CS434/534: Mobile Computing and Wireless Networks http://zoo.cs.yale.edu/classes/cs434/ Y. Richard Yang 08/30/2012
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 3
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.shtml http://www.wireless.att.com/coveragevie wer/
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Mobile Device Usage
Source: O2 6
Mobile Traffic Growth
Source: Cisco 7
Mobile Computing Changing Our Lives
Source: TIME mobility survey; June-July 2012
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10 Use Cases of Mobile Computing Changing the World
Source: TIME survey; June-July 2012
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Mobile Computing Features with Larger Effects
Source: TIME survey; June-July 2012
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Mobile Computing Changing Our Lives
Source: TIME survey; June-July 2012
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Mobile Computing Changing Our Lives
Source: TIME survey; June-July 2012
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Mobile Computing Changing Our Lives
Source: TIME survey; June-July 2012
http://www.time.com/time/interactive/0,31813,2122187,00.html
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Use Case: Home Networks
satellite WiFi 802.11g/n WiFi
WiFi Bluetooth NFC
UWB
bluetooth WiFi
cellular
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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 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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Use Case: Seamless Handoff--Always Best Connected LAN, WLAN 780 kbit/s
GSM 53 kbit/s Bluetooth 500 kbit/s
UMTS Rel. 5 400 kbit/s
LAN 100 Mbit/s, WLAN 54 Mbit/s
UMTS, DECT 2 Mbit/s GSM/EDGE 135 kbit/s, WLAN 780 kbit/s GSM 115 kbit/s, WLAN 11 Mbit/s
UMTS Rel. 6 400 kbit/s 17
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-helddevices (V2D) communications
More info: http://www.its.dot.gov/intellidrive/index.htm
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Collision Avoidance : V2V Networks stalled vehicle warning
bland spots
http://www.gm.com/company/gmability/safety/news_issues/releases/sixthsense_102405.html 20
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 A 15-minute human visit leads to 20% offspring mortality
Patch Network
Gateway Transit Network
Basestation
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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-thefield, MAN, WAN
Development and deployment of localization infrastructures location: GPS, AGPS, …
Development and deployment of sensor networks 25
Wireless Bit Rates
1.2 kbps
9.6 kbps
384 kbps 2 Mbps
100 Mbps 1 Gbps
NMT 1981
GSM 1992
IMT-2000 2001 (WCDMA; CDMA)
IMT-Advanced ~2012
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Enabling Infrastructure: Networks Standard GSM GPRS Class 10 GSM EDGE Evolution CDMA EV-DO Rev. 0 CDMA EV-DO Rev. A CDMA EV-DO Rev. B WiFi: 802.11b Flash-OFDM: Flash-OFDM WiFi: 802.11g WiFi: 802.11a LTE WiMAX: 802.16m WiFi: 802.11n HSPA+ LTE Advanced (Cat 8) WiFi: 802.11ac (8aAP; 4a ST)
All units are Mbps
Peak Downlink Peak Uplink Tech 0.0856 0.0428 1.6 0.5 TDMA/FDD 2.458 0.1536 CDMA/FDD 3.1 1.8 CDMA/FDD 4.9 1.8 CDMA/FDD 11 11 DSSS 15.9 5.4 Flash-OFDM 54 54 OFDM 54 54 OFDM 300 75 OFDMA/MIMO 365 376 MIMO/SOFDMA 600 600 OFDM/MIMO 672 2998.6 3470
168 CDMA/FDD/MIMO 1497.8 MIMO 3470 MU-MIMO
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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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Processing Capability: Javascript Benchmark
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Processing Capability: Javascript Benchmark
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Processing Capability: Javascript Benchmark
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Processing Capability: Javascript Benchmark
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Processing Capability: Javascript Benchmark
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Processing Capability: Javascript Benchmark
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Sensing Capability (iphone 4)
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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
Reception vs. Power
*Cerpa, Busek et. al
What Robert Poor (Ember) calls “The good, the bad and the ugly” 40
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 S1
R1
R2
Exposed terminal R1
S1
Wireless security
S2
R2
eavesdropping, denial of service, … 44
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 • data • smaller graphical displays • 802.11/3G
Tablet/Laptop
Mobile phones • voice, data • simple graphical displays • GSM/3G/4G
Performance/Weight/Power Consumption 46
Challenge 5: Changing Regulation and Multiple Communication Standards
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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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Wireless Communication Standards
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What Will We Cover?
Class Info: Personnel 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 page http://zoo.cs.yale.edu/classes/cs434/ 51
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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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. 53
Course Topic: Communications/Connectivity Physical layer: channel and diversity Link layer: channel sharing Network and transport: routing, reliability
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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 56
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
OS/Application Platform
Communications
Sensing
Security (will not cover)
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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 “Fundamentals of Wireless Communication”, by David Tse and Pramod Viswanath, Cambridge University Press (available online)
“802.11 Wireless Networks: the Definitive Guide” by Matthew Gast, O’Reilly (available online)
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Suggested Reference Books (2) “The Android Developer’s Cookbook”, by James Steele and Nelson To
“Hello, Android”, by Ed Burnette
Developer guide: http://developer.android.com/guide/components/index.html 61
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 62
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 Project
35%
Assignments
35%
Exam
20%
Class Participation
10%
More important is what you realize/learn than the grades 64
Class Survey 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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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 69
Mobile Computing Changing Our Lives
Source: TIME survey
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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) 71
