Wireless Home Networking - Index of

Figure 2-8:
Look for this
logo on the
box of your
new 802.11n
gear.
The next big thing: 802.11n
The IEEE has been at work for several years defining a newer wireless networking
standard, 802.11n. As we write in late 2007, 802.11n is a draft standard,
meaning there’s still work to be done before the final IEEE standard is
ratified (which won’t happen, by all accounts, until 2009!). But even though
802.11n isn’t a finalized standard, it is very close to the final standard, close
enough that the folks who make 802.11 chips have begun mass producing
802.11n chips, and the folks who make networking gear have begun putting
these chips into products that they are labeling “802.11n.” Even more importantly,
the Wi-Fi Alliance has begun certifying 802.11n products — meaning
that you can buy equipment that has been certified to interoperate with other
manufacturers’ products. So you can buy an 802.11n router from company X
and an 802.11n network adapter from company Y and have full confidence
that they’ll work together. Figure 2-8 shows the Wi-Fi Alliance certification
logo you’ll find on 802.11n draft-compliant gear (in this case, this gear is also
compliant with 802.11b, a, and g).
Keep these few things in mind about 802.11n:
Chapter 2: From a to n and b-yond
� Speed: The theoretical maximum speed of 802.11n is 248 Mbps — five
times faster than 802.11g. Real-world speeds have been measured in test
centers at about 100 Mbps (five times faster than 802.11g). With 802.11n,
wireless can be a real alternative to wired networks, even for highperformance
applications such as sending video around the home.
� Distance: 802.11n uses a special technology called MIMO (multiple inputs,
multiple outputs) that modifies how signals are sent and received across
your system’s antennas. A MIMO system can send and receive data across
more than one antenna at a time, and can use special signal processing to
actually beam form the signal to extend its range and power in a certain
direction. Although no one wants to quantify it exactly (or, to be more
exact, everyone has a different figure), you can expect MIMO to extend
the range of your wireless network by a factor of 2 or more.
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