Optimal AP positioning

Hardware Questions and Recommendations
1

First, I apologize in advance for this novice question. I searched the forums and the documents and couldn't find anything like what I'm looking for.

I'm placing several access points in an apartment building and want the APs to reach the greatest number of apartments (with at least an adequate signal). I've already discovered that what I'd do in my own home — just place it up high, centrally located, with the antennas pointing different directions — does not work well in this concrete and metal highrise.

What features does OpenWRT offer to help people tune the placement of an AP and the direction of the antennas? I know the status screen shows the signal strength of various connected devices, but it is there support for outputting a "WiFi Heatmap" that uses the results from all the devices simultaneously? (Ideally, it would also support visualizing multiple APs in the roaming network and, of course, be a 3-D map since this is a high rise building and the strongest signal is often from another floor.)

Since I can't find anything like that, I'm thinking this is something I may need to create. If I do, what is the best source of data for the quality of connection in OpenWRT? Should I use iwinfo wlan0 assoclist. If so, does it make more sense to look at the signal strength in dBm or try to use the MCS index table? How long should I have the program wait for OpenWRT to settle after an adjustment in position or antenna angle?

And finally, I'm thinking that it may make sense to get a bunch of cheap esp32 or pi zero w devices so I can standardize the location and hardware of the test clients. Surely someone else has thought of this before, so please let me know where I can find such a project. I'd rather buy their devices, if they work with OpenWRT, instead of re-inventing the wheel.

Thanks!

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Do a signal survey (ubiquiti but works for any vendor.
= https://youtu.be/Z9JvUUauJCM

= https://help.ui.com/hc/en-us/articles/221029967-Optimizing-WiFi-Connectivity-and-Reducing-Latency

= https://play.google.com/store/apps/details?id=com.ubnt.usurvey

3

I'd recommend the WiFiman as well for this task, instead of using the built-in antennas of OpenWRT routers. All devices are different and none is really calibrated. So you want numbers from a single device that moves around, not from multiple devices that can produce the same output format.

Where do you intend to put the APs in relation to the apartments? Can you put the APs in the apartments? Think about something like the Cudy AP3000 (not the outdoor one but the disc shaped one) ceiling mounted. On a purely psychological level, giving every resident the feeling of having their own AP is a good thing, even if they are technically spanned a huge common network.

Using a greater number of APs with lower power settings each will help against "stickyness" when it comes to clients being willing to roam from one AP to another. You don't want huge overlapping areas of barely but still acceptable signal strength.

That's why I'd recommend a greater number of cheaper devices with lower power settings over a smaller number of potentially more expensive device with higher power settings. Hence, put one AP in each apartments living room.

This is an additional argument for probing via smartphone while running around and against letting the APs probe: You want to know how good your roaming clients are able to see the APs, not how good your APs can see the roaming clients.

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