Computer Science lecturer

1. Chapter 6
Wireless communication

2. Wireless communication
• Wireless communication is an important area
of telecommunication and networking.
• The communication between two or more
than two devices without any physical
connection is called wireless communication.
• The data can be transmitted and receive using
electro magnetic waves in open space.

3. Wireless communication
• Wireless communication enable the user to
communicate any where.
• It is also known as un-guided media or
unbounded media because it is freedom from
wires and they are not connected by wires.
• The data can be send over well defined
channel.
• Each channel has fixed frequency bandwidth
and capacity.

4. Components of wireless network:
• There are two main components of wireless
network
• A) ACCESS POINT:
• It is used in wireless network
• It act as a central transmitter and receiver of
radio signals.
• It is a point where wireless signals are
generated.

5. Components of wireless
communication
• WIRELESS CLIENT:
• A computer or device that get facilitates with
wireless LAN is called wireless client.

6. ADVANTAGES OF WIRELESS
COMMUNICATION
• MANAGEABILITY:
user can easily connected to different
network without any change of physical
connection.
• EXTANDABILITY / SCALABILITY:
adding new computer to this network is
very easy.
we can expand wireless network.

7. Advantages of wireless communication
• REACH OF A NETWORK:
– It can be expandable to place where wired
network can not reach.
• ELIMINATING WIRES COST EFFECTIVE:
– Easy to install
– It is cost effective than buying and installing
cables.

8. • FREE TO MOVE / MOBALITY:
– User can access internet at different point at
home.
– User can roam around the wireless network
without disconnection.
• CONNECT AUTOMATICALLY – if within range
– Home/ office network

9. • LAST MILE DATA DELIVERY:
–Wireless network can be very suitable
replacement for wired connections in
area where it may be difficult to extend
the cable network.

10. • ONE TIME INVESTMENT:
– Wireless network requires a one time investment
and hence are cheaper.
• Fast setup:
– If a computer have a wireless adapter locating a
wireless network is very simple

12. Disadvantages of wireless network
• Security :
– Wireless network is more vulnerable to attack by
un-authorized user, so particular attention has to
be paid to security.
• Coverage:
– in some buildings getting consistent coverage can
be difficult leading to black spot where no signal
are available.

13. • Installation problem:
– you may suffer interference if other in same
building also user wireless technology.
• Or
– Where other source of radio signals are present
this could lead to poor communication
• transmission speed :
– Wireless transmission can be slower than wired
transmission and also less efficient.

14. • Speed:
– wireless network is slower than wired network
while transferring file over local area network
(LAN)
• Building characteristics:
– The physical characteristics of a building can
effect the performance of wireless network.

15. • Affect bandwidth:
– if the number of computers on wireless network
is increase then it will suffer the bandwidth.

16. Wireless communication terminologies
• Radio signals:
– Radio signals are electro magnetic waves that are
use as a medium in wireless communication.
– The frequency range of radio signals are 3khz to
1Ghz.
• Radio transceivers ( transmitter or receiver)
– Radio transceiver is a wireless communication
device that are used to send or receive radio
signals
– Radio transceiver is a full duplex that send or
receive data simultaneously.

17. • Wireless access point:
– it is a point from where a radio signals are
generated
–It is usually connected to a router that serve
multiple user with in define area
–It is used to connect one user to another user
with in wireless local area network
–When people move beyond the range of one
access point they are automatically handed
over to the next one

18. LINE OF SIGHT COMMUNICATION
• Line of sight is electro magnetic radiation
which means the waves are traveling in a
straight line from source to destination.
• The common example of line of sight is
–TV remote ( short distance ) and cellular
transmission ( long distance )

19. SHORT DISTANCE
COMMUNICATION
• The information is transfer form one
computer or device to another
computer or device in a few meter or
kilo meter is known as short distance
wireless communication.

