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.
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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. |
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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. |
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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. |
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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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