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A deep dive into why Wi-Fi kind of sucks

arstechnica.com

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Re: A deep dive into why Wi-Fi kind of sucks

#121

Post by esaym »

bennofs wrote: post #55
willidiots wrote: post #9

I build public Wi-Fi networks, you've probably used one of them. AMA if you have Wi-Fi questions. To say it "sucks" is a bit harsh. It's delivering multiple hundreds of Mbps to you via an unlicensed contention-based medium. The air interface is like sending packets over a noisy Ethernet hub; it's impressive it works as well as it does. That said, this article's a good primer on some of the protocol's fundamental chal…

I've got a weird problem at my home where WiFi connection on my laptop gets really bad as soon as some particular other laptop connects to the WiFi. Reconnecting fixes the issue. Any idea what might cause this or how to gather more information on potential causes?

I had the same issue with a $300 netgear prosafe AP. When certain 802.11ac clients would connect (mostly cell phones), it would randomly get periods of of complete grid lock in the wlan. All clients would have good signal strength but they had no data throughput. Disconnecting and reconnecting the offending client would restore the wlan throughput.

The best I could see from packet sniffing was that these certain mobile clients would go into some kind of sleep mode, and when/if packets were transmitted to them, they would not respond with the proper ack (sometimes), the AP would then hang the whole wlan waiting for the ack (I guess). I tried several different netgear prosafe access points (all of them 802.11n). The only thing that worked was getting rid of my netgear hardware and replacing them with a Mikrotik wAP ac.

Re: A deep dive into why Wi-Fi kind of sucks

#122

Post by gcr »

JoshTriplett wrote: post #99
willidiots wrote: post #32

Earlier quoted context omitted.

Yes and nothing special, as long as the clients and AP are moving consistent to each other. If the client is moving >10MPH relative to a fixed AP (i.e. you're driving past the AP in your car), Wi-Fi doesn't handle that well. Your movement creates Doppler shift in your RF signal, which Wi-Fi can't adjust for (vs. e.g. LTE which does).

> If the client is moving >10MPH relative to a fixed AP (i.e. you're driving past the AP in your car), Wi-Fi doesn't handle that well. Your movement creates Doppler shift in your RF signal, which Wi-Fi can't adjust for (vs. e.g. LTE which does). Perhaps current-generation WiFi has more of an issue with that, but I've helped build systems that used a much older generation of WiFi in an ad-hoc (no AP) mode between node…

Goodness gracious. What was the range of your network? Trying that on a consumer AP would instantly lose the signal, I'd imagine

Re: A deep dive into why Wi-Fi kind of sucks

#123

Post by esaym »

koolba wrote: post #14
willidiots wrote: post #9

I build public Wi-Fi networks, you've probably used one of them. AMA if you have Wi-Fi questions. To say it "sucks" is a bit harsh. It's delivering multiple hundreds of Mbps to you via an unlicensed contention-based medium. The air interface is like sending packets over a noisy Ethernet hub; it's impressive it works as well as it does. That said, this article's a good primer on some of the protocol's fundamental chal…

Which router do you recommend? Is the 5G band consistently worse than the default (i.e. constant connection drops) or is that just my experience?

For the price, I think the best set up is getting what ever ethernet only router that has your needed feature set (or just use a box with linux/shorewall), and then for wifi, running cat5 with POE to some Mikrotik wAP access points.

Re: A deep dive into why Wi-Fi kind of sucks

#124

Post by JoshTriplett »

gcr wrote: post #122
JoshTriplett wrote: post #99

Earlier quoted context omitted.

> If the client is moving >10MPH relative to a fixed AP (i.e. you're driving past the AP in your car), Wi-Fi doesn't handle that well. Your movement creates Doppler shift in your RF signal, which Wi-Fi can't adjust for (vs. e.g. LTE which does). Perhaps current-generation WiFi has more of an issue with that, but I've helped build systems that used a much older generation of WiFi in an ad-hoc (no AP) mode between node…

Goodness gracious. What was the range of your network? Trying that on a consumer AP would instantly lose the signal, I'd imagine

Miles, easily. But we had three major advantages:

1) We had a shoulder-mounted directional antenna pointed at the rocket.

2) The rocket had a cylindrical patch antenna wrapped around it.

3) Wifi channel 1 is in an amateur radio band, which means we can amplify it beyond the normal limits. We ran it at 1W.

Re: A deep dive into why Wi-Fi kind of sucks

#125

Post by searchfaster »

Many poeple also don't understand, how easy it is to frame a deauth packet and disconnect clients from APs. Hotels are known to use this to kick you out of using your own personal hotspot on phones. Thankfully 802.11w PMF solves this and FCC has started imposing fines on hotels doing this.

Re: A deep dive into why Wi-Fi kind of sucks

#126

Post by [deleted] »

bsenftner wrote: post #10

My day to day happiness quotient shot up the day I ditched my wireless wifi and ran Ethernet cables through my spaces. I'd realized I was constantly noticing wifi issues, and an apple mbp I use for email seems to drop wifi every half hour. But no longer, with them all wired up! Realizing there are USB3 to Ethernet gadgets really hits home how our modern technology is market-driven-dumb and anti-consumer: all modern l…

[deleted]

Re: A deep dive into why Wi-Fi kind of sucks

#128

Post by lend000 »

gcr wrote: post #122
JoshTriplett wrote: post #99

Earlier quoted context omitted.

> If the client is moving >10MPH relative to a fixed AP (i.e. you're driving past the AP in your car), Wi-Fi doesn't handle that well. Your movement creates Doppler shift in your RF signal, which Wi-Fi can't adjust for (vs. e.g. LTE which does). Perhaps current-generation WiFi has more of an issue with that, but I've helped build systems that used a much older generation of WiFi in an ad-hoc (no AP) mode between node…

Goodness gracious. What was the range of your network? Trying that on a consumer AP would instantly lose the signal, I'd imagine

Normal Wifi is extremely low power by regulation -- the medium itself is capable of much more, and I assume this project used different antennas than you find in your router.

Re: A deep dive into why Wi-Fi kind of sucks

#130

Post by joecool1029 »

JoshTriplett wrote: post #124
gcr wrote: post #122

Earlier quoted context omitted.

Goodness gracious. What was the range of your network? Trying that on a consumer AP would instantly lose the signal, I'd imagine

Miles, easily. But we had three major advantages: 1) We had a shoulder-mounted directional antenna pointed at the rocket. 2) The rocket had a cylindrical patch antenna wrapped around it. 3) Wifi channel 1 is in an amateur radio band, which means we can amplify it beyond the normal limits. We ran it at 1W.

Eh, I run 1W EIRP on consumer equipment and it's legal[1]. Assuming you are in US? Or not?

[1]: https://www.air802.com/fcc-rules-and-regulations.html

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