Flying farther faster with Wi-Fi Draft N

By Lisa Phifer

Broadband routers that include 802.11 Wi-Fi are very popular for connecting notebooks, smartphones, DVRs, and game consoles throughout your home to the Internet.  But old Wi-Fi routers that use 802.11b/g can only reach a top speed of 54 Mbps and span distances of 100-200 hundred feet.  In this tip, we explain how you can double or triple your home network's reach by replacing your old router with a new Draft N model.

802.11a, b, g, n – What's the difference?

Most early wireless broadband routers were based on 802.11b, which had a maximum data rate of 11 Mbps.  Throughput is typically about half the data rate and declines as the distance between your wireless router and notebook increases.  That means that a wireless notebook could send maybe 5 Mbps when used right next to an 802.11b router.  But carry that notebook to a more distant corner of your home and throughput will fall to 1 Mbps and eventually disconnect altogether where wireless signal is just too weak.

For home networks, the next successful generation of wireless routers was based on 802.11g, an update which increased maximum data rate to 54 Mbps without any noticeable change in range.  This means that an 802.11g notebook that could send 5 Mbps when connected to your old 802.11b router could probably send up to 27 Mbps when connected to an 802.11g router at the same distance.

Around the same time that 802.11g hit the market, businesses started using wireless products based on 802.11a.  Like 802.11g, 802.11a can reach speeds up to 54 Mbps – but it is not backwards compatible with 802.11b.  That means that 802.11a notebooks can only communicate with 802.11a routers.  Why would businesses want to do that?  Because 802.11a uses a different, much larger set of radio channels, letting business networks work more reliably inside office buildings filled with wireless routers.

Figure 1. When buying new Wi-Fi products, look for this Draft N brand

Today's hot new wireless router technology is 802.11n – specifically, something called "Draft N" (see Figure 1).  802.11n is backwards compatible with ALL earlier wireless products: 802.11b, 802.11g, and 802.11a.  But Draft N products can reach speeds up to 300 Mbps –- that's 6 times faster than 802.11g!  Furthermore, Draft N products use multiple antennas to extend their range and operate more reliably.  Depending on your home, a new Draft N notebook could send up to 150 Mbps when communicating with a new Draft N router, at twice the distance experienced with 802.11g.

Do you really need Draft N?

You might be thinking that 54 Mbps already sounds like a big number –- particularly if your broadband Internet connection tops out somewhere between 3 and 10 Mbps.  And it's true –- if your home network is only used by a couple of notebook users for web surfing at any given time, speed is not a good reason to upgrade to Draft N.

However, many home networks can see very significant benefits with Draft N.

• Reliability: Older 802.11a/b/g products use just one antenna to transmit just one "stream" at a time.  Every wall or door that stream passes through makes the signal weaker and slightly garbled.  If the stream encounters a source of interference, such as a microwave oven or cordless telephone, it becomes further garbled.  This is why older wireless notebooks drop connections unexpectedly, even when fairly close to a router.

  New Draft N products can transmit the same stream through multiple antennas at once.  Each stream follows a slightly different path to reach the receiver, so this gives you a better chance of overcoming signal degradation caused by obstacles and interference.  Particularly inside homes where there are many walls and doors and microwaves ovens and cordless phones, Draft N products will operate much more reliably, sustaining higher data rates and dropping fewer connections.

• Reach:  In theory, older 802.11a/b/g products could reach up to 300 feet.  In practice, those walls and doors described above reduced their effective reach to maybe 100 feet inside a typical home.  Those multiple antennas used by Draft N products not only improve reliability –- they actually double or even triple their effective reach

  This benefit depends on your environment.  If you're using wireless in a wide open space (like outdoors) you will not experience increased reach with Draft N.  But if you're using wireless inside your home, trying to connect from your second floor office to your basement router at the opposite corner of the house, you're going have a much better shot at sustaining a usable connection over this distance using Draft N.

• Capacity: The higher throughput delivered by Draft N can be "sliced and diced" in two different ways.  First, if you have many users competing for the same wireless router, Draft N is going to be able to support 5-6 as many people as before, using the same old applications (web surfing, email, etc).  This is important for businesses, but it could also be beneficial at home as you install more and more Wi-Fi-enabled devices (DVRs, gaming consoles, etc).

  Alternatively, instead of slicing a bigger pie into a larger number of small pieces, Draft N can give a handful of users much larger pieces of that bigger pie.  This is particularly important to support new high-throughput applications like streaming music and video over wireless.  If you want to download videos to your wireless DVR, or listen to Internet radio through your wireless receiver, or use Wi-Fi handsets to make phone calls using an Internet voice service like Skype or Vonage, these applications chow down bandwidth.  Draft N can support these new applications with plenty left over for uninterrupted web surfing. 

What you'll need to use Draft N

If you've decided to upgrade to Draft N, the first thing you'll need is a contemporary wireless router.  Certified Draft N products have been available since the summer of 2007, so most routers purchased from retail stores today fit this bill.  Avoid old 802.11g routers gathering dust on the discount rack and make sure that any router that claims to speaks 802.11n actually wears the Draft N brand (shown in Figure 1 above) somewhere on the box.  Only products that pass interoperability tests get to use that brand – stay away from "no name" products that skipped those tests and may well be cranky when paired with some other-vendor products.

Next, you'll need contemporary wireless client devices.  Because Draft N is backwards compatible with older 802.11a/b/g devices, you'll have no trouble connecting your existing notebooks and DVRs and desktops to a Draft N router.  You may even experience better reliability when using those older devices with your new router.  But you will not experience speeds above 54 Mbps or noticeably better reach unless you also upgrade your wireless client devices.  For example, your next new notebook will probably come with Draft N.  In the meantime, you might add a Draft N USB adapter to your old notebook.

While it's no problem to use both old and new wireless client devices with your new Draft N router, it is important to configure your new router to accept both 802.11g and 802.11n connections.  As show in Figure 2 below, many Draft N routers support several modes of operation – just choose the mixed mode that reflects the composition of your own home network.  Don't choose 802.11n-only unless you are sure that you do not have any older wireless clients – otherwise they will not "hear" your wireless router and their incessant chatter will actually degrade performance for everyone.

What should you really expect from Draft N?

In the very best case, under ideal conditions, you'll see Draft N clients close to your router operating at data rates of 300 Mbps.  But don't be surprised to see many clients operating at slower rates.  As shown in Figure 3, different clients may end up at different data rates, reflecting their capabilities, their distance from the router, and all of the obstacles and interference sources in between.