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
Mobile Computing Changing Our Lives
11Source: TIME survey; June-July 2012
Mobile Computing Changing Our Lives
12Source: TIME survey; June-July 2012
Mobile Computing Changing Our Lives
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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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)
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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Challenge 2: Open Wireless Medium
Wireless interference
Hidden terminals
S1
S2
R1
R1
S1 R1 S2
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Challenge 2: Open Wireless Medium
Wireless interference
Hidden terminals
Exposed terminal
S1
S2
R1
R1
S1 R1 S2
R1 S1 S2 R2
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Challenge 2: Open Wireless Medium
Wireless interference
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
Mobile Computing Changing Our Lives
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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