cs43 4 /53 4 : mobile computing and wireless networks zoo.cs.yale/classes/cs43 4

CS434/534: Mobile Computing and Wireless Networks

http://zoo.cs.yale.edu/classes/cs434/

Y. Richard Yang

08/30/2012

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Outline

Pervasive wireless networks and mobile applications

Challenges facing wireless networks and mobile computing

Course information

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Goal of 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

Pervasive Mobile Devices

“In many parts of the world, more people have access to a mobile [wireless] device than to a toilet or running water.” [Time Aug. 2012]

Many industrial countries reach at least 90% mobile phone subscription penetration rate [see phone penetration rates sheet]

PEW Internet and American Life Project: “The mobile device will be the primary connection tool

to the Internet for most people in the world in 2020”

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Pervasive Wireless Networks

Wireless coverage:http://www.verizonwireless.com/

wireless-coverage-area-map.shtmlhttp://www.wireless.att.com/

coverageviewer/

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Mobile Device Usage

Source: O2

Mobile Traffic Growth

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Source: Cisco

Mobile Computing Changing Our Lives

8Source: TIME mobility survey; June-July 2012

10 Use Cases of Mobile Computing Changing the World

9Source: TIME survey; June-July 2012

Mobile Computing Featureswith Larger Effects

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Source: TIME survey; June-July 2012


13Source: TIME survey; June-July 2012 http://www.time.com/time/interactive/0,31813,2122187,00.html

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Use Case: Home Networks

WiFi

WiFi

cellular

bluetooth

UWB

satellite WiFi

802.11g/nWiFi

BluetoothNFC

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Use Case: Mesh Networks

Many users still don’t have broadband reasons: out of service

area; some consider expensive

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Use Case: Mesh Network for Disaster Recovery/Military 9/11, Tsunami, Hurricane Katrina,

South Asian earthquake … Wireless communication and

mobile computing capabilitycan make a difference between life and death ! rapid deployment efficient resource and energy usage flexible: unicast, broadcast, multicast,

anycast resilient: survive in unfavorable and

untrusted environments

http://www.att.com/ndr/

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UMTS,DECT2 Mbit/s

UMTS Rel. 6400 kbit/s

LAN100 Mbit/s,WLAN54 Mbit/s

UMTS Rel. 5400 kbit/s

GSM 115 kbit/s,WLAN 11 Mbit/s

GSM 53 kbit/sBluetooth 500 kbit/s

GSM/EDGE 135 kbit/s,WLAN 780 kbit/s

LAN, WLAN780 kbit/s

Use Case: Seamless Handoff--Always Best Connected

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Use Case: Traffic Signal Advisor

http://www.princeton.edu/~ekoukoum/SignalGuru.html

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Use Case: Vehicular Networks

Traffic crashes resulted in more than 41,000 lives lost/year

Establishing vehicle-to-vehicle (V2V),

vehicle-to-infrastructure (V2I) and

vehicle-to-hand-held-devices (V2D) communications

More info: http://www.its.dot.gov/intellidrive/index.htm

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Collision Avoidance : V2V Networks

stalled vehicle warning

http://www.gm.com/company/gmability/safety/news_issues/releases/sixthsense_102405.html

bland spots

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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

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Google Glass

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Use Case: Habitat Monitoring

Patch Network

Transit Network

Basestation

Gateway

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

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Wireless and Mobile Computing

Driven by technology and vision Mobile device capabilities and platforms Global communication infrastructures

The field is moving fast

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Enabling Infrastructures

Development and deployment of wireless infrastructures networking: in-room, in-building, on-campus,

in-the-field, MAN, WAN

Development and deployment of localization infrastructures location: GPS, AGPS, …

Development and deployment of sensor networks

Wireless Bit Rates

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1.2 kbps 9.6 kbps

NMT1981

GSM1992

IMT-20002001

(WCDMA; CDMA)

