Background of Ad hoc Wireless Networks

Student Presentations

Wireless Communication Technology and Research

Ad hoc Routing and Mobile IP and Mobility

Wireless Sensor and Mesh Networks

Mobile and Ad hoc Networks

Introductory LectureIntroductory Lecturehttp://web.uettaxila.edu.pk/CMS/SP2012/teAWNms/

Objectives

Where is Wireless Communication today? Where has it come from in the last decade? What is its future potential?

Introduction to Mobile Ad hoc, Sensor and Mesh networks What are key research areas in wireless communication? How do the features in Ad hoc wireless networks different from

traditional wireless systems (WiFi: 802.11a/b/g/n, 3G, mobile WIMAX: 802.16e)?

Mobility issues Security and other issues Research topics

Text Books

AD HOC NETWORKS Technologies And Protocols

by Prasant Mohapatra and Srikanth Krishnamurthy

The handbook of AD HOC WIRELESS NETWORKS

by Mohammad Ilyas

Text Books

Ad Hoc Mobile Wireless Networks Protocols and Systems

by C.K. Toh

Mobile Ad hoc Networking

by Stefano Basagni, Marco Conti,

Silvia Giordano and Ivan

Stojmenovic

Overview of the Course Introduction

Foundations of Wireless Communications - Wireless Channel

Foundations of Wireless Communications – Modulation

Review of Networking Wireless Physical and MAC layer Wireless Area Networks (WPAN,

WLAN, WWAN) and MAC Layer

Wireless MAC protocols Wireless Routing Wireless TCP Mobile IP Quality of service Wireless Sensor Networks Mobile Ad hoc Networks Vehicular Ad hoc Networks Mesh Networks Wireless Network Security Standardization

Research Papers Physical and MAC layer Routing in Wireless

Opportunistic routing and network coding

Network Layer and Routing Routing Metrics Geographic Routing

Routing and Scalability Routing Algorithms Algorithmic foundations for

scalability Energy issues Sensor Networks Wireless Routing Security

Trust and Reputation systems Incentives, mechanisms, etc.

Physical and link level issues

Presentations

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Objectives of course

Learn about challenges in wireless networking What forces us to reconsider many traditional

designs? Understand state-of-the-art in wireless/ubiquitous

systems Get a broad view of the ongoing research in the

wireless domain Have a good understanding of their capabilities and

limitations

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Course Materials

Course Web page http://web.uettaxila.edu.pk/CMS/SP2012/teAWNms Visit regularly Announcements Lecture Notes and Assignments

Research papers Pdf/ps version of the papers will be on the Web page ~30 papers, Combination of classic and recent work.

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Reading Papers Is this a vision/position/direction paper, or just a

measurement/implementation? How the paper is compared to others? Can I mentally categorize this paper somewhere in the

taxonomy? “Differs from X as follows; has the following in common with Y”

What is the most important contribution?

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Reading Papers (2) Does this advance the state of the art? Did you learn anything new? Does it provide evidence which supports/contradicts

hypotheses? Is there experimental validation? Any technical flaws? Will the paper generate discussion in the class? How readable is the paper? Is the paper relevant to a broader community?

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Covered Topics (will try!)

Overview The challenges, technologies, and trends

Wireless Fundamentals Source and channel coding Frequency spectrums

Wireless LAN MAC protocols

Wireless Internet – Mobile IP

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Covered Topics (2)

Routing for Wireless Ad Hoc Routing

TCP in wireless enviroment Power Management wireless Sensor Networks Quality of Services (QoS) Hybrid Wireless Networks – Architectures– Pricing,

Power Control, Load Balancing Special Topics

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Why wireless networks? Mobility: to support mobile applications Costs: reductions in infrastructure and operating

costs: no cabling or cable replacement Special situations: No cabling is possible or it is

very expensive. Reduce downtime: Moisture or hazards may cut

connections.

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Why wireless networks? (cont.)

Rapidly growing market attests to public need for mobility and uninterrupted access

Consumers are used to the flexibility and will demand instantaneous, uninterrupted, fast access regardless of the application.

Consumers and businesses are willing to pay for it

0

100

200

300

400

500

600

700

1993 1994 1995 1996 1997 1998 1999 2000 2001

The Two Hottest Trends inTelecommunications Networks

Source: Ericsson Radio Systems, Inc.

