msn presentation

8/7/2019 msn presentation

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A survey on

Sensor NetworksPrabhu Teja G

M.Tech. in Network & Internet Engg.

Dept. Of Computer Science

School of Engg. & Tech.Pondicherry University


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What is SENSOR?

What is SENSOR NODE?

and

What is (Mobile) SENSOR NETWORK?


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From Human senses to devices

Instruments are more precise. They give

us an exact temperature, humidity,

heart rate

You feel COLD

You feel WET

You feel your heart

pumping!

Thermometer Exercise Meter

Heart Monitor

Rain GaugeHumidity Meter

What is a Sensor?


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Some Important Definitions

Sensor:A transducer that converts a physical phenomenon such as

heat, light, sound, or motion into electrical or other signals that maybe further manipulated by other apparatus.

Sensor Node:

A basic unit in a sensor network, with on-board sensors,

processor, memory, wireless modem, and power supply. It is oftenabbreviated as node. When a node has only a single sensor onboard, the node is sometimes also referred as sensor, creatingsome confusion.

Sensor Network:A wireless sensor network consists of a large number of tiny,

low-cost, low-power, sensor nodes, which are capable of observingthe environment, processing data and communicating each other byradio.


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P2P

Wireless

WirelessAd-hoc

Wireless

Mesh

Wireless

Sensor

Mobile

Ad-hoc

MobileSensor

StaticSensor

Wired

hierarchy of

network types

hybrid

iMANETInVANETVANET


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P2P Network:

A network without the notion of clients or servers,but only equal peer nodes that simultaneously function

as both clients and servers

Wireless Ad-hoc Network:

-A wireless ad hoc network is a decentralizedwireless network. The network is ad hoc because it does

not rely on a preexisting infrastructure, such as routers in

wired networks or access points in managed

(infrastructure) wireless networks.

-Each node participates in routing by forwardingdata for other nodes, and so the determination of which

nodes forward data is made dynamically based on the

network connectivity.


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Wireless Mesh Network:

WMNs is a self organized, self configured and

decentralized wireless network. There are two kinds of nodesin WMN:

1. Mesh router. 2. Mobile client.

-Mesh routers with powerful capacities and lower mobility

are automatically setup and maintain wireless connectionforming the backbone of WMNs.

-It provides interconnections among all networked

nodes, where each node can send and receive data directly to

each other

- WMNs are able to automatically discover topologychange and self adaptively modify routing for more efficient

data transmission

- WMNs are teach to achieve load balance by routing

parts of data to gateway nodes with lower load


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Mobile Ad-hoc Networks:

A mobile ad-hoc network is a collection of autonomous mobile

nodes that communicate with each other over wireless links without any

central administration.

In ad-hoc networks, each host has to act as a router for itself to

communicate with hosts outside its transmission range due to the

limited range of each host's wireless transmission.

Types of MANET

Vehicular Ad Hoc Networks (VANETs) are used for communication

among vehicles and between vehicles and roadside equipment.

Intelligent vehicular ad hoc networks (InVANETs) are a kind of

artificial intelligence that helps vehicles to behave in intelligent

manners during vehicle-to-vehicle collisions, accidents, drunken

driving etc.

Internet Based Mobile Ad-hoc Networks (iMANETs) are ad-hoc

networks that link mobile nodes and fixed Internet-gateway nodes.

In such type of networks normal ad-hoc routing algorithms don't

apply directly.


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Wireless Sensor Networks


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Some more Definitions for Sensor Networks:

A sensor network is composed of a large number of sensornodes, which are densely deployed either inside the phenomenon orvery close to it.

or

Sensor Networks (WSN) are usually a set of battery-suppliedsmall devices. A sensor network can be described as a collection ofsensor nodes which co-ordinate to perform some specific action.

or

Sensor networks are dense wireless networks of small, low-cost sensors, which collect and disseminate environmental data.

or

Sensor network (WSN) is a computer network consisting of

large number of small devices distributed in different placesor

A network consisting of spatially distributed autonomousdevices using sensors to cooperatively monitor physical orenvironmental conditions, such as temperature, sound, vibration,pressure, motion or pollutants, at different locations


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My definition for WSN

A wireless sensor network consists of a largenumber of tiny, low-cost, low-power, batteryoperated and coordinated sensor nodes, whichare capable of observing the environment,processing data and communicating each other by

radio, are deployed densely over the monitoringarea to perform a specific task such astemperature, sound, vibration, pressure, motion orpollutants at different locations.

