Tuesday, February 12, 2013

How 802.11ac is set to transform wireless


David Crookes looks at the new brand of superfast wi-fi and explains why it is set to be the essential upgrade

It can be quite difficult to inject a little panache into something like a discussion about a new wireless standard. Not that some companies haven’t given it a go. In the Generation of Wi-fi Technical White Paper, Cisco, “the worldwide leader in networking that transforms how people connect, communicate and collaborate”, wrote of 802.11ac, the emerging standard from the Institute of Electrical and Electronics Engineers (IEEE). It compared it to the movie The Godfather Part II. Why? “It takes something great and makes it even better,” it said.
Despite that rather limp line, it does achieve this very feat. Speedy wireless networking, as we know, is incredibly important, and the standard that we have is great. We use it for our smartphones and tablets whenever it’s available because it’s better than 3G and it doesn’t eat up your data allowance, which is partiularly important if you have a 4G device. However, 802.11ac surpasses what we have. It is superfast wi-fi on a scale that we haven’t had before.
This is great for a number of reasons. Wireless communication has become a very important aspect of our lives. Hooking up to the internet wirelessly is not just about extending a home network any more. It’s more about connecting our various gadgets, be they tablets, smartphones or laptops and it’s about doing this wherever we are. The PC doesn’t even really come into it. The majority of people will have a wired connection for these machines, but when we’re using gadgets for ever greater periods of time, we need to do it at ever increasing speeds and that is what’s on the table.
What it does is address one of the problems with the standard of wi-fi we have today, a standard that is referred to as 802.11n. This established standard was introduced in a different era, at a time when we used laptops solely for on-the-go computing and we didn’t think about the possibilities of hooking up our mobile phones to access the internet.
Tablets were a failed nightmare by Microsoft and a lucid dream by Apple. And when these gadgets did indeed come out and take our attention, 802.11n was more than enough for us. It worked well. But things change. And that’s because, for all of the greatness that 802.11n offered over its predecessors, the fact is that the 2.4 GHz band on which it operates is chock-a-block and it just doesn’t work as effectively as it once did for the needs of today.

Comparing standards

Just as 4G is better than 3G, so 802.11ac is faster and therefore more comfortable for heavier users than 802.11n. If we’re delving into figures, then the new standard can achieve a data transfer speed that exceeds 1Gbps. Compare that to 802.11n, which cannot really go much further than 450Mbps and you can see it’s like a Porsche compared to a Ford. Why? Because in the same way, one is just simply better than the other.
Okay, we’ll explain further. It’s because 802.11n is capable of transmitting data at a maximum bandwidth of 150Mbps per transmit device (or more technically, per spacial stream) whereas 802.11ac can hit speeds of 433Mbps per spatial stream. Currently 802.11n can only facilitate three spatial streams maximum, but 802.11ac can handle up to eight. Is that fast? Well, multiply 433 times eight and you get 3,464. Now add Mbps on the end and you get an idea of what we’re talking about. To be even simpler, this is equating to a top speed of 3.5Gbps.
But why does it all matter? Well, workplaces want to see business conducted on the go and in order to achieve this, great unplugged solutions must be found. The 802.11ac standard is a brilliant way of rapidly transferring encrypted data and it can do Compare that to 802.11n, which cannot really go much further than 450Mbps and you can see it’s like a Porsche compared to a Ford. Why? Because in the same way that one film can be better than another, it just is all of this without the need for a wired Ethernet connection and all of the restrictive binds that this brings.
Speed is certainly necessary. Even in our homes, we want far more than we used to. Everything is becoming connected. You can use your iPhone to control iTunes on another computer and have the results beamed to speakers in a different room entirely. You can watch a movie whenever you want on LoveFilm and Netflix. Satellite TV and cable companies offer catch-up services and smart televisions also allow for such luxury.
This has caused an explosion in the volume of internet wi-fi traffic and the demands on those signals. Tablet and smartphone devices are more popular, but wi-fi has also been displacing Ethernet in business. All of this is meaning more users adding to the load. There are also more devices per user, because not only are we carrying those phones but also laptops, tablets, handheld games consoles and more, and this has created a dense population of devices with varying transmit power levels, generating more traffic and creating new wi-fi design considerations.
Users are also running bandwidth-hungry apps such as Apple’s iCloud and Google Drive, and cloud computing is becoming so popular that this will only increase. Add to that high-definition video, web conferencing, social networking apps, videoconferencing and music streaming services, to name just a few, and you can clearly see the effect this is having on the existing technology. These services consume far more bandwidth than the low-speed data transfers of yesterday and there has to be something that can cope with it.
Consumers understand their changing needs and it’s why they are aware of the load that performing many tasks will place on their data plans. Instead of using their 500MB or 1GB of paid-for mobile phone data, they’re hopping onto wi-fi whenever they’re in range of a hotspot or home router, and the 3G/4G carriers don’t try to convince them to do otherwise. Indeed, they virtually push people to switch to wi-fi, snapping up companies that offer hotspots and ensuring that connection is free. One of the reasons for this, of course, is to take the burden off their own networks and avoid costly mobile phone traffic jams.
With 802.11ac in place, a lot of these issues are solved for reasons we will discuss later. This is a technology that is not only wonderful for consumers but great for business too. Imagine, 20 years ago, the notion of holding video conference calls. It might have sounded a little sci-fi, if not impractical or incredibly expensive. Today, with applications like Skype, Apple’s FaceTime, and other high-end, high-def web conferencing services, holding a telephone conference call is starting to feel arcane in comparison.
Again, however, the trouble with these kinds of high-end conveniences is that they quickly eat up bandwidth and when bandwidth gets eaten, things slow down greatly. The market realises this, which is why there are already routers and other products on the market catering for 802.11ac wi-fi. This is comes despite the fact that the specifics for what will officially qualify as 802.11ac are still being ironed out by the IEEE. Companies considering an upgrade may want to consider waiting for the IEEE’s final verdict (said to be due sometime in 2013) before launching an expansion of their wireless connectivity hardware, but the possibilities are hanging tantalisingly before us.

