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

Posted by Soulskill on 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."

13 of 101 comments (clear)

  1. 802.11ac by Anonymous Coward · · Score: 5, Funny

    The anonymous coward version of wi-fi.

  2. Re: not exactly gigabit by marco.tedaldi · · Score: 5, Insightful

    Actually it isn't. By far! 1. On a gigabit wired network you get 1Gbit of transfer speed. There is a very small percentage lost to coding but you get well over 100MB/s (up to about 120MB/s) trough a Gbit connection. If you get slower speeds and don't know why, than start searching for the bottleneck! 2. The 400Mbit to 800MBit in a WLAN is the "wire speed". I've never seen transfer rates that are more than 70% of this. So, I expect to get maybe 56MB/s (which is already quite good) out of "GBit WLAN" while I get 120MB/s out of an Ethernet connection almost all the time. Still impressive how they even reach such speeds! That's engineering at it's best!

  3. Re:Stability? by _merlin · · Score: 3, Insightful

    2.4GHz is far too crowded. Switch to 5GHz and you should see an improvement, particularly if you're in the same room as the AP.

  4. Why not properly implement 802.11n first? by Anonymous Coward · · Score: 5, Interesting

    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.

    1. Re:Why not properly implement 802.11n first? by girlintraining · · Score: 5, Informative

      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.

      --
      #fuckbeta #iamslashdot #dicemustdie
    2. Re:Why not properly implement 802.11n first? by AmiMoJo · · Score: 3, Interesting

      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.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
    3. Re:Why not properly implement 802.11n first? by wagnerrp · · Score: 4, Informative

      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.

  5. Re:Now try it in urban neighborhood by heypete · · Score: 5, Interesting

    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.

  6. Re: not exactly gigabit by Sarten-X · · Score: 3, Interesting

    Reaching far back to my Cisco knowledge from 2003-ish, that's because 802.11 requires acknowledging every single packet, whereas wired Ethernet allows a larger window, so several packets get sent before an acknowledgement. I don't know if that's still the case (perhaps a modern network engineer will confirm, please), but that could be the reason for seeing just about double the transfer speed through a wire. On wireless, you're using almost twice as many packets to receive the same data.

    --
    You do not have a moral or legal right to do absolutely anything you want.
  7. Don't judge too much from early implementations by mysidia · · Score: 3, Interesting

    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.

    1. Re:Don't judge too much from early implementations by AmiMoJo · · Score: 3, Interesting

      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.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
  8. Re: not exactly gigabit by coofercat · · Score: 3, Funny

    To get those higher speeds outside the lab, you'll need some wifi spray

  9. Re:Stability? by wagnerrp · · Score: 3, Informative

    Switch to 5GHz and you should see an improvement

    Combined with further reduction in range. With an ASUS N56U, in the middle of nowhere with no interference, 2.4GHz becomes unreliable at around 700ft. 5GHz drops out somewhere around 450ft.