WiFi is a popular term that is
used referring to wireless communications between
computers and other computer related devices. Regular
radio waves are use to broadcast and receive just like a
pair of walkie talkies, but on a much higher frequency.
These days you will find many areas around
town that offer free WiFi internet access, but the most common
use for WiFi is in the home. If you have high speed Internet
(DSL, Cable, Satellite, etc) and have a piece of equipment
that is called a wireless router, then you have WiFi.
In
the illustration above you will see what equipment is
used in a typical home WiFi network. In some
cases an Internet service provider will supply
a wireless router/modem combination when you
subscribe to their service.
The main benefit of
WiFi is cordless internet access. Many electronic
devices have WiFi built-in and can access the internet
anywhere within range of your wireless router. This
means that while using a WiFi laptop computer you can
browse the internet from your couch. If you own a WiFi
Internet Radio you can listen to over 14,000
stations in your bedroom, kitchen, or bathroom. Some
cell phones have WiFi internet access also.
An
electronic device
cannot communicate with a WiFi router unless
it has a WiFi receiver/transmitter (otherwise called
a WiFi card or module) built-in. Most newer
laptops have a built-in WiFi card which can communicate
with nearby wireless routers. If your computer does not
have built-in WiFi then you can purchase a USB
WiFi Antenna for it. Modern USB WiFi
antennas can be connected to almost any computer to
enable or improve WiFi communication.
WiFi
works
using two-way communication between devices. For example:
When you type "CCrane" into the Google search bar
and press "Go", you are sending a request from your computer
to your router using WiFi. The router uses
it's WiFi to receive your request and forward it over
the internet to Google. When Google replies, they send
you the results of your request back over the internet
to your router. Your router then forwards the results
via WiFi back to your laptop computer. In this scenario
the use of WiFi communication takes place only between
your computer and the router.
There
are several
different types of WiFi, but the end result is
still the same, wireless communication. In the technical
world WiFi is translated to 802.11, which is a
group of standards created by the Institute of
Electrical and Electronics Engineers (IEEE). Listed
below are several different types of WiFi.
 |
802.11a -
Referred to as "Wireless A" was the first popular
version of WiFi that was developed in 1999. It
uses the 5 Gigahertz (GHz) radio band and can
communicate at a data rate of 54 Megabits per
second (Mbps). 802.11a was initially plagued with
problems such as high cost for components,
low reliability, and moderate range. This fueled
the market to adopt the more reliable and
affordable 802.11b and 802.11g technologies.
Today 802.11a is much more reliable and has
increased range equaling that of
802.11b. Typical indoor range is about 100
feet. Typical outdoor range is about 300
feet. |
 |
802.11b - Referred
to as "Wireless B" was also developed in 1999,
began to gain popularity in late 2000. Using the
2.4 GHz radio band it can communicate at a maximum
data rate of 11 Mbps although the typical
throughput fluctuates between 6 and 7 Mbps.
802.11b gained much momentum as the WiFi
leader because of the low cost of parts and good
reliability. Because of this reliability
802.11b is typically used in point-to-point
and point-to-multi-point long distance
applications.
Many
other devices such as cordless phones, bluetooth
modules, and microwave ovens share the 2.4 GHz
radio band. These devices can cause interference
and WiFi "drop out", especially when multiple 2.4
GHz items are used simultaneously. Typical
indoor range is about 100 feet. Typical outdoor
range is about 400
feet. |
 |
802.11g -
Referred to as "Wireless G" it was developed in
2003. It uses many of the same
modulation techniques as 802.11a but operates in
the 2.4 GHz radio band. The maximum data rate is
54 Mbps but typical throughput is closer
to 19 Mbps. 802.11g is often used
simultaneously with 802.11b to give the client user
better reliability in different environments and
backwards compatibility with older technology.
Considerably higher data throughput can be
achieved when using 802.11g only.
802.11g is susceptible to interference
caused by other devices using the congested 2.4
GHz radio band. Typical indoor range is about 100
feet. Typical outdoor range is about 400
feet. |
 |
802.11n -
Referred to as "Wireless N" it is the newest type
of WiFi that is expected to be finalized in
November 2009. Currently several companies are
selling "Draft N" WiFi equipment based on the
latest developments and approvals with this
technology. 802.11n is faster and can broadcast
further then previous WiFi standards.
It
can use both the 2.4 GHz and the 5 GHz radio bands
and can pass data at a maximum speed of 600 Mbps.
Maximum speed is better achieved by using the 5
GHz band only. Typical data throughput is 75 Mbps
depending on the signal quality. Many 802.11n
routers can simultaneously broadcast 802.11b,
802.11g, and 802.11n giving the client WiFi user
more compatibility with older technology.
Because 802.11n uses multiple
channels to send and receive data, the equipment
requires multiple radios which raises the cost for the
consumer. Wireless "N" routers can have up to four
antennas to send and receive faster, but this speed is
"bottle necked" by the number of antennas that the
client WiFi device is equipped with. Typical indoor
range is about 200 feet. Typical outdoor range is about
800
feet.
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Copyright 2009 by
C. Crane Company,
Inc.
1001 Main Street
Fortuna, CA 95540
(800)
522-8863 |
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