IEEE 802.11 is the set
of standards that define communication for wireless LANs or WLANs. The
technology used in 802.11 is branded to consumers as Wi-Fi.
According to the name ,
IEEE 802.11 is overseen by the IEEE, specifically the IEEE LAN/MAN Standards
Committee (IEEE 802). The current version now in use is of 802.11-2007. Actually, IEEE 802.11 is the
set of technical steps for implementing Wi-Fi. Selling products under this
trademark is checked by an industry trade association named as Wi-Fi Alliance.
IEEE 802.11 standards
have its roots from a year 1985 decision by the U.S. Federal Commission for
Communication that opened up the ISM band which has no license use. It was
formally released in 1997. That original standard was called IEEE 802.11-1997.
“802.11 standards” or the “802.11 family of
standards” are commonly used. However to be more precise ,now this time only
one standard existing is (IEEE 802.11-2007) but many changes commonly known as amendments
include 802.11a ,802.11b, 802.11g, and 802.11n.
This Linksys WRT54GS Wi-Fi router from 2005
works on the 2.4 GHz “G” standard, is able to transmit 54 megabits
Netgear dual-band router from 2013 uses the AC standard, is able to
transmit 1900 megabits per second.
The 802.11 family consists
of a series of half-duplex over-the-air modulation techniques
that use the same basic protocol. The first wireless networking standard in the
family was 802.11-1997 , but on market 802.11b was the first time widely
accepted, supported by 802.11a, 802.11g, 802.11n, and 802.11ac. Other standards
(c–f, h, j) are service changes that are used to extend the idea of the existing
802.11b and 802.11g both
use the 2.4 GHz ISM band ,now
it is operating in the United States under Part
the U.S. Federal Communications Commission Rules
and Regulations. By using this choice of
frequency band, 802.11b and g equipement may occasionally suffer interference from microwave ovens, cordless
telephones, and Bluetooth devices.
802.11b and 802.11g control their interference and susceptibility to
interference by using direct-sequence spread spectrum (DSSS)
and orthogonal frequency-division multiplexing (OFDM)
signaling methods, respectively. 802.11a uses the 5 GHz U-NII band, which, for much of the
world, offers at least 23 non-overlapping channels rather than the 2.4 GHz
ISM frequency band offering only three non-overlapping channels, where other
adjacent channels overlap—see list
of WLAN channels. Better or worse performance with higher or
lower frequencies (channels) may be realized, depending on the environment.
802.11n can use either the 2.4 GHz or the 5 GHz band; 802.11ac uses
only the 5 GHz band.
The segment of the radio frequency spectrum
used by 802.11 varies between countries. In the US, 802.11a and 802.11g devices
may be operated without a license, as allowed in Part 15 of the FCC Rules and
Regulations. Frequencies used by channels one through six of 802.11b and
802.11g fall within the 2.4 GHz amateur radio band.
Licensed amateur radio operators may operate 802.11b/g devices under Part
the FCC Rules and Regulations, allowing increased power output but not
commercial content or encryption.
802.11a is the first Wi-Fi
wireless network communication standards which is
created in the IEEE 802.11 standards family.
The 802.11a specification was ratified in 1999. At that
time, the only other Wi-Fi technology being readied for the market
were 802.11b. (The
original 802.11 did
not gain widespread deployment due to its excessively slow speed.) 802.11a and
these other standards were incompatible, meaning that 802.11a devices cannot
communicate with the other kinds and vice versa.
An 802.11a wireless network supports a maximum
theoretical bandwidth of 54 Mbps,
substantially better than the 11 Mbps of 802.11b and on par with what 802.11gwould start
to offer a few years later. The performance of 802.11a made it an attractive
technology, but achieving that level of performance required using relatively
higher cost hardware.
802.11a gained some adoption in corporate network
environments where cost was less of an issue. Meanwhile, 802.11b and early home
networking exploded in popularity during the same time period. 802.11b and then
802.11g (802.11b/g) networks dominated the industry within a few years. Some
manufacturers built devices with both A and G radios integrated so that they
could support either standard on so-called a/b/g networks, although these were
less common as relatively few A client devices existed.Eventually, 802.11a
phased out of the market in favor of newer standards.802.11a should not be
confused with 802.11ac, a much
newer and more advanced standard.
and Wireless Signaling:
U.S. government regulators in the 1980s opened three
specific wireless frequency bands for public use – 900 MHz (0.9
GHz), 2.4 GHz, and 5.8 GHz (sometimes called 5 GHz). 900 MHz proved too low of
frequency to be useful for data networking, although cordless phones used
802.11a transmits wireless spread spectrum radio signals in the 5.8 GHz frequency range. This
band was regulated in the U.S. and many countries for a long time, meaning
that 802.11a networks did not have to contend with signal interference from
other kinds of transmitting devices. 802.11b networks utilized frequencies
in the often unregulated 2.4 GHz range and were much more susceptible to radio
interference from other devices.
802.11b was the first Wi-Fi wireless network
communication technology to gain mass adoption with consumers. It is one of
many Institute of Electrical and Electronics Engineers
(IEEE) standards in the 802.11 family. 802.11b products were made obsolete and
phased out by the newer 802.11g and 802.11n Wi-Fi standards.
