Mobile and wireless networking in mobile computing

1. Mobile Computing
Lecture #02
By
Hannan Bin Liaqat
Department of CS& IT
University of Gujrat

2. Today’s Lecture Agenda
 What is Wireless Networks?
 Types of Wireless Networks
 History of Wireless Networks
 Advantages of Wireless Networks
 Disadvantages of Wireless Networks

3. What is Networks?
Definition:
Two or more computer or computing devices connected
together through connecting devices
Purpose of networking:
1- Communication
2- Sharing

4. Types of Networks
There are mainly two types of networks
1- Wired networks
2- wireless networks
Wired Networks:
In which all computer or computing devices are connected
through guided medium (cables)

5. Types of Networks
Wireless Networks:
in which all computers and computing devices are connected
through unguided medium (radio waves)

6. Wireless Networks …
 Wireless Networks operate in almost the same way
as wired Networks
 Using the same networking protocols
 Supporting almost the same applications

7. Types of Wireless Networks
There are mainly two types of wireless networks
1- Infrastructural wireless networks
2- Infrastructure less wireless networks
Infrastructural wireless networks:
Definition:
Infrastructure wireless networks are the wireless network that
contains wireless router/access point and enables other
computers connect to it wirelessly. This is the common
deployment to build a home wireless network.

8. Infrastructural wireless networks:
Diagram:
Basics Elements
1- wireless router/Access point
Responsible for sending packets between wired network
and wireless hosts in its “area”
2- computers (lap top)/other devices
3- applications running on the computers

9. Infrastructure less wireless networks
Ah Hoc Networks
 Infrastructure less networks are also called Ah hoc networks
 In this type of communication devices or computers
communicate directly with each other without the need for a
wireless router or access point
Basics Elements
1- computers (lap top)/other devices
Each computer is responsible for sending/forwarding packets
to other computers in its area (transmission range)
2- applications running on the computers

10. Infrastructure less wireless networks
Ah Hoc Networks

11. Early history of wireless
communication
 Many people in history used light for communication
 heliographs, flags
 150 BC smoke signals are used for communication;
(Polybius, Greece)
 1794, optical telegraph
 Introduction of electromagnetic waves:
 1831 Faraday demonstrates electromagnetic induction
 J. Maxwell (1831-79): theory of electromagnetic
Fields, wave equations (1864)
 H. Hertz (1857-94): demonstrates with an experiment
the wave character of electrical transmission through
space

12. History of wireless communication
I
 1895 Marconi
 first demonstration of wireless telegraphy (digital!)
 long wave transmission
 1907 Commercial transatlantic connections
 huge base stations
 1915 Wireless voice transmission New York - San Francisco
 1920 Discovery of short waves by Marconi
 reflection at the ionosphere
 smaller sender and receiver, possible due to the invention of the
vacuum tube
 1926 Train-phone on the line Hamburg - Berlin
 wires parallel to the railroad track

13. History of wireless communication
 1928 many TV broadcast trials (across Atlantic, color TV, TV news)
 1933 Frequency modulation
 1958 A-Netz in Germany
 analog, 160MHz, connection setup only from the mobile station, no
handover, 80% coverage, 1971 11000 customers
 1972 B-Netz in Germany
 analog, 160MHz, connection setup from the fixed network too (but
location of the mobile station has to be known)
 1982 Start of GSM-specification
 1983 Start of the American AMPS (Advanced Mobile Phone
System, analog)
 1984 CT-1 standard (Europe) for cordless telephones

14. History of wireless communication
 1986 C-Netz in Germany
 analog voice transmission, 450MHz, hand-over possible, digital
signaling, automatic location of mobile device
 1991 Specification of DECT
 Digital European Cordless Telephone (today: Digital Enhanced
Cordless Telecommunications)
 1992 Start of GSM
 1994 E-Netz in Germany
 GSM with 1800MHz, smaller cells, supported by 11 countries
 1996 HiperLAN (High Performance Radio Local Area Network)
 1997 Wireless LAN - IEEE802.11
 1998 Specification of GSM successors
 for UMTS (Universal Mobile Telecommunication System
1.13.1

15. Advantages of Wireless Networks
 Minimum installation issues
 Freedom to roam
 Scalability
 No cables

16. Disadvantages of Wireless Networks
 Careful planning of network essential
 Environment generally unfriendly
 Security
 Safety
 Spectrum licenses
 Poor data rates