384 kbps2 Mbps

100 Mbps1 Gbps

IMT-Advanced~2012

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Enabling Infrastructure: Networks

Standard Peak Downlink Peak Uplink TechGSM GPRS Class 10 0.0856 0.0428GSM EDGE Evolution 1.6 0.5 TDMA/FDDCDMA EV-DO Rev. 0 2.458 0.1536 CDMA/FDDCDMA EV-DO Rev. A 3.1 1.8 CDMA/FDDCDMA EV-DO Rev. B 4.9 1.8 CDMA/FDDWiFi: 802.11b 11 11 DSSSFlash-OFDM: Flash-OFDM 15.9 5.4 Flash-OFDMWiFi: 802.11g 54 54 OFDMWiFi: 802.11a 54 54 OFDMLTE 300 75 OFDMA/MIMOWiMAX: 802.16m 365 376 MIMO/SOFDMAWiFi: 802.11n 600 600 OFDM/MIMO

HSPA+ 672 168 CDMA/FDD/MIMOLTE Advanced (Cat 8) 2998.6 1497.8 MIMOWiFi: 802.11ac (8aAP; 4a ST) 3470 3470 MU-MIMO

All units are Mbps

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Enabling Infrastructure: Measurements

Source: A Close Examination of Performance and Power Characteristics of 4G LTE; Mobisys’12

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Improving Infrastructure: Power Efficiency

Source: A Close Examination of Performance and Power Characteristics of 4G LTE; Mobisys’12

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Enabling Device Capabilities, Platforms

Improving device capabilities, mobile application frameworks, applications, e.g., andriod iphone/ipad windows phone

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Processing Capability:Javascript Benchmark

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Sensing Capability (iphone 4)

Why is the Field Challenging?

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Challenge 1: Unreliable and Unpredictable Wireless Coverage

*Cerpa, Busek et. al

What Robert Poor (Ember) calls “The good, the bad and the ugly”

Wireless links are not reliable: they may vary over time and space

Reception v. Distance Reception vs. Power

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Challenge 2: Open Wireless Medium

Wireless interferenceS1

S2

R1

R1

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Wireless interference

Hidden terminals

S1

S2

R1

R1

S1 R1 S2

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Hidden terminals

Exposed terminal

S1

S2

R1

R1

S1 R1 S2

R1 S1 S2 R2

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Hidden terminals

Exposed terminal

Wireless security eavesdropping, denial of service, …

S1

S2

R1

R1

S1 R1 R2

R1 S1 S2 R2

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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,embeddedcontrollers

Mobile phones• voice, data• simple graphical displays• GSM/3G/4G

Smart phone• data• smaller graphical displays• 802.11/3G

Tablet/Laptop

PPerformanceerformance/Weight/Power Consumption/Weight/Power Consumption

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Challenge 5: Changing Regulation and Multiple Communication Standards

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Challenge 5: Changing Regulation and Multiple Communication Standards

cellular phones satellites wireless LAN

cordlessphones

1992:GSM

1994:DCS 1800

2001:IMT-2000

1987:

CT1+

1982:Inmarsat-

A

1992:Inmarsat-BInmarsat-M

1998:Iridium

1989:CT 21991:DECT 199x:

proprietary

1997:IEEE 802.11

1999:802.11b, Bluetooth

1988:Inmarsat-

C

analogue

digital

1991:D-AMPS

1991:CDMA

1981:NMT 450

1986:NMT 900

1980:

CT01984

:CT1

1983:AMPS

1993:PDC

2000:GPRS

2000:IEEE 802.11a

Fourth Generation

(Internet based)

Wireless Communication Standards

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What Will We Cover?

