An Introduction to WIFI standards

The IEEE 802.11 which stands for Institute of electrical and electronics engineers is a standard
of communication between computers and wireless devices used worldwide for Wireless local
area network (WLAN). These standards were set by IEEE LAN/MAN Standard committee in
5GHZ and 2.4 GHz public spectrum bands. Some of the widely used standards include: the
802.11b, 802.11a, and 802.11g. Other WIFI standards include the 802.11c, 802.11d, 802.11f, 802.11i and 802.11e.


802.11b

Year developed *1999
Bandwidth support *Up to 11 Mbps, comparable to Ethernet.
Operating Frequency *2.4GHz ISM
Transfer Rate (theoretical) 1, 2, 5.5, 11Mbps
Transfer Rate (throughput) *4Mbps (average)
Mechanism *Direct Sequence Spread Spectrum (DSSS)
Channels Available *11 (3 non-overlapping)
Maximum Range *175ft. (average)
Advantages *Lowest cost; signal range is best and is not easily obstructed
Disadvantages *Slowest maximum speed; supports fewer simultaneous users; appliances may interfere on the unregulated frequency band
Other *Can incur interference from microwave ovens, cordless phones, and other appliances using the same 2.4 GHz range.

802.11a

Year developed *1999
Bandwidth support *To 54 Mbps and signals in a regulated 5 GHz range.
Operating Frequency *5.8 GHz Unlicensed National Information Infrastructure (UNII)
Transfer Rate (theoretical) up to 54Mbps
Transfer Rate (throughput) *20 - 36 (approximate average)
Mechanism *Orthogonal Frequency Division Multiplexing (OFDM
Channels Available *12 (all non-overlapping)
Maximum Range *80ft. (average)
Advantages *Fastest maximum speed; supports more simultaneous users; regulated frequencies prevent signal interference from other devices
Disadvantages *Highest cost; shorter range signal that is more easily obstructed
Other *Due to its higher cost, 802.11a fits predominately in the business market, whereas 802.11b better serves the home market.

802.11g

Year developed *2002
Bandwidth support *Up to 54 Mbps
Operating Frequency *2.4 GHz
Transfer Rate (theoretical) 54Mbps
Transfer Rate (throughput) *20 - 30 (average)
Mechanism *Complimentary Code Keying (CCK), OFDM
Channels Available *Complimentary Code Keying (CCK), OFDM
Maximum Range *175ft (average)
Advantages *Fastest maximum speed; supports more simultaneous users; signal range is best and is not easily obstructed
Disadvantages *Costs more than 802.11b; appliances may interfere on the unregulated signal frequency
Other *Attempts to combine the best of both 802.11a and 802.11g.
*802.11g access points will work with 802.11b wireless network adapters and vice versa.


802.11c
This standard is responsible for helping to ensure effective bridged connections between access points.
Companies and universities often utilized this standard when attempting to span their networks across
various environments such as building and other wide-spread installations requiring bridged
communication

802.11d
After its initial inception, 802.11 had very little to worry about in regards to stepping on the proverbial
electronic feet of others. The introduction of the 802.11d standard task group has its sights set on
making the widespread proliferation and adoption of 802.11 a globally pleasant experience. 802.11d is
an ongoing standard group which seeks to further enhance as well as define new PHY requirements that
comply with regulatory standards existent within other countries. This standard is of particular
importance for groups which utilize the 5 GHz band as the use of the frequency differs dramatically

from country to country.

802.11f
The main function of the 802.11f standards work group is to help resolve the issue of inter-compatibility
between access points from different vendors. The 802.11 protocol was initially designed without such
specific constraints as to allow for maximum flexibility when working with different systems. However,
the rapid proliferation of diverse wireless networking technology from numerous vendors has spawned
the need for an established standard allowing users to maximize their mobility. The focus of the 802.11f
working group is to help promote WIFI allowing for enhanced compatibility between various wireless
vendors and their products.

802.11i
After WEP encryption was effectively surpassed in August 2001, the 802.11i work group began to
receive more attention, specifically since its main focus is enhanced wireless security. 802.11i is a two
layer standard group which focuses both on issues concerning 802.1X (not a part of the 802.11 standard)
and network security, as well as a deeper look into a specific WEP security fix called Temporal Key Integrity (TKI).

802.11e
802.11e is a standard of increasing importance as the utilization of wireless transmission of voice and
video continues to expand on a daily basis. Since its inception the 802.11 standard has lacked any
mechanism for the prioritization and organization of wireless network traffic. The focus of the 802.11e
standard work group is to promote and improve Quality of Service for both audio and video across the
entire 802.11 standard. Its implementation will allow for backwards compatibility with existing wireless