Mobile TelephoneUsers

Internet Users

Millions

Years

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Growth of Home wireless

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Wireless is THE Key Driver for the Future Internet

Historic shift from PC’s to mobile computing and embedded devices… >2B cell phones vs. 500M Internet-connected PC’s in 2005 >400M cell phones with Internet capability, rising rapidly Sensor deployment just starting, but some estimates ~5-10B units by

2015

INTERNET INTERNET

WirelessEdge Network

WirelessEdge Network

INTERNET INTERNET

~500M server/PC’s, ~100M laptops/PDA’s

~750M servers/PC’s, >1B laptops, PDA’s, cell phones, sensors

20052010

WirelessEdge Network

WirelessEdge Network

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Market Size

Wireless as the common case vs. the exception Laptop (54%) vs. desktop sales

(46%) >2B cell phones vs. 500M Internet-

connected PCs Estimates of ~5-10B wireless

sensors by 2015

Rapid deployment of new technology Highly dynamic environment Must accommodate

new/unexpected technologies

•9 million hotspot users in 2003 (30 million in 2004)

•Approx 4.5 million WiFi access points sold in 3Q04

•Sales have tripled by 2009•Many more non-802.11 devices

Staggering Market Statistics

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Why is it so popular?

Flexible Low cost Easy to deploy Support mobility

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Applications ?

Ubiquitous, Pervasive computing or nomadic access. Ad hoc networking: Where it is difficult or impossible to

set infrastructure. LAN extensions: Robots or industrial equipment

communicate each others. Sensor network where elements are two many and they can not be wired!.

Sensor Networks: for monitoring, controlling, e

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Infostations

Mobile hosts traveling through fixed network Good for periodic download or upload of bulky data Wireless islands (interconnected by wired network)

Gas stations Here and there on the freeway

Possibly an invisible infrastructure with mobile-aware applications In reality, you may need to know to go to it Original paper assumes this: information kiosks

Coverage is spotty Cost is lower than complete coverage

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Ad hoc networks

Collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration.

Hop-by-hop routing due to limited range of each node Nodes may enter and leave the network Usage scenarios:

Military Disaster Relief Temporary groups of participants (conferences)

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Sensor networks Deployment of small, usually wireless sensor nodes.

Collect data, stream to central site Maybe have actuators

Hugely resource constrained Internet protocols have implicit assumptions about

node capabilities Power cost to transmit each bit is very high relative to

node battery lifetime Loss / etc., like other wireless Ad-hoc: Deployment is often somewhat random

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Ad hoc networks, continued

Very mobile – whole network may travel Applications vary according to purpose of

network No pre-existing infrastructure. Do-it-yourself

infrastructure Coverage may be very uneven

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Networked Embedded Computers

Network

networked appliances sensors historical sites & other

locations

Connected to network send and/or receive

May be embedded only for network access

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extendibility & scalability

Embedded Peer

Network

Composite devices (HW+SW) security system

Distributed composites vs. hardwired devices

client-defined composites

ease of change

reuse of constituents

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Networked Embedded Computers

Network

Issues Late binding

Naming Discovery IPC User-interface deployment Multi-appliance control

Access control Existing social protocols not supported by

existing mechanisms All co-located users can use

appliance Restriction to contents per user

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Location-Aware Computing

Motivation location-based action

nearby local printer, doctor nearby remote phone directions/maps

location-based information

real person’s location history/sales/events

virtual walkthrough story of city

augmented touring machine

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Pose-Aware Computing

Operations based on locations and orientations of users and devices

Motivation Augmented reality

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Wearable Pose-Aware Computers

Computers on body track body relative

movements monitor person train person

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EmbeddedMobile

Interactive

Beyond Desktops/Servers

WearableActive badge

Location

Sensor

Flight Simulator

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Summary

Need to be connected from everywhere and anytime.

Need to be connected on movement Need to good quality service on those situation. Interworking with the existing networks

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Classification of Wireless Networks

Mobility: fixed wireless or mobile Analog or digital Ad hoc (decentralized) or centralized (fixed base

stations) Services: voice (isochronous) or data (asynchronous) Ownership: public or private

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Classification of Wireless Networks

Area: wide (WAN), metropolitan (MAN), local (LAN), or personal (PAN) area networks

Switched (circuit- or packet-switched) or broadcast Low bit-rate (voice grade) or high bit-rate (video,

multimedia) Terrestrial or satellite

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What is special on wireless?