Wireless sensor networks (WSNs) are mainlyused in the emergency services. It can also becalled Emergency Services Networks (ESNs).


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Sensor networks Vs Ad hoc networks:

The number of nodes in a sensor network canbe several orders of magnitude higher than thenodes in an ad hoc network.

Sensor nodes are densely deployed.

Sensor nodes are limited in power,computational capacities and memory.

Sensor nodes are prone to failures.

The topology of a sensor network changesfrequently.

Sensor nodes mainly use broadcast, most adhoc networks are based on p2p.

Sensor nodes may not have global ID.


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Sensor Network ApplicationClasses


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Applications of sensor networks

Military applications Enhanced logistics systems to monitor friendly forces, equipment

and ammunition.

Enhanced surveillance systems to detect intruders, chemical or

biological attacks, underwater targets, firing guns and theirlocations.

Enhanced discovery systems that can run in inaccessible or

contaminated terrains and beyond the enemy lines.

Enhanced targeting and target tracking systems.

Enhanced guidance and navigation systems

Reconnaissance of opposing forces and terrain

Battle damage assessment system


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Environmental applications

Forest fire detection

Bio-complexity mapping of theenvironment

Flood detection

Precision agriculture


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Health applications Tele-monitoring of human physiological data

Tracking and monitoring patients and doctorsinside a hospital

Drug administration in hospitals


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Home and other commercial applications

Home automation and Smart environment

Interactive museums

Managing inventory control

Vehicle tracking and detection

Detecting and monitoring car thefts


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Vehicle Tracking


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Some more Interesting Applications

Environmentalmonitoring CENS-UCLA

50 node seismicmonitoring set up

Terrestrial monitoring:based on observingthe biological andchemical cycles ofnature.

Aquatic monitoring:Monitoring of streamsand river


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Habitat Monitoring:

David Culler and his

team at UC Berkeley

have deployed since

2002 a network of more

than 20 motes on the

Great Duck Island2 to

monitor the islands

habitat and the breeding

habits of Leach Storm

Petrels

UC Berkeley project on

monitoring redwood

trees

ExScal: Extreme Scale

Wireless Sensor

Networking (Anish Arora

at Ohio State Univ):

demonstration covered an

area 1.3km by 300m with

about 1000 sensor nodes

and around 200 backbone

nodes

One possible application:

detection & classification of

multiple intruder types over

an extended perimeter.



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Precision Agriculture Camalie Net

Wireless SensorNetwork at CamalieVineyards - Mt.

Veeder, Napa Valley,California

Accenture incollaboration with Intelhas a WSN at PickberryVineyard in NorthernCalifornia

SPANN Lab., IIT-B atSula Wines

WSN for small agriculturefarms CEDT, IISc


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Disaster Response

CalIT2: Wireless InternetInformation System forMedical Response inDisasters (WIISARD)project is investigatingthe best way to triagecasualties and managecare in chaotic situationsfollowing disasters, suchas a biological attack, abridge collapse or an

earthquake

SPANN-Lab. IITB: EarlyWarning Systems forLandslide Prediction



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Introduction & History


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WSN: Brief History

Earliest: In 1994 DARPAfunded research on LowPower Wireless IntegratedMicro sensor

In 2003, Technology Reviewfrom MIT, listed WSN on thetop, among 10 emergingtechnologies that wouldimpact our future WSN can be viewed as a

disruptive technology

So far, a lot work has beendone in this area but still along way to go And the strategy workshop

is still very relevant

Base

Station

Internet

Cloud

Sensor Nodes

Aggregator

A Typical Architecture

Information

Processing

Center


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Sensor Network Architecture


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WSN node components

Low-power processor. Limited processing.

Memory. Limited storage.

Radio. Low-power.

Low data rate.

Limited range.

Sensors.

Scalar sensors:temperature, light, etc.

Cameras, microphones.

Power.

