CSE370 Wireless and Mobile Networks

Jie Gao 01/25/2010 ACK: Slides borrowed from Richard Y. Yang.

Outline • Introduction to wireless networks and mobile computing • Challenges facing wireless networks and mobile computing • Introduction to wireless physical layer

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Goal of Wireless Networking and Mobile Computing

“People and their machines should be able to access information and communicate with each other easily and securely, in any medium or combination of media – voice, data, image, video, or multimedia – any time, anywhere, in a timely, cost-effective way.” Dr. G. H. Heilmeier, Oct 1992 3

Enabling Technologies • Development and deployment of wireless/mobile technology and infrastructure • Miniaturization of computing machinery . . . -> PCs -> laptop -> PDAs/smart phones -> embedded computers/sensors • Improving device capabilities/software development environments, e.g., – andriod: http://code.google.com/android/ – iphone: http://developer.apple.com/iphone/ – windows mobile 4

Pervasive Use of Mobile Wireless Devices • There are ~4 billion mobile phones – Over 50 countries have mobile phone subscription penetration rates higher than that of the population (Infoma 2007) – http://en.wikipedia.org/wiki/Mobile_phone_penetrati on_rate

• The mobile device will be the primary connection tool to the Internet for most people in the world in 2020. PEW Internet and American Life Project, Dec. 2008

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At Home

WiFi

WiFi 802.11g/n

satellite WiFi

UWB

Infrared

bluetooth WiFi cellular

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At Home: Last-Mile • Many users still don’t have broadband – reasons: out of service area; some consider expensive

• Broadband speed is still limited – DSL: 1-6 Mbps download, and 100-768Kbps upload – Cable modem: depends on your neighbors – Fios: limited availability – Insufficient for several applications (e.g., highquality video streaming) Wireless mesh network: high-speed Internet Access 7

On the Move

Source: http://www.ece.uah.edu/~jovanov/whrms/

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On the Road

GSM/UMTS, cdmaOne/cdma2000, WLAN, GPS DAB, TETRA, ...

road condition, weather, location-based services, emergency 9

Example: IntelliDrive (Vehicle Infrastructure Integration) • Traffic crashes resulted in more than 41,000 lives lost in 2007 • Establishing vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) and vehicle-to-hand-helddevices (V2D) communications – safety: e.g., intersection collision avoidance/violation warning/turn conflict warning, curve warning – mobility: e.g., crash data, weather/road surface data, construction zones, emergency vehicle signal pre-emption More info: http://www.its.dot.gov/intellidrive/index.htm

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Collision Avoidance : V2V Networks


stalled vehicle warning

 blind spots

Automated safety features: lane change alert, blind spot detection, sudden stopping, forward collision warning with automatic braking, and intersection collision warning. It can also connect with infrastructure, pedestrians and cyclists. 11

Collision Avoidance at Intersections • Two million accidents at intersections per year in US

Source: http://www.fhwa.dot.gov/tfhrc/safety/pubs/its/ruralitsandrd/tb-intercollision.pdf 12

Disaster Recovery/Military • 9/11, Tsunami, Hurricane Katrina, South Asian earthquake, Haiti … • Wireless communication and mobile computing capability can make a difference between life and death ! – – – –

http://www.att.com/ndr/ rapid deployment efficient resource and energy usage flexible: unicast, broadcast, multicast, anycast resilient: survive in unfavorable and untrusted environments

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Habitat Monitoring: Example on Great Duck Island Patch Network

A 15-minute human visit leads to 20% offspring mortality

Gateway Transit Network

Basestation

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Social Networking On the Move • Find out where your friends are. – So you can have coffee with him/her.

• Where is a good, nearby coffee shop? • Is a table available there? • What is the lunch menu at the café? • I am new to campus, what is this building, where is the gym? 15

An Intelligent Environment Virtual world Internet

Users Mobile Networks

Sensor Networks

Physical world

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Wireless and Mobile Computing • Driven by technology and vision – wireless communication technology – global infrastructure – device miniaturization – mobile computing platforms

• The field is moving fast 17

Why is the Field Challenging?