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Instructor• Y. Richard Yang, [email protected], AKW 308A

• office hours: to be posted• Ramki Gummadi, [email protected], AKW 413

Teaching fellow• To be posted• office hours: to be posted on class page

Course home pagehttp://zoo.cs.yale.edu/classes/cs434/

Class Info: Personnel

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Class Goals Learn both fundamentals and applications of

wireless networking and mobile computing

Obtain hands-on experiences on developing on wireless, mobile devices wireless networking: GNU radio mobile computing: Android (you may explore IOS

or Windows Mobile in your project)

Discuss challenges and opportunities in wireless networking and mobile computing

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Application

Transport

Network

Data Link

Physical

Medium

Data Link

Physical

Application

Transport

Network

Data Link

Physical

Data Link

Physical

Network Network

Radio

Often we need to implement a function across multiple layers.

The Layered Reference Model

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Course Topic: Communications/ConnectivityPhysical layer: channel and diversity

Link layer: channel sharing

Network and transport: routing, reliability

Course Topic: Mobile OS/App Framework

Android app framework Activity, service, intent, content provider,

handler/AsyncTask, … Virtualizing mobile OS

Measuring/profiling mobile app Why are web browser slow on smartphones? Why did some small percentage of

Pandora’s traffic is responsible for a large fraction of energy use on my phone? …

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Course Topic: Mobile Network App Techniques Informed usage of networks

MatchMaking

Using peer-to-peer connections Wifi Direct, Microcast, NFC

Hybrid mobile/cloud/server Cloud messaging Code partition (MAUI, Cloudlet) Aggregation (SmartVNC) Storage partition

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Course Topic: Sensory Framework/App

Location Localization (GPS, lateration, acoustic,

siganture) Location based services

• Google MapView, Map API

Sensing Detecting the environment using cameras,

microphones, and collaborations• signalGuru, Darwin Phone

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Course Topics

Communications Sensing Security (will not

cover)

OS/Application Platform

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Class Materials

Chapters of reference books

Selected conference and journal papers

Other resources MOBICOM, SIGCOMM, Mobisys proceedings IEEE Network, Communications, Pervasive

magazines

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Suggested Reference Books

“802.11 Wireless Networks: the Definitive Guide” by Matthew Gast, O ’Reilly (available online)

“Fundamentals of Wireless Communication”, by David Tse and Pramod Viswanath, Cambridge University Press (available online)

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Suggested Reference Books (2)

“Hello, Android”, by Ed Burnette

“The Android Developer’s Cookbook”, by James Steele and Nelson To

Developer guide: http://developer.android.com/guide/components/index.html

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What You Need to Do

Your prerequisite motivated, critical basic programming skill

• Gnuradio: GUI, python, C++• Android: Java, C (if you decide to hack into the kernel)

Your workload class participation

• actively participate in class discussions 3-4 assignments One project One midterm

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Class Project

Goal: obtain hands-on experience We’ll suggest potential topics You may also choose your own topic Initial proposal + midterm progress

report + final report + [presentation] We provide help in obtaining

Mobile devices Amazon/Google cloud service accounts

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Grading

More important is what you realize/learn than the grades

Project 35%

Assignments 35%

Exam 20%

ClassParticipation

10%

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Class Survey

Please take the class surveyhelp me to determine your

background

help me to determine the depth and topics

suggest topics that you want to be covered

Questions?

Backup

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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


70Source: TIME survey

IMT Advanced Requirements

All-IP communications. Peak data rates

100 Mbit/s for high mobility 1 Gbit/s for low mobility

Scalable channel bandwidth, between 5 and 20 MHz, optionally up to 40 MHz

Peak link spectral efficiency 15 bit/s/Hz (downlink); 6.75 bit/s/Hz (uplink)

System spectral efficiency 3 bit/s/Hz/cell (downlink) 2.25 bit/s/Hz/cell (indoor)

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cs43 4 /53 4 : mobile computing and wireless networks zoo.cs.yale/classes/cs43 4

Documents

mobile wireless device

mobile computing capability

mobile applicationschallenges

use cases of mobile

time survey

pervasive mobile devicesin

goal of mobile computingpeople

time mobility survey