Pico Cell in an educational enviroment

Unanswered Question
May 5th, 2008


I work in a school withoaround 1000 stundents. We have a current WLan network with around 75 autonomous Cisco1231 APs.

I've got now 2 WiSM blades and am currently migrating all the APs to LWAPP.

We have a quite dense network and up to 250 clients simultaneous connected to those APs. All the so far migrated APs are set power level to auto, but all have level 1 so far, which means full power output.

Would here Pico Cell mode help?

And more important, would it work with all different kinds of laptops?

We don't have any influence onto the laptops, drivers and so on. The Cisco manual advises not to use Pico Cell mode in a mixed enviroment.



I have this problem too.
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bwilmoth Fri, 05/09/2008 - 05:36

pico cell mode parameters are on the controller. Using these parameters, you can manually specify global values for

receiver sensitivity threshold, clear channel assessment (CCA) sensitivity threshold, and transmit power values across

all access points registered to a given controller. High-density networking is supported on all Cisco lightweight access points except the wireless mesh access points

patoberli Fri, 05/09/2008 - 06:18

Thanks for the answer, but it doesn't really answer any of my questions :(

dennischolmes Fri, 05/09/2008 - 09:52

Pico cell will not help you here as you do not have the proper density of APs to perform a pico cell deployment. Proper LWAPP guidelines for deployment contrast greatly with autonomous ones. Autonomous guidelines were 100% power, 10% cell overlap, and -65 cell edges. LWAPP best practices are 50% power,20-30% overlap of cells, and -65 cell edges. From these guidelines you can deduce that you will need approximately 30-40% more APs to complete a good LWAPP deployment. The rule of thumb is approximately 1 AP per 2500-3000 square feet. These numbers are for data coverages only. In a dense capacity coverage scenario, plan on no more than 20 users per AP (make sure to change the default from 12 under auto rf settings)and add additional APs. The controller will reduce the power and adjust the channel settings accordingly. You should never see APs powered at the highest setting. This is in essence a type of pico cell deployment as the cell size is significantly smaller. True pico cell is when you may cluster several APs with directional antennae at the same location with each AP covering a directionalized coverage sector at very low power. This scenario was used at a major stock brokerage floor in NYC.

SHANNON WYATT Fri, 05/16/2008 - 18:08

It could be that the access points are at max power due to high signal attenuation through the walls. I've done a bunch of schools, and some of the walls a quite dense, particularly in older schools. Schools always have block walls due to strict fire codes, so that will knock the signal, plus lockers, brick mold, access point placement, etc, with have a further impact. If that is the case the access points may not hear a neighbor on the same channel at a sufficient level to auto-rf the power down.


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