Sensors

Processor

Radio

Storage

P

O

W

E

R

WSN device schematics


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WSN Nodes Sensor nodes have local processing capability

Sensor nodes can be randomly and rapidly deployed even in places

inaccessible for humans

Sensor nodes can self organize to communicate

Sensor nodes can collaboratively work

A sensor node might vary in size from that of a shoebox down to the size of

a grain of dust

The cost of sensor nodes is variable, ranging from hundreds of dollars to a

few pennies, depending on the size of the sensor network and the

complexity required of individual sensor nodes

Size and cost constraints on sensor nodes result in corresponding

constraints on resources such as energy, memory, computational speed and

bandwidth


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Evolution of Sensor nodes

Military Networks of Sensors Early 1950s, long-range acoustic sensors (hy-

drophones), called the Sound Surveillance

System (SOSUS),deployed in the deep basins of

Atlantic & Pacific oceans for submarinesurveillance

Networks of air defense radars

Warning and Control System (AWACS) planes for all-

weather surveillance, command, control, andcommunications.

Air Delivered Seismic Intrusion Detector (ADSID)

system, used by US Air Force in the Vietnam war.


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Evolution of Sensor Networks(Cont.)

Next generation Wireless sensor Nodes WINS from UCLA

In 1996, the Low Power Wireless Integrated

Microsensors (LWIMs) were produced by UCLA and

the Rockwell Science Center. In 1998, the same team built a second generation

sensor node-the Wireless Integrated Network

Sensors (WINS)

The WINS processor board The WINS radio board


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Evolution of Sensor Networks(Cont.) Motes from UC Berkeley

In 1999, the Smart Dust project at UC Berkeley

released the first node, WeC

WeC was built with a small 8-bit, 4 MHz Atmel mi-

crocontroller (512 bytes RAM and 8 KB ash

memory), which consumed 15 mW active power and

45 W sleeping power

WeC also had a simple radio supporting a data rate

up to 10 Kbps, with 36 mW transmitting power and 9

mW receiving power. Later on, Rene and Dot were built in 1999 and2000,

respectively, with upgraded microcontrollers.

Mica family was released in 2001, including Mica ,

Mica2, Mica

2Dot, and MicaZ


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(a) WeC(b) Mica family

(c) Telos (d) Spec prototype

Motes from UC Berkeley


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PicoRadio from UC Berkeley In 2003, the Berkeley Wireless Research Center

(BWRC) presented the first radio transmitter,PicoBeacon, purely powered by solar andvibrational energy sources.

BWRC also produced SoC based sensor nodesinstead of using COTS components

In 2002, PicoNode II was built using two ASIC chipsthat implemented the entire digital portion of theprotocol stack

the chip set consumed an average of 13 mW when threenodes were connected.

PicoNode III integrate a complete PicoNode into asingle small aspect-ratio package.


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Evolution of Sensor Networks(Cont.) AMPS from MIT

AMPS I AMPS II- highly integrated sensor node comprised of a

digital and an analog/RF ASIC

interesting feature of AMPS-II is that the node will be ableto operate in several modes-

Either as a low-end stand-alone guarding node, a fully functionalnode for middle-end sensor networks,

or a companion component in a more powerful high-end sensorsystems.

it favors a network with heterogeneous sensor nodes formore efficient utilization of resources.

AMPS-I from MIT

Q

Q

Q

Q

Q


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Other commercial products and testbeds for

Sensor Networks

Ember products

Sensoria WINS

Pluto mote

PC104 testbed and

Gnome testbed


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Why Microscopic Sensor Nodes?

The transition from large to small scale sensor nodes has several

advantages.

(1) Small sensor nodes are easy to manufacture with much lower cost

than large scale sensors.

(2) With a mass volume of low cost and tiny sensor nodes, they can be

deployed very closely to the target phenomena or sensing field at an

extremely high density.

(3) Since computing and communication devices can be integrated with

sensors, large-sample in-network and intelligent information fusion

becomes feasible. The intelligence of sensor nodes and the

availability of multiple onboard sensors also enhances the flexibility of

the entire system.

(4) Due to their small size and self-contained power supply, sensor nodescan be easily deployed into regions where replenishing energy is not

available, including hostile or dangerous environments. The

survivability of nodes also increases with reduced size.

