This upload explains briefly about Wireless Networks. I prepared this project as part of my summer vacation holiday homework for Class 12.

1. WIRELESS
COMPUTER NETWORK
Created by :
Rishabh Rawat
Class XII

2. WIRELESS NETWORK
 Wireless network is a technology which enables people to
communicate and access applications and information without wires.
This provides freedom of movement and the ability to extend
applications to different parts of a building, city, or nearly anywhere
in the world from a location that they prefer.
 Many types of wireless communication systems exist that takes place
between devices such as personal digital assistants (PDAs), laptops,
personal computers (PCs), servers, and printers. Eventually, most
electronics offer wireless network connections.
 The information can take the form of e-mail messages, web pages,
database records, streaming video or voice.

3. Types of Wireless Networks
WLANS : Wireless Local Area Networks allow users in a local
area, such as a university campus or library, to form a
network or gain access to the internet. A temporary network
can be formed by a small number of users without the need of
an access point; given that they do not need access to
network resources.
WPANS: Wireless Personal Area Networks :The two current
technologies for wireless personal area networks are Infra
Red (IR) and Bluetooth (IEEE 802.15). These will allow the
connectivity of personal devices within an area of about 30
feet. However, IR requires a direct line of site and the range
is less.

4. Types of Wireless Networks
WMANS: Wireless Metropolitan Area Networks: This
technology allows the connection of multiple networks in
a metropolitan area such as different buildings in a city,
which can be an alternative or backup to laying copper
or fibre cabling.
WWANS: Wireless Wide Area Networks: These types
of networks can be maintained over large areas, such as
cities or countries, via multiple satellite systems or
antenna sites looked after by an ISP. These types of
systems are referred to as 2G (2nd Generation) systems.

5. TRANSMISSION
METHODS
1. 802.1x EAP
 The Extensible Authentication Protocol (EAP) is a layer 2 process that allows a
wireless client to authenticate to the network. There are two varieties of EAP: one
for wireless and one for LAN connections, commonly called EAP over LAN (EAPoL).
 One of the concerns in wireless is allowing a WLAN client to communicate to
devices behind an AP. Three standards define this process: EAP, 802.1x, and Remote
Authentication Dial In User Service (RADIUS). EAP defines a standard way of
encapsulating authentication information, such as a username and password or a
digital certificate that the AP can use to authenticate the user.802.1x and RADIUS
define how to packetize the EAP information to move it across the network.

6. TRANSMISSION METHODS
2. WPA
 Wi-Fi Protected Access (WPA) was designed by the Wi-Fi Alliance as a
temporary security solution to provide for the use of 802.1x and
enhancements in the use of WEP until the 802.11i standard would be
ratified. WPA can operate in two modes: personal and enterprise mode.
Personal mode was designed for home or SOHO usage. A pre-shared
key is used for authentication, requiring you to configure the same key
on the clients and the AP. With this mode, no authentication server is
necessary as it is in the official 802.1 x standards. Enterprise mode is
meant for large companies, where an authentication server will
centralize the authentication credentials of the clients.

7. TRANSMISSION METHODS
3. WPA2
 WPA2 is the IEEE 802.11i implementation from the Wi-Fi Alliance.
Instead of using WEP, which uses the weak RC4 encryption algorithm,
the much more secure Advanced Encryption Standard (AES)–counter
mode CBC-MAC Protocol (CCMP) algorithm is used.
4. Infrared
 Infrared (IR) radiation is electromagnetic radiation of a wavelength
longer than that of visible light, but shorter than that of microwave
radiation. The name means "below red" (from the Latin infra, "below"),
red being the color of visible light of longest wavelength.

8. TRANSMISSION METHODS
5. Bluetooth
 Bluetooth is an industrial specification for wireless personal area
networks (PANs). Bluetooth provides a way to connect and
exchange information between devices like personal digital
assistants (PDAs), mobile phones, laptops, PCs, printers and digital
cameras via a secure, low-cost, globally available short range radio
frequency.
 The range of Bluetooth is 33 feet for class 2 Bluetooth (most
Bluetooth and headphones are common class 2 devices).
 Class 1 Bluetooth provides a range of 328 feet.

9. TRANSMISSION METHODS
6. FHSS
 Frequency-hopping spread spectrum is a spread-spectrum method of
transmitting radio signals by rapidly switching a carrier among many
frequency channels, using a pseudorandom sequence known to both
transmitter and receiver making it highly resistant to noise and interference.
Bandwidth can be utilized more efficiently.
 Signals are difficult to intercept. A Frequency-Hop spread-spectrum signal
sounds like a momentary noise burst or simply an increase in the background
noise for short Frequency-Hop codes on any narrowband receiver except a
Frequency-Hop spread-spectrum receiver using the exact same channel
sequence as was used by the transmitter.

10. TRANSMISSION METHODS
7. DSSS
 Direct-sequence spread spectrum is a modulation technique where
the transmitted signal takes up more bandwidth than the information
signal that is being modulated, which is the reason that it is called
spread spectrum. DSSS uses one channel to send data across all
frequencies within that channel. Complementary Code Keying (CCK) is
a method for encoding transmissions for higher data rates, such as
5.5 and 11 Mbps, but it still allows backward compatibility with the
original 802.11 standard, which supports only 1 and 2 Mbps speeds.
802.11b and 802.11g support this transmission method.

11. TRANSMISSION METHODS
8. OFDM
 Orthogonal frequency-division multiplexing, also called discrete
multitoned modulation (DMT), is a transmission technique based
upon the idea of frequency-division multiplexing (FDM). OFDM
increases data rates by using a spread spectrum: modulation. 802.11a
and 802.11g support this transmission method.
 Used in some wireless LAN applications, including WiMAX and IEEE
802.11a/g
 Used in many communications systems such as: ADSL, Wireless LAN,
Digital audio broadcasting.

12. RANGE AND SPEED
The layout of the building can reduce the range as well
as speed.
A lot of concrete walls can reduce the range.
The size of the antenna and the placement greatly
affect the range of their signals.
The weather and amount of water vapour in the air can
affect the signals strength and range.
The size of the antenna and its signal can affect your
speed

13. Advantages of a Wireless Network
 The main advantage of a wireless network over a wired one is that users can
move around freely within the area of the network with their laptops,
handheld devices etc. and get an internet connection.
 Users are also able to share files and other resources with other devices that
are connected to the network without having to be cabled to a port.
 Not having to lay lots of cables and put them through walls etc. can be a
considerable advantage in terms of time and expense. It also makes it easier to
add extra devices to the network, as no new cabling is needed.
 Wireless networks can sometimes handle a larger amount of users because
they are not limited by a specific number of connection ports.

14. Disadvantages of a Wireless Network
 It can require extra costs and equipment to set up, although
increasingly routers have built-in wireless capability, as do
devices such as laptops, handheld devices, modern DVD
players, and TVs.
 Setting up a wireless network can sometimes be difficult for
people who are not experienced with computers.
 File-sharing transfer speeds are normally slower with wireless
networks than they are with cabled. The speeds can also vary
considerably according to your location in relation to the
network.

15. THANK
YOU…