Цитата: sfstudio от 30/07/2019, 18:56

Кратенько о работе MU-MIMO и ограничениях оного (раскладка по слайсам):

Any MU-MIMO devices can communicate simultaneously on the same time slices, thereby increasing total throughput. 
To illustrate this, let's take a home network with five 802.11ac client devices:
 
One 2x2 SU-MIMO client (device A)
One 1x1 SU-MIMO client (device B)
One 2x2 MU-MIMO client (device C)
Two 1x1 MU-MIMO clients (devices D and E)
The following table illustrates what would happen on a quad-stream (4x4) router that does not support MU-MIMO, 
when all devices are communicating simultaneously.
 
            Spatial Streams 
Time Slice | 1 | 2 | 3 | 4 |
     1     | A | A | - | - |
     2     | B | - | - | - |
     3     | C | C | - | - |
     4     | D | - | - | - |
     5     | E | - | - | - |
Notice that it takes five time slices to service five devices talking at once, with some spatial streams completely unused.
This means wasted bandwidth, with only 35% of the theoretical bandwidth actually usable. On larger networks with dozens of devices,
this can be a serious problem, especially when you consider that 4x4 MIMO clients are rare.
 
Now let's see what happens on a quad-stream MU-MIMO router, in an ideal situation:
 
            Spatial Streams 
Time Slice | 1 | 2 | 3 | 4 |
     1     | A | A | - | - |
     2     | B | - | - | - |
     3     | C | C | D | E |
It now takes only three time slices to handle all devices.
Notice how the MU-MIMO devices can now all talk at the same time on the same time slice.
The SU-MIMO devices can't communicate at the same time and still get their own time slices as the router cycles them round-robin,
but you now have far less wasted bandwidth – 58% of the bandwidth can now be utilized when all devices communicate at the same time.
 
The above examples assume that all devices are all communicating at the same time, and that all transmissions are of the same size.
The full benefit of MU-MIMO can only be realized when all devices on the network support MU-MIMO, since legacy SU-MIMO devices cannot
share time slices the way MU-MIMO devices can. Also, we're ignoring the effects of interference, client distance from router,
or other environmental or technical factors, so real-world performance will not look exactly like this.

Цитата: sfstudio от 05/12/2020, 19:08

Пояснения (на пальцах) по одной из самых полезных плюшек 802.11ax (wifi 6) ака  preamble puncturing.

Цитата: sfstudio от 13/10/2021, 11:31

Отлично написанная заметка на тему почему высокий уровень сигнала не говорит о надёжной связи. Читать.

Цитата: sfstudio от 15/09/2022, 13:02

О модуляциях в общем и о QAM в частности https://ru.fmuser.net

Цитата: sfstudio от 06/02/2023, 14:36

https://www.duckware.com/tech/wifi-in-the-us.html

Отличная статья под заголовком "Принятие обоснованных решений по апгрейду беспроводных маршрутизаторов/точек доступа"

На самом деле содержание гораздо шире по тематике.

Крайне рекомендуем к прочтению. Отдельного внимания заслуживают ссылки по ходу статьи.

Цитата: sfstudio от 31/08/2023, 13:25

Полезная табличка зависимости   минимально необходимого SNR от режимов работы тракта (чейны, полоса, модуляция и т.д.).

Цитата: sfstudio от 06/11/2023, 13:38

Описание использования 802.11f (iaap) в контексте реализации поддержки Fast Transition (802.11R). К сожаленю той самой интерпортабельности между вендорами (ради которой это и затевалось) как раз и нет и видимо уже не будет.