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

2. 2 More Information  Office (chengzhi): OLSSON 210  E-mail address : chengzhi@cs.virginia.educhengzhi@cs.virginia.edu  Office hour (chengzhi): Tuesday & Thursday 5:15-6:30 pm

3. 3 First Thing to Do !  Everything is in the Web  Syllabus, materials, presentation schedule, … http://www.cs.virginia.edu/~cs851-2/course.html

4. 4 Seminar Requirements  Students should have excellent background on computer networks  Every student needs to do two presentations (begin at Sep 10) o Students need to sign up their first presentation schedule before Sep.4  Each presentation will cover one or two papers  For each presented paper, every student needs to hand in a simple summary which contains: o What is the problem the paper wants to solve? o What is the background? o What are the contribution of the paper? o What is the new idea in the paper? o What is the weakness in the paper?  Term project o Performed in small group which consists of 3~4 students. o Suggested topics will be provided before Sep. 10 o Students need to find their partner before Sep. 12

5. 5 Selected Topics 1.Wireless Medium Access Control 2.IEEE 802.11 3.Mobile Ad Hoc Routing 4.Mobile IP 5.TCP over Wireless Link 6.Energy Efficient and Power Aware Protocols 7.Capacity of Wireless Network 8.Mobile Data Management 9.Address auto configuration 10.Location Discovery/Tracking Multicast in Mobile Ad Hoc Network (option) Security (option)

6. 6 1. Wireless Medium Access Control  “MACA - A New Channel Access Method for Packet Radio”. In Proceedings of the 9th ARRL Computer Networking Conference, London, Ontario, Canada, 1990.  ``MACAW: A Media Access Protocol for Wireless LANs.'' V. Bharghavan, A. Demers, S. Shenker, and L. Zhang, ACM Sigcomm '94, London, UK. September 1994.  "Dual busy tone multiple access (DBTMA): A multiple access control scheme for ad hoc networks", J. Deng and Z. Haas, in IEEE Trans. on Communications, vol. 50, no. 6, 2002.

7. 7 2. IEEE 802.11  "IEEE 802.11 Wireless Local Area Networks“, B. Crow, I. Widjaja, L. Kim, P. Sakai, IEEE Communications Magazine, Vol. 35, No. 9, Sep 1997, pp. 116-126. Also see Chapter 9 in.IEEE 802.11 Standard specification, 1999  “Does the IEEE 802.11 MAC protocol work well in multihop wireless ad hoc networks?”, Xu and T. Saadawi, IEEE Communications Magazine, Vol. 39, No. 6, pp. 130-137, June 2001.  "Real-Time Traffic Over the IEEE 802.11 Medium Access Control Layer", Joao L. Sobrinho and A. S. Krishnakumar, Bell Labs Technical Journal, Autumn 1996

8. 8 3. Mobile Ad-Hoc Routing  “Dynamic source routing in ad hoc wireless networks”, David B. Johnson, David A. Maltz, in Mobile Computing, editor T. Imielinski and Hank Korth, Kluwer  “The performance of query control scheme for the zone routing protocols”, Z. Haas and M. R. Pearlman, in IEEE Trans. on Networking, vol. 9, no. 4, 2001  “Location-Aided Routing (LAR) Mobile Ad Hoc Networks”, Youngbae Ko and N. H. Vaidya, MOBICOM'98, October 1998,

9. 9 4. Mobile IP  "Mobile Networking through Mobile IP“, C. Perkins, IEEE Internet Computing, Vol. 2, No. 1, 1998 "Mobile IP" C. Perkins, IEEE Communications Magazine, Vol. 35, No. 5, 1997.

