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Is there any data on real-world performance improvement from beamforming with consumer gear? I know anecdotally 802.11ac is way better than 802.11n (much less .

Is there any data on real-world performance improvement from beamforming with consumer gear? I know anecdotally 802.11ac is way better than 802.11n (much less .11g) but there's so many related improvements in it that I don't understand how helpful the beamforming part is.

stagger87 7y ago
I can't point you to any study or data, but I've worked around WiFi enough to know that beamforming is one of the first optimizations performed in multi antenna scenarios, mainly because of how easy it is to do. A 3dB bump in SNR for a 2x1 antenna configuration might allow you to transmit at the next modulation depth (QAM16 vs QPSK for instance). That will increase throughput and reduce the retry rate. At low SNRs it can increase router range.
namibj 7y ago
In our hackerspace, using 3 antennas in an ubiquity "UFO" danling in front of a shelf, communicating 2~3m to a thinkpad with afaik 2 antennas, using an 80MHz 5GHz 802.11ac configuration, we get consistently >500Mbit/s (iirc hovering at roughly 600Mbit/s) (unidirectional) to the NAS (1000BASE-T wiring, 1-2 switches in-between) when mounted via NFS. A single stream can't get more than ~420Mbit/s _in the lab_.
labcomputer 7y ago
I'd love to see some data on this too. One proxy for the benefit of beamforming might be the the available modulation types and coding rates in the various wifi specs. The wikipedia articles on 802.11g, .11n, and .11ac have tables showing the nominal data rate for different MCS indicies (modulation and coding scheme). Notably, 11n adds a 5/6 coding rate to 64 QAM modulation (on top of 2/3 and 3/4 found in 11g). In addition to that, 11ac adds another two rates with 256 QAM (3/4 and 5/6). Since higher modulation indicies are generally only useful at higher S/N ratios, you might argue some combination of the following: 1. These higher rates exist only to boost the advertised speed of 802.11 products, and are useless in real-world scenarios 2. These rates are intended to be used when sitting very close to an 802.11 AP 3. These rates are intended to be used with directional antennas 4. These rates are useful in the real world and made possible by the antenna gain provided by beamforming. If you believe the last one, then the benefit is around 30% to 50% more throughput (the data rate MCS-9 is 1.48x MCS-6). That's not counting the benefit you get from having multiple spatial streams, so the benefit is available in a scenario where the AP has multiple antennas and the devices has only one.

stagger87 7y ago

I can't point you to any study or data, but I've worked around WiFi enough to know that beamforming is one of the first optimizations performed in multi antenna scenarios, mainly because of how easy it is to do. A 3dB bump in SNR for a 2x1 antenna configuration might allow you to transmit at the next modulation depth (QAM16 vs QPSK for instance). That will increase throughput and reduce the retry rate. At low SNRs it can increase router range.

namibj 7y ago

In our hackerspace, using 3 antennas in an ubiquity "UFO" danling in front of a shelf, communicating 2~3m to a thinkpad with afaik 2 antennas, using an 80MHz 5GHz 802.11ac configuration, we get consistently >500Mbit/s (iirc hovering at roughly 600Mbit/s) (unidirectional) to the NAS (1000BASE-T wiring, 1-2 switches in-between) when mounted via NFS. A single stream can't get more than ~420Mbit/s _in the lab_.

labcomputer 7y ago

I'd love to see some data on this too. One proxy for the benefit of beamforming might be the the available modulation types and coding rates in the various wifi specs. The wikipedia articles on 802.11g, .11n, and .11ac have tables showing the nominal data rate for different MCS indicies (modulation and coding scheme). Notably, 11n adds a 5/6 coding rate to 64 QAM modulation (on top of 2/3 and 3/4 found in 11g). In addition to that, 11ac adds another two rates with 256 QAM (3/4 and 5/6). Since higher modulation indicies are generally only useful at higher S/N ratios, you might argue some combination of the following: 1. These higher rates exist only to boost the advertised speed of 802.11 products, and are useless in real-world scenarios 2. These rates are intended to be used when sitting very close to an 802.11 AP 3. These rates are intended to be used with directional antennas 4. These rates are useful in the real world and made possible by the antenna gain provided by beamforming. If you believe the last one, then the benefit is around 30% to 50% more throughput (the data rate MCS-9 is 1.48x MCS-6). That's not counting the benefit you get from having multiple spatial streams, so the benefit is available in a scenario where the AP has multiple antennas and the devices has only one.