Download What is Mobile and Wireless Computing?

Department of Computer Science
Southern Illinois University Carbondale
CS441 – Mobile & Wireless
Computing
Wireless Network Challenges
Dr. Kemal Akkaya
E-mail: [email protected]
© Kemal Akkaya
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Class Administration: Personnel
 Instructor
 Dr. Kemal Akkaya, [email protected], Faner 2138
 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
[email protected]
 Office hours
 T:1:30-3:30pm or
 By Appointment
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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
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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
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Grading Policy and Class Survey
 Grading
Group project
25%
Midterm Exam
15%
Final Exam
20%
Quizzes
5%
Assignments
10%
Presentation
15%
Hands-on Labs
10%
 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
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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
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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 1/3rd 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
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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.
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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 WAN Generations:
 1G (Past)
 AMPS, TACS: No data
 2G (Past/Present)
 IS-136, GSM: <10Kbps
circuit switched data
 2.5G (Past/Present)
 Wireless LANs
 GSM-GPRS, GPRS-136:
<100Kbps packet
switched
 IEEE 802.11 : SIU’s LAWN,
 Wireless PANs
 e.g. Infrared: Bluetooth
 Ad-hoc networks
 3G (Present/Immediate
Future)
 IMT-2000: <2Mbps packet
switched
 e.g. Emergency relief, military
 Sensor networks
 4G (Future)
 e.g. Environmental sensing-MICA
motes
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 20-40 Mbps!!
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Examples
802.11 / WiFi
Wireless LAN
PicoNet
Bluetooth
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Applications: Home Networking
Courtesy Dr. Richard Yang, Yale
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Applications: Outdoor Networking
UMTS, WLAN,
DAB, GSM,
cdma2000, TETRA, ...
Personal Travel Assistant,
PDA, laptop,
GSM, UMTS, WLAN,
Bluetooth, ...
Courtesy Dr. Richard Yang, Yale
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Application: Environmental Monitoring
Wireless
Sensor
Nodes
monitor an
area of
interest
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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
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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
10-100 Mbps for Ethernet
100 Mbps for FDDI
155 Mbps for ATM
1 Gbps for Gigabit Ethernet
© Kemal Akkaya
 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
 Wired networks
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 Disconnections
 Same characteristics
 Outdoor: Radio
 Indoor: Infrared
 Rural Areas: Satellite
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Heterogeneous Devices
Mobile phones
• voice, data
• simple graphical displays
• GSM
Sensors,
embedded
controllers
Laptop
• fully functional
• standard applications
• battery; 802.11
PDA
• data
• simpler graphical displays
• 802.11
Desktop
• fully functional
• standard applications
• unlimited power supp
• Gbps Ethernet
Performance/Weight/Power Consumption
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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
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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
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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
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