Challenge 1: Unreliable and Unpredictable Wireless Coverage  Wireless links are not reliable: they may vary over

time and space Reception v. Distance

*Cerpa, Busek et. al

Asymmetry vs. Power

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Challenge 2: Open Wireless Medium • Wireless interference S1

R1

S2

R1

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Challenge 2: Open Wireless Medium • Wireless interference S1

R1

S2

R1

• Hidden terminals S1

R1

S2

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Challenge 2: Open Wireless Medium • Wireless interference S1

R1

S2

R1

• Hidden terminals S1

R1

S2

• Exposed terminal R1

S1

S2

R2

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Challenge 2: Open Wireless Medium • Wireless interference S1

R1

S2

R1

• Hidden terminals and S1

R1

R2

• Exposed terminal R1

S1

• Wireless security

S2

R2

– eavesdropping, denial of service, … 23

Challenge 3: Mobility • Mobility causes poor-quality wireless links • Mobility causes intermittent connection – under intermittent connected networks, traditional routing, TCP, applications all break

• Mobility changes context, e.g., location

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Challenge 4: Portability • Limited battery power • Limited processing, display and storage

Sensors, embedded controllers

Smart phone Laptop • data • simpler graphical displays • fully functional • standard applications • 802.11/3G • battery; 802.11

Mobile phones • voice, data • simple graphical displays • GSM/3G

Performance erformance/Weight/Power /Weight/Power Consumption

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Challenge 5: Changing Regulation and Multiple Communication Standards cellular phones 1981: NMT 450

satellites

1986: NMT 900

1992: GSM

1994: DCS 1800

analogue

1984: CT1

1988: InmarsatC 1991: 1991: CDMA D-AMPS 1993: PDC

2000: GPRS

wireless LAN

1980: CT0

1982: InmarsatA

1983: AMPS

cordless phones

1992: Inmarsat-B Inmarsat-M

1987: CT1+ 1989: CT 2 1991: DECT

1998: Iridium

199x: proprietary 1997: IEEE 802.11 1999: 802.11b, Bluetooth 2000: IEEE 802.11a

2001: IMT-2000

digital Fourth Generation (Internet based)

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Evolution of Mobile Systems to 3G

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3G Networks

http://en.wikipedia.org/wiki/List_of_mobile_network_operators_of_the_Americas#United_States

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What Will We Cover?

Class Goals • Learn both fundamentals and applications of wireless networking and mobile computing • Obtain experience on developing mobile, wireless systems • Discuss challenges and opportunities in wireless networking and mobile computing 30

The Layered Reference Model

Application

Application

Transport

Transport

Network

Network

Data Link Physical Radio

Network

Network

Data Link

Data Link

Data Link

Physical

Physical

Physical Medium

Often we need to implement a function across multiple layers.

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Course Topics • Communications: – physical layer: channel and diversity – link layer: MAC (sharing and power management), reliability – network layer: routing, mobility management – transport over wireless

• Mobile foundational services – localization, security

• Application developments – app. adaptation to handle mobility, portability – develop for heterogeneous devices 32

Course Topics Application Development

Communications Transport

Locations

Network

Location Management

Data Link

Localization

Security

Physical

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Class Materials • Chapters of reference books • Selected conference and journal papers

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Suggested Reference Books • REQUIRED: "Mobile Communications, Second Edition," by Jochen Schiller, Addison Wesley. 2nd Ed. August 2003.

• Wireless Networking, Anurag Kumar, D. Manjunath, Joy Kuri, Morgan Kaufmann.

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Suggested Reference Books (2) • “Fundamentals of Wireless Communication”, by David Tse and Pramod Viswanath, Cambridge University Press, 2005. (available online)

• Principles of Wireless Networks, by Kaveh Pahlavan, Prashant Krishnamurthy, Prentice Hall.

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What You Need to Do • Your prerequisite – motivated, critical – basic programming skill – Knowledge on computer networking & operating systems

• Your workload – – – – –

Class participation Homework assignments 30% Class project 30% Late midterm exam 40% No final exam 37

Instructor • Jie Gao • jgao@cs • Office hour: Monday Tuesday 5:30-7pm @ CS1415 (or check my webpage) or by appointment • http://www.cs.sunysb.edu/~jgao/CSE370spring10/

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Questions?