CS434/534: Mobile Computing and Wireless Networks

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

Y. Richard Yang

08/30/2012

2

Outline

Pervasive wireless networks and mobile applications

Challenges facing wireless networks and mobile computing

Course information

3

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”

4

Pervasive Wireless Networks

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

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

coverageviewer/

5

6

Mobile Device Usage

Source: O2

Mobile Traffic Growth

7

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

10

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

14

Use Case: Home Networks

WiFi

WiFi

cellular

bluetooth

UWB

satellite WiFi

802.11g/nWiFi

BluetoothNFC

15

Use Case: Mesh Networks

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

area; some consider expensive

16

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/

17

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

18

Use Case: Traffic Signal Advisor

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

19

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

20

Collision Avoidance : V2V Networks

stalled vehicle warning

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

bland spots

21

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

22

Google Glass

23

Use Case: Habitat Monitoring

Patch Network

Transit Network

Basestation

Gateway

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

24

Wireless and Mobile Computing

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

The field is moving fast

25

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

26

1.2 kbps 9.6 kbps

NMT1981

GSM1992

IMT-20002001

(WCDMA; CDMA)

384 kbps2 Mbps

100 Mbps1 Gbps

IMT-Advanced~2012

27

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

28

Enabling Infrastructure: Measurements

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

29

Improving Infrastructure: Power Efficiency

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

30

Enabling Device Capabilities, Platforms

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

31

Processing Capability:Javascript Benchmark

32

Processing Capability:Javascript Benchmark

33

Processing Capability:Javascript Benchmark

34

Processing Capability:Javascript Benchmark

35

Processing Capability:Javascript Benchmark

36

Processing Capability:Javascript Benchmark

37

Processing Capability:Javascript Benchmark

38

Sensing Capability (iphone 4)

Why is the Field Challenging?

40

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

41

Challenge 2: Open Wireless Medium

Wireless interferenceS1

S2

R1

R1

42

Challenge 2: Open Wireless Medium

Wireless interference

Hidden terminals

S1

S2

R1

R1

S1 R1 S2

43

Challenge 2: Open Wireless Medium

Wireless interference

Hidden terminals

Exposed terminal

S1

S2

R1

R1

S1 R1 S2

R1 S1 S2 R2

44

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

45

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

46

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

47

Challenge 5: Changing Regulation and Multiple Communication Standards

48

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

49

What Will We Cover?

51

Instructor• Y. Richard Yang, yry@cs.yale.edu, AKW 308A

• office hours: to be posted• Ramki Gummadi, ramki@cs.yale.edu, 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

52

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

53

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

54

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? …

55

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

57

58

Course Topics

Communications Sensing Security (will not

cover)

OS/Application Platform

59

Class Materials

Chapters of reference books

Selected conference and journal papers

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

magazines

60

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)

61

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

62

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

63

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

64

Grading

More important is what you realize/learn than the grades

Project 35%

Assignments 35%

Exam 20%

ClassParticipation

10%

65

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

67

Evolution of Mobile Systems to 3G

68

69

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)

71