1. © Kemal Akkaya Mobile & Wireless Computing 1 Department of Computer Science Southern Illinois University Carbondale CS441 – Mobile & Wireless Computing Wireless Network Challenges Dr. Kemal Akkaya E-mail: kemal@cs.siu.edu

2. © Kemal Akkaya Mobile & Wireless Computing 2  Instructor  Dr. Kemal Akkaya, kemal@cs.siu.edu, Faner 2138@cs.siu.edu  Office hours Monday, Wednesday 1-2pm, Friday 9-9:50am. E-mail is the best way to communicate with me  Class Web Site  http://www.cs.siu.edu/~cs441  Teaching assistant  Mr. Ismail Guneydas guneydas@siu.edu  Office hours T:1:30-3:30pm or By Appointment Class Administration: Personnel

3. © Kemal Akkaya Mobile & Wireless Computing 3 Class Administration  No Textbooks  I will provide slides for each chapter  There can be some papers for reading  Check the web site frequently  A reference book  “Ad Hoc Wireless Networks, by Murthy and Manoj, 1st Ed., Prentice Hall, 2004.  We’ll cover a few chapters from this book  Networking Background  Nice to have a networking and operating systems background but not mandatory Rose’s Networking Tanenbaum’s Networking  We’ll briefly cover them in the class

4. © Kemal Akkaya Mobile & Wireless Computing 4 What You Need to Do  Your prerequisites  Basic concepts of operating systems and networks  Highly motivated, critical, dedicated  Your workload  Homework assignments Reading and summary of some papers/textbook chapters Explanation for some questions/topics etc.  Hands-on Labs 3-4 labs with Sensor motes  Two exams Midterm Final -Comprehensive  Class project (in a small group of around 3 people) Pick a simple protocol Explain and summarize how it works Implement it in C, C++  Report and presentation on a topic you choose We will suggest topics, provide resources Topics will be chosen among hot areas in pervasive computing

5. © Kemal Akkaya Mobile & Wireless Computing 5 Grading Policy and Class Survey  Grading  Please take the class survey  Help me to determine your background  Help me to determine the depth and topics  Suggest topics that you want to be covered Group project25% Midterm Exam15% Final Exam20% Quizzes5% Assignments10% Presentation15% Hands-on Labs10%

6. © Kemal Akkaya Mobile & Wireless Computing 6 Mobile and Wireless Data Networks  Experiencing a tremendous growth over the last decade  Wide deployment of access infrastructure In-door, out-door, MAN, WAN  Growth of Wireless Data  Miniaturization of computing machinery : laptop  PDA  embedded sensors  Increasing mobile work force  Luxury of tether less computing  Information on demand anywhere/anyplace  Some Facts:  In 2005, more than 1/3 rd of internet users had internet connectivity through a wireless enabled device (750 million users)!!! (Source: Intermarket group)  In the year 2004 revenue from wireless data was $34B, and by the year 2010 the number of wireless data subscribers will hit 1B!!  What is Mobile and Wireless Computing?  Distributed systems with portable computers and wireless communications  User can access data anytime, anywhere

7. © Kemal Akkaya Mobile & Wireless Computing 7 Buzzwords  Mobile Computing  Distributed systems with mobile users In-door/Out-door Vehicle/human speed  Nomadic Computing  Similar to Mobile computing Focuses more on in-door communications  Pervasive Computing : Ubiquitous Computing  May add some user interface integration  Some says : AI + Mobile Computing stuff  Applications:  Military Border control, target tracking, intrusion detection etc.  Civil Habitat monitoring, search and rescue, meeting rooms etc.

8. © Kemal Akkaya Mobile & Wireless Computing 8 Wireless Network Types  Satellite networks  Iridium (66 satellites)  Qualcomm’s Globalstar (48 satellites)  Wireless WANs/MANs  CDPD (Cellular Digital Packet Data )  GPRS (General Packet Radio Service)  Wireless LANs  IEEE 802.11 : SIU’s LAWN,  Wireless PANs  e.g. Infrared: Bluetooth  Ad-hoc networks  e.g. Emergency relief, military  Sensor networks  e.g. Environmental sensing-MICA motes Wireless WAN Generations:  1G (Past)  AMPS, TACS: No data  2G (Past/Present)  IS-136, GSM: <10Kbps circuit switched data  2.5G (Past/Present)  GSM-GPRS, GPRS-136: <100Kbps packet switched  3G (Present/Immediate Future)  IMT-2000:<2Mbps packet switched  4G (Future)  20-40 Mbps!!