(5) The high node density enables system-level fault tolerance through

node redundancy.


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Mobile Sensor Networks


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Definition A mobile wireless sensor network owes its name to the

presence of mobile sink or sensor nodes within the network.

A mobile sensor network is composed of a distributedcollection of nodes, each of which has sensing, computation,

communication and locomotion capabilities

The mobile sensor node is in fact an enhanced sensor node.It not only has all the capabilities of the static sensor node, butalso realizes mobility by adding a robotic base and a driverboard.

Networks are capable of self-deployment; i.e., starting fromsome compact initial configuration, the nodes in the networkcan spread out such that the area covered by the network ismaximized.


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Sensors Vs. Mobile Sensors Mobile sensor networks have more powerful network

capabilities such as self-deployment, network repair andevent tracking.

In Static Sensor Network, the sensor nodes localize onlyfirst time during deployment. In case of Mobile Sensor

Network, nodes collect the data by moving from oneplace to another place hence localization is needed.

Mobile sensor networks are more energy efficient, bettertargeting and provide more data fidelity than Static

Sensor Network

The advantages of mobile WSN over static WSN arebetter energy efficiency, improved coverage, enhanced

target tracking and superior channel capacity


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System Overview The complete system architecture of a mobile sensor

network includes a group of mobile sensor nodes, abase station, upper communication networkinfrastructures and clients

A base station is used to bridge the sensor network toanother network or platform, such as Internet.

A mobile sensor network is well suited for distributed

measurement and control applications.

The sensor nodes are scattered in the targetenvironment and they form a multi-hop meshnetworking architecture


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Architecture


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Its architecture can be divided into three layers:

Node layer-consists of all the sensor nodes that can beeither static or mobile. This layer is directly embeddedinto the physical world to get all kinds of data.

Server layer-includes a personal computer or a singleboard computer running server software.

Client layer-includes local clients and remote clients.The devices of the client layer can be any smart

terminals, such asP

Cs,P

DAs,P

ocketP

Cs and smartphones.

The server layer and the client layer communicate witheach other and they form a typical example of Internet.


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Mobile Node Design Mobile sensor node is in fact a mobile robot that can

communicate with other nodes wirelessly in the multi-hopsensor network

Add various locomotion modules to the sensor nodes sothat they can move from place to place.

Propose a wheel-based mobile node architecture that canbe regarded as a simple differential drive robot

Wireless sensor node is a resource-constrained device.

When we add mobility to it, we cannot expect it to be aspowerful as conventional mobile robots


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Structure Decomposition

Exploded view of the proposed mobile node structure


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A prototype of the mobile sensor node

-The mobile node, which isnamed as RacemoteZ

-Provides a novel robotic

platform for adding controlled

mobility to wireless sensor

-The size of RacemoteZ is

105 mm90 mm80 mm.

-Easy to assemble or

disassemble the node

-System up-gradation is

possible


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Software Architecture of Mobile Node

The software environment for the sensor nodes isTinyOS, an open-source operating system designed for

wireless embedded sensor networks

The embedded software modules of the mobile node.


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MSNs Type 1: Robots with Sensors

Type 1: Successors of Stationary WSNs.

Artifacts created by the distributed robotics and lowpower embedded systems areas.

Characteristics

Small-sized, wireless-capable, energy-sensitive, as theirstationary counterparts.

Feature explicit (e.g., motor) or implicit (sea/air current)mechanisms that enable movement.

CotsBots (UC-

Berkeley)

MilliBots (CMU) LittleHelis

(USC)

SensorFlock (U

of Colorado

Boulder)


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MSN Type 1: Examples

Example: Chemical Dispersion Sampling

Identify the existence of toxic plumes.

SensorFlock: An Airborne Wireless Sensor Network of Micro-Air Vehicles

Micro Air Vehicles (UAV

Unmanned Aerial Vehicles)Ground Station


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SenseSwarm: A new framework where data acquisition is

scheduled at perimeter sensors and storage at core

nodes.

