Does OFDMA Really Work? Part 2

JohnB_123

Regular Contributor
Excellent piece @thiggins

So if I read this correctly, you've proven that cheap AX/Wifi6 routers like the AX-58U and the RAX15 aren't discernible--or even inferior-- to 4+ year old AC/Wifi5 routers like the R7800?
 

Razor512

Senior Member
It seems like in general all of the newer standards produced lower latency than the R7800, though the RAX15 ended up producing significantly worse results when OFDMA was enabled.

While it is nearly impossible too scientifically test, I wonder if OFDMA will have any improvements in normally congested environments, e.g., an urban area where it is normal to see 100+ access points in range and no one seems willing to use Ethernet, even when they have a desktop PC in the same room as their router. Over time as more people move to OFDMA, will WiFi become less bad in those areas?
 

thiggins

Mr. Easy
Staff member
So if I read this correctly, you've proven that cheap AX/Wifi6 routers like the AX-58U and the RAX15 aren't discernible--or even inferior-- to 4+ year old AC/Wifi5 routers like the R7800?
No. All AX routers had lower latency than the two AC routers tested. But the lower latencies were not due to OFDMA.

AX routers can provide other advantages over AC routers, especially for 2.4 GHz AX devices. But OFDMA isn't one of the advantages.
 

JohnB_123

Regular Contributor
No. All AX routers had lower latency than the two AC routers tested. But the lower latencies were not due to OFDMA.

AX routers can provide other advantages over AC routers, especially for 2.4 GHz AX devices. But OFDMA isn't one of the advantages.
Very helpful, thanks Tim.

Since I've put ethernet to all my stationary devices, the only AX devices we have are mobile - and I haven't seen a discernible difference with our RT-AX88U vs. our Netgear AC router whatsoever.
 

digital10

Regular Contributor
It's possible that OFDMA may some day evolve to provide some of its touted advantages. But I think it will take years, as it did with MU-MIMO.
I thought there is an article here saying MUMIMO didnt show any real benefits and sometimes will give worse performance
 

thiggins

Mr. Easy
Staff member

StR

Occasional Visitor
Here is the link
https://www.smallnetbuilder.com/wireless/wireless-features/33100-why-you-don-t-need-mu-mimo

Three years later, I'm told by colleagues at octoScope that MU-MIMO can provide total throughput gain. I have not verified this myself. But MU-MIMO testing will be incorporated into the upcoming new Wi-Fi test suite.
Do you know if those new findings about MU-MIMO have been published somewhere?
I was trying to find any followup on that initial report (thank you for posting it), and that seems to be the only real test of MU-MIMO performance.

Any pointers to the more recent tests/reports/... would be appreciated.
I am considering an upgrade from a non-MU-MIMO router to a more recent technology, and trying to decide which technology will actually yield a reasonable gain. Per your test, OFDMA doesn't seem to offer much of a gain for a real-life setting. The question now is whether MU-MIMO does.

Of course, the progressively higher QAM level provides the advantage ( n -> ac -> ax). But I have a suspicion that in my case working MU-MIMO could in principle offer a better advantage.
 

coxhaus

Part of the Furniture
I heard Cisco enterprise guys mention it when talking on a video with the new catalyst wireless APs about wireless at an airport with 300 or 400 connections and getting benefit. No specifics. And I did not understand. Do you have that many connections with 1 wireless AP?
 

thiggins

Mr. Easy
Staff member
And I did not understand. Do you have that many connections with 1 wireless AP?
That would not be good practice for normal APs. Maybe for a Xirrus AP that has multiple radios.
 

coxhaus

Part of the Furniture
Maybe then it would be 300 or 400 users on a virtual AP. Does MU-MIMO make sense across a virtual AP? I would not think so since it is hardware.

I guess I will have to wait and see what they do.
 
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