5G wi-fi

When you throw all of this into the mix, then you begin to see just why 802.11n is becoming old. The way it operates doesn’t allow for the multiple uses of devices that we are now demanding, and it doesn’t keep up with our fresh needs - needs that are constantly evolving and will do for some time to come.
So what will 802.11ac actually do for you? Quite often, 802.11ac is referred to as 5G wi-fi. The wireless connection is fast, the range is better and it’s more reliable too. Consumers will notice the difference in the same way that current customers of EE’s 4G mobile broadband can see (when it works) the faster speeds in comparison to 3G mobile broadband.
When you consider that you will be able to get a 1.3Gbps connection with 802.11ac if you’re using three antennas, then you begin to see the possibilities. In general, you’re looking at speeds that are three times faster, although tests have proved that the reality of getting 1.3Gbps is lower than you would expect and that, in fact, 800Mbps is more the case (standard 802.11ac offers speeds of up to 450Mbps, which in practice equates to around 225Mbps of usable throughput on devices).
There’s no arguing that this is still a fast speed and you should always take manufacturer claims with a pinch of salt anyway because they depend on so much. However, that is also true of 802.11n - and you will notice the difference between ac and n.
One of the most interesting aspects of 802.11ac, however, is the capability of the routers. As you will undoubtedly know, wi-fi is omnidirectional but what 802.11ac routers can do is direct the transmission and work out the location of the device it is beaming to. Not only can this reduce interference, but it can also offer a stronger signal. When you think about the main use of consumer wi-fi at the moment - that is, to stream videos or play games online - this kind of technology will be a godsend. Forget buffering on a wi-fi connection. We’re going to be seeing wireless broadband of a standard that wired connections provide.
“The way that I see it, 802.11ac can be a very interesting piece of technology that can be used in certain types of locations, and the majority of the members were discussing that for areas, locations and venues where there’s a high volume of customers and it is quite busy - like New York City, for example,” said Tiago Rodrigues, program director of the Wireless Broadband Alliance (WBA). “802.11ac coverage will prove to be very beneficial, not only because of high bandwidth but the capacity for these low-range, high-speed locations.”

How does it increase speed?

There are three different ways that 802.11ac achieves an increase in raw speed. It has greater channel bonding, which means we’re looking at a maximum of 80MHz (or in some cases 160MHz), which is massively up on the 40MHz of 802.11n. There’s denser modulation too, given that the new, faster standard can achieve 256 quadrature amplitude modulation (compared to 64QAM).
Finally, there’s more multiple input, multiple output (MIMO). MIMO capabilities were introduced in 802.11n. Getting technical, radios spread a user’s data into multiple spatial streams, and they’re transmitted through multiple antennas, propagating over the air along different paths. When all streams reach the client, the data are recombined.
Things will move even quicker when we see the second or third wave of 802.11ac products since, this will bring with it multi-user MIMO. It supercharges the MIMO capabilities by increasing the number of bits moved per megahertz of spectrum. While 802.11n’s ‘single-user’ MIMO will only benefit a single device at a time, 802.11ac MU-MIMO allows multiple streams to be assigned to different clients, increasing the total bandwidth that can be transmitted simultaneously. When it boils down to it, we see 802.11ac with eight spatial streams - double that of 802.11n.
So here you can see incredible increases in speed, testament to 802.11ac being faster and more scalable than its predecessor and having the capabilities of gigabit Ethernet wireless LAN for significant improvements in the number of clients supported by an access point (AP). This standard significantly increases bandwidth available over the wi-fi link and network capacity for densely populated environments, extending wireless capabilities to a variety of uses such as real-time video streaming and wireless back-up.
One of the reasons why 802.11ac is so effective is that the actual distance a 5GHz signal can travel is less than a 2.4GHz one, but the amount of data that can be transferred is much larger. This means you will naturally get better performance near the edge of a 5GHz signal than you would at the equivalent distance from a 2.4GHz one. 5GHz also tends not to travel through walls very well, which sounds like a problem, but it actually means diminished interference from nearby wireless networks.To get around potential problems with wall penetration, 802.11ac will include standards based support for a technology called Beamforming. This is a specialised method of radio-frequency transmission that can be integrated across a range of devices from APs to laptops and smartphones. It greatly improves link robustness and wireless performance and this enables, for instance, the seamless streaming of HD video in locations where devices could previously maintain only minimal connection to the network.
Sure the benefits of 802.11ac will be dependent, in many cases, on the device you use, but no one can argue that each is a leap forward. PCs and laptops will see gigabit speeds in a wireless format. Home entertainment devices will be capable of streaming HD content, and it’s worth mentioning 802.11ad here. This is also due to be ratified in 2013 and is designed to deliver extremely high bandwidth at short ranges, replacing technologies like HDMI. It will complement 802.11ac.

