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Wireless Networking Communications

Wi-Fi Gets Multi-Gigabit, Multi-User Boost With Upgrades To 802.11ac (arstechnica.com) 74

Posted by msmash from the new-standards dept.
The Wi-Fi Alliance has announced its certification program for IEEE 802.11ac Wave 2, a technology that has been around on the market for more than a year. Wave 2 can deliver up to 6.8Gbps and lets an access point interact with more than one device at a time. Wave 2 features MIMO (or MU-MIMO) which improves the MIMO technology that lets Wi-FI transmit over more than one stream through the air. Wave 2 standard utilizes channels up to 160MHz wide (up from 80MHz channels available with Wave 1). It also creates more spatial streams and uses spectrum more efficiently, the industry group said on Wednesday. Ars Technica adds:On top of MU-MIMO, wider channels, and more streams, the Wi-Fi Alliance says Wave 2 features now being certified bring "support for a greater number of available channels in 5GHz," a change that "makes more efficient use of available spectrum and reduces interference and congestion by minimizing the number of networks operating on overlapping channels." You may have already noticed routers supporting some of these features, since the specification details have been available for a few years. In fact, routers with MU-MIMO started appearing in July 2014, and you can find routers that use 160MHz channels. The certification program takes a while to catch up with real-world implementations, but it ensures compatibility between devices and may spur faster adoption by vendors. End-user devices such as phones, tablets, and laptops must also be updated to take advantage of new features such as MU-MIMO.
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Wi-Fi Gets Multi-Gigabit, Multi-User Boost With Upgrades To 802.11ac More

Wi-Fi Gets Multi-Gigabit, Multi-User Boost With Upgrades To 802.11ac

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  • moo-mimo (Score:3)

    by The-Ixian ( 168184 ) on Wednesday June 29, 2016 @04:12PM (#52415731)

    I am now going to spend the rest of the day muttering moo-mimo under my breath....

  • Laws of physics? (Score:1)

    by Anonymous Coward

    Is there anybody knowledgeable that can explain how a a wi-fi channel with bandwidths in the tens of MHz can deliver 6.8 Gbps? Even with MIMO, I feel like that shouldn't be possible (unless maybe they are talking about the 60 GHz band). Did they change the modulation to some crazy scheme?

    • Re:Laws of physics? (Score:4, Informative)

      by Locke2005 ( 849178 ) on Wednesday June 29, 2016 @04:44PM (#52415963)
      The Nyquist limit only applies to amplitude encoding. Higher bitrates can be achieved by encoding information via attributes like phase as well, which should get you up to 16 times the bit rate. Not sure what the actual bandwidth of a WiFi channel is, there may be some overlap between adjacent channels.

      • Re: (Score:1)

        by Anonymous Coward

        Wrong. Adding phase only doubles the bandwidth.

        However, with high signal to noise ratio you can encode the amplitude (as well as phase) in high precision and use that to push more bits. Without noise, there would be no limit on how much data you can push through even the narrowest bands.

    • Re: (Score:1)

      by Anonymous Coward

      One of the articles explains it in layman's terms: 802.11ac Wave 1 does 433Mbps with 80MHz channels. That's more than 5 bits per Hz, so this is obviously a fair weather optimum when SNR is excellent. Anyway, Wave 2 doubles the channel bandwidth to 160MHz and supports 4 spatial streams, so if you assume that you can get high SNR on 160MHz channels and have four completely non-interfering spatial streams, you get 433Mbps*2*4=3.4Gbps. The specification is supposed to go up to 8 spatial streams, but they're not

    • With more than (two? three?) antennas there are some issues that keep you from synthesizing and extracting as many completely independent channels as there are antennas at the end with the fewer antennas, but it approaches that.

      Also: If you've got one central site (like a hotspot or cell tower or coherent array of them) with a lot of antennas and a number of remote devices with only one or a few, you can do things like "steerable null" - computing waveforms that send signals to several remote sites arrang

      • Lost the start of that, trying to recover . Quick summary.

        Imagine a flickering-LED optical transmitter on the side of one hill, and (instead of an optic fiber to a receiver) a telescope pointed at it with a photodiode at the corresponding point of the image. The Nyquist limit applies to the amount of data you can send that way (and forward-error-correction coding schemes exist that approach the maximum theoretical bitrate).

