back to article WTF is... 802.11ac?

Wireless networks are never fast enough, but for the moment at least they are generally quicker at shifting packets of data than the broadband connections they're typically linked to. That's changing. Broadband speeds are rising, especially those fed through fibre-optic lines. Fortunately, Wi-Fi is keeping up. A number of chip …


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  1. Jonathan White
    Thumb Down


    I think it's somewhat unlikely punters are going to jump at 802.11ac routers unless/until there's a sufficient groundswell of products which would connect to them. And we're not just talking about laptops with dongles any more - phones, tablets, media streamers, consoles, remote controls even. All stuff that uses B/G and or N, which isn't easily upgradeable like your average PC.

    It's a bit chicken and the egg though - nobody will buy the routers without the clients and nobody will make clients until there's an established demand through people having routers.

    As a bare minimum, the routers have to be backwards compatible and even then you're talking about several years of natural wastage of equipment before the new .ac compatible kit achieves critical mass. By which point of course home broadband will have moved on again...

    Basically put, there needs to be something more than the 'ooh, shiny' about it for it to get adopted in anything less than geological time. I don't really hear a lot of people complaining about how their home wifi isn't speedy enough, and most people right now are too skint to think about upgrading their entire wifi setup for what may not immediately be an obvious benefit.

    It strikes me a bit like 3D telly. Yes, at a technical level there is a USP there. But I think they're going to have a hard time convincing people their current kit isn't 'good enough'.

  2. defiler

    Gotta love copper

    I had a bit of a diatribe written about wireless networking and how every time I think the new standard could finally rid me of copper at home, yet by the time it's available my needs have moved beyond it. I deleted it because it was a bit rambling, and I have a better point to raise.

    Why do so few new houses these days come with data cabling? Seriously, it's a wired world. 802.11 is all very convenient, but for throughput and reliability you can't beat a bit of copper wire. TVs are coming with ethernet ports, surround-sound receivers are coming with them, as are telephones, DVD/BD players, games consoles, network video players (well, duh...), printers, music players, you name it. Sure, some of them come wireless too, but for streaming data (for video in particular, but also games or software updates) a wired connection is just better.

    It wouldn't add much to the cost of a new house, and it would be a value-added differentiator in the market. As would under-floor heating and solar water-heating panels.

    Anyway, 802.11ac - all jolly clever and a good fallback for when there's no cable. But why the hell is there never any cable? And my sympathies to the folks in rented accommodation who have *no* chance of running cables...

    1. Charles 9

      Maybe for new homes that are bought...

      ...but many old homes are still on the market, and retrofitting a home for Ethernet (especially a multi-story house) can be problematic. Then there is the issue of flats and other properties that are rented rather than sold. IIRC most rental agreements mandate no new holes in the walls bigger than a nail hole, and wired properties don't have as much influence as rent and location.

    2. Anonymous Coward
      Anonymous Coward

      You have issues with your plan.

      I did my old house to Cat6 standard, all well and good.

      But I knew where my pc was going to sit.

      I knew where my broadband was going to sit.

      I didn't have a laptop at the time

      So here is where your plan falls apart:


      Where do you put your cables, nr the power? (So you'll need shielding then). Mulitple places in each room?


      You'll still need wireless for your phones, laptops, tablet pc's, the next big thing.


      And in 10 years when you have all this obsolete cabling (Remeber thin-net, Cat3 etc?)


      And remember 99.9999% of people will never actually use it. It may shcok you, but most people really don't give a toss about the harddware side, they want ease of use.

      Did I mention Cost?

      1. the-it-slayer


        That is backwards logic to wiring a house up with ethernet. Really, it should be part of all new housing plans to at least have one point in each room.

        Cost: £80 for 100m Cat6 Shielded / £20 Faceplates / Free drill-walls / £30 8-Port Switch (one-off investment of £130)

        Then you can add a wi-fi access point (£50) in a cental location (living room?) and spend less upgrading kit. More static devices (TVs, Radios etc) are coming along with ethernet ports. 1Gbps around the home will be enough for the next 10 - 15 years or so. My bug bear is leaving the routing/switching/wi-fi to one device. Why not distribute CAT6 to modularise all the kit? And you can run any cable from the port under carpets or through some nice thin trunking to tidy it up. Unlike the cabling is going to run past 100m in total from switch to device.

        Anyway, I've lost count how many people have asked me to sort out their "wireless" connection at home. It's still too complicated in terms of the comms/negoiating security protocols and always fails somehow in a multi-functioned router (mostly the bottom of the barrel kit from most ISPs).

