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Comment by revelation | Hacker News Reader

That's what 802.11ad is for, which can transmit over 60GHz (which limits it to basically one room, as it's quite readily attenuated by even air).

That said, at 60GHz of course bandwidth is awesome. TP-Link has a router:

http://www.theverge.com/2016/1/5/10721550/tp-link-talon-ad72...

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60GHz (which limits it to basically one room, as it's quite readily attenuated by even air).

Living in a condo tower where I can see -- and have my network interfered with by -- 70 other wifi networks, I consider this to be a feature rather than a disadvantage.

This kind of problem should be solved by transmission power control. Power is capped by standard to avoid reaching nash equilibrium. Also, Wi-Fi has various OBSS coexistence mechanisms to detect overlapping networks and cooperate with them to reduce power simultaneously for mutual advantage.

Have any security researchers investigated the possibility of abusing these coexistence mechanisms for malicious purposes? Could be worth checking out, I think.

I would expect that the only "malicious" purpose achievable is a DoS through service degradation. Can you think of something else?

Here's an interesting attack: Suppose there are three non-overlapping channels and 70 APs, most/all of which try to pick the least congested channel. Can you persuade 67 of the 70 APs that a particular channel is very congested and best avoided, while leaving that channel uncongested and usable for the few remaining APs? Can you do so without client cooperation from the three favoured APs?

This has been used by establishments that offer paid wifi services to block portable wifi hotspots, http://qz.com/482304/the-fcc-is-cracking-down-on-companies-t...

On many networks you can just forge 802.11 disassociation frames and drop people off the wifi altogether. (In fact, enterprise wifi vendors will sell this to you as a feature - the premise being that you'll use it to keep corporate-owned laptops off unapproved access points - but there's potential for FCC trouble even there.)

> That said, at 60GHz of course bandwidth is awesome.

The carrier frequency doesn't tell you much about the information capacity of the channel. The width of the frequency band used is key, which is why bandwidth is often (incorrectly) used as a synonym for data rate.

60GHz is the central frequency, and tells you nothing of the width of the frequency band. The ratio of the width of the frequency band to your data rate (amongst other factors, including antenna gain and processing gain) tells you your signal-to-noise ratio.

That's right of course, though there is certainly a strong correlation between carrier frequency and width of frequency band.

A whitepaper quotes the nominal channel bandwidth at 2.16GHz with four channels available [1].

1: http://cdn.rohde-schwarz.com/pws/dl_downloads/dl_application...

At that router - LOL. "7gbps wireless throughput". Great. "1gbps ethernet port"... err?

Assuming your device can support 802.11ad, too, of course.

Thats actually OK. Advertised wifi speeds usually manage 20% of that in real life so sounds about right.

Bullshit, your device is at fault and not the protocol. I bought a 802.11ac dongle with external 10dbi gain antennas and have been enjoying extreme speeds and connection strenght throughout the house, not to mention to the routers of 30 of my neighbours.. And that's only 5GHz. For comparison, at my desk three walls away I used to get about 40-50nW signal level off my built-in adapter and antenna in my Lenovo laptop. With the new setup - 60mW... The router sends at 100mW. We're talking pushing 90MB/s+ constantly no matter where in the house with absolutely no connection drops.

Can you tell us what model router and dongles you are using?

>Bullshit

Well thats not nice.

Speeds will vary greatly depending on whether proprietary booster tech is in use, which in turn will depend on the combination of hardware both on the sending and receiving side.

oh and while we're on the topic of bullshit (seeing how you were so blunt to go there) - signal levels are measured in decibels, not nW. nW is a measure of power fed to the antenna. Your comment is about as plausible as someone claiming their car is 40 gallons fast.

Transmission power in milliwatts (mW) is directly convertible to decibel-milliwatt (dBm).

This is arguing if your car is doing 1 to 60 miles or 1 to 100km in 4.3 seconds.

For the most part you measure transmition power in mW and received signal strength in dBm.

RSSI -- Receive Signal Strength Indicator -- is reported in dBm, which is a log-scale unit of watts. +20dBm is approx. the max transmit power for WiFi, and equates to 100mW. 1nw is eqivalent to -60dBm which is a pretty decent signal strength for WiFi, but won't provide max data rate. By comparison, the minimum power to operate at 1Mbps is about -98dBm.

Then again, receiving at 60mw (+17dBm) would overdrive any of the WiFi devices I ever tested and path loss of just 3dB (assuming +20dBm transmit power) is not achievable over the air, even with a near-field antenna. Keep in mind many devices actively tamper with the RSSI value reported up through NDIS, so while it's possible for a card to report it is receiving at +17dBm, unless you have hard-wired the hirose connectors between AP and STA it's not actually the case. Nor would a receiver work very well with so little path loss in any case, it would be completely over-driven.

