Wireless deployment in a skyscraper

5smonsey · ‎07-11-2007

Are there any deployment guides for deploying wireless A/B/G in a multi-story building?

Thanks!

scottmac · ‎07-11-2007

I havent seen or heard of any.

The big trick, of course, is keeping your signal in, and all the other signals out.

You can only really do that by

1.) Using the right antennas,

and

2.) Maintain the signal levels (enough, but not too much, with some to spare for overlap and drop-out coverage)

Oddly enough, one of the hazards in this environment is that your signal spill is interpreted by another system/WLAN as an attack or as rogues, and the other company implements some flavor of rogue mitigation (like "immediately send a (spoof) disconnect / disassociate to all rogues").

I'd bet there is enough environmental variety, you could fill a book. Unfortunately, because there is such a diversity of circumstances, the only way to be sure about an installation is a very tight site survey.

High-rise or commercially dense areas only amplify the need. It's absolutely critical to do the site survey and document everything.

If you do find a good reference, please post it up here.

Good Luck

Scott

5smonsey · ‎07-11-2007

Ahh...guess I needed to give a few more facts!

60 story building, we have the entire building. I'm using the 1000 series access points.

I'm not worried about channel overlap on the A side but on the B/G side I would like to know the best deployment options. Of course I'm concerned with getting the most bang for the buck on throughput. If I'm deploy this on every floor not only do I have channel issues on the same floor but on floor above and below.

I guess one answer is to let the controller figure out it all out. But is that the best solution? Is there a white paper on the deployment is a multi-story building?

ericgarnel · ‎07-12-2007

The b/g side will auto adjust as best as it can given the # of APs, obstructions, interference,e tc.

You will most definately need to do a thorough site survey, keeping in mind hidden obstactles like elevator shafts, beams, electrical rooms, etc. The biggest issue I typically see with wireless installs in large buildings, is lack of wired infrastructure. This will bite you if the building has a limited amount of physical infrastructure to deploy the wireless

on. Also, it helps to have an electrician on hand to validate the ability to get a wire to where you want to deploy an Ap.

scottmac · ‎07-12-2007

It's just not that easy. Choosing the antenna and power output becomes more important the higher up you go.

These are "line of sight" frequencies. I work on the sixth floor if a mostly-glass building. We can (and have, as a demonstration)worked through open wireless systems over a mile away from a 1200 series with a 5.5db omni antenna.

I have also been able to connect (and work through)to our demo system from a booth in a restaraunt several blocks away.

Altitude can be your friend, it can be your enemy, depending on your setup and what you are trying to accomplish.

Your best option to contain the RF is the type of antenna (and placement of same)and then the amount of power fed to those antennas. It may be necessary to have many more APs then you think you'll need, just so you can localize and contain the RF.

You need a good, comprehensive site survey. There is no substitute. Failure to do a good site survey will cost you much, much more in the long run.

FWIW

Scott