IEEE
802.11 Standard Tutorial
In 1997
the IEEE
adopted the first wireless local area network (WLAN) standard, IEEE 802.11.
This standard defines the media access control (MAC) and physical (PHY)
layers for a LAN with wireless connectivity. It addresses local area networking
where the connected devices communicate over the air to other devices
that are within close proximity to each other.
Since the initial
establishment of the 802.11 standard working group, it has been extended
with numerous task groups, designated by the letters a through i. Groups
a, b, and c have completed their tasks, and the results amended to the
original standards. The details of each task group are listed below.
802.11b has been particularly
successful, and there are many product currently available on the market
that use this standard. Products based on 802.11a products are in development
by many companies as well. Because the standards use different portions
of the spectrum, however, 802.11a and 802.11b are not compatible. Consequently,
a new task group, 802.11g, hopes to provide the high data rate of 802.11a,
while maintaining backward compatibility with 802.11b products.
802.11 Task Groups
The task groups of
the 802.11 standard are:
802.11a - Created
a standard for WLAN operations in the 5 GHz band, with data rates of
up to 54 million bits per sec (Mbps). Published in 1999. Products based
on this standard are expected in early 2002. One company using this
standard is Atheros (http://atheros.com/). Work completed.
802.11b - Created
a standard (also known as WiFi) for WLAN operations in 2.4 GHz band,
with data rates of up to 11 Mbps. Published in 1999. Products based
on 802.11b include public space Internet kiosks, WLAN services such
as Wayport,
and wireless home networking products such as the Macintosh
AirPort. Work completed.
802.11c - Provided
documentation of 802.11-specific MAC procedures to the ISO/IEC (International
Organization for Standardization/International Electrotechnical Commission)
10038 (IEEE 802.1D) standard. Work completed.
802.11d - Publishing
definitions and requirements to allow the 802.11 standard to operate
in countries not currently served by the standard. Ongoing.
802.11e - Attempting
to enhance the 802.11 MAC to increase the quality of service possible.
Improvement in capabilities and efficiency are planned to allow applications
such as voice, video, or audio transport over 802.11 wireless networks.
Ongoing.
802.11f - Developing
recommended practices for implementing the 802.11 concepts of Access
Points and Distribution Systems. The purpose is to increase compatibility
between Access Point devices from different vendors. Ongoing.
802.11g - Developing
a higher-speed PHY extension to the 802.11b standard, while maintaining
backward compatibility with current 802.11b devices. The target data
rate for the project is at least 20 Mbps. Ongoing.
802.11h - Enhancing
the 802.11 MAC and 802.11a PHY to provide network management and control
extensions for spectrum and transmit power management in the 5 GHz band.
This is will allow regulatory acceptance of the standard in some European
countries. Ongoing.
802.11i - Enhancing
the security and authentication mechanisms of the 802.11 standard. Ongoing.
More Info:*
IEEE
802.11 Working Group
ZD
Net 802.11 Article, July 2001
Intelligraphics
Introduction to 802.11
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11/29/01 |