PA Algorithm for finding the perimeter

DRA/HDRA Data Replication Algorithms

s1

s2 s3

s4s5

s6

s7

s8

Perimeter-Based Data Replication and Aggregation in Mobile Sensor Networks


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MSN Type 1: Advantages

Advantages of MSNs

Controlled Mobility

Can recover network connectivity.

Can eliminate expensive overlay links.

Focused Sampling

Change sampling rate based on spatial

location (i.e., move closer to the physicalphenomenon).


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MSN Type 2: Smartphones

Type 2: Smart phones, the successors of our

dummy cell phones Mobile:

The owner of the smart-phone is moving!

Sensor: Proximity Sensor (turn off display when getting close to ear)

Ambient Light Detector (Brighten display when in sunlight)

Accelerometer (identify rotation and digital compass)

Camera, Microphone, Geo-location based on GPS, WIFI, Cellular

Towers,

Network: Bluetooth: Peer-to-Peer applications / services

WLAN, WCDMA/UMTS(3G) / HSPA(3.5G): broadband access.


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MSN Type 2: Smart phones

Type 2: Smart phones, the successors of ourdummy cell phones

Actuators: Notification Light, Speaker.

Programming Capabilities on top of LinuxOSes: OHAs Android (Google), Nokias

Maemo OS, Apples OSX,


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Intelligent Transportation Systems with VTrack

Better manage traffic by estimating roads taken by

users using WiFi beams (instead of GPS) .

Graphics courtesy of: A .Thiagarajan et. al. Vtrack: Accurate, Energy-Aware Road Traffic Delay Estimation using

Mobile Phones, In Sensys09, pages 85-98. ACM,(Best Paper) MITs CarTel Group


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BikeNet: Mobile Sensing for Cyclists.

Real-time Social Networking of the cycling community

(e.g., find routes with low CO2 levels)

Left Graphic courtesy of: S. B. Eisenman et. al., "The BikeNet Mobile Sensing System for Cyclist Experience

Mapping", In Sensys'07 (Dartmouths MetroSense Group)


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Mobile Sensor Network Platforms

SensorPlanet*: Nokias mobile device-centric large-

scale Wireless Sensor Networks initiative.

Underlying Idea:

Participating universities (MITs CarTel, DartmouthsMetroSense,etc) develop their applications and share the

collected data for research on data analysis and mining,

visualization, machine learning, etc.

Manhattan Story Mashup**: An game where 150 players

on the Web interacted with 183 urban players in

Manhattan in an image shooting/annotation game

First large-scale experiment on mobile sensing.


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Other Types of MSNs?

Body Sensor Networks (e.g., Nike+): Sensor in shoes

communicates with I-phone/I-pod to transmit the distance

travelled, pace, or calories burned by the individual wearing

the shoes.

Vehicular (Sensor) Networks (VANETs): Vehicles communicate

via Inter-Vehicle and Vehicle-to-Roadside enabling Intelligent

Transportation systems (traffic, etc.)


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Design Challenges

Why are Sensor Networkschallenging/unique from a research point of

view?

Typically, severely energy constrained. Limited energy sources (e.g., batteries).

Trade-off between performance and lifetime.

Self-organizing and self-healing. Remote deployments.

Scalable. Arbitrarily large number of nodes.


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Design Challenges (Cont.)

Heterogeneity. Devices with varied capabilities.

Different sensor modalities.

Hierarchical deployments. Adaptability.

Adjust to operating conditions and changes inapplication requirements.

Security and privacy. Potentially sensitive information.

Hostile environments.


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Technical Issues


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Sensor Deployment

Sensors positioned far from the phenomena

Several sensors deployed near the phenomena and sending time

series to a central system


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Deployment and Self-organization

Most sensor nodes are deployed in regions which have no

infrastructure at all. A typical way of deployment in a forest would be tossing the

sensor nodes from an aero plane. In such a situation, it is up to

the nodes to identify its connectivity and distribution.

Self organization of ad hoc networks includes both

communications self-organization and positioning self-organization.

The nodes must wake up, detect each other, and form a

communication network

Localization

In most of the cases, sensor nodes are deployed in

an ad hoc manner. It is up to the nodes to identify

themselves in some spatial co-ordinate system. This

problem is referred to as localization.


