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So you have been asked to design for this:

A predictive model won't even get you close here. The environment is too complex. You need to do an APoS survey to find out what the RF actually does in an environment like this.

So what is an APoS survey? APoS stands for AP on a stick. APoS surveys are used in the design phase of a deployment. While they are very useful they are not always done. APoS is more accurate than a predictive however, it is often not done due to time and cost. It usually takes about an hour per APoS location and in a large facility, this can get expensive quickly. Therefore, in more standard spaces such as a carpeted office, a wireless engineer will often instead take wall attenuation measurements and enter that information in Ekakau or a similar product and produce a predictive design. Keep in mind that when creating a predictive model there can be surprises like a room that looks like all the others but 50 years ago was a radio studio. Soundproofing anyone?

In an APoS survey, an AP, preferable the model you plan to deploy, is mounted to a stick and moved to various locations to see how RF propagates. My APoS rig looks like this. I'll discuss how to put one together in another post.

To perform an APoS perform the following steps:

-Configure the AP to match the settings you plan to deploy

-Place the rig in the area that you anticipate placing your first AP. Survey using Ekahau. Adjust the APoS rig location until the RSSI at the cell edges is what you need it to be.

-Freeze the AP in the survey software.

Move the APoS rig to the next location and repeat the previous steps until you have completed the entire survey.


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