        How about powerline tech? Not perfect, but I'm sure that tech will be refined for 1Gbps connections in future.

      2. defiler

        @AC 09:52 - issues with my plan

        Well, it-slayer covered most of the cost aspect. As a retro-fit it's a pain in the ass, but it's easy whilst building.

        Where to put sockets? When the houses are designed, they have people design the room layouts and plan on where to put power sockets and aerial sockets. It'd be figured out then.

        Not saying you wouldn't need wireless, but that you would want wired for many appliances.

        I remember thin-ethernet, Cat3 etc. But any cable I've been involved with installing in the past 10 years has been Cat5e / Cat6. They're all good for 10Mb/sec to 1000Mb/sec and beyond. That's the cable spec that the IEEE work to.

        Many people won't care, but you're suggesting that only 25 homes in the UK would use it? Exaggeration, I suspect. As more devices become connected, it'll become far more convenient and reliable to just plug them in rather than rely on wireless. Especially for devices that may be so cheap that they can't warrant a wireless card, or those that need a lot of bandwidth or low latency.

        Cost? Peanuts in a new-build.

        As for Charles, I did specifically mention rented accommodation. That's a bugger. And I know that most housing stock in the UK is not new-builds. But unless the cabling goes into the new-builds it won't be there when the houses are re-sold. As I said, wireless is a good fallback, when you can't sling a cable in or when it'd be inconvenient. But it seems to be being adopted as the default position. I've yet to need/want more than 802.11g at home because the high-speed stuff is wired.

        I'm not picking on the new spec (other than that it'll take bloody ages to get released). It's very clever, and progress is generally a good thing. I'm taking a shot at the housebuilders who have the opportunity to get us all hooked up from the start, but won't take it. That said, looking at the new-builds near me they can't even build the bloody roofs properly, so maybe that would be a better priority...

      3. BlackMoonWolf

        You're exaggerating...

        Yes. You're exaggerating the issue... GREATLY.

        Don't do that. Please. It's not NEARLY as expensive as you're trying to make it sound.

        Especially if you're getting your materials on ebay.

        If you do it right and do it YOURSELF...the cost is actually fairly minimal and the cable job will last a pretty long time.

    3. BlackMoonWolf

      Wireless will NEVER outdo copper for throughput and consistency.

      It's true. All of it. Copper has all of the advantages over wireless - hands down.

      If I were in a position to buy a house these days... I would absolutely refuse to accept a house that does not either:

      A.) Already have the groundwork inlaid


      B.) Has potential for it without costing me an arm and a leg.

      As a cable guy with experience in the telco industry as well as commo in the US Army, I know the benefits of copper very well. It'd be silly and even feels obligatory to me.

      As for the people who rent? They COULD run cable if they wanted to. But they can't just go drilling holes and mounting plates in walls. They could at least run the cable and keep it squared away with various devices or at least pinch it between the floor boards and the carpet in the halls.

      There is ALWAYS a way to run cable. Through ANY situation. It just takes time, know-how (there's always the internet) and...sometimes...LOTS of patience. :P

      I rent in a duplex. I have the fortune of having additions built in here and there. I can run everything from my server cabinet in my office (far corner of the place) and into the closet. There I have drilled a hole that leads into the hall over the drop ceiling that the landlord so thoughtfully installed. That leads to about anywhere else in the place including my living room, bedroom and kitchen.

      Yep... I ran solid CAT6 all the way through. It's all gigabit and it's ridiculously fast.

      The landlord doesn't care what I do with the place as long as I know WTH I'm doing and I patch it up when I leave. He actually appreciates that I took the time to replace most of the electrical outlets and even a few ceiling fans. I do all of the electrical myself . It saves him the time and he takes it off of my rent. :)

      I mounted a WiFi AP central to the place so I don't have coverage issue. But...I only ever use it for my laptop, Android phone and Nintendo Wii. That's really not a whole lot of traffic, though...

      But for absolute, problem-free connectivity, copper is always the way to go. None of these IEEE standards that they keep pumping out every few years impresses me in the least bit. Honestly... For any device that's going to be roaming - why would you even NEED that kind of speed in the first place?

      The industry is a funny thing like that... It's great that they're willing to innovate and move forward... But sometimes I think that they could focus on simply making what we already have work more efficiently rather than creating new and unnecessary standards that no one is really going to give much care for.

      Whatever works, I guess. But I remain a "Cable Dog" for as long as I need data transferred. :)

  3. Neil 7


    There goes the 5GHz neighbourhood!!

    It would be nice if the vendors could agree on some standard 11ac marketing terms, so that you would know whether you're buying a 1-antenna, 4-antenna or 8-antenna device, or whatever other specification variances there might be from implementation to implementation.

