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Wireless Networking & Mobile Computing

ECE 256, CS 215

Spring 2009

Romit Roy ChoudhuryDept. of ECE and CS

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Course Logistics

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Welcome to ECE 256

Timings: Tu/Thu 11:40am to 12:55pm Location: 216 Hudson Hall Course TA: Rahul Ghosh rahul.ghosh@duke.edu

Office hours: Wed 2:30 - 4:00pm

Insructor: Romit Roy ChoudhuryPh.D from UIUC in Summer, 2006Research in Networks, Dist Sys, Mobile

Comp.

Email me at romit@ee.duke.eduVisit me at 203 Hudson Hall

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Welcome to ECE 256

Prerequisite: ECE 156 or CS 114Else, come and talk to me

Grading: Participation/Presentation: 10% Homework (Paper reviews, etc.): 20% 1 mid-term exam: 20% Semester-long project: 50%

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Welcome to ECE 256

Class broadcast email:ece_256_01@ee.duke.edu

Course Website:http://www.ee.duke.edu/~romit/courses/s09/ece256-sp09.html Most course related information will be posted on the

website

Please check course website frequently

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Welcome to ECE 256

Make up classes Will be occasionaly necessary due to travel Would like to schedule on a case by case basis

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Course Contents

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Shifting Trends

The edge of the internet becoming wireless

Single hop networks

Multi-hop networks

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Many Benefits due to Wireless

Significantly lower cost No cable, low labor cost, low maintenance

Ease Minimum infratructure - scatter and play

Unrestricted mobility Unplugged from power outlet

Ubiquity Available like water/electricity - holy grail

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If everything goes right, the future will be

“An invisible Internet hanging from a visible Internet …”

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The Future

RFID and Sensor Networks

Citywatchers, WalmartIntel, Philips, Bosch …

Personal AreaNetworks

Motorola, Intel,Samsung …

Mesh Networks andWireless Backbones

Microsoft, Intel, Cisco …Internet

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But, what does it take for that mobile/wireless future to become feasible?

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Research

PHY

MAC / Link

Network

Transport

Security

ApplicationIncentives

Channel fluctuations

Spatial Reuse

MobilityEnergy Savings

EavesdroppingLoss Discrimination

Privacy

Ubiquitous Services

Interference Mgmt.

Enabling wireless ubiquity.Showing what is feasible, and

what is not …

Enabling wireless ubiquity.Showing what is feasible, and

what is not …

Applications that exploit ubiquity and mobility.

Challenges underlying such applications

Applications that exploit ubiquity and mobility.

Challenges underlying such applications

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Research

PHY

MAC / Link

Network

Transport

Security

ApplicationIncentives

Channel fluctuations

Spatial Reuse

MobilityEnergy Savings

EavesdroppingLoss Discrimination

Privacy

Ubiquitous Services

Interference Mgmt.

Wireless Networking

Wireless Networking

MobileComputing

MobileComputing

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This Course

Introduces fundamentals of wireless channel The departure from wired networks … Emerging innovations in EE, communications area

Exposes implications on protocol design At MAC, Network, Transport, Security Investigates gap between idea and and actual system Considers theoretical aspects

Envisions new mobile computing applications Identifies challenges underlying them Resolves these challenges into a full system solution

Allows you to design/develop your own ideas Ideally extending the state of the art

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At the End of this Course …

You understand Physical layer (radios, rate, antennas, channels) MAC protocols (who gets the chance to talk) Routing (path selection algorithms and issues) Reliability (wireless congestion control, rate control) Security (attackers may overhear, pretend, misbehave)

Applications (social networks, personal networks, P2P networks) Application related challenges

• Localization (extracting the location of a device)• Mobility (how it helps and disrupts communication)• Privacy (how to protect a user from being tracked)

Energy-awareness (how it percolates various network functions) Emerging Topics (interference cancellation, multicast, rural

nets) Capacity (what is feasible, what are performance bounds)

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What this Course Does Not Cover

Not a wireless communications course Does not cover

Modulation schemes Transmitter/Receiver design Signal processing and antenna design Source coding / channel coding Etc.