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Sensor Network Technology

Sensor nets often wireless towards sensors-May use Wi-fi 802.11

-Often use ZigBee 802.15.4 (low-power)

-Other technology under development and use

Sensor net gateways often use Web access

-Is good standard for heterogeneity

Sensor net gateways may use differenttechnologies towards Internet

-Often wired with normal technologies

-Often wireless e.g. cellular or Wi-fi


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Sensor Network Topology


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Software Issues


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Operating System

Typically less complex than the general purposeoperating systems, because

special requirements of sensor network applications

resource constraints in sensor network hardwareplatforms

Embedded operating systems such as eCos oruC/OS for sensor networks can be used

Wireless sensor network hardware is not differentfrom traditional embedded systems

Embedded operating systems are often designedwith real-time properties

Operating systems specifically for sensor networksdo not have real-time support


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Operating System(Cont.)

TinyOS is perhaps the first operating systemspecifically designed for wireless sensornetworks

TinyOS is based on an event-drivenprogramming model instead of multithreading

TinyOS programs are composed into eventhandlers and tasks with run to completion-semantics

Programs written for TinyOS are written in aspecial programming language called nesC extension to the C programming language

NesC is designed to detect race conditionsbetween tasks and event handlers.


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Software

What is the role of software in sensornetworks?

Energy is the scarcest resource of

WSN nodes, and it determines the lifetime of

WSNs

WSNs are meant to be deployed in

large numbers in various environments,

including remote and hostile regions

Ad-hoc communications as key


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Software(Cont.)

Algorithms and protocols need to address the followingissues:

Lifetime maximization

Robustness and fault tolerance

Self-configuration

Some of the "hot" topics in WSN software research are:

Security

Mobility (when sensor nodes or base stations aremoving)

Middleware: the design of middle-level primitivesbetween the software and the hardware


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Algorithms And Protocols

An algorithm for a Sensor Network is

implicitly a distributed algorithm.

Algorithmic research in Sensor Networksmostly focuses on

Energy Efficiency

Localization & Time Synchronization

Routing


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MAC for Energy Efficiency

Medium Access Control (MAC) protocolsdesigned for ad hoc networks primarily focused on optimizing fairness and

throughput efficiency, with less emphasis on energyconservation

MACs for sensor network are enhanced Protocols such as MACAW and IEEE 802.11

eliminate the energy waste caused by collidingpackets in wireless networks

MAC protocols for sensor networks is to reducethis idle power

consumption by setting the sensor radios into asleep state


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MAC protocols

Sensor MAC(S-MAC) First MAC for Sensor Networks

nodes create a sleep schedule for themselvesthat determines at what times to activate their

receivers and when to set themselves into asleep mode.

Timeout-MAC (T-MAC) Solution for limitations of the original S-MAC

protocol T-MAC to eliminate idle energy further by

adaptively setting the length of the active portionof the frames


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MAC protocols

DMAC By staggering the wakeup times, DMAC

reduces the large delays observed in packets

that are forwarded for more than a few hops

TRaffic-Adaptive Medium Access

(TRAMA)

TRAMA attempts to reduce wasted energy

consumption caused by packet collisions


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Localization(Cont.)Localization algorithms can be roughly

classified into two categories(Depending on whetherabsolute range measurements

(point-to-point distances, angles, etc.) are used or not)

range based and

range-free.

Range-basedalgorithms usually need somespecial hardware to obtain accurate absoluterange measurements can achieve higher localization accuracy than

range-free algorithms. Range-free algorithms do not need special

hardware and are low costly more attractive in recent years.


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Localization Algorithms for MSNs

All are based on the Sequential Monte

Carlo (SMC) method

SMC method provides simple simulation-based

approaches to estimating the distribution

Weighted Monte Carlo Localization (WMCL)

Energy efficient algorithm

.


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Time Synchronization

To enable applications such as target

tracking, sensor networks require time

synchronization

Romers Algorithm

Reference-Broadcast Synchronization (RBS)


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Routing protocols

It is a great challenge for routing in a WSN,because since it is not easy to grasp the whole network

topology, it is hard to find a routing path

sensor nodes are tightly constrained in terms ofenergy, processing, and storage capacities. Thus,they require effective resource management policiesto increase the overall lifetime of sensor networks

Routing Protocols for WSNNetworkStructure BasedProtocolsProtocol Operation BasedProtocols


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Routing Protocols(cont.)