    1. BristolBachelor Gold badge

      "There goes the 5GHz neighbourhood!!"

      Yes, and it seems that they probably still won't mandate anything in the spec that makes stuff play together well.

      We still have problems with channel allocation, and with networks that are either completely open, or have some form of security but you can't join them without typing in 160 character random pass frases (much fun on an iphone screen!). Some of the "free" routers here cannot be configured by the homeowner, so are stuck with which channels they are on, and some kit still refuses to use channel 11...

      What's wrong with networks being able to co-operate? How about a network has to support a "contact the operator" function that allows you to send a message to the network owner without having to try to work out who they are? How about a network that lets devices connect openly, but then the two sides agree public/private keys in each direction to secure the link?

      Instead, they try to blinly up the speeds, and can post some marginally ok (compared to GbE) datarates, but only inside an EMC chamber, 1m from the AP, no other devices, and certainly none using the older standards.

  4. Flocke Kroes Silver badge

    Multiple antennas

    At short ranges there are N signals. Each of the N signals are sent to each of the N antennas with a different delay. Each signal leaves the sender in a slightly different direction. The result is that the receiver gets a different signal from each antenna. N times the bandwidth.

    At long range there is only one signal which is sent to each of the N antennas with a different delay. That signal is concentrated in the direction of the receiver. The receiver gets copy of that signal with a different delay from each of its antennas. It delays each copy by a different amount and combines them into a strong signal. The result is a directional antenna that improves the signal to noise ratio.

  5. Dotter

    5G WiFi

    Is it really necessary to start encroaching on the *G format? There's enough out there with 3G, 4G, LTE, WiMax and combinations thereof.

    Good old Buffalo.

    1. Anonymous Coward

      The Gs are different

      The G in 5G stands for gigahertz because that's the frequency it uses. The G in 3G and 4G stands for generation and refers to how many different network standards there have been.


      1. Anonymous Coward
        Anonymous Coward

        No not OK. 11n and 11a are 5G as in GHz standards in case you did not know. 11n is also 2.4 GHz. 11a is only 5GHz like 11ac.

        5G stands for Generation. See the Broadcom slides, and how continuity works.

  6. MD Rackham


    "Faster frequency" and "lower wavelength?" Seriously?

    How about "higher frequency" and "shorter wavelength."

  7. Anonymous Coward

    BTW, it is the channel bandwidth that really decides which frequencies to use. To achieve these speeds an 80MHz and even 160 MHz channel bandwidth is used.

    This is ridiculous in the 2.4 GHz. Each channel is 20MHz, so 160 MHz transmissions would use 8 spaced channels. There are only 13 overlapping channels in most countries.

    So 2.4 GHz is basically congested, and 5GHz is where the next steps in standard will take place.

    It also means 11ac won't come cheap for a while! Even 11n 5G commands a fair premium today. Most ISPs won't spend the cash, BT is the only one I can think of, but they cost a lot more as well.

    But come fibre optics and this may well be necessary.

  8. This post has been deleted by its author

  9. Andus McCoatover


    Well, one should ask Stephen Fry.

    "The 'ac' bit refers to the fact it uses Alternative Currants. This enables the Elektrons, Darkons and Polaroid photons to more easily invade the mind than plain old AC, thus removing the need for any kind of receiver or retriever - including I may add, a Labrador.

    By simply eating dried grapes, which conveniently are sent in packets, perfect reception is guaranteed."

  10. This post has been deleted by its author

  11. A Known Coward

    5Ghz and brick walls

    The article misses the critical problem with 5Ghz and why 802.11a never took off in the home - it's stopped almost dead by solid walls. This isn't much of a problem in a typical office environment which is either open plan or uses thin partition walls, but in homes more than 40 years old in the UK solid brick interior walls are common.

    At just 20 ft and with one brick wall between me and the access point 2.4Ghz out-performs 5Ghz despite the 2.4Ghz spectrum being immensely crowded (12+ networks operating).

    Then there's the issue of older gear which only supports 802.11g (2.4Ghz). Many wireless n routers/access points offer both 2.4Ghz and 5Ghz but not at the same time. If you live in a modern property with plaster board internal walls and are lucky enough to be able to use 5Ghz you still have to replace/upgrade older laptops etc.

    1. TeeCee Gold badge
      Thumb Up

      Never mind homes more than 40 years old in the UK, try the continent now. Reinforced concrete is de rigeur for modern housing construction over here. A nice thick bit of concrete with steel mesh in it is all but impenetrable to 5Ghz stuff. Like you I am stuck in heavily congested 2.4Ghz.

