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Unit 7: Wireless Networks

7. ..................................... systems use frequency division multiplexing to divide the bandwidth Notes
into specific frequencies that are assigned to individual calls.
8. ..................................... systems are digital, and use either TDMA (Time Division Multiple
Access) or CDMA (Code Division Multiple Access) access methods.

7.3 Wi-Fi

Wi-Fi, developed on IEEE 802.11 standards, is widely used technology advancement in wireless
communication. As the name indicates, WI-FI provides wireless access to applications and data
across a radio network. WI-FI sets up numerous ways to build up a connection between the
transmitter and the receiver such as DSSS, FHSS, IR–Infrared and OFDM.
The development on WI-FI technology began in 1997 when the Institute of Electrical and
Electronic Engineers (IEEE) introduced the 802.11 technology that carried higher capacities of
data across the network. This greatly interested some of major brands across the globe such as
the world famous Cisco Systems or 3COM. Initially, the price of Wi-Fi was very high but around
in 2002, the IT market witnessed the arrival of a break through product that worked under the
new 802.11g standards. In 2003, IEEE sanctioned the standard and the world saw the creation of
affordable Wi-Fi for the masses.
Wi-Fi provides its users with the liberty of connecting to the Internet from any place such as
their home, office or a public place without the hassles of plugging in the wires. Wi-Fi is quicker
than the conventional modem for accessing information over a large network. With the help of
different amplifiers, the users can easily change their location without disruption in their network
access. Wi-Fi devices are compliant with each other to grant efficient access of information to the
user. Wi-Fi location where the users can connect to the wireless network is called a Wi-Fi hotspot.

Example: There are many wi-fi hotspots available to the public today, including airports,
hotels, Starbucks, Panera Bread, and other free wi-fi hotspots.
Through the Wi-Fi hotspot, the users can even enhance their home business, as accessing
information through Wi-Fi is simple. Accessing a wireless network through a hotspot in some
cases is cost-free while in some it may carry additional charges. Many standard Wi-Fi devices
make the Wi-Fi experience convenient and pleasurable for the users.

Example: Standard Wi-Fi devices are PCI, miniPCI, USB, Cardbus and PC card,
ExpressCard
Distance from a wireless network can lessen the signal strength to quite an extent; some devices
such as Ermanno Pietrosemoli and EsLaRed of Venezuela Distance are used for amplifying the
signal strength of the network. These devices create an embedded system that corresponds with
any other node on the Internet.
The market is flooded with various Wi-Fi software tools. Each of these tools is specifically
designed for different types of networks, operating systems and usage type. For accessing
multiple network platforms, Aircrack-ng is by far the best amongst its counterparts. The preferred
Wi-Fi software tools list for Windows users is: KNSGEM II, NetStumbler, OmniPeek, Stumbverter,
Wi-Fi Hopper, APTools. Unix users should pick any of the following: Aircrack, Aircrack-ptw,
AirSnort, CoWPAtty, Karma. Whereas, Mac users are presented with these options: MacStumble,
KisMAC, Kismet. It is imperative for users to pick out a Wi-Fi software tool that is compatible
with their computer and its dynamics.
Wi-Fi uses radio networks to transmit data between its nodes. Such networks are made up of
cells that provide coverage across the network. The more the number of cells, the greater and

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