1.Network Structure Based protocols Depend on the system architecture of

the network.

These protocols are classified again

into three categories:

Data centric or flat routing protocols,

Hierarchical routing protocols, and

Location based routing protocols.


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Routing protocols(Cont.)2.Protocol operation based protocols

These are classified into five categories:

Negotiation based routing protocol

Multi-path based routing protocol

Query-based routing protocol

QoS-based routing protocol and

Coherent-based routing protocol


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Factors influencing sensor

network design


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Factors influencing sensor network

design

Fault Tolerance

Scalability

Hardware Constrains Sensor Network Topology

Environment

Transmission Media Power Consumption

F i fl i k


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design

Fault tolerance

Fault tolerance is the ability to sustain sensornetwork functionalities without any

interruption due to sensor node failures.

The fault tolerance level depends on theapplication of the sensor networks.


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Factors influencing sensor

network design

Scalability

Scalability measures the density of the

sensor nodes.

Density = (R) =(N R2)/AR Radio Transmission Range

Q T


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design

Production costs

The cost of a single node is very important to

justify the overall cost of the networks.

The cost of a sensor node is a very

challenging issue given the amount offunctionalities with a price of much less than a

dollar.


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designHardware constraints


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design

Sensor network topology

Pre-deployment and deployment phase

Post-deployment phase

Re-deployment of additional nodes phase

F t i fl i t k


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designEnvironment Busy intersections

Interior of a large machinery

Bottom of an ocean Surface of an ocean during a tornado

Biologically or chemically contaminated field

Battlefield beyond the enemy lines

Home or a large building

Large warehouse Animals

Fast moving vehicles

Drain or river moving with current.


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designTransmission media

In a multi-hop sensor network,

communicating nodes are linked by awireless medium. To enable global operation,the chosen transmission medium must beavailable worldwide.

Radio infrared

optical media


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design

Power Consumption

Sensing Communication

Data processing


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Communication Architecture

Communication architecture of


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sensor networks

Combine power androuting awareness

Integrates date with

networking protocols Communicates power

efficiently through thewireless medium

Promotes cooperative

efforts among sensornodes.

Sensor Network Protocol stack


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Communication architecture of sensor


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networks

Propagation Effects

Minimum output power

(dn 2=


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sensor networksOpen research issues

Modulation schemes

Strategies to overcome signal propagation

effects

Hardware design: transceiver


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sensor networks

Data link layer:

The data link layer is responsible for themultiplexing of data stream, data frame detection,

the medium access and error control.

Medium Access Control Power Saving Modes of Operation

Error Control


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networksMedium access control

Creation of the network infrastructure

Fairly and efficiently share communication

resources between sensor nodes

Existing MAC protocols (Cellular System,

Bluetooth and mobile ad hoc network)



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networks

MAC for Sensor Networks

Self-organizing medium access control for sensor networks

and Eaves-drop-and-register Algorithm

CSMA-Based Medium Access Hybrid TDMA/FDMA-Based



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sensor networks

Power Saving Modes of Operation

Sensor nodes communicate using short data

packets The shorterthe packets, the more dominance

of startup energy

Operation in a power saving mode is energy

efficient only if the time spent in that mode is

greater than a certain threshold.

C i ti hit t f


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sensor networks

Error Control

Error control modes in Communication Networks(additional retransmission energy cost)

Forward Error Correction (FEC)

Automatic repeat request (ARQ)

Simple error control codes with low-complexity encodingand decoding might present the best solutions for sensor

networks.


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MAC for mobile sensor networks

Determination of lower bounds on theenergy required for sensor network self-

organization

Error control coding schemes. Power saving modes of operation

C i ti hit t f


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sensor networksNetwork layer:

Power efficiency is always an important

consideration. Sensor networks are mostly data centric.

Data aggregation is useful only when it does not

hinder the collaborative effort of the sensor nodes.

An ideal sensor network has attribute-basedaddressing and location awareness.