Channel characteristics Half-Duplex Location dependency Very noisy channel, fading effects, etc.,

Resource limitation Bandwidth Frequency Battery, power.

Wireless problems are usually optimization problems.

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What is special on wireless?

Mobility in the network elements Very diverse applications/devices. Connectivity and coverage (internetworking) is a

problem. Maintaining quality of service over very unreliable

links Security (privacy, authentication,...) is very serious

here. Broadcast media. Cost efficiency

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Big issues!

Integration with existing data networks sounds very difficult.

It is not always possible to apply wired networks design methods/principles here.

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Internet Design Goals

1. Connect existing networks initially ARPANET and ARPA packet radio network

2. Survivability- ensure communication service even in the presence of

network and router failures

3. Support multiple types of services

4. Must accommodate a variety of networks

5. Allow distributed management

6. Allow host attachment with a low level of effort

7. Allow resource accountability

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Problems

Host mobility is not considered in the design. There is a hierarchal design. How Ad hoc wireless

networks can be handled A layered design. Layer should be independent of

each other. It is not work at all in wireless TCP Battery shortages; Etc,.

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Disconnection / store & forward

Many Internet protocols assume frequent connectivity

What if your node is only on the Internet for 5 minutes every 6 hours? How do you browse the web? Receive SMTP-based email?

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High availbility requirements

No QoS assumed from below Reasonable but non-zero loss rates

What’s minimum recovery time? 1 RTT

But conservative assumptions end-to-end TCP RTO

Interconnect independent networks Federation makes things harder:

My network is good. Is yours? Is the one in the middle working? Scale

Routing convergence times, etc.

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Trends Multimedia over IP networks

Next Generation Internet with features for “soft” QoS RSVP, Class-based Queuing, Link Scheduling

Voice over IP networks Packet Voice and Video RTP and ALF

Intelligence shifts to the network edges Better, more agile software-based voice and video codecs

Programmable intelligence inside the network Proxy servers intermixed with switching infrastructure Java code: “write once, run anywhere”

Implications for cellular network infrastructure of the 21st century?

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Issues Scalability

Must scale to support hundreds of thousands of simultaneous users in a region.

Functionality

Computer-phone integration Real-time, multipoint/multicast, location-aware

services, security Home networking, “active” spaces,

sensors/actuators

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Issues(2) Leverage evolving IP traffic models Provisioning the network for the extrapolated traffic and

services Proactive Infrastructure

Computing resources spread among switching infrastructure

Computationally intensive services: e.g., voice-to-text Service and server discovery

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Wireless Differences 1

Physical layer: signals travel in open space Subject to interference

From other sources and self (multipath) Creates interference for other wireless devices Noisy lots of losses Channel conditions can be very dynamic

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Wireless Differences 2

Need to share airwaves rather than wire Don’t know what hosts are involved Hosts may not be using same link technology Interaction of multiple transmitters at receiver

Collisions, capture, interference Use of spectrum: limited resource.

Cannot “create” more capacity easily More pressure to use spectrum efficiently

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Wireless Differences 3

Mobility Must update routing protocols to handle frequent

changes Requires hand off as mobile host moves in/out

range Changes in the channel conditions.

Coarse time scale: distance/interference/obstacles change

Fine time scale: Doppler effect Other characteristics of wireless

Slow

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Growing Application Diversity

Relay Node

Access Point

Sensor

Wired Internet

Ad-Hoc/Sensor Networks

Collision Avoidance:Car Networks

Wireless Home Multimedia

Mesh Networks

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Challenge: Diversity

New architectures must accommodate rapidly evolving technology

Must accommodate different optimization goals Power, coverage, capacity, price

INTERNET INTERNET

WirelessEdge Network

WirelessEdge Network

INTERNET INTERNET

20052010

WirelessEdge Network

WirelessEdge Network

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Spectrum Scarcity

Interference and unpredictable behavior Need better management/diagnosis tools

Lack of isolation between deployments Cross-domain and cross-technology

Why is my 802.11 not working?

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Other Challenges

Performance: Nothing is really working well Security: It is a broadcast medium Cross layer interception

TCP performance

Assignment #1

Introduce Yourself: Name: Adeel Akram Department: Telecom Engineering Department Email Address: adeel.akram@uettaxila.edu.pk Cell/Contact Number: 0323-5030712/051-

9047566 Define terms highlighted in Yellow colour

Q&A

?