History of 802.11b
Until the mid 1980s, the use of radio frequency space around
2.4 GHz was regulated by government agencies around the
The U.S. Federal Communications Communication (FCC) initiated
the change to deregulate this band, previously limited to so-called ISM
(industrial, scientific, and medical) equipment. Their goal was to encourage
the development of commercial applications.
Building commercial wireless systems on a large scale requires
some level of technical standardization among vendors. That’s where the IEEE
stepped in and assigned its 802.11 working group to design a solution, which
eventually became known as Wi-Fi. The first 802.11 Wi-Fi standard,
published in 1997, had too many technical limitations to be widely useful, but
it paved the way for the development of a second generation standard called
802.11b (nowadays called “B” for short) helped
launch the first wave of wireless home networking. With its introduction in
1999, manufacturers of broadband routers like Linksys began selling Wi-Fi routers
alongside the wired Ethernet models they had been producing before.
Though these older products could be difficult to set up and
manage, the convenience and potential demonstrated by 802.11b turned Wi-Fi
into a huge commercial success.
802.11b connections support a theoretical maximum data rate
of 11 Mbps. Although comparable to traditional Ethernet (10 Mbps), B performs significantly
slower than all newer Wi-Fi and Ethernet technologies.
802.11b and Wireless
Transmitting in the unregulated 2.4 GHz frequency range, 802.11b
transmitters can encounter radio interference from other wireless household
products like cordless telephones, microwave ovens, garage door openers, and
802.11 and Backward
Even the newest Wi-Fi networks still support 802.11b. That’s
because each newer generation of the main Wi-Fi protocol standards has
maintained backward compatibility with all previous generations: For example,
802.11g routers and access points support both G and
B clients – called 802.11b/g networks
routers and access points support N, G and B clients – 802.11b/g/nnetworks
routers and access points support AC, N, G and B clients – 802.11b/g/n/ac networks
This backward compatibility feature has proven critical to the
success of Wi-Fi, as consumers and businesses can add newer equipment to their
networks and gradually phase out old devices with mimimal disruption.
802.11g is an IEEE standard Wi-Fi wireless networking technology. Like other versions
of Wi-Fi, 802.11g (sometimes referred to simply as “G”)
supports wireless local area network (WLAN) communications
among computers, broadband routers, and many other consumer devices.
G was ratified in June of 2003, and replaced the older 802.11b (“B”) standard, later
eventually replaced by 802.11n (“N”) and newer standards.
How Fast Is 802.11g:
802.11g Wi-Fi has ability to support a maximum network bandwidth of 54 Mbps, which is higher than the 11 Mbps rating of B and less than the 150 Mbps or greater speeds of
N. Similarly many other kinds
of networking, G is not able to achieve the maximum rating in practice; 802.11g
connections hit an application data
transfer rate limit between 24 Mbps and 31 Mbps.
G incorporated is a radio communication technique known as Orthogonal
Frequency Division Multiplex that was introduced to Wi-Fi with 802.11a . OFDM technology enabled G and A to get
greater network performance than B.
On the other hand, 802.11g chosen the same 2.4 GHz range of communication
frequencies introduced to Wi-Fi with
802.11b.Using this frequency gave Wi-Fi devices greater signal range than what A can offer. 14
possible channels that 802.11g can work on, though some are illegal in some
countries. The frequencies from channel 1-14 range between 2.412 GHz to 2.484
GHz.G was specially designed for cross compatibility.
What is meanings of that
devices can coordinate wireless networks even when the wireless access point runs a different Wi-Fi version.The newest 802.11ac Wi-Fi equipment today can support
connections from G clients.
802.11g for Home
Networking and Travel:
Numerous brands and models of computer laptops and other Wi-Fi
devices were manufactured with Wi-Fi radios supporting G. As it combined some
of the best elements of A and B, 802.11g became the predominant Wi-Fi standard
at a time when the adoption of home networking exploded worldwide.Many home
networks today still operate using 802.11g routers. At 54 Mbps, these routers can keep up with
most high-speed home internet connections including basic video streaming and
online gaming usages.
They can be found inexpensively through both retail and
secondhand sales outlets. However, G networks can reach performance limits
quickly when multiple devices are connected and simultaneously active, but this
is true for any network that’s consumed by too many devices.In addition to G
routers designed for fixed installation in homes, 802.11g travel routers also gained substantial popularity with
business professionals and families who needed to share a single wired Ethernet connection among their wireless
devices.G (and some N) travel routers can still be found in retail outlets but
have become increasingly uncommon as hotel and other public internet services
shift from Ethernet to wireless hotspots.
802.11n is a standard (IEEE) for Wi-Fi wireless local network communications, contract in
2009.802.11n is designed to exchange the 802.11a, 802.11b and 802.11g Wi-Fi
Wireless Technologies in 802.11n:
802.11n uses multiple wireless
antennas in tandem for transmitting and receiving data. The term MIMO refers to
the ability of 802.11n and like other technologies to coordinate multiple
simultaneous radio signals. MIMO is used to increase the range and throughput of a wireless
network. An other technique employed by 802.11n that involves increasing the
channel bandwidth. Such networks
802.11a/b/g, and each .11n device that uses a preset Wi-Fi channel on which is
used for transmitting. Such channel will use a larger frequency range , also
increasing data throughput.
connections that support maximum theory based network bandwidth upto300 Mbps
which primarily depends on the number of
wireless radios incorporated into devices.