Grade II listed building installation, deployed AP's not cutting it!

[wildflower1977]

Hi,

I have deployed 15 x AIR-LAP1042N-E-K9 with a AIR-CT5508-25-K9 into a grade two listed building, it has 18inch thick concrete/brick walls which are seriously hindering signal propagation.  I am not allowed to drill any holes to extend the cabling infrastructure or mount antenna's on the walls or ceilings around the building.  I have placed the data VLAN on the 2.4Mhz range and the voice VLAN on the 5Ghz range.  Data users are not complaining but are fairly static in areas of coverage.  The voice signal is poor once out of a room with an AP in it which is a problem for the 7921 mobile users as they are roaming around the site.  I have boosted the signal as much as possible on the controller and have manually set the channel assigments to reduce co-channel interference. 

I have also set the 5Ghz to 40mhz from 20mhz (not sure if this is a good idea or not)

I have the option of deploying another couple of 1042N's in the surrounding rooms but fear the corridor space will still suffer from poor signal.  The 1042N does not have the option of adding external antennas so I have looked at other models.

would a AIR-LAP1242AG-E-K9 with four external antennas (2x2.4Mhz AIR-ANT2422DB-R, 2x5Ghz AIR-ANT5135DB-R) provide a stronger/better signal? the gain is listed as 2.2dBi and 3.5dBi respectively, the internal antenna on the 1042 is listed as 2.4Mhz/4dBi and 5Ghz/3dBi

Would the voice be better served on the 2.4Mhz rather than 5Ghz?

in summary, should I

A. just deploy more 1042Ns

B. replace some/all of the 1042N's with 1242AG with antenna (I have another site to reuse them on)

C. swap the voice and data frequency

  

AIR-CT5508-25-K9

[Stephen Rodriguez]

Was a site survey done prior to the installation of the AP?  At this point, a validation/remediation survey could help as well, to find where more AP would need to be placed.

Manually setting the power and channel, probably isn't going to buy you alot either, if the signal degredation is that bad, the AP are going to boost power, and still not hear each other.

Swapping the frequency would help the Voice clients sure, but the data clients would probably tend to have the same issues that voice is seeing now. 

If the RSSI/SNR isn't good, there's not much to be done with out adding infrastructure.  But just putting up AP to try to 'band-aid' isn't the best option either.

My recommendations would be

1.) get a validation/remediation survey done, so you know where to put the AP to best help the RF

2.) install said AP

if the above is not an option

3.) Put AP in the corridors

with option 3, I would try to find an inexpensive/free tool so you can get an ideas of the signal strength from the surronding AP, so that you don't over saturate an area, or under cover it.

HTH,

Steve

[wildflower1977]

a site survey was carried out prior to deployment, its was only after AP's had been deployed the client decided that 7921 handsets would be issued 'because wireless is everywhere now'  The graphic below shows the 67% signal strength of the network for voice. 

If using 1242AG's wouldn't provide any benefit I'll just deploy additional 1042N's across the top and bottom of the picture.

[Stephen Rodriguez]

ah, so the survey was done for data then, which usually means a -75 dbm cell edge w/15db SNR, where with voice we want a -65dmb cell edge w/ 25db SNR.

You're going to need to add AP, adn if you have WCS or Airmagnet, you can use that in planner mode to plot where the AP need to be, to get proper cell edge and overlap.

HTH,

Steve