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802.11
In 1997, the Institute of Electrical and Electronics Engineers (IEEE)
created the first WLAN standard. They called
it 802.11 after the name of the group formed to oversee its
development. Unfortunately, 802.11 only supported a maximum bandwidth 2
Mbps -
too slow for
most applications. For that reason, ordinary 802.11 wireless products
are no longer being manufactured.
802.11b
IEEE expanded on the original 802.11 standard in July 1999, creating the
802.11b specification. 802.11b supports bandwidth up to 11 Mbps,
comparable to traditional
Ethernet.
802.11b uses the same radio signaling frequency - 2.4 GHz - as the
original 802.11 standard. Being an unregulated frequency, 802.11b gear
can incur interference from microwave ovens, cordless phones, and other
appliances using the same 2.4 GHz range.
However, by installing 802.11b gear a reasonable distance from other
appliances, interference can easily be avoided. Vendors often prefer
using unregulated frequencies to lower their production costs.
802.11a
When
802.11b was developed, IEEE created a second extension to the original
802.11 standard called 802.11a. Because 802.11b gained in popularity
much faster than did 802.11a, some folks believe that 802.11a was
created after 802.11b. In fact, 802.11a was created at the same time.
Due to its higher cost, 802.11a fits predominately in
the business market, whereas 802.11b better serves the home market.
802.11a
supports bandwidth up to 54 Mbps and signals in a regulated 5 GHz range.
Compared to 802.11b, this higher frequency limits the range of 802.11a.
The higher frequency also means 802.11a signals have more
difficulty penetrating walls and other obstructions. Because 802.11a and
802.11b utilize different frequencies, the two technologies are
incompatible with each other. Some vendors offer hybrid 802.11a/b
network gear, but these products simply implement the two standards side
by side.
802.11g
In 2002 and 2003, WLAN products supporting a new standard called
802.11g began to appear on the scene. 802.11g attempts to combine
the best of both 802.11a and 802.11b. 802.11g supports bandwidth up to
54 Mbps, and it uses the 2.4 GHz frequency for greater range. 802.11g is
backwards compatible with 802.11b, meaning that 802.11g access points
will work with 802.11b wireless network adapters and vice versa.
The Next
Generation of Wireless LAN Emerges with 802.11n
Word just in that the 802.11n proposal was confirmed:
The IEEE task group on high-throughput wireless local area
networking has confirmed the joint proposal group draft which itself
came out of the Enhanced Wireless Consortium. Now 802.11n will move
forward relatively rapidly to ratification, even though that formal
process of finalizing details could take until 2007. That won’t
delay shipping products at this point.
What is 802.11n:
802.11n uses a technology called MIMO, which
stands for multiple-in, multiple out. In
layman's terms, it means a device could have
multiple antennas that handle more than one
data stream at a time, thus speeding the
transfer of data tremendously. According
to test, data rates of up to 600 MBps could
be expected. 802.11n devices would also be
backwards compatible with the earlier
802.11a, b and g specifications.
"This past October Atheros set out with
the Enhanced Wireless Consortium to break
the 802.11n stalemate and accelerate a draft
that defines significantly higher wireless
LAN performance," Atheros president and CEO
Craig Baratt said in a statement.
"We have achieved this objective and are
confident that our customers can now
manufacture products with unprecedented
performance based on our technologies that
conform to this new draft."
802.16 WiMAX
(Worldwide Interoperability for Microwave)
The U.N. telecom agency approved the
wireless technology for inclusion in 3G
mobile standards, signaling a win for Intel
and defeat for competing technologies.
Find more stories in:
WiMax
Under
Construction
10/07
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