This is course on Design, analysis, and implementation of

protocols and algorithms in (mobile) wireless network systems

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Some other Thoughts

Dilemma1. Teach very advanced stuff for the networking

pro2. Teach from absolute scratch for the

uninitiated

I will try to strike a balancePlease bear with me if materials are

sometimes too easy/difficult for YOU

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Course Structure

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Course Structure

I will present most lectures and papers You present once in entire semester (30

minutes) 2 students present in one class

For every class, read 2 of assigned papers Write reviews for each and email TA before class Bring printed copy to class A random set of reviews will be graded :)

Several recommended readings Make an effort to read them I understand that you cannot do so always

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Course Structure

1 open-book mid term, No Final Exam Tentative date of mid-term: Mar 31

Semester-long class project In groups of 2 (max 3) Focus on this from early on

Class ends with a final project poster/demo Submit conference-style paper Prize for 3 best projects

•Potentially funded by industry

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Class Participation / Presentation,Reading Assignment,

andCourse Project

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Participation / Presentation

Ask lots of questions. Period. I strongly encourage you to ask, disagree,

debate

Class presentation You present one paper (30 minutes) Pick an open slot (ones not marked “Romit”)

•Earlier you pick, more options you have to choose from•Deadline is Jan 22, 2008

Email me your choice of paper (and date) Don’t worry about not knowing the topic of ppt

•By that time, you will know enough

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Reading Assignment

Read the papers assigned for reading Critic / Review them carefully Reviews should not be more than a page

Email reviews to TA + Bring a hard copy to class

Random set of reviews will be graded I might upload selected reviews on a webpage

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Thoughts on Reading Papers

Know why you are reading the paper Reading for absorbing concepts (class assignment)

•Read fully, think, reread, ask, challenge

Reading for excitement (deciding project topic)•Read initial parts, don’t try to understand everything, get

a feel

Reading for problem identification •Read the problem carefully

Reading to discriminate (before finalizing project)•Read solution, ensure your ideas different, analyse

performance

MostImportant

MostImportant

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Course Research Projects

Projects consist of 3 parts: Problem identification Solution design Performance evaluation

Each paper you read is someone’s project Many papers are actually student’s class

projects Read them critically Ask yourself

• Is the problem really important ? Should you care ?• Is the solution sound ? Under what assumptions? Do

you have other (better) ideas ?• Is evaluation biased ? Are reults shown only in good

light?

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More on Projects

Discuss your thoughts, ideas with me They need not be cooked, and can have many

flaws Statistically, every 18 ideas lead to one decent

idea

If you like an area / direction Read many many related papers

Don’t try to come up with a quick solution Ensure your problem is a new, real problem Finding the solution is typically easy

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More on Projects

Protocol evaluation typically requires coding Think what you would like to do Options are:

•Coding on real devices (like sensors, phones, routers)

•Coding in existing network simulators (ns2, Qualnet, etc.)

•Coding your own simulator

•Theoretical projects involve MATLAB, CPLEX, etc.

Project ideas take time … think now and then Spending 3 hours for 10 days better than 10 hours

for 3 days

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More on Projects

Find a project partner early Discuss reviews, papers, potential project

themes

Class project often bottlenecked by platform Think of the evaluation platform during project

selection If you are not familiar with the Linux OS, it’s a

bad idea to do a project involving router-prorgamming

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Some Closing Thoughts

This class is about research Be active, ask questions, debate, and disagree

Don’t worry too much about grades It does not matter as much as you think

Read a lot - this is a hot research area If you are hunting for MS/PhD area, read even

more

Interact with me Even if you have ZERO clue of what’s going on

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Hello! I am ECE 256

Any Questions?

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ECE 256 Assignment 1

Watch:

Assignment Due: Tuesday, Jan 22Group work allowedTheater preffered, TV acceptable

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Questions ?

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Welcome to ECE 256

Please fill up student survey Helps me in designing the course better

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Towards Ubiquity

Focus on wireless multihop networks

Initial applications in military Emering commercial technologies and

applications•For example …

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AC

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