20. • There are some common short
distance wireless communication
technologies which are given below.
–WIFI
–Wi-max
–Bluetooth
–Infrared

21. WIFI
• WIFI stand for wireless fidelity .
• It allow computer or other device to
communicate over wireless signals.
• WIFI is most popular technology use radio
waves to provide high speed internet.
• WIFI use 802.11 standard that are developed
by IEEE (institute of electrical and electronics
engineering)

22. WI-MAX
• WI-MAX stand for world wide interoperability
for micro wave access.
• It provide fast internet access and multi media
services.
• Wi-max use 802.16 standard for wireless
access up to 30 – 50 km

23. DIFFERENCE BETWEEN WIFI AND
WI-MAX
FEATURE WIFI WI-MAX
MAXIMUM SPEED 54 mbps 100 mbps
RANGE 100 meter 40-50 kilometer
COVERAGE Indoor Outdoor
USERS Hundred Thousands

24. Bluetooth
• Bluetooth is open wireless technology used for
transmitting data over short range distance.
• It is mostly used in mobile and fixed electronic
device.
• Bluetooth cover short distance up to 10 meters.
• Bluetooth does not require line of sight positioning
like infrared.
• The maximum data transfer of Bluetooth is 1mbps
• Bluetooth network is also known as piconet or PAN

25. Infrared
• Infrared waves are used for short distance
communication.
• Infrared waves use line of sight propagation.
• Infrared waves can not penetrate through
wall or objects.
• The data rate of infrared waves are very low.

26. Application of infrared
• Car looking system ( automatic locking and
unlocking the door of a car)
• Security system (burger alarm)
• Use in toys.

27. LONG DISTANCE WIRELESS
COMMUNICATION
• In long distance wireless communication the
information is transfer from one device to
another device in a large geostationary area.
• There are some common long distance
wireless technologies which are given below.
• A) cellular communication
• B) (GPS) Global Positioning System

28. CELLULAR COMMUNICATION
• Cellular communication is mostly used in data
communication and telecommunication.
• It is the foundation of wireless mobile
communication that connects the user in
different location where wired network can not
reached.

29. • In cellular transmission a single high power
transmitter (cell) is replaced by many low power
transmitters because the range of these small
and low power transmitter are very small and
the area is divided into cells and each cell has its
own antenna.
• The cellular network cover the entire country
and serves million of users/ subscribers
• Each cell cover 500 m to 35 km area.

31. GPS
• GPS stands for global positioning system.
• GPS is satellite based navigation system
that are used to locate the exact position
of people and things anywhere on the
surface of the earth.
• It was developed by department of
defence (DoD).
• It consist of 24 satellite moving around
surface of the earth about 12500 miles
above the earth surface.

32. • The satellite are travelling at the
speed of 7000 miles an hour.
• The 24 satellite are divided into 6
orbits and in each orbit there are 4
satellite.
• GPS work in any weather condition
anywhere in the world.
• It has no subscription fee or setup
charges for using the GPS.

33. GPS SEGMENTS
• Gps consist of three major segments which
are given below.
• 1) space segment:
• It consist of 27 satellites ( 24 are in operation and 3
are extras).
• These satellites are 20,200 km or 12500 miles
above the earth surface.
• 2) user segment:
• It consist earth based GPS receiver
–It determines the position and time of
translated information by using the signals
taking from the satellite .

34. CONTROL SEGMENTS
• It consist of tracking station.
• One control station and four monitoring
station.
• It consist of global network that track any
object of the surface of the earth.

35. Categories of satellite
• There are three major categories of satellite.
• GEO:
– Geo stationary earth orbit.
– These satellites are in the orbit of 35863 km above the
earth surface.
– These satellites are fixed in the sky.
– Ground based antenna do not need to track them
– One geo satellite can not cover the whole earth it take
minimum 3-4 satellite to cover or to provide global
transmission
– Time taken by geo satellite to revolve around the earth
is 24 hours

36. MEO (medium earth orbit)
• These satellite are in the orbit of 12000 km to
22000 km above the earth surface.
• It is mostly used in GPS for navigation
communication.
• MEO are higher than LEO and lower than Geo.
• It is also used in telecommunication.
• Application : GPS

37. LEO ( LOW EARTH ORBIT)
• These satellite are in the orbit of 500 to 2000
km above the earth surface.
• These satellite are used for many purposes
such as satellite communication and
surveillance.
• It is also used for data communication such as
email and video conferencing.
• Application : Communication

38. MOBILE DEVICE COMMUNICATION
• MOBILE:
–Mobile is a portable telephone that does not
used wired connection.
• MOBILE COMMUNICATION
–Mobile communication must be able to
allow roaming.
–ROAMING:
• The ability to provide services to mobile phone
user to use the mobile communication outside
their homes.

