Wireless Deployment question

[IT Services]

Good Morning,

I am in need of some help. We are looking to deploy wireless to one of our retail locations. The site is currently under remodel so the time is now to put in a better solution.

We currently have Cisco Small Business AP541n deployed and we lose connectivity on our iDevices when they go into the kitchen area. The kitchen area is surrounded by refrigerators and we have stainless steel between the serving area and the kitchen. We ASLO have a Planar video wall (Cat 6 shielded is powering the video panels). Well this stuff seems to be causing interference but i dont have any numbers around that.

I dont have any tools to perform a WLAN survey prior to redeploying wireless. Well my question is:

The area is rougly 800 - 900 square feet and i was thinking of installing two 3602 clean air AP's to combat what i can only assume is heavy interference and noise. Would it cause issues with 2 AP's that close together?

Is this a recommended deployment or should I have a single AP with clean air trying to work best in that environment. Oh the environment is in a major (like the largest) metropolitan area in the world.                   

[Scott Fella]

To be honest, you can even go with three AP's by your safe with two. Hard to say because areas that can attenuate signal, you should have access point in. That's why I said three would be ideal if you know where you might have coverage or not. Typically you don't want to just have one Ap. The reason being is redundancy and better coverage.

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[IT Services]

Scott Fella wrote:
To be honest, you can even go with three AP's by your safe with two. Hard to say because areas that can attenuate signal, you should have access point in. That's why I said three would be ideal if you know where you might have coverage or not. Typically you don't want to just have one Ap. The reason being is redundancy and better coverage.

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Thanks Scott. I spoke with our vendor about this as well and they helped confirm some of my thoughts. I will plan for 3 AP's and install 2, check the spectrum and information recorded by the APs and go from there.

[Leo Laohoo]

The area is rougly 800 - 900 square feet and i was thinking of installing two 3602 clean air AP's to combat what i can only assume is heavy interference and noise.

If you are not going to deploy wireless LAN controller (WLC) then deploying an AP with CleanAir is a waste of time.  Unfortunately, you don't have a choice because all the new APs (1600, 2600, 3600 & 3700) are all CleanAir capable.

Another thing:  What made you decide on 3600?  Cisco recently announced the newer 3700 and if you check the catalogue, the prices for the 3700 is no different to the 3600.  The only gotcha for the 3700 is the 20.0w PoE.  You can operate at 15.4 but this lowers MIMO rates.

I dont have any tools to perform a WLAN survey prior to redeploying wireless.

It ain't that complicated.  All you need is a laptop with 802.11a/b card and a wireless scanner.  Configure the AP as autonomous, ensure the AP Tx power is set to 60% only and disable 802.11b.  Do a site survey with 802.11a.  Make sure that your signal doesn't go below -70 dBi.

[IT Services]

Leo Laohoo wrote:
The area is rougly 800 - 900 square feet and i was thinking of installing two 3602 clean air AP's to combat what i can only assume is heavy interference and noise.
If you are not going to deploy wireless LAN controller (WLC) then deploying an AP with CleanAir is a waste of time.  Unfortunately, you don't have a choice because all the new APs (1600, 2600, 3600 & 3700) are all CleanAir capable.
Another thing:  What made you decide on 3600?  Cisco recently announced the newer 3700 and if you check the catalogue, the prices for the 3700 is no different to the 3600.  The only gotcha for the 3700 is the 20.0w PoE.  You can operate at 15.4 but this lowers MIMO rates. 
I dont have any tools to perform a WLAN survey prior to redeploying wireless.
It ain't that complicated.  All you need is a laptop with 802.11a/b card and a wireless scanner.  Configure the AP as autonomous, ensure the AP Tx power is set to 60% only and disable 802.11b.  Do a site survey with 802.11a.  Make sure that your signal doesn't go below -70 dBi.

These AP's will be running in Flex Connect mode to a 5508. Come on man give me more cred than that

We have a 10 pack of 3602i hanging around and that is what we have been purchasing the last year. We dont have a PoE+ switch for this location anyway.

Unfortunately we move to fast to have the time to get to this location to perform such survey. Its in the middle of a remodel and I wont get the approval to travel right now. Craziness. I don't have hands on site that could perform this work either.

[Leo Laohoo]

Come on man give me more cred than that

Search me!  You forgot to mention this. 

We have a 10 pack of 3602i hanging around and that is what we have been purchasing the last year.

Doh!  Too bad.

Unfortunately we move to fast to have the time to get to this location to perform such survey.

You have no idea how this actually helps you.  A lot!

So let me get this important detail correctly:  The shop's refurbishment is NOT YET complete?  If this is the case, then you are at the best position to do a wireless site survey.  You DO NOT want to do a survey when the place is empty or being torn down or being refurb.  You want to do a survey when everything is done particularly when furnitures and fixture are already installed.  I'm not forcing the issue.  It's just my AU$0.05 .

[stamper.brian]

If your going to go with 3 you might want to look at going with four.  Only reason being if your using RRM the TPC Alogrithm uses the 3rd highest neighbor to set levels.  So a total of 4 AP's needed. Odd justification to put up yet another AP but figured I'd throw it out there for you to think about. 

Transmit Power Control Algorithm

The TPC algorithm, run at a fixed ten minute interval by default, is used by the RF Group Leader to determine the APs’ RF proximities and adjust each band’s transmit power level lower to limit excessive cell overlap and co-channel interference.

Note: The TPC algorithm is only responsible for turning power levels down. The increase of transmission power is a part of the Coverage Hole Detection and Correction algorithm’s function, which is explained in the subsequent section.

Each AP reports an RSSI-ordered list of all neighboring APs and, provided an AP has three or more neighboring APs (for TPC to work, you must have a minimum of 4 APs), the RF Group Leader will apply the TPC algorithm on a per-band, per-AP basis to adjust AP power transmit levels downward such that the third loudest neighbor AP will then be heard at a signal level of -70dBm (default value or what the configured value is) or lower and the TCP hysteresis condition is satisfied. Therefore, the TCP goes through these stages which decide if a transmit power change is necessary:

1. Determine if there is a third neighbor, and if that third neighbor is above the transmit power control threshold.
2. Determine the transmit power using this equation: Tx_Max for given AP + (Tx power control thresh – RSSI of 3rd highest neighbor above the threshold).
3. Compare the calculation from step two with the current Tx power level and verify if it exceeds the TPC hysteresis.
   • If Tx power needs to be turned down: TPC hysteresis of at least 6dBm must be met. OR
   • If Tx power needs to be increased: TPC hysteresis of 3dBm must be met.

An example of the logic used in the TPC algorithm can be found in the Transmit Power Control Algorithm Workflow Examplesection.