Overview of Wireless Technology
What is Wi-Fi?
Wi-Fi (short for Wireless Fidelity)
is a wireless communications technology used to transmit data from one network
device to another by radio. In contrast to wired computer networks, which use
cable to connect devices together, wireless networks use transceivers equipped
with antennas to transmit and receive data.
"You see, wire telegraph is a kind of a very, very long cat.
You pull his tail in New York and his head is meowing in Los Angeles. Do you
understand this? And radio operates exactly the same way: you send signals
here, they receive them there. The only difference is that there is no
cat."
--Albert Einstein
Wi-Fi technology is also called “fixed wireless”, since the communications
devices are at fixed locations (such as homes, offices or outdoor sites), as
opposed to mobile devices (such as cell phones and handheld two-way radios).
Where is Wireless Technology Used?
Wireless technology is used in places where it is
difficult, expensive or impossible to install wired networks.
Because of its wide applications, wireless technology can be used for
high-speed Internet access, for integration of cellular communications with
computer networks, in Voice-over-Internet (VoIP) telephony systems, in
security systems using video surveillance and other security and fire alarm
equipment, in commercial-quality audio broadcast systems, in process
monitoring and environmental monitoring systems, and for other purposes
requiring transmission of data, voice, and video.
Wireless networking is used in business to create, expand, or modernize local
area networks: for example, if a computer network must be built quickly in a
new department or office of a company, if employees at remote sites must be
connected to the existing LAN, or if networks must be set up at temporary
sites. Wireless technology can be used to create a network that smoothly
integrates the wired and wireless segments into a single infrastructure.
Benefits of Wireless Networking
Wireless networking has the following advantages
over wired networking:
Lower Cost. Where communications are
needed between sites located more than 100 meters apart, wireless networking
is cheaper than expensive cable and the installation costs involved.
Efficiency. Setting up wireless computer networks doesn’t require
the long, labor-intensive and expensive work required to install cables.
Wireless communications equipment can be installed quickly and effortlessly.
Mobility. If a company moves to a different office or building,
the money spent to purchase and install cables in the old office is lost,
because those cables cannot be removed and re-installed. In contrast to wired
systems, a complete set of wireless communications equipment can be easily
removed and re-installed at a new location.
High Data Transmission Speed. The maximum data transmission speed
via wireless computer networks is above the 100 Mbps that is the maximum data
transmission speed in 100-megabit wired systems.
High-Quality Communications. The use of wireless equipment in
buildings provides high-quality communications regardless of weather and
atmospheric conditions.
Information Security. The security of wireless networks is
ensured by the same means used for security in wired channels: data encryption
and a multilevel system for protection against unauthorized access.
Compatibility with Wired Networks. The use of standard data
transmission and network access protocols makes wireless systems fully
compatible with wired computer systems. This makes it possible to integrate
existing wired LAN and new wireless segments into a single infrastructure.
Large Coverage Zone. The operating range of wireless
communications equipment ranges from hundreds of meters to up to 50 kilometers
(30 miles). The use of directional high-gain antennas and booster and repeater
stations enables reliable, high-quality communications over unlimited
distances.
Flexibility. In places where the wired telecommunications system
is insufficient or nonexistent (for example, in sparsely populated or
mountainous terrain), wireless communications is the only cost-effective
solution for connecting remote sites to the LAN and for providing Internet
access for the remote sites.
Accessibility. Due to its high efficiency, mobility and ease of
installation and maintenance, wireless networking has become accessible to not
only large and medium-sized businesses, but also small businesses.
Quick Recovery of Expenses. Since wireless communications are
practically maintenance-free, they are less expensive than cable
communications. Investments in wireless networking are recovered quickly.
Operating Range and Data Transmission Speed
The operating range and data transmission speed
in a wireless LAN depend on the type of network adapters used and the number
of access points servicing the network. For wide area networks, the network
throughput is determined by the communications devices and antennas used in
the bridges connecting the remote sites. The operating range and speed of a
wireless device are determined by the protocol used in the device, the power
of the radio transmitter, the modulation technology used, the antenna gain,
the length of the antenna cables, and such factors as the presence of
obstacles and interference in the radio visibility zone of the device. The
higher the frequency of the radio signal used by a wireless device, the more
sensitive it is to various types of obstacles that block the microwave
radiation in the given band (for example, building walls made of dense
materials, metal structures, and trees).
Wireless LANs built to various standards have different data transmission
speeds. The maximum theoretical data transmission speed in wireless LANs
ranges from 11 Mbps to 54 Mbps depending on the standard used. The use of
add-on software makes it possible to increase this speed to 100 Mbps or more.
Wireless Internet Access
The data transmission speed provided by wireless
technology is well suited to the Internet access applications currently
available. The slowest wireless device is at least three times faster than a
dedicated T1 channel and just as fast as the most advanced broadband DSL and
satellite communications systems. High-speed wireless devices provide
transmission speeds comparable to the trunk cable channels used by Internet
service providers to connect to backbone nodes.
Network Security
Some customers may have the misconception that
wireless computer networks are less secure than wired computer networks, but
the same means used to protect cable networks are used to protect wireless
networks, making them just a secure as wired networks. Wireless network safety
is ensured by a multilevel system for protection against unauthorized access
and encryption of the data transmitted using the Wired Equivalent Privacy (WEP)
encryption standard and a 64-bit or 128-bit key.
Equipment Setup
All wireless computer devices can be set up
easily using a web interface.
Licensing of Radio Transmissions
In many countries (including the USA), the 2.4
GHz and 5 GHz frequency bands are reserved for industrial, scientific, and
medical uses, and a license or official permit is not required to use them. In
the majority of countries of the former USSR, the use of the 2.4 GHz band does
not require a license or special permit if used in a local area network in
buildings, enclosed storage sites, or on company premises.
Is Wireless Networking Right for You?
If you need to decide which network to
chose—wired or wireless—one of your main criteria should be the network
throughput that its users need to work efficiently. Keep in mind that the
speed of the slowest wireless device is much higher than the speed of a
dedicated Internet cable line. However, this speed is insufficient in LANs
with a large number of users and heavy data traffic, or if your company needs
to frequently exchange large files. For example, if your company is a
professional graphic design or multimedia producer, wireless networking isn’t
right for you. Otherwise, wireless networking will help you avoid excessive
wiring and the installation and maintenance of the cable-based infrastructure.
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