Why are people down voting this?

If you buy a cheap AC router and expect a tiny built antenna to max out the bandwidth you will be disappointed.

I get over 1Gbit real tested bandwidth between my main desktop using a decent dongle with external antennas and a high end router.

Even iscsi works well with this setup the NAS is connected on 10gig Ethernet to my router. With MU/MIMO you can also get full duplex if you set it up. The dongle is built into the motherboard and it's connected via pcie. Before that I had an asus pcie x4 wireless card which worked just as well(maybe even better).

Probably because his comment was rude while also not being particularly constructive. If he'd said it more nicely, it might have been better received.

> ... while also not being particularly constructive.

Eh?

The guy mentioned that he switched from using the built-in antenna on his laptop to a honking external antenna and now gets 720mbit/s performance anywhere in his house. That's quite constructive. I guess the only way it could get more constructive is if he mentioned the model of hardware involved... but I expect that you'd get similar results with any AP capable of 720mbit/s transfer to a single client. If your AP is fast enough, then it's all about SNR.

>but I expect that you'd get similar results with any AP capable of 720mbit/s transfer to a single client.

One should expect that, but almost no one uses wireless that way. If you have just a single client the most efficient method is to run a cat5 cable and get 1000mbit/s at a much lower cost than putting in expensive AC equipment, barring an expensive engineering issue of making a cable reach that place. The problem with wireless is everybody has to play nice and be able to see each other or it quickly falls to the 20% actual usable bandwidth rather quickly. Do you have neighbors with a wide bandwidth AC router and healthy streaming video habit? Don't expect to get max data transfer rates. Do you have lots of portable devices, especially cell phones that like to go into low power mode, or get set in places where they can reach the router but become hidden nodes to other clients in the network?

On the flipside, is it ok that we are still shipping 1gb lan ports like 20 years after they became commonplace? I'd hope that at least enthusiast class hardware would start using 10gb at some point.

I have a Intel WiGig laptop + dock that uses wireless ad under the hood.

The bandwidth can be used for much more than just network transfers. I've personally had 2 1080P displays playing video + USB3 external hard drive transferring at max speed + Gigabit Ethernet transfers using the dock without anything skipping a beat.

Wireless ad docking + wireless charging on a laptop will be absolutely amazing.

That's 7Gbps shared between all connected wireless devices connected to 8-24 1Gbps switched wired ports.

I must admit this is the first I hear of ad standard so I'm a little concerned that by the time I've got the tech in hand my internet options are already at the next level. (I should add that its all relative - 100mbps is just fine for my needs to be honest & will be for a long time)

Its a touch ironic. In my previous country it was the opposite way round - nobody could imagine a situation where the internet link could saturate the wifi. No I've got the opposite problem...

60GHz also limits you to direct line of sight. 60GHz propagates similar to a spotlight.

How "direct" are we talking? I'm sitting 4 meters away from my router - but with a thin prefab wall in between.

At 60GHz it's almost more appropriate to compare to a laser pointer. The wall will probably be a problem.

A quick google suggests I might still be fine. Its advertised as "in the same room" so it will probably punch through a thin non-stone wall.

> non-stone wall

Drywall is made of stone.

Drywall impedes RF signals much less than stone.

A sheet of paper will block the signal, so it probably won't go through that wall.

The laser analogy is definitely accurate given today's technology. I just don't think they'll be able to productize something that has that high of an antenna gain. I'm really hoping and thinking that we'll see some smart antenna advances.

It will depend on the material, but I don't think 802.11ad can even penetrate through sheetrock. Honestly it may even be so bad that a sneeze could knock your connection out for a few seconds.

You'll get about 10 metres in an office with cubicles with chest high partitions. Page 6 of the paper "A High Speed Wireless LAN" by Skellern, Lee and others in the Jan/Feb 1997 edition of IEEE Micro has a diagram showing coverage for OFDM in a typical office at a centre frequency of 40GHz. 60GHz will be worse than this, as oxygen in the air absorbs 60GHz quite stongly [2]. I'm not sure how the power transmitted by 802.11ad compares to the above measurements, but the measuremensts in the paper were taken with 60GHz WiFi in mind, so they should be representative.

[1] http://www.jwdalton.com/papers/ieee_micro_1997_wlan.pdf

[2] https://transition.fcc.gov/Bureaus/Engineering_Technology/Do...

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Edit for clarity. And I should also mention I'm an author on that paper.

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