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802.11ac 'Gigabit Wi-Fi' Starts To Show Potential, Limits 101

Posted by Soulskill
from the good-for-streaming-that-4k-video-nobody-makes dept.
alphadogg writes "Vendor tests and very early 802.11ac customers provide a reality check on 'gigabit Wi-Fi' but also confirm much of its promise. Vendors have been testing their 11ac products for months, yielding data that show how 11ac performs and what variables can affect performance. Some of the tests are under ideal laboratory-style conditions; others involve actual or simulated production networks. Among the results: consistent 400M to 800Mbps throughput for 11ac clients in best-case situations, higher throughput as range increases compared to 11n, more clients serviced by each access point, and a boost in performance for existing 11n clients."
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802.11ac 'Gigabit Wi-Fi' Starts To Show Potential, Limits

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  • 802.11ac (Score:5, Funny)

    by Anonymous Coward on Wednesday October 09, 2013 @05:12AM (#45079683)

    The anonymous coward version of wi-fi.

    • by Anonymous Coward
      Does it mean there's another layer of privacy for surfing the net??
  • Ideal situations (Score:2, Interesting)

    by Anonymous Coward

    "Among (sic) the results: consistent 400M (sic) to 800Mbps throughput for 11ac clients in best-case situations"

    Best case being: the only device on the network; inside a Faraday cage; on the dark side of the Moon; 3 centimetres away from the antenna.

    BTW: Google.... fuck your dictionary. It IS centimetres.

  • by Anonymous Coward

    With 20+ APs contending for their own slice of half or third of 5 ghz band. 802.11ac took the best feature of the 5 Ghz band, plenty of non overlapping channels, then turned into back into the quagmire of the 2.4 Ghz band by allowing 80 and 160 Mhz spectrum usage. Of course, the router manufacturers are going to enable 160 Mhz by default even when everyone in the neighborhood is on a 25 Mbps cable modem connection.

    • by heypete (60671) <pete@heypete.com> on Wednesday October 09, 2013 @06:42AM (#45079999) Homepage

      Fortunately 5GHz penetrates walls very poorly -- I have a 6cm thick concrete interior wall (I'm in Switzerland, after all, they love concrete) that separates too rooms. The 5GHz signal in the room without an AP is so bad that my network card (a PCI-Express card for a desktop with three external antennas) essentially refuses to connect. 2.4GHz works fine. This is in an area with exactly zero 5GHz Wi-Fi users within range, a noise floor of about -95dBm, and no other sources of interference.

      Channel bonding on 5GHz makes a lot of sense due to its extremely short range.

      • by AmiMoJo (196126) *

        My experience is that 5GHz penetrates several walls and the floor up to my bedroom only slight less well than 2.4GHz. YMMV etc. but I can also see a few other people slowly getting on to 5GHz as well (fortunately all on the default channel, stupid Virgin routers).

      • by damaki (997243)
        Radio signal shaping is used to overcome range limitations. As seen in the Canard PC Hardware french magazine, 5 Ghz in *pinpoin*t mode performs mostly better than raw 2.6, even with walls on the way. Though if you're totally out of 5GHz range, you'll use the 2.4GHz range.
      • by Anonymous Coward

        not my fault you live in a converted bomb shelter.

    • by neokushan (932374)

      The speed of your internet connection is irrelevant to the speed of your home network connection. There is such a thing as a LAN.

      • by wagnerrp (1305589)
        No. The AC is saying that even though most people are only using their wireless access point for access to their internet connection, and their internet access is only 25Mbps, they will still feel the need to use an entire 160MHz swath (or be too ignorant to configure it to not use that much spectrum).
      • Many people use only internet-bound traffic and would be fine with the WiFi speed being capped to the nearest matching speed.
    • by skids (119237)

      At 80MHz in the US there will be 5 non-overlapping channels. This may sound only 66% better than 3, but the topology of the packing problem makes it many, many times better than 3.

      I doubt 160MHz will be in use by people that have to actually manage frequencies, except near the offices of the PHB. I could only see that becoming a problem in dense apartment buildings with many individually "administered" OTS systems -- in residential neighborhoods the 5G will be pretty much stopped by walls, at least to the

  • by Anonymous Coward

    Linux driver support for most of the 802.11ac devices are still iffy which doesn't help.

