|
FHSS and 802.11b/g Not Friends |
|
|
|
|
Written by Jim Geier
|
|
Monday, 02 April 2007 |
|
Before getting too far with a wireless LAN deployment, especially in hospitals, check if there are any FHSS systems that might be operating nearby that could cause significant RF interference to an 802.11b/g system.
802.11 FHSS (frequency hopping spread spectrum) wireless LANs have become mostly obsolete; however, you still find them supporting older applications. The problem is that FHSS, which occupies the entire 2.4GHz band, causes significant interference to 802.11b/g signals, which only occupy approximately one third of the 2.4GHz band. It doesn't matter what you select, FHSS takes a toll on 802.11b/g (and not vice versa). This has become an issue with a hospital that I'm currently working with - they have an existing FHSS network supporting an important physician communications system, and they want to install 802.11b/g network to support a new wireless language interpreter application (which doesn't interface with FHSS). I've also seen FHSS causing damaging interference to 802.11b/g in several other cases. So, be sure to carefully survey for the presence of FHSS networks before installing 802.11b/g.
|
|