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sensor networks

Maximum available power (PA) route:

Route 2

Minimum energy (ME) route: Route 1

Minimum hop (MH) route: Route 3

Maximum minimum PA node route:

Route 3

Minimum longest edge route: Route 1

Energy Efficient Routes



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sensor networksInterest Dissemination

Sinks broadcast the interest

Sensor nodes broadcast the advertisements

Attribute-based naming

The areas where the temperature is over 70oF

The temperature readbya certain node


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sensor networks

Data aggregation

Solve implosion and overlapProblem

Aggregation based on same

attribute of phenomenon

Specifics (the locations ofreporting sensor nodes) should

not be left out



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sensor networks

Several Network Layer Schemes for Sensor

Networks



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sensor networks

Open research issues

New protocols need to be developed to addresshigher topology changes and higher scalability.

New internetworking schemes should be developed

to allow easy communication between the sensor

networks and external networks.



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sensor networks

Transport layer:

This layer is especially needed when the system is

planned to be accessed through Internet or otherexternal networks.

TCP/UDP type protocols meet most requirements

(not based on global addressing).

Little attempt thus far to propose a scheme or todiscuss the issues related to the transport layer of a

sensor network in literature.


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Because acknowledgments are too costly,

new schemes that split the end-to-end

communication probably at the sinks may

be needed.



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networks

Application layer:

Management protocol makes the hardware andsoftware of the lower layers transparent to the

sensor network management applications. Sensor management protocol (SMP)

Task assignment and data advertisement protocol(TADAP)

Sensor query and data dissemination protocol(SQDDP)



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sensor networks

Sensor management protocol (SMP)

Introducing the rules related to data aggregation, attribute-basednaming, and clustering to the sensor nodes

Exchanging data related to the location

finding algorithms

Time synchronization of the sensor nodes

Moving sensor nodes

Turning sensor nodes on and off

Querying the sensor network configuration and the status ofnodes, and reconfiguring the sensor network

Authentication, key distribution, and security in datacommunications


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Some Other Interesting


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g

Applications

MIT d'Arbeloff Lab The ring

sensor

Monitors the physiological status of

the wearer and transmits theinformation to the medical

professional over the Internet

Oak Ridge National Laboratory

Nose-on-a-chip is a MEMS-based

sensor

It can detect 400 species of gases

and transmit a signal indicating the

level to a central control station

iB tt


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iButton

A 16mm computer chip armored in a stainless

steel can

Up-to-date information can travel with aperson or object

Types of i-Button

Memory Button

Java Powered Cryptographic iButton

Thermochron iButton

iB tton Applications


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iButton Applications

Caregivers Assistance Do not need to keep a bunch of keys. Only one

iButton will do the work

Elder Assistance They do not need to enter all their personal

information again and again. Only one touch of

iButton is sufficient They can enter their ATM card information andPIN with iButton

Vending Machine Operation Assistance


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iBadge - UCLA

Investigate behavior of children/patient

Features:

Speech recording / replaying Position detection

Direction detection / estimation(compass)

Weather data: Temperature, Humidity,

Pressure, Light


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iBadge - UCLA

Some Application work in India


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Some Application work in India DRDO project on theoretical aspect, mote

development and deployment (IISc.) WSN for critical emergency applications (Amirta

Univ., IIT-Bombay, IIT-Delhi, IIT-Kgp)

WSN for tracking and monitoring in undergroundmines (Central Mining Research Institute)

Underwater wireless sensor networks (NPOL)

WSN for Agriculture (IISc, IIT-Bombay)

Pollution monitoring (IIT-Delhi, IIM-Kolkata, IIT-Kgp)

WSN for Biomed (IIT-Bombay)

Many IITs have WSN test beds Many other theoretical and application work in India

The above list is by no means complete, it is only illustrative

Academic Research to Industry


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Academic Research to Industry

WSN is transiting fromactive academic researchto industry.

Start-up companies suchas:

Crossbow Technologies Dust Networks

Ember

Millennial Net

Tendril Networks

Scalable NetworkTechnologies

Airbee Wireless (India;will be giving a demo)

Virtualwire (Delhi, India)

WSN can be a greatenabler for component

manufacturers

system integrators

software servicesproviders

OEMS

application developers

and other end users.


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gracias

msn presentation

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