9. © Kemal Akkaya Mobile & Wireless Computing 9 Examples PicoNet Bluetooth 802.11 / WiFi Wireless LAN

10. © Kemal Akkaya Mobile & Wireless Computing 10 Applications: Home Networking Courtesy Dr. Richard Yang, Yale

11. © Kemal Akkaya Mobile & Wireless Computing 11 Applications: Outdoor Networking Courtesy Dr. Richard Yang, Yale

12. © Kemal Akkaya Mobile & Wireless Computing 12 Application: Environmental Monitoring Wireless Sensor Nodes monitor an area of interest

13. © Kemal Akkaya Mobile & Wireless Computing 13 Challenges of Wireless Computing  1) Wireless Communication  Implications of using wireless communication for mobile computing  The differences between wireless and wired media  2) Mobility  Consequences of mobility on mobile application and system design  3) Poor Resources due to Portability  Pressures that portability places in the design of mobile end-systems

14. © Kemal Akkaya Mobile & Wireless Computing 14 1) Wireless Communication  Limited Transmission Range  10m-500m  Limited Bandwidth  Wireless networks deliver lower bandwidth than wired networks 1 Mbps Infrared communication 11 Mbps wireless local radio communications (shared), IEEE 802.11b 9.6 Kbps for wide-area wireless communication  Wired networks 10-100 Mbps for Ethernet 100 Mbps for FDDI 155 Mbps for ATM 1 Gbps for Gigabit Ethernet  Disconnections  Network partitions  Stall all applications  Uncertainty of Performance  Variance of bit errors  Variance of delays  Variance of bandwidth  Security  Easy to intrude in the wireless network  Heterogeneous devices and network connections  Wired links Same characteristics  Outdoor: Radio  Indoor: Infrared  Rural Areas: Satellite

15. © Kemal Akkaya Mobile & Wireless Computing 15 Heterogeneous Devices Performance/Weight/Power Consumption Sensors, embedded controllers Mobile phones voice, data simple graphical displays GSM PDA data simpler graphical displays 802.11 Laptop fully functional standard applications battery; 802.11 Desktop fully functional standard applications unlimited power supp Gbps Ethernet

16. © Kemal Akkaya Mobile & Wireless Computing 16 2) Mobility  Ability to change locations while connected to the network  A mobile computer can change its server DNS server, print server, etc.  Dynamic Environment  Network Access Point Changes  Address changes: IP address  Network Performance Changes  Bandwidth, delay, error rate etc.  Available resources change  Depends on the network it connected to  Data consistency changes  Writing/Reading to/from mobile databases  Security changes  Endpoint authentication harder

17. © Kemal Akkaya Mobile & Wireless Computing 17 3) Poor Resources  Mobile devices are fundamentally different from stationary machines such as desktop computers  Must be designed with variety of constraints in mind, such as size and power consumption – properties much like a wristwatch  They should also be portable  Portability Constraints Include  Low power consumption You would not want to carry a battery that is bigger than your computer!  Increased risk of data loss Physical damage Unauthorized access Loss and Theft  Small user-interfaces Requires a different windowing scheme Buttons versus Recognition  Limited on-board storage, memory, CPU etc Physical restrictions, power constraints

18. © Kemal Akkaya Mobile & Wireless Computing 18 Summary  Wireless communication brings challenging network conditions  Slow and sometime disconnected communication  Mobility causes greater dynamicisim of information  Portability results limited resources to be available on board  Mobile computing designers should consider these issues in designing mobile systems, applications and networks that are comparable with the traditional stationary computing and communication in terms of operation, performance, and availability  Very active research area in the last decade  Many interesting research problems