Beyond 802.11n: Gigabit Wi-Fi

You think 802.11n's 300 Mbps is fast? Just wait until you see Wi-Fi's forthcoming 1 Gigabit per second devices.
Written by Steven Vaughan-Nichols, Senior Contributing Editor

If you set up 802.11n Wi-Fi just right, you can get remarkable speeds from it. But, as fast as 802.11n can go, up to 300Mbps, Gigabit Wi-Fi promises to more than triple that speed. Vroom!

That's the good news. The bad news is that it's going to be a while before we see Gigabit Wi-Fi. It's not that the technology isn't available to pull this kind of speed off. If anything the problem is that there are too many technologies that Wi-Fi chip vendors can use to deliver the 1Gbps (Gigabit per second) goods.

All-together, there are three proposed Gigabyte Wi-Fi standards. These are IEEE 802.11ac, 802.11ad and Wireless Gigabit aka WiGig.

First, there's 802.11ac. This is the next step up for the old 802.11a Wi-Fi standard. This was, and still is, a 5GHz Wi-Fi standard with a speed range of 54Mbps (Megabits per second). Vendors were slow to get 802.11a equipment out the door. When 802.11g came along, which works in the 2.4GHz range, could produce the same speed, and was compatible with the older and slower 802.11b, 802.11a became something of an orphaned technology.

Now with 802.11ac, 802.11a is making a kind of comeback. This new standard will continue to work on the 5Ghz band, but it will provide larger channels for data throughput. Today, 802.11a uses 20 MHz-wide channels, 802.11ac will be using either 40 MHz or 80 MHz-wide or perhaps even 160 MHz channels to deliver data. 802.11ac may also make use of MU-MIMO (multiple user-multiple input, multiple outputs). In MU-MIMOs simultaneous streams will be transmitted to different users on the same channels.

Exactly how will it work? We don't know yet. The standard is still far from set in stone. If all works out, 802.11ac devices will start showing up in late 2011 or early 2012 with speeds just touch 1Gbps.

That's option number one, but wait, there's more. 802.11ad and WiGig promises to deliver blazing hot 6Gbps speeds, but they'll deliver it in the 60GHz range. The downside of this millimeter band Wi-Fi is that its range will be in feet rather than yards. 802.11ad and WiGig APs will be able to cover a room, but not much more.

802.11ad, is based on WiGig, but the two aren't quite on the same page. I suspect eventually they'll sync up with each other. The last thing anyone wants is a repeat of the long, slow slog to 802.11n standardization.

WiGig has the support of Wi-Fi powers Atheros, Broadcom, and Intel. It's being designed specifically for streaming high-definition video. Its designers' goal is for future Wi-Fi adapters to be able to support 802.11g's 2.4 GHz for backwards compatibility and range, 802.11n and 802.11ac's 5GHz for performance, and 802.11ad/WiGig's 60GHz for short-range, HD video data transfers.

Last, but not least, there's companies working on reaching Gigabit speeds within 802.11n. You see 802.11n supports up to 4 antennas. If you use 802.11n's 5Ghz channels and four antennas you can, in theory, bond multiple channels together to reach 1Gbps. So far, no one's selling four antenna 802.11n devices, but it's only a matter of time.

Atheros is already shipping chipsets that can support up to three data streams at once. Atheros claims that devices using it new high-speed 802.11n chipsets can reach up to 450Mbps. Even before that, Marvell was shipping pre-standard 802.11n chipsets with three antenna support back in 2008. Smaller silicon foundries, such as Quantenna Communications, are already shipping 802.11n chipsets that can support four antennas.

Before you get too excited about seeing 1Gbps speeds in the next few months, you should keep in mind that the 802.11n bonding solutions are all, at this point, pretty much restricted to devices that all use the same chipsets. So, for example, even if you did get a Quantenna Full-11n AP (access point), it wouldn't deliver 1Gbps speeds to your Apple MacBook Pro. Not only does the MacBook Pro have the wrong silicon inside, it doesn't support that many antennas.

But, products are beginning to appear that come with higher-speed 802.11n built-in. For example, newer model Apple Airport Extreme uses a Marvell chipset to support three antennas.

So, one way or the other, you can expect to see faster Wi-Fi soon. In the short term, as enhanced 802.11n devices appear, you'll need to look closely at device compatibility to get the maximum possible 802.11n speed. Down the road though, as 802.11ac, 802.11ad, and WiGig devices start shipping you can look forward to easy access to 1Gbps and faster wireless speeds.

Speaking as someone who's always throwing serious amounts of data through the air in my home-office while wirelessly streaming HD video to my HDTV, I can't wait to see these new technologies arrive.

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