1. Mobile Computing
Lecture Materials By
Bintang Eka Putera

2. Background WHAT IS MOBILITY? A person who moves
between different geographical locations
between different networks
between different communication devices
between different applications

3. What is Mobility?
Mobile computing is about both physical and logical computing entities that move
Physical entities
computers change locations
Logical entities
a running user application or a mobile agent migrating over internet

4. New Forms of Computing Distributed Computing (Client/Server)
Wireless Computing
Nomadic Computing
Mobile Computing
Ubiquitous Computing
Pervasive Computing
Invisible Computing

5. Comparison to Wired Network
Wired Networks
Mobile Networks
high bandwidth
low bandwidth variability
can listen on wire
high power machines
high resource machines
need physical access(security)
low delay
connected operation
low bandwidth
high bandwidth variability
hidden terminal problem
low power machines
low resource machines
need proximity
higher delay
disconnected operation

6. Nomadic computing refers to limited migration
migration is within a building at a pedestrian speed
interleaved pattern of user relocation and indoor connections
users carrying laptop with wireless access are engaged in nomadic computing

7. Mobile computing
requires wireless h/w to support outdoor mobility and handoff from one h/w to the next at a pedestrian or vehicular speed
traveler in car using laptop / smart phone / mobile device connected with a GSM/WCDMA/HSPA phone engaged in mobile computing

8. Ubiquitous computing or pervasive computing
refers to access to computer network all the time at any location by any person
can not be realized unless mobile computing matures

9. Nomadic – Mobile – Ubiquitous
Applications
Network
No Network
Fixed Network
Fixed Wireless Network
Wireless Network
Computing Systems
Nomadic Computing
Mobile Computing
Ubiquitous Computing

10. Heterogeneous Wireless Communication World

11. Heterogeneous Wireless Communication World

12. Heterogeneous Wireless Communication World

13. Heterogeneous Wireless Communication World
Heterogeneous wireless networks consists of
Cellular networks
WLAN networks
other access technologies
Users should be able to access various services from various networks with varying properties in terms of data rates, SNR, latency, coverage, price etc.
Multiple devices or multi-mode devices may be used to access various services which add to the complexity of the system
Mobile communication in such a scenario requires automatic rearrangement of communication and services
These adaptive services need to be centered around the user since multiple networks and operators may be present

14. Wireless Communication Technology

15. Main Topics What is Mobile Computing? Wireless Communication Systems
Mobile Communication Systems Architecture
Key Technologies of Mobile Computing
Applications

16. What is Mobile Computing?
A simple definition could be: Mobile Computing is using a computer (of one kind or another) while on the move

17. What is Mobile Computing?
Another definition could be: Mobile Computing is when a (work) process is moved from a normal fixed position to a more dynamic position.

18. What is Mobile Computing?
A third definition could be: Mobile Computing is when a work process is carried out somewhere where it was not previously possible.

19. What is Mobile Computing?
Mobile Computing is an umbrella term used to describe technologies that enable people to access network services anyplace, anytime, and anywhere.

20. Wireless Communications
RADIO!
Radios are Listeners not Speakers !
Radio signals received in Limited Area
Radios use various frequencies
Radio Communication is Analog
Wireless Communications
First thing that comes in mind that has anything to do with wireless is …

21. Wireless Communications
So HOW TO send
Digital data on {Analog / Digital} Signal?
Wireless Communications
First thing that comes in mind that has anything to do with wireless is …

22. Wireless Communications
Can Transmit (Tx) & Receive (Rx)
Can Interpret Analog signal
Can convert Analog signal to Digital data
Can send and receive signal in some Area
Can connect to other devices in this Area
Can stay connected while moving
Would have “enough” bandwidth for Tx
Wireless Communications
We need devices that

23. Wireless Communications
Devices operate on various Frequencies
Two devices can “Talk” on same Frequency
Many devices need many frequencies LF MF HF
VHF
UHF
SHF
EHF
Freq (Hz)
105
106
107
108
109
1010
1011

24. Security concerns normal network point of attachment is a wall tap
wireless access makes network attachment too easy
Security concerns
Authentication is critical

25. Security concerns any transmitter can also be a receiver!
some wireless networks provide secure airlinks (e.g., CDPD/Cellular Digital Packet Data)
made more difficult by spread spectrum technologies
Security concerns
Exposure to over-the-air wiretapping

26. Security concerns
Mobile agent security