1. Basic Concepts of Wireless
Communication System
Prepared by: Mr. Gilbert De Castro

2.  Computer Networking
 Data Communication
 Transmission Media
 Distributed System
Objectives

3. Basic Principle of Networks
Computer network
 Collection of computers
and devices connected
via communications
devices and
transmission
media
 Bunch of computers
hook together in some
way
 Each particular message
is usually routed to a
particular computer

4. Basic Principle of Networks
Networking
 Is the problem of
delivering a message
from a source to a
destination
 The problem of giving
meaning to these
messages received is
called communication

5. Use of Computer Networks
 Networks for Companies
 Resource sharing – Saves time and money.
 Dynamic rerouting – Having alternative source of supply
data
Basic Principle of Networks

6.  Networks for people
 Access to remote information – Great source of
information
 Person-to-person communication
 Interaction between a person and a database
 Person-to-person interaction
 Interactive entertainment
 Network gaming
 Video-on-demand
Basic Principle of Networks

7. Advantages of networking
 Connectivity and communication
 Data sharing
 Hardware sharing
 Internet access
 Internet access sharing
 Data security and management
 Performance enhancement and balancing
 Entertainment
Basic Principle of Networks

8. Basic Principle of Networks
Communication channel
 Is a pathway over which
information can be
transferred
 Information sent over a
channel has source (often
called the transmitter), from
which the information
originates
 And destination (often called
the receiver), to which the
information is delivered
Channel

9. Communication channels
Any communication has a direction associated with it
 Simplex channel – is a channel whose direction of
transmission is unchanging
 Half-duplex channel – is a channel in which the
direction may be reversed, but the transmission does
not occur at the same time
 Full-duplex channel – is a channel that allows
simultaneous exchange in both directions
Basic Principle of Networks

10. Types of Transmission Technologies
 Point-to-point network – consist of many connections
to individual pairs of machines
 Broadcast networks – all the machines on the
network share a single channel
Basic Principle of Networks

11. Network Topologies
 Computer networks come in different shapes and
sizes
 The network’s topology can be thought of as its
“shape”, the way the computers on the network are
connected
 Network topologies are categorized into the five
basic types
Basic Principle of Networks

12. Characteristics of effective data communication
 Delivery
 Accuracy
 Timeliness
Basic Principle of Networks

13. Components of data communication
 Message
 Sender
 Receiver
 Medium
 Protocols
Basic Principle of Networks

14. Protocol
 Formal description of set of rule sand conventions
that govern how devices on a network communicate
 Control aspects of data communication, which
include the following:
 How the physical data is built
 How computers connect to the network
 How the data is formatted for transmission
 How the data is sent
 How to deal with errors

15. Basic Principle of Networks
Network Topologies
Bus network
 A common channel
connect all devices
 All computers and
devices connect to
central cable, or bus

16. Basic Principle of Networks
Ring network
 All messages travel in a ring,
either in clockwise or
counterclockwise direction
 Cable forms closed ring, or
loop, with all computers and
devices arranged along ring
 Data travels from device to
device around entire ring, in
one direction

17. Basic Principle of Networks
Star network
 All devices connect to a
central device, called hub
 All data transferred from
one computer to another
passes through hub

18. Basic Principle of Networks
 Tree network -
Integrates multiple star
topologies together into
a bus

19. Basic Principle of Networks
 Mesh network – involves
the concept of routes,
where a message is sent
on the network can take
any of several possible
paths from source to
destination
 Popular topologies are
bus, ring, and star

20. Communications device
 Hardware component that enables a computer to
send and receive data, instructions and information
 Occurs over cables, telephone lines, cellular radio
networks, satellites, and other transmission media

21. Communication Devices
 Modem
 Network Card
 Gateway
 Router
 Wireless Access Point
 Hub

22. Modem
• Converts digital signals to analog signals and vice versa
 Dial up modem
 ISDN and DSL modems
 Wireless modem

23. Network Card
 Adapter card, PC Card, or flash card that enables
computer or device to access network
 Sometimes called network interface card (NIC)

24. Gateway
 Links network using different protocols
 Contain devices such as protocol translators

25. Router
 Connects multiple networks and determines the
fastest route for sending data over the network

26. Wireless Access Point
 Connects wireless communication devices

27. Hub
• Device that provides central point for cables in
network

28. Communication Channel
 Transmission media on which data travels in
communications system
 Transmission media - are materials capable of carrying
one or more signals
 Bandwidth - amount of data that can travel over a
communications channel
 Physical Transmission Media
 Wireless Transmission Media

29. Physical Transmission Media
 Wire, cable, and other tangible materials used
to send communications signals
 Twisted-pair cable
 Coaxial Cable
 Fiber-optic cable

30. Twisted-pair cable
 Used for telephone systems and network cabling

31. Coaxial Cable
 Often used for cable television wiring

32. Fiber-optic cable
 Capable of carrying
significantly more
data at faster speeds than
wire cables
 Less susceptible to
interference (noise) and,
therefore, more secure,
Smaller size (thinner and
lighter)

33. Wireless transmission media
 Radio Signal
 Microwaves
 Satellites
 IrDA
 Bluetooth
 Wi-Fi

34. Radio Signal
 Broadcast radio distributes
radio signals over long and
short distances
 Cellular radio is form of
broadcast radio used for
mobile communications

35. Microwaves
 Earth-based reflective
dish used for microwave
communications
 Must transmit in straight
line with no obstructions

36. Satellites
 Space station
that receives microwave
signals from earth-based
station, amplifies signals,
and broadcasts signals back
to any number of earth-
based stations

37. IrDA ( Infrared Data Association)
 Physical specifications communications protocol
standards for the short-range exchange of data over
infrared light waves

38. Bluetooth
 Short-range radio waves transmit data between
Bluetooth devices
 Short distance transmission of about 30 feet

39. Wi-Fi
 Wireless Fidelity
 Connecting electronic devices wirelessly

40. Basic Principle of Networks
Distributed Systems
 There is considerable confusion between a computer
network and a distributed system
 The key distinction is that in a distributed system, the
existence of multiple autonomous computers is
transparent to the user
 The user can type a command to run a program, and it
runs
 It is up to the operating system to choose the best
processor for the application, send the necessary data
and place the result to the proper location

41. Basic Principle of Networks
Client/Server
 Extension of distributed data
processing wherein it provides
the best of both centralized and
distributed data processing
 Client – issues a request to a
server to ask for work to be
done
 Server – usually a host machine
that provides database,
printing, storage and
communications

42. Basic Principle of Networks
Types of network design
The networking industry refers to nearly every type of
network as an “area network”.
 Local Area Network (LAN)
 Wide Area Networks (WAN)

43. Basic Principle of Networks
Local Area Network (LANs)
 Connect network devices
over relatively short
distances
 Usually owned by an
individual or corporation
 Network in limited
geographical area such as
home or office building

44. Basic Principle of Networks
Wide Area Networks (WANs)
 Span a large physical distance
(geographically-dispersed
collection of LANs) and
mostly owned by any one
organization but rather exist
under collective or distributed
ownership and management
 Network that covers large
geographic area using many
types of media
 Internet is world’s largest
WAN