Wifi 6 speed issues

[ZohebSk]

In my office, Meraki MR36 access points are being used, and we want to achieve full Wi-Fi 6 compatibility. However, on end-user laptops, the Wi-Fi link speed shows less than 500 Mbps. Since the laptops are Wi-Fi 6 compatible, we expect the link speed to reach around 1.0 Gbps to 1.2 Gbps, but this is not happening.

The same Meraki MR36 access points are deployed at another location, and there the link speed shows up to 1.2 Gbps. From a configuration perspective, at the location where 1.2 Gbps is achieved, only one RF profile is configured (the default RF profile). At our location, where the issue is observed, four different RF profiles are configured.

Could the multiple RF profiles be causing this issue, or is there any other configuration or RF-related factor that could be limiting the Wi-Fi 6 link speed?

[Karsten Iwen]

Which link speed are you referring to? What the client is reporting? Then the different profiles could be a reason as they can be configured differently for the channel bandwidth. But if you see something around 1Gig, you might have too wide channels configured and depending on your density a smaller channel-width could me more useful. But most importantly, it should be consistent amoung all APs.

[ww^]

Most clients support 2 streams. You can verify client capability from the dashboard client page.

You can check supported data rates here. For example based on 2 streams, 80 mhz the max would be 1200mbps on 11ax.

Maybe the other client support a single stream or the client/ap is configured a lower (40hz) channel width.

https://mcsindex.com/

[joey.debra]

Hey, when running 80 MHz channels, you could be able to achieve a PHY rate of 1200 but only if you are within a high receive strength.

If you are using 40 MHz channels then you will most likely get up to PHY up to 570.

You have to take into account that most clients have 1x1 or 2x2 antenna configurations.

The question of course is: does your application require those high speeds or are you just doing it for kicks/speedtests?

[Philip D'Ath]

Typically, in built-up business areas, people use 20 MHz channels, which provide an access rate of around 144 Mb/s (with two spatial streams).

The reason people use narrow channels instead of wide 80Mhz channels is that you often get other nearby businesses using WiFi using part of the spectrum you want to use, and you either spend a lot of time waiting for the whole 80Mhz to become free to transmit a packet, or you experience packet corruption. You can also get intermittent performance, good one minute, bad the next.

20Mhz channels provide a greater chance of getting uncongested bandwidth, making their actual throughput much more predictable.

Sometimes, if the area is not built up, I use 40 MHz channels (573 Mbps access rate).

Try different channel widths and measure the actual throughput (e.g., copying a file from a server) to see which is faster. Don't be surprised if the 80 MHz wide channel is slower, or if its speeds are up and down all over the place.

[Rasmus Hoffmann Birkelund · Accepted solution]

Also, the thing is that regulations specify EIRP, in terms of power density, meaning that an AP may not transmit more than a certain level of milliwatts per MHz BW. So if a station is bound by regulations to not transmit more than 1 W per MHz BW, for a 20 MHz channel you are transmitting at maximum 50 mW. And as the channel become wider, the station will transmit even less.

So using a wider channel versus a narrow, really comes with a trade off, on what you want/need. A narrow channel means more channels, higher transmit power, but a "smaller highway", whereas a wider channel means less channels to work with, less transmit power, but more room on the "highway" to move data.

If you reference https://mcsindex.com/, you can see what theorethical speeds you may achieve, depending on channel widths and available SNR.