1. Mobile Computing and Wireless Networking
CS 851 Seminar 2002 Fall
University of Virginia

2. First Thing to Do ! http://www.cs.virginia.edu/~cs851-2/course.html
Everything is in the Web
Syllabus, materials,

3. What Are We Going to Learn?
What are the challenges facing Mobile Computing?
What are fundamental principles in Mobile Computing
What is the state-of-the-art research for Mobile Computing?
What are the open problems?

4. Selected Topics Vision and Challenges Wireless Medium Access Control
IEEE  
Mobile Ad Hoc  Routing   
Mobile IP  
TCP over Wireless Link
Energy Efficient  and Power Aware Protocols  
Capacity of Wireless Network  
Mobile Data Access/Dissemination  
Address auto configuration  
Location Discovery/Tracking   
Multicast in Mobile Ad Hoc Network (option)  
Security (option)

5. How Are We Going to Learn?
Select new and representative papers for each topic
Each student needs to do two presentations
Each presentation will cover one or two papers (begin at Sep 10)
Before each lecture, every student needs to hand in a simple summary about the presented papers (begin at Sep 10)
Term project performed in small group which consists of two students. (Suggested topics will be provided before Sep. 15)

6. Challenges of Mobile Computing
[1] “Some computer science issues in Ubiquitous Computing” by M. Weiser 1993
[2] “The challenges of Mobile Computing” by G. H. Forman & J. Zahorjan 1994
[3] “On some principles of Nomadic Computing and Multi-Access Communications” by L. Kleinrock 2000
[4] “Pervasive Computing: Vision and Challenges” by M. Satyanarayanan 2001

7. What is Mobile Computing?
Building distributed systems with portable computers and wireless communications to allow mobile users to access services and resources at anytime from anywhere
Advances of wireless communication & portable computers make computers users do not need to maintain a fixed position in the network and enables almost unrestricted mobility. However, network resources and application software do not follow mobile users. There are many problems to provide computing and communication capacities to mobile users.

8. Buzzwords Nomadic Computing, Pervasive Computing
Ubiquitous Computing, Mobile Computing,
Nomadic Computing, Pervasive Computing
Mobile Computing and Nomadic Computing are about building distributed systems with portable computers and wireless communications
Mobile Computing: focus on out-door mobility with pedestrian or vehicular speed
Nomadic Computing: focus on in-door mobility with pedestrian speed
Ubiquitous Computing ==Pervasive Computing (AI + Mobile Computing)
creating environments saturated with computing and communication capacity yet gracefully integrated with human users (or enhancing computer use by making many computers available throughout the physical environment, but making them effectively invisible to the users)

9. Many Applications Military environments Civilian environments
soldiers, tanks, planes
Civilian environments
taxi cab network
meeting rooms
sports stadiums
boats, small aircraft
Emergency operations
search-and-rescue
policing and fire fighting
Killer application
Anywhere and anytime access to the Internet

10. Evolution of Computing
Freedom from Collocation (space & time)
Flexible Resource Usage
Single User OS
Time Sharing
Networked Computing
Mobile Computing
Pervasive Computing

11. Three Challenges Wireless communication Mobility
Poor local resources due to portability

12. Wireless Communication
Limited transmission range (IEEE < 300 meters)
Limited bandwidth
IEEE ~ 2 mbps
IEEE a ~54 mbps
IEEE b ~ 11 mbps
IEEE g ~ 20mbps
Frequent disconnections or network partitions
Uncertainty of performance
Variance of bit error
Variance of latency
Variance of bandwidth
Easier for intruders to insert themselves into networks

13. Mobility Mobility  Dynamic Environment Network
Address migration (network access point varies)
High performance variability (error rate, latency, cost, connectivity …)
Hardware
Lighter
More robust
Lower power
Available resources change
Correctness of information changes

14. Poor local resources due to portability
CPU
Memory
limited battery life time
All these challenges are instinct and need innovative and system-wide solutions

15. Five Areas for Achieved Results
Mobile networking
Mobile information management
Adaptive techniques
Power management and energy saving
Location sensitivity

16. Mobile Networking Mobile Ad-Hoc networks Mobile IP Wireless TCP
Multiple Access Control
Distributed scheduling algorithms
Mobile ad-hoc routing
Security
Mobile IP
Wireless TCP
I-TCP
Snoop TCP

17. Mobile Data Management
Data delivery modes
Server push
Client pull
Hybrid
Data organization
Data consistency management
Disconnected operation
Weak connected operation

18. Adaptive Techniques
Exploiting dynamical (networking, physical, users) information to perform effective mobile computing
Adaptive resource management
Adaptive networking
Application-aware adaptations
Example: a videoconferencing application can display only the speaker if bandwidth is low, else all participants

19. Power Management and Energy Saving
Topology control of ad-hoc networks using transmit power adjustment
Power aware routing protocols
Power aware MAC protocols

20. Location Sensitivity Location-aware applications
Discover and take advantage of contextual information such as user location, nearby people and devices, and user activity
Ex.
What resources (printers, ect.) are available “here”?
Where is the “nearest” hospital?
How do I get from “here” to the nearby public library
Location information systems
Indoor location tracking system
Outdoor logical location determination system without GPS

21. Summary Dedicate your time and make contributions Mobile computing
Very active and evolving research field
Plenty of interesting research problems
We will learn a lot in this course
Understand the state of the art
New ideas and new results
New ways of using mobile computing
It will be Very Rewarding
Dedicate your time and make contributions

22. Evolution of Computing
Freedom from Collocation (space & time)
Flexible Resource Usage
Single User OS
Time Sharing
Networked Computing
Mobile Computing
Pervasive Computing