I am well versed in how WISPs work.

Ubiquiti, Cambium, Mikrotik, Radwin, etc. they all have at least one product line that uses a modified version of WiFi that works exactly in the way I described (well, a lesser extent for Mikrotik). In those modes, a WiFi-only device will *not* work in any capacity. They become a single-vendor ecosystem. Ubiquiti and Cambium also have product lines that are completely unrelated to WiFi.

The APs no longer have separate frequencies, but they reuse frequencies, usually in an ABAB pattern.

Even if on different frequencies there is indeed conflict (without GPS sync) as the RF emissions don't have a hard stop at the channel edge.

There's still a HUGE gap between the need for GPS sync in fixed wireless and the need for fiber.

-----
Mike Hammett
Intelligent Computing Solutions

Midwest Internet Exchange

The Brothers WISP

From: "Baldur Norddahl" <baldur.norddahl@gmail.com>
To: "NANOG" <nanog@nanog.org>
Sent: Wednesday, June 2, 2021 4:00:27 PM
Subject: Re: New minimum speed for US broadband connections

The kind of WISP we have around here is one or more AP on a tower or corn silo and that one tower will cover a huge area by line of sight. There will be nothing like you describe as each AP has separate frequency and therefore no conflict. The gear is more or less standard wifi, often Ubiquity.

If the density becomes great enough for scalability to be an issue, you have a business case for fiber.

802.11ax has options for longer guard intervals to make it work at greater distances.

On Wed, Jun 2, 2021 at 9:33 PM Mike Hammett <nanog@ics-il.net> wrote:

To have any sort of scalability, you take the free-for-all CSMA/CA and split it into uplink\downlink TDMA time slots. All APs transmit at the same time, then all APs listen at the same time.

You then need to have the same uplink\downlink ratio on all APs in the system. To change the regulatory dynamics of upload\download then requires reconfiguration of the whole ecosystem to facilitate that, resulting in wasted cycles.

BTW: A lot of WISPs use heavily modified versions of WiFi, but a lot also use platforms that have nothing in common with WiFi. Very, very few use straight 802.11. Why? Because it sucks at scale.

Also, the extension of 802.11ax into the 6 GHz band will have variable results. Your usage is still a second class citizen (as it should be) to licensed users of the band.

-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com

Midwest-IX
http://www.midwest-ix.com

From: "Baldur Norddahl" <baldur.norddahl@gmail.com>
To: "NANOG" <nanog@nanog.org>
Sent: Wednesday, June 2, 2021 11:07:45 AM
Subject: Re: New minimum speed for US broadband connections

tir. 1. jun. 2021 23.57 skrev Mike Hammett <nanog@ics-il.net>:

Requiring a 100 meg upload really changes up the dynamics of the WISP capabilities, resulting in fiber-only at a cost increase of 20x - 40x... for something that isn't needed.

I will admit to zero WISP experience but wifi is symmetrical speed up/down so why wouldn't a WISP not also be?

Wifi 6E higher speed and base control of clients, subchannels, simultaneously transmission from multiple clients etc. All good stuff that should allow a WISP to deliver much higher upload.

As soon a certain threshold is reached, higher speed will not cause more utilisation of the airwaves.

The WISP will need to invest in wifi 6E gear, which I suspect is the real problem.

Regards

Baldur