Wireless Deployment question

Question

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.                   

Answer 1

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:
Determine if there is a third neighbor, and if that third neighbor is above the transmit power control threshold.
Determine the transmit power using this equation: Tx_Max for given AP + (Tx power control thresh – RSSI of 3rd highest neighbor above the threshold).
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.