        Now imagine a billboard on the hill, with an array of flickering-LED optical transm

  • Gee thanks (Score:3)

    by Locke2005 ( 849178 ) on Wednesday June 29, 2016 @04:39PM (#52415933)
    Thanks for the reminder that I screwed myself by getting an integrated cable modem/802.11ac router. Meaning the router is controlled by Comcast. Meaning the firmware cannot be upgraded. Ever.

    • Is there anything that says you have to use their wireless router? Why not just have it serve as a router to a wireless router you buy yourself? That way you can have all of your own machines connect to your own private network on a router that you can control and a firewall you can configure. If Comcast wants to have a public wireless access point then it will be completely separate from your stuff (or at least safer). All that it would look like to them would be a single PC connected to their integrated

    • That shouldn't be a problem. Simply turn off the wi-fi radios on the router, but leave DHCP and other services on (usually, there is no way to turn off those anyways), then setup your new wi-fi router as strictly an access point rather than a router. There is like a million tutorials out there. E.g.

      http://www.speedguide.net/arti... [speedguide.net]

  • Software-only change or new hardware? (Score:4, Insightful)

    by swb ( 14022 ) on Wednesday June 29, 2016 @04:57PM (#52416033)

    Is this the kind of thing where most wave 1 devices can be software upgraded to wave 2 devices? Or is it yet another case of tossing out the silicon?

    I would guess the glowing vendor support for this on one of TFS links would lead me to believe this will require new hardware.

    From an AP support perspective, it really is annoying to have so many active fucking client standards to support. All the gee-whiz latest features are marginal benefits when half the spectrum is used by brain damaged clients vomiting all over the spectrum using old standards.

    • The announcement talked about certain chipsets being certified so it looks like it's new hardware. But some have been out for a little but so if you bought a top end wireless router recently you might be in luck.

  • You mean to tell me that all the Ethernet cable I just finished running through my house is pointless.

    Dammit!

    • Re: (Score:1)

      by Anonymous Coward

      Not at all, put a few clients onto the network and watch it come to a crawl over wifi. At least with Ethernet you can aggregate ports for more concurrent bandwidth.

    • your ethernet cable/fiber won't get congested with all your neighbor's traffic, so it's throughput and latency will be consistent

      • Re: (Score:3)

        by klui ( 457783 )

        Ethernet is not half duplex has less overhead. And if OP installed Cat6 those cables will most likely support 10 Gbps for short distances common in the home or 5 Gbps N-baseT.

    • You gotta be kidding. I have a 1200Mbps (AC1200, three streams) 802.11ac wireless network, and the fastest file transfer I have seen between two computers in the same living room was about 20MB/second using Windows file transfer (the PCs has 2-stream AC900 802.11ac cards). As soon as I leave the room, the file transfer speed gets down to about 100Mbps ethernet. Your gigabit Ethernet will still be faster than any wi-fi implementations for years to come.

  • So does this mean it will finally stream video as well as 100mb hard-wired Ethernet?

    • I would say yes. I have a 802.11ac wireless network using a 3-stream router (AC1200) and a bunch of AC900 clients (2-stream 802.11ac) using 80MHz wide channel, and I am seeing wireless transfer file speeds of about 20MB/second if both computers are in the same living room with the access point. So that's already faster than 100Mbps Ethernet.

      If I go to the second floor, then depending on time of the day, the windows file transfers can drop down to 5-10MB/second (I suppose it's thanks to interference from nei

  • So when are we going to get this: https://threatpost.com/ibm-unv... [threatpost.com]

    I mean it's not like I've been waiting or asking for it for years: https://it.slashdot.org/commen... [slashdot.org]
    https://mobile.slashdot.org/co... [slashdot.org]

    Shared key WPA2 means that anyone who knows the shared key can decrypt other people's traffic if they managed to sniff the 4-way handshake messages:
    https://mrncciew.com/2014/08/1... [mrncciew.com]
    http://www.howtogeek.com/20433... [howtogeek.com]

    It's true using WiFi means you still have to trust the entity providing it, but that's the same wi

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