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Contributor II
Posts: 52
Registered: ‎03-07-2011
Recommended Transmit EIRP in Dorms

I'm curious to see what everyone is using for their EIRP in dorms.  The documentation mentions that assuming you're mounting to the ceiling, you should have a minimum of 9.  But, is anyone using anything higher values?  Have these helped coverage issues you may have had?

 

I'm having issues particularly in a dorm that I'd never had issues with previously.  It's an easy dorm, as it's a square, seven floors.  I have four AP-105s deployed per floor, in the hallways, alternating corners and middles.  My problem is in the rooms on the corners, on floors where the APs are deployed in the middle of the halls rather than the corners.  The strategy was that the AP on the floor above in the corner should handle the floor below.

 

I've set the power in that dorm to 12 currently, but am hesitant to increase it any more than that without some confirmation that it wouldn't be any harm in doing so.

 

Suggestions?  :-)

Guru Elite
Posts: 21,270
Registered: ‎03-29-2007
Re: Recommended Transmit EIRP in Dorms

daringone wrote:

I'm curious to see what everyone is using for their EIRP in dorms.  The documentation mentions that assuming you're mounting to the ceiling, you should have a minimum of 9.  But, is anyone using anything higher values?  Have these helped coverage issues you may have had?

 

I'm having issues particularly in a dorm that I'd never had issues with previously.  It's an easy dorm, as it's a square, seven floors.  I have four AP-105s deployed per floor, in the hallways, alternating corners and middles.  My problem is in the rooms on the corners, on floors where the APs are deployed in the middle of the halls rather than the corners.  The strategy was that the AP on the floor above in the corner should handle the floor below.

 

I've set the power in that dorm to 12 currently, but am hesitant to increase it any more than that without some confirmation that it wouldn't be any harm in doing so.

 

Suggestions?  :-)


While we are waiting for input from others on your question may I suggest you take a look at  the Next Generation Wireless Architecture for Multimedia-Grade Residence Halls VRD here:  http://www.arubanetworks.com/wp-content/uploads/NextGenAppNote_2012-06_28.pdf  please do, because it will give you ideas about approaches based on your specific deployment.

 

 



Colin Joseph
Aruba Customer Engineering

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Occasional Contributor II
Posts: 26
Registered: ‎10-16-2008
Re: Recommended Transmit EIRP in Dorms

If you have Airwave you can check to see how many other Access Points are seen on the same channel.  Also from the controller cli you can run the command "show ap monitor ap-list ap-name "ap-name-here" channel 1 essid "SSID-here"

I run it for the channel the AP is currently on but you can also run it for all the channels.   I also specify the BSSID so I do not get duplicate entries for the same AP for each SSID.    If you can see 3 or more other APs on the same channel with an avg-rssi of 20 or higher then co-channel interference could be an issue and turning the minimum power up could make it worse.  Of course every environment is different.   We have started to move the access points into the rooms to avoid this issue.

 

 

Chris Hart

Northwestern University

Contributor II
Posts: 52
Registered: ‎03-07-2011
Re: Recommended Transmit EIRP in Dorms

cjoseph wrote:

While we are waiting for input from others on your question may I suggest you take a look at  the Next Generation Wireless Architecture for Multimedia-Grade Residence Halls VRD here:  http://www.arubanetworks.com/wp-content/uploads/NextGenAppNote_2012-06_28.pdf  please do, because it will give you ideas about approaches based on your specific deployment.

 


This information would have been useful three years ago when we deployed.  The Aruba engineer on site might have said something :-/

 

The capital cost of moving APs into the rooms makes that a deal breaker.  I've got to roll with what I have and make it as efficient as possible.

MVP
Posts: 4,301
Registered: ‎07-20-2011
Re: Recommended Transmit EIRP in Dorms

 

A couple of things that could help you :

- Doing a site survey but of course since the school year started that may not be possible

- You could try using the Visual RF in Airwave or the standalone version and using a JPeg or CAD file of the building you can determine the layout and it can give you an idea of how you can adjust your power levels 

 

The type of structure the building is made of (CMU block, Drywall , etc..) and how you have your APs deployed will determine how you have to adjust your power levels Min/Max .

 

Another to thing is that the power levels for 802.11a might be different than the one for 802.11g since the .11g signal travels further compare to .11a

Thank you

Victor Fabian
Lead Mobility Engineer @ Integration Partners
AMFX | ACMX | ACDX | ACCX | CWAP | CWDP | CWNA
Aruba
Posts: 1,377
Registered: ‎12-12-2011
Re: Recommended Transmit EIRP in Dorms

I would utilize Airwave.  Take all these APs and place them into a folder.  Give them a day...go back into Airwave (make sure you're at 7.7.x) and check the RF capacity dashboard.  That will tell you a good overview of the channel utilization.  IF you have a low client count and a high channel utilization number (sustained throughout the day with little client traffic), then there is CCI occuring in this location most likely.  ARM should power down based on the RF profile attached to this AP group.  You may be able to raise the min Tx power based on your findings.  Also, with the RF Health Report in Airwave, you can check for adverse affects and hopefully be proactive before any issues get called in should raising from 12 to 15 cause any issues.  

 

IF you are thinking about playing around with EIRP and other RF metrics, I strongly advise moving all APs from this dorm into their own AP group so you can make tweaks to them without affecting the other APs in other buildings on campus.

 

Wrap up - use the RF capacity dashboard and RF Health Report in Airwave to verify and post-verify and RF changes you make!

 

Hope this helps!

 

 

Seth R. Fiermonti
Consulting Systems Engineer - ACCX, ACDX, ACMX
Email: seth@hpe.com
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