  • by Anonymous Coward on Wednesday October 09, 2013 @06:41AM (#45079995)

    Hardware manufacturers I'm pointing my my finger at you. The most powerful features of 802.11n are largely unimplemented. Laptop/tablet/phone Support for 3 spatial streams is about as rare and rocking horse shit. Support for even 5 ghz is spotty at best and its hard to find out if whatever piece of hardware you want to consider buying even supports it. Heck even 2 spatial streams at 2 ghz is something your lucky to get unless you spend more than $699 on a laptop. The lowest common denominator for 802.11n and what the "wireless n" wifi support really means for half the devices on the market is a single spatial stream 802.11n at 2 ghz, which is 65 Mbps max. I can buy a mid range smartphone with 4g support and the wifi is still single spatial stream at 2 ghz. Hardware manufacturers have no incentive to put better implementations of 802.11n in their because most customers aren't savvy enough to tell the difference and demand better from device manufacturers. 802.11n is on old specification. There's no excuse why 2 spatial streams can't be the minimum. The silicon to do this is cheap and has been refined for many years.

    802.11ac will probably suffer the same fate. The minimum implementation to get the "wireless ac" sticker on the box is going to be what half to three quarters of the devices on the market will support, even 10 years from now.

    • by girlintraining (1395911) on Wednesday October 09, 2013 @07:17AM (#45080125)

      802.11ac will probably suffer the same fate. The minimum implementation to get the "wireless ac" sticker on the box is going to be what half to three quarters of the devices on the market will support, even 10 years from now.

      Every technology will suffer the same fate. Look, the problem isn't the technology, but noise pollution. The noise floor across the whole of the RF spectrum is rising by an average of 1db a year. That means that every three years, the 'room' gets twice as loud. Every new technology we roll out, every new device, is just another nail in that coffin. Like every other natural resource, humans just consume and consume, gorging themselves to excess until eventually there's nothing left.

      In the 1930s, a single AM broadcast tower could cover most of a region in the US in the evening. Certain frequencies carried a worldwide range, albeit due to the unpredictable nature of the ionosphere, you never knew just where in the world your low power signal would land. They did this using spark gap radios and shit with vaccum tubes in it. Today, the same feat can only be achieved with DSPs because the noise floor has come up so much most of the signal is trash after only a couple hundred miles.

      Cell phone companies are continually trying to keep up with ever denser concentrations of towers; And it's not because of data-thirsty hipster iphones... it's because a few hundred milliwatts barely gets you across the street anymore. It's a regulatory nightmare just finding a spot for a new tower and getting it approved... and companies fall farther behind every year on meeting coverage goals.

      We aren't just sucking up bandwidth on a per-frequency basis... every radio device contributes to global noise. Our RF spectrum is dying the death of a thousand papercuts. And all of this we can blame on two things; A complete lack of government coordination to share bandwidth and unify technologies using something like SDR across all wireless devices, brought on by competition by various companies to be the last man standing at the auctions and with technology able to "scream" just a little bit louder than the competition through a dizzying array of RF engineering cheats to increase effective broadcast power in a way the FCC can't penalize.

      Your tax dollars at work people.

      • by AmiMoJo (196126) * <(mojo) (at) (world3.net)> on Wednesday October 09, 2013 @08:29AM (#45080499) Homepage

        It's not quite that bad. The demand for low power devices that run a long time on batteries is actually reducing transmit power in many applications. It will take time for people to upgrade, and unfortunately certain devices like wifi routers will still be quite shouty as they advertise to non-existant 802.11b clients, but the trend is generally towards lower power and higher data rates (which mean less time with the transmitter turned on). Strategies for sharing available spectrum are also improving, from basic frequency hopping to things like directional signal shaping in 802.11ac.

        We are also starting to use spectrum more efficiently. For example switching to digital TV gave us more channels in less spectrum.

        Noise floor isn't necessarily all that important for modern devices either. Consider that GPS signals are actually below the thermal noise floor when received on the ground. DSPs are cheap.

      • > The noise floor across the whole of the RF spectrum is rising by an average of 1db a year.

        You are correct, but not for the reasons you discussed. If the millions of Transmitters were clean and well designed, they would not cause RF interference to other users (except where they were sharing common frequencies).

        The problem is that much of the electronics junk generate spurious harmonics. Plasma TV's, PC's, BPL, etc. all put out a horrendous range of broadband rubbish.

        This is compounded by many manufact

        • by wagnerrp (1305589)

          In an effort to reduce costs, they have universally changed to using switch-mode supplies.

          And here I thought we switched to the far more complex switched mode power supplies because linear ones have terrible efficiency and power factor.

          • by Kaenneth (82978)

            In an effort to reduce costs, they have universally changed to using switch-mode supplies.

