December 6th, 2004, 09:01 PM
2.4gHz vs. 5gHz Wireless?
Just a quick question that should be simple to answer for you wireless gurus out there. I have a basic understanding of wireless technology, but given that I don't have a whole lot of wireless toys to play with over here, the scope of my knowledge is rather limited.
So I've been told that there has been a problem with 802.11g equipment running at 2.4gHz in that phones that run on the same frequency cause interference on the network. My understanding is that new 5gHz technology has recently been released. Do the 5gHz devices eliminate this problem, and thus are they a better investment than older 2.4gHz equipment? If not, how does one approach this problem?
December 6th, 2004, 11:37 PM
Interference with Coordless phones isn't really a big issue (especially with 11g) unless it's very crowded where you live... but it could happen. The WiFi gear can change channels to transmit on, but if you have a lot of phones and then a lot of wireless cards then I would think twice but in a normal environment they work well within the allocated space. You will also find microwave towers and long haul communications systems using this spectrum. Now for the kicker... the reason wi-fi and phones exist in this frequency is because it was originally a testing spectrum that was translated into an arena where users and developers could transmit without a license and thus no FCC approval is necessary to operate.
The same goes for 5ghz. The FCC allocated spectrum in the 5 Ghz range for unlicensed devices. It's new BUT you will find phones and other devices using the spectrum as well. The good news is the new spectrum has more non-overlapping channels and should reduce interference issues by using dynamic frequency selection and transmit power control (802.11h). The devices will actually reduce their output power when interference is detecded. The bad news, is you would be on cutting edge. If this is at home, fun - if at work, lack of interopability and support for various 802.11 standards could kill you. Now a word on standards.
They are defined with their selected operating environment and are static until approved and device chipsets are modified. An 802.11g device CANNOT communicate with a 5ghz device UNLESS it's a hybrid and then it connects with it's 802.11g interface (back in that 2.4 Ghz spectrum) or it connects via 802.11a wich is allocated to use 5ghz. So you have to either go wait for 802.11h all the way or make a hybrid system. It's never easy is it? If you do go 5gig then don't buy any phones there, keep them at 2.4G but you have to use 802.11x -g. Hope I kept all that straight.
You can always change the channel on the access point or buy a 900 mhz phone. The real advantage of 5ghz, and it's expensive, is the emerging 802.11h standard.
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