Question about Beamforming technology and Wi-Fi signal coverage

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lazer5

New Around Here
Hi,

I used to (wrongly) believe that Beamforming technology was a clever way to get around the EIRP limits imposed by the regulators, in which a perfectly controlled synchronization of the phases of the radio waves emitted from two antennas results in higher wave amplitudes of the radiated signal in a certain direction.

Now I've come across this webpage https://documentation.meraki.com/MR/Radio_Settings/EU_Compliance_Information which states that for equipment that employs Beamforming technology an expected gain of 3 dB has to be put into the equation for calculating the EIRP. 3 dB is basically equal to a doubling of the transmit power, therefore I think 3 dB must be the maximum that can be gained from adding up the waves emitted from two antennas.

However, wouldn't that mean if the Beamforming tech of a certain device was working less than optimal (i.e. steering of the "beam" towards the client device not 100% precise), then the signal range should be inferior to that of a Wi-Fi router without Beamforming technology that just radiates the permitted signal level all round equally?

Apparently there are manufacturers of Wi-Fi routers that give the user the option to turn Beamforming on or off, but I have one from TP-Link and they don't seem to offer control over the Beamforming feature on the routers that utilize it. So I am unable test myself if either Beamforming on or off would result in better coverage.

Does anyone here have experience with Beamforming technology in Wi-Fi routers? Does it actually improve Wi-Fi connectivity in general?

My personal experience is that my previous older AC router (also TP-Link) that didn't support things like Beamforming, OFDMA, MU-MIMO used to have better coverage in the 2.4 GHz band (the 5 GHz I've never really investigated) and I am wondering why this might be?
 

thiggins

Mr. Easy
Staff member

Matt Gast's 802.11 books are my go-to source for answering questions like this.

The short story is beamforming is most effective at improving throughput at mid-range. In other words, it extends the flat portion of a rate vs. range curve. It doesn't extend range, i.e. it doesn't move the point where the RvR curve crosses the x axis.

Beamforming is essential for proper MU-MIMO operation. It took a LONG time (years) for manufacturers to get MU-MIMO to the point where it actually improved total throughput utilization in multi-client situations. Even now, it's hard to see MU-MIMO's gain in real-world use, unless you specifically test for it, which isn't easy.
 

lazer5

New Around Here
Thank you very much! The online book you've linked to is absolutely great!

The insert "Transmit Power Limitations And Beamforming" gives a good insight into what the EIRP formula on that Cisco webpage means in practical terms.

Given that this technology is complex and took years to implement properly I wonder how well it could possibly work in those routers that are made on a really small budget?
There are already routers on sale for less than 40€ (for example TP-Link Archer C6 or A6) boasting about their MU-MIMO and Beamforming features.

Anyway, I guess the next time I upgrade my home router I will be looking at the one's from Asus, as they seem to allow much more control over all the features than TP-Link does nowadays.
 

sfx2000

Part of the Furniture
Given that this technology is complex and took years to implement properly I wonder how well it could possibly work in those routers that are made on a really small budget?
There are already routers on sale for less than 40€ (for example TP-Link Archer C6 or A6) boasting about their MU-MIMO and Beamforming features.

It's baked into the chipset firmware and enabled by the drivers...
 

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