            And here I thought we switched to the far more complex switched mode power supplies because linear ones have terrible efficiency and power factor.

            power usage is a cost.

      • by wagnerrp (1305589) on Wednesday October 09, 2013 @08:48AM (#45080653)

        In the 1930s, a single AM broadcast tower could cover most of a region in the US in the evening.

        That's because back in the 1930s, AM stations like WLW were operating at half a megawatt.

    • I'd be more inclined to blame standards bodies(though, depending on how they are structured, that could go right back to hardware manufacturers, albeit probably not the really low-margin box-slinger ones, more the silicon guys).

      When it comes to 'features' that customers can see, manufacturers are crazy responsive (sometimes to the point of just making them up, or lying about them; but so it goes...) You care about the sticker price? We shave every penny that doesn't remove a bullet point from the spec sh
    • by AmiMoJo (196126) *

      Two spacial streams means two antennas, which is why ultra compact phones don't do it. Larger devices are just being cheap - even if the silicone and the antennas are cheap there are patent licencing fees to pay too.

    • by tlhIngan (30335)

      Hardware manufacturers I'm pointing my my finger at you. The most powerful features of 802.11n are largely unimplemented. Laptop/tablet/phone Support for 3 spatial streams is about as rare and rocking horse shit. Support for even 5 ghz is spotty at best and its hard to find out if whatever piece of hardware you want to consider buying even supports it. Heck even 2 spatial streams at 2 ghz is something your lucky to get unless you spend more than $699 on a laptop. The lowest common denominator for 802.11n an

  • by mysidia (191772) on Wednesday October 09, 2013 @07:50AM (#45080249)

    Have they implemented the full 256QAM 5/6 rate yet with full 80+80MHZ bonding yet? (160 MHZ of channel bandwidth) using 8 transmit antennas and 8 receive antennas on both AP and wireless clients?

    I expect early APs and early chipsets will not yet fully implement all the advantageous features 802.1AC has to offer

    They'll have made compromises to save money.

    • by AmiMoJo (196126) * <(mojo) (at) (world3.net)> on Wednesday October 09, 2013 @10:10AM (#45081279) Homepage

      Realistically few devices will ever implement 16 antennas. Aside from the impracticality of fitting 16 antennas into a portable device the power consumption of all those LNAs and PAs is going to be considerable, as is the DSP power needed to decode and correlate it all.

      • by mysidia (191772)

        Realistically few devices will ever implement 16 antennas.

        It's 8 antennas. 8 on the AP, and 8 on the client.

        I do see APs implementing all 8 Antennas, so they can achieve high throughput to other APs, and achieve a larger number of clients.

        There are still plenty of benefits to a 4 antenna device connecting to an 8 antenna AP.

  • Seems I can't use speed as an argument for wired ethernet any more, as I'm not getting consistently over 60 MB/s with wired anyway, for file transfers. Technology is finally catching up, or alternatively, wired technology and OS-level file transfer efficiency have stagnated for long enough.

    Some possible caveats, why wired may still be good: 1) Does this include client-to-client transfers, or are those half the speed? 2) Is there any directionality such that multiple clients can use more than the correspond

    • by EmagGeek (574360)

      You're probably being limited by the R/W speed of your hard drive and O/S.

      I consistently get 100MB/s over my network between two machines that are capable of reading and writing at least that fast to their storage systems, and this is with cheap Realtek gigabit equipment.

    • 1.) Wired ethernet will give you more than that; as another responder said you're likely to be limited by the write speed of your storage devices. If you really want to test it, create a RAM disk on both machines, and transfer a file from one RAM disk to another - you'll see yourself saturate the line pretty quickly.

      2.) Wireless is inherently half-duplex, because you can't transmit and receive at the same time on the same frequency. Dual-band technology was supposed to help out with that, but it only works

  • I'm getting 7-9 MB/sec with my 802.11ac adapter, whether on the 2.4GHz band or the 5GHz band. So at least the theoretical speed of wireless G is finally real.
    It is much faster than the 2.5MB/sec I was getting on the so-called "a/b/g/n" adapter.

    For comparison, on actual gigabit ethernet, I get about 88-100MB/sec.

  • No number for worst case latency - Something needed so VoIP actually works.

    I suppose it is not very good or they would have mentioned it.

  • My summery of the technology would be.

    Got a bleeding edge MB last month, included ac wifi. Looked into buying an ac router. Not that many actually available, and the few that were cost 150-250$.

    I will stick with my g router which probably is worth about 10$.

    I will wait until they become a bit more affordable.

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