TP enabled; the presence of other bluetooth devices (e.g., Smartphones) has the same impact on signal to noise ratio.

[Moroner]

Both Wi-Fi and Bluetooth use the same frequencies, so they will interfere. Since Bluetooth uses frequency hopping, and Wi-Fi channels based on a subband, the interference is there by design.

Bluetooth version 1.2 has a WiFi compatibility mode, which tries to avoid channels used actively by WiFi. This will help to reduce the problem. Unfortunately, all current Thinkpads have only version 1.1.

[kjarrett]

Great.

I just ordered a bluetooth mouse.

I'll let you all know how it works out...

-kj-

[dfumento]

If you use the 'a' standard instead of 'b' or 'g' it will not interfere with the Bluetooth because 'a' runs at about 5GHz. 'a' will also not interfere with the 5.8GHz cordless phones. You just have to be certain that your client and your router run in 'a'.