I would use EAP225-Outdoor every 50 to 100m, but not CPEs. The EAP has a 360º antenna beam width while CPEs have 65º in one direction only. CPEs are designed for directional links between two CPEs over very long distances in the kilometers range, they are not meant to feed client devices. What's more, EAP225-Outdoor supports fast roaming, what could help when the lift moves from one WiFi cell to the next.

The EAP225 mesh uses a private channel (hidden SSID) in the 5 GHz band. Of course, traffic in the 2.4 GHz band of a meshed node will be forwarded over the mesh network, too, else it would not make much sense to mesh APs.

802.11k/v roaming does not depend on the frequency band, it works with 802.11b/g/n/ac all together.

Regarding 500 ft distance (it's 150m, right?): I doubt your embedded WiFi clients will cover this range – especially not in the 2.4 GHz band – even with a CPE, unless you have strong directional antennas connected to the embedded devices, too. That's why CPEs perform best if used pair-wise and why it suffers performance when used with standard clients.

As for repeater mode: I don't recommend this mode at all in business applications, since (with any repeater!) you will face problems such as the Hidden Node Problem. A repeater is o.k. to improve a weak signal by extending it's reach from a living room to a kitchen, but it has no place in professional deployments.

You might try to mount a CPE210 at the bottom of the lift and the other one on the ground, but note that relatively small angle the RF energy will be concentrated in:

Your main AP (if repeating) must be inside this 65º angle then, too (Hidden Node Problem still not solved then).

nack wrote

That's my reasoning for installing the CPE extenders every 50 meters (in pairs), so that the wifi client inside the lift just needs to communicate with the nearest CEP extender and that will forward that back to the AP. Is my understanding here wrong?

Yes, I think it's wrong, because you assume that the CPE's signal will cover the horizontal area somehow if the lift passes by the CPE - you wrote you want to mount them horizontally 90º reversed, right?

Personally, I would prefer this setup if using CPEs at all: a CPE mounted at the bottom of the lift and another one mounted on the ground. Both CPEs connected by cable, the one at the ground with the router and the one at the lift's bottom with the embedded device:

Alternatively, using EAP225-Outdoor the setup would look like this: two EAP225-OD WLAN cells, each EAP mounted in half the height of its signal coverage (which is ~100 to 150m). You can turn the antennas 90º to improve the vertical coverage, not shown in the picture):

Depending on how strong the WiFi signal your embedded device is you probably will need three EAP225, but I would try with two first. No need to connect the EAPs to the router for a test of WiFi coverage, only for final deployment you would need to install cables to the router on the ground (if not using mesh).

As for the hidden node problem, I was planning to set different static channels on different CPEs in the chain in order to avoid channel interference. Would that help?

No. If using repeater mode you can't select different channels. All CPEs must use the same channel in this mode.

That's the problem: there can be only one active sender at any time. Either CPE #1 sends data or CPE #2 sends data or CPE #3 sends something or the embedded device (ED) sends data on the selected channel. What's more, APs are always listening for senders to determine when the channel becomes free, so that they can acquire it. If your ED sends to CPE #3, the CPE has to send the data to CPE #2, which in turn has to send it to CPE #1 for final forwarding to the router.

Let's assume that CPE #1 sends back a reply to the ED, first sending it to CPE #2, which then sends it to CPE #3. Your ED doesn't see the signal of CPE #2 and itself starts sending more data to CPE #3. Collisions happen and CPE #3 sees only garbagge b/c CPE #2 and the ED use the same channel at the same time. That's called the Hidden Node Problem. The devices can't determine whether the channel is free b/c they don't »see« each other in this chain. Some nodes are hidden.

Would the EAP225 mesh cirumvent/reduce such issues?

Yes if you only use the 2.4 GHz band for communication of an EAP with the embedded device and the 5 GHz band only for meshing.

No if you also use the 5 GHz band for communication with clients and meshing. But since EAPs support faster wireless speeds and even MU-MIMO (multi-user MIMO), the Hidden Node Problem has not that big impact as with a N300 SISO or SU-MIMO device (CPEs are single-user MIMO). In the real world, mesh is working fine even when the 5 GHz band is used for communication with clients and for meshing at the same time. At least that's my experience so far with small mesh networks.

Anyway, I would definitely use cable (or fiber with media converters if distance is more than 100m) to connect the AP's with the router on the ground floor, except if the WiFi link is not critical: then I would try EAP-OD and mesh. When using CPEs I would set it up as shown above.

Personally, I would avoid repeater mode in any case (we had MUCH troubles with many installations using old Broadcom WDS repeater mode 10 years ago, so we do not support it anymore in our hotspot installations since then).

nack wrote

 

Sorry, I am not able to visualize how that would look like. Would it look like this:

 

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Yes, but antennas in parallel, this way:

Secondly, do I need the Omeda controller application running on a computer to manage the EAP-225 mesh? It seems like yes, as per this page. 

For seamless roaming, yes, the controller needs to be running. See the note in Q3 of the FAQ on the page you are referring to. Note that the embedded system would have to support 802.11k/v roaming, too.

Basically CPE A and B will face each other where A will be an AP using Channel 1 and B will be a client. Then I will link CPE B to another CPE C via an Ethernet cable. CPE C will be configured as another access point using a different Channel 2 but using the same SSID and password, and so on. 

Might probably work, but I would use CPEs as shown in my previous post: embedded system wired to CPE #2 mounted at the lift, CPE #1 on the ground, so the wireless link is supposed to stay active even when the lift is moving, since no survey/reconnection for the SSID is needed.

If you can solve the task, please give feedback here; it woud be valuable for the community.