10. 10 5. Wireless TCP  “I-TCP: indirect TCP for mobile hosts”, ICDCS 1995  “Improving TCP/IP Performance over Wireless Networks”, Hari Balakrishnan, Srinivasan Seshan, Elan Amir, Randy H. Katz. Proc. 1st ACM Conf. on Mobile Computing and Networking, Berkeley, CA, November 1995.  "Analysis of TCP performance over mobile Ad-Hoc networks", G. Holland and N. Vaidya, Mobicom 1999

11. 11 6. Energy Efficient and Power Aware Protocols  “An energy efficient MAC protocol for wireless sensor networks”, W. Ye, J. Heidemann, and D. Estrin, in Proceedings of IEEE INFOCOM'02.  “Power-Aware Routing in Mobile Ad Hoc Networks”, S. Singh, M. Woo and C. Raghavendra, MOBICOM'98.  “Span: An Energy-Efficient Coordination Algorithm for Topology Maintenance in Ad Hoc Wireless Networks”, Benjie Chen, Kyle Jamieson, Hari Balakrishnan, and Robert Morris, MobiCom 2001.

12. 12 7. Capacity of Wireless Networks  “Capacity of ad hoc wireless networks”, J. Li, C. Blake, D. S. J. De Couto, H. I. Lee, and R. Morris,in Mobicom 2001.

13. 13 8. Mobile Data Management  “Scheduling Data Broadcast In Asymmetric Communication Environments”, N. H. Vaidya and S. Hameed, ACM/Baltzer Wireless Networks (WINET), 2001.  "A Mobile Transaction Model That Captures Both the Data and Movement Behavior," M. Dunham, A. Helal, and S. Balakrishnan, ACM/Baltzer MONET Journal, Vol 2, 1997, pp. 149-162.  "Data consistency in intermittently connected distributed systems", E. Pitoura and B. Bhargava, IEEE Trans on Knowledge and data engineering, vol. 11, no. 6, 1999

14. 14 9. Address Auto Configuration  “Duplicate Address Detection in Mobile Ad Hoc Networks”, Nitin Vaidya, ACM MobiHoc, June 2002.

15. 15 10. Location Tracking  “The Cricket Compass for Context-Aware Mobile Applications”, Priyantha et al., MobiCom 2001  “GPS Free Positioning in Mobile Ad Hoc Networks”, Proceedings of IEEE ICSS2001

16. 16 Introduction [1] “Some computer science issues in Ubiquitous Computing” by M. Weiser 1993 [2] “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

17. 17 What is Mobile Computing?  Creating distributed systems with portable computers and wireless communications to allow mobile users to access resources at anytime from anywhere (refer to “Challenges of Mobile Computing”)

18. 18 Buzzwords 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 (refer to “Anytime, anywhere computing: Mobile Computing and Technology”)  Ubiquitous Computing ==Pervasive Computing (AI + Mobile Computing)  creating environments saturated with computing and communication capacity yet gracefully integrated with human users (refer to “Pervasive Computing: Vision and Challenges” )

19. 19 Many Applications  Military environments  soldiers, tanks, planes  Civilian environments  taxi cab network  meeting rooms  sports stadiums  boats, small aircraft  search-and-rescue  policing and fire fighting  Killer application  Anywhere and anytime access to the Internet

20. 20 Evolution of Computing Freedom from Collocation (space & time) Flexible Resource Usage Single User OS Time Sharing Networked Computing Mobile Computing

21. 21 Three Challenges  Wireless communication  Mobility  Poor local resources due to portability

22. 22 Wireless Communication  Limited transmission range  Limited bandwidth o IEEE 802.11a ~54 mbps o IEEE 802.11b ~ 11 mbps o IEEE 802.11g ~ 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

23. 23 Mobility  Mobility  Dynamic  Network access point changes  Network performance changes (error rate, latency, cost, connectivity …)  Available resources change  Data consistency changes  Application changes oLoss of bandwidth triggers change from color to B&W  Security changes oEndpoint authentication harder oDevices become more vulnerable

24. 24 Poor local resources due to portability  CPU  Memory  limited battery life time All these challenges are instinct and every mobile computing problem is related to one or more than one these challenges

25. 25 Five Areas for Achieved Results refer to “Pervasive Computing: Vision and Challenges”  Mobile networking  Mobile information management  Adaptive techniques  Power management and energy saving  Location sensitivity Topic 1,2,3,4 Topic 8 Topic 10 Topic 6 Topic 5

26. 26 Summary  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