39. • Mobile communication is a wireless form of
communication in which data & voice is
transfer from one device to another device.
• Now mobile communication act as backbone in
business transaction & success.
• There are some features & limitation of mobile
communication which are given below.

40. FEATURES OF MOBILE COMMUNICATION
• Easy communication:
–User can communicate with anyone, anytime,
anywhere.
• Easy connection:
–Devices can be connected anytime, anywhere
any network.
• Use same frequency:
–Same frequency can be use for multiple links
as long as they are in different cell.

41. • USE LESS POWER:
– Mobile devices use less power as compared to
single transmitter.
• LARGE COVERAGE AREA:
– It reuse the frequency therefore it cover large area.
• ROAM SERVICES:
– It is the fastest way of communication because it
provide the services of roaming all around the
world.
• LOW COST:
– The cost of messaging and talking wirelessly is
lower than talking and messaging using wired
network.

42. PROVIDE BETTER SERVICES.
• Mobile communication can provide better
services of MMS , GPRS , WAP.
• (Multimedia Messaging Service)
– MMS stands for Multimedia Messaging Service.
Whenever you send a text with an attached file, like a
picture, video, emoji, or a website link, you're sending
an MMS.
• (General Packet Radio Services)
– General Packet Radio Services (GPRS) is a best-effort
packet-switching protocol for wireless and cellular
network communication services

43. • WAP: wireless application protocol
– Definition(s): A standard that defines the way in
which Internet communications and other
advanced services are provided on wireless
mobile devices.

45. LIMITATION OF MOBILE
COMMUNICTION
• The following the are the limitation of
mobile communication:
• SECURITY ISSUE :
–in mobile communication the big
problem is security.
–Mobile communication is less secure
than wired communication

46. BATTERY POWER ISSUE
• The other big problem of mobile
communication is battery power
because mobiles generally uses a
battery & charger is not plug in every
time.

47. CONNECTION PROBLEM
• You may not be able to receive
signal in some areas depending
where are you especially signals
can not work in mountains and
rural areas.

48. SLOW CONNECTION
• Mobile communication is slower
than wired communication.
• INTERFERENCE:
–Due to bad weather condition
rain and thunderstorm you face
a problem of dropping the
signals.

49. HIGH COST
• New device and technology are
costly to purchase.
• HEALTH HAZARDS:
–Mobile phone produce some
ultra voilet rays which are very
dangerous for health.

50. • The continuous releasing a signals
from mobile can be a reason of
cancer problem .
• Road accident is due to using mobile
phone while traveling.

51. Requirements of mobile
communication
• PSTN:
– It is made from local networks.
– It inter connects the telephone and
communication devices by telephone line.
• MTSO:
– It is the main central office for connecting
telephone.
– MTSO control manage track and locate user call

52. • CELL SITE:
– It is also known as cell tower where BTS (antenna)
is located.
– It provide coverage within a cell.
• MSU:
– It consist a control unit and transceiver which
transmit and receive radio transmission with cell
site.
• MS:
– MS contain mobile equipment and SIM .
– MS start working when sim is inserted into
relevant jacket or chip

53. • BSS (base station sub station )
–BSS consist BTS ( base transceiver
station ) located at antenna site
and a BSC ( base station controller )
• NSS ( Networking and switching
sub system )
–NSS main part of MSC ( mobile
switching services center )

54. PARTS OF NSS
• HLR ( home location register )
– it consist the database which store the
user information permanently.
• VLR ( visitor location register )
• It temporary store the user
information what ever mobile is
currently in its area.

55. OSS ( OPERATION SUB SYSTEM )
• There are three area in OSS
–Network operation and
maintenance.
– subscription management (
including billing and recharge )
–Mobile equipment mangement