      Fortunately my router does 2.4 and 5 simultaneously, so things close enough to it can still get the benefit.

      1. Charles 9

        Question about the mesh...

        ...if that mesh somehow ended up stuck in the earth, would that possibly turn the mesh into a shunt, meaning radio signals have an even harder time getting through (seeing as how the mesh might earth the signals)?

        1. BlackMoonWolf

          Not likely

          Depends on what the mesh is made of.

          Mesh would just about have to be made of some kind of metal composite material in order to cause any real interference. Even then, if the mesh itself is made of woven steel, it's a shielding and would not interfere with the signal in the cable.

          Otherwise your signal would be mostly unaffected. Even if the "shunt" as you call it were to encase the cable, the signal would experience negligible interference at best.

          As long as you're using the right type of cable for the right purpose; it's actually really hard to create interference for copper unless your run is (much) longer than the type of cable is rated for. Cable type and length are the factors you should be most concerned with.

          Otherwise... If you're going to run cable underground, you'd want to go with CAT6 OSP STP CMX Shielded UV Direct Burial Cable. (Been eyeing this for a while myself... If I'm going to spend money on a reel, I might as well buy the stuff I can do ANYTHING with. Right?)

 <---link to an ebay auction for example purposes.

          That would prevent any issues you're thinking of.

  12. Steve Kennedy

    5GHz in UK

    In the UK there are 3 sub bands in 5GHz known as Bands A, B and C.

    A and B are license exempt (20omW EIRP for Band A, indoor use only, 1W EIRP Band B indoor and outdoor, Band C is lightly licensed and can be used for say fixed links between buildings).

    I believe the Ofcom regulations only allow for 20MHz channels in 5GHz bands, so currently it would be illegal to use 802.11ac, there's also not enough channels to support the higher speeds of 802.11ac.

    1. Anonymous Coward
      Anonymous Coward

      Not true

      You should think of it more as channel bonding. 5Ghz routers in the UK already use 40 MHz. Ofcom regulates the partition of the channel, you cannot use 25 MHz say, but mulitples of 20MHz are permitted in the 5GHz band and the roll off and shaping requirements per channel are very lax.

      If you have seen a 2.4G Wifi transmission on a spectrum analyser you will know what I mean :)

  13. Andy 70

    yeah yeah, wifi maybe usefull shock story.

    <long rambling personal expirience story cut>

    copper. run some wire for your backbone devices. even if it's powerline.

  14. Kirbini

    Less interference? Don't think so.

    "The standard has other tricks up its sleeve to boost throughput. It widens the 5GHz band's sub-channels from 802.11n's 40MHz to 80MHz and 160MHz, reducing the data-slowing impact of interference from other networks on other channels."

    Ok, let me get this straight. You widen the channels thereby creating even more channel overlap and that's supposed to decrease interference? Um, that's not really how it works.

  15. Alan Brown Silver badge

    powerline networking + 5Ghz

    = happy campers who don't spillover into the next room.

    If you're going to wire for networking, then run ducts. That way it's not a major undertaking to redo things.

    New builds mostly have foil backed plasterboard and that's an even nastier barrier to 5GHz than mesh reinforced concrete or iron oxide brick stacks. Most of the time the only way 5Ghz can get out is via the doorway.

    Every technology sucks. You just have to choose which suckage you can put up with.

  16. James Pickett


    I'd much rather have more range, then at least I'd get 54Mb! We have a lot of old houses round here, with brick and sometimes stone walls. Most Wi-fi is useless more than one room away, and even then is half the speed.

  17. Disgruntled of TW

    54Mbit/s = 1.5MByte/s (ish)

    So .... that's on an 802.11g network with a single busy client pulling SMB data from a server. Now, why aren't there concurrent client benchmarks reminding everyone that Wifi is fundamentally a CSMA/CA network. I.e. you have rather limited *concurrent* bandwidth. Even Wimax (slightly off topic) struggles with concurrency when many clients want to transmit at the same time - it pretends to be token ring to "trick" you, ultimately nailing available bandwidth to the floor as distance increases.

    This is one reason why we moved quickly to switching ethernet frames and star network designs instead of using hubs with the old yellow/red coax cable [SMILE]. Showing my age.

    Fundamentally, Wifi will *never* replace cable for anything other than light traffic, low user count applications e.g. at home or browsing. The radio spectrum/Niquist-Shannon theorem just doesn't support it. Chucking more channels/frequencies at it is sticking tape and string. Is that a MIMO access point I see before me, or a hedghog?

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