Problems, problems

There are problems, of course. There always are. Although we’re looking at incredibly fast wi-fi, most tablet devices are not designed to support it. Currently with 802.11n, tablets and smartphones can support around 65Mbps maximum (and in usability terms, less than half of that). However, 802.11ac can raise this and consumer manufacturers will soon be tapping into the technology.
“Apple is a big believer there, because they’re looking to use 802.11ac in the home. You’re going to start seeing 802.11ac-capable consumer products,” said Perry Correll, director of product marketing at wi-fi technology firm Xirrus. However, the iPad today is listed as supporting 802.11a/b/g/n wi-fi (802.11n 2.4GHz and 5GHz), so we’re not there yet.
Yet the protocol is already making its way into products. Asus unveiled what it claims is the first laptop to support 802.11ac, and Cisco has unveiled its Linksys EA6500 router, the company’s first 802.11ac router, which boasts wireless speeds of up to 1.3Gbps.
Even so, Nicolas Ott, MD of government, mobile and enterprise at Arqiva, does not think the new protocol will have such a major impact on the market and that consumers are really after seamlessness and security. “Right now the wi-fi experience for a customer is not always satisfactory, because it’s not always as seamless as it could be,” he said. “I think that any wi-fi protocol evolution that allows greater security and greater seamlessness is a good thing. However, it’s early days to say whether the 802.11ac protocol is going to be the right one or not. But I do think it’s a very important step forward.”
And of course it is. The 802.11ac standard using the 5GHz frequency band as opposed to the 2.4GHz of older tech brings many benefits. One of the most obvious is that this frequency is not as well used whereas 2.4GHz is. This means the latter will have lots of interference from other devices sharing that radio signal, whether it be a phone or a baby monitor, and it also means that this won’t be a problem on 5GHz. Even better, 802.11ac doesn’t entail you having to throw out your old stuff either. Even if your device can only talk to 802.11a, b, g and n signals, you will be absolutely fine with 802.11ac, because it’s backwards compatible.
One thing that 802.11ac will also do is improve battery life. And it will do so by up to six times, because the reason the batteries drain on devices is often because they’re working hard to catch a weak signal. You can sometimes see when a signal is low that the battery falls quicker. The design of 802.11ac allows for a much better signal strength because it has much better antennas. The battery life is also improved because the 802.11ac chip ends up using less power to transfer the same amount of data, and because the data transfers at a much higher speed, the radio in the phone only has to power on for a fraction of the time that it does with 802.11n. This is a very similar philosophy to the design of things like Intel’s Core processors, which are designed to sleep as much as possible, only waking to get tasks done as quickly as they can before dropping back to a low power state.

So let’s go

It is clear, then, that faster wi-fi is desirable. It’s been around for longer than your think: Quantenna released the first 802.11ac chipset for retail wi-fi routers and consumer electronics on 15th November 2011. Redpine Signals released the first low-power 802.11ac technology for smartphone application processors on 14th December 2011. And there have been announcements by Broadcom, Netgear, Buffalo Technology and Asus since.
This is the moment for 802.11ac. Things are moving fast, even if the IEEE is taking its time to give it the official seal of approval. Then again, these things do take a while. It took 802.11n seven years to move from Draft N status, but that was a disaster of a launch. There is determination not to make 802.11ac the same as that. There’s obviously a need for a far faster interface than what we’re using now, and the Wi-Fi Alliance is obviously doing everything it can to keep it moving with an expected official okay in 2013.
“The goal of 802.11ac is to provide data speeds much faster than 802.11n, with speeds of around 1Gbps,” said Frank Dickson, Vice President of Research at In-Stat. “By 2015, In-Stat projects that 100% of mobile hotspot shipments will be 802.11ac-enabled.” And that, it has to be said, will be music to our non-buffering ears. mm

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