wireless sensor networks: a survey dr monica r mundada associate professor, dept. of cse, msrit

Wireless Sensor Networks: A Survey

Dr Monica R MundadaAssociate Professor,Dept. of CSE, MSRIT

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Outline

Introduction Applications of sensor networks Factors influencing sensor network

design Communication architecture of

sensor networks Conclusion

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Introduction

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

Random deployment Cooperative capabilities

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Introduction

Sensor networks VS ad hoc networks: The number of nodes in a sensor network can be

several orders of magnitude higher than the nodes 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 changes

frequently. Sensor nodes mainly use broadcast, most ad hoc

networks are based on p2p. Sensor nodes may not have global ID.

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Applications of Sensor networks

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Applications of sensor networks

Military applications Monitoring friendly forces, equipment

and ammunition Reconnaissance of opposing forces and

terrain Battlefield surveillance Battle damage assessment Nuclear, biological and chemical attack

detection

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Applications of sensor networks

Environmental applications Forest fire detection Biocomplexity mapping of the

environment Flood detection Precision agriculture

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Applications of sensor networks

Health applications Tele-monitoring of human

physiological data Tracking and monitoring patients

and doctors inside a hospital Drug administration in hospitals

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Applications of sensor networks

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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Factors Influencing Sensor Network Design

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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

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Factors influencing sensor network design

Fault tolerance

Fault tolerance is the ability to sustain sensor network functionalities without any interruption due to sensor node failures.

The fault tolerance level depends on the application 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

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Factors influencing sensor network 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 of functionalities with a price of much less than a dollar.

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Factors influencing sensor network design

Hardware constraints

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Factors influencing sensor network design

Sensor network topology Pre-deployment and deployment phase Post-deployment phase Re-deployment of additional nodes

phase

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Factors influencing sensor network design

Environment 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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Factors influencing sensor network design

Transmission media In a multihop sensor network,

communicating nodes are linked by a wireless medium. To enable global operation, the chosen transmission medium must be available worldwide.

Radio infrared optical media

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Factors influencing sensor network design

Power Consumption

Sensing Communication Data processing

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Communication architecture of sensor

networks

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Communication architecture of sensor networks

Combine power and routing awareness

Integrates date with networking protocols

Communicates power efficiently through the wireless medium

Promotes cooperative efforts among sensor nodes.

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Communication architecture of sensor networks

Physical layer: Address the needs of simple but

robust modulation, transmission, and receiving techniques.

frequency selection carrier frequency generation signal detection and propagation signal modulation and data

encryption.

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Communication architecture of sensor networks Propagation Effects

Minimum output power (dn 2=<n<4) Ground reflect – Multihop in dense sensor net work

Power Efficiency Modulation SchemeM-ary Modulation schemeUltra wideband(impulse radio)

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Communication architecture of sensor networks

Open research issues Modulation schemes Strategies to overcome signal

propagation effects Hardware design: transceiver

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Communication architecture of sensor networks

Data link layer:

The data link layer is responsible for the multiplexing 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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Communication architecture of sensor networks

Medium 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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Communication architecture of sensor 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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Communication architecture of sensor networks

Power Saving Modes of Operation Sensor nodes communicate using short

data packets The shorter the 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.

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Communication architecture of 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 encoding and decoding might present the best

solutions for sensor networks.

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Communication architecture of sensor networks

Open research issues MAC for mobile sensor networks Determination of lower bounds on

the energy required for sensor network self-organization

Error control coding schemes. Power saving modes of operation

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Communication architecture of sensor networks

Network 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-based addressing and location awareness.

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Communication architecture of 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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Communication architecture of sensor networks

Interest Dissemination

Sinks broadcast the interest Sensor nodes broadcast the advertisements Attribute-based naming“The areas where the temperature is over 70oF ” “The temperature read by a certain node ”

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Communication architecture of sensor networks

Data aggregation

Solve implosion and overlap Problem

Aggregation based on same attribute of phenomenon

Specifics (the locations of reporting sensor nodes) should not be left out

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Communication architecture of sensor networks

Several Network Layer Schemes for Sensor Networks

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Communication architecture of sensor networks

Open research issues

New protocols need to be developed to address higher 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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Communication architecture of sensor networks

Transport layer: This layer is especially needed when the

system is planned to be accessed through Internet or other external networks.

TCP/UDP type protocols meet most requirements (not based on global addressing).

Little attempt thus far to propose a scheme or to discuss the issues related to the transport layer of a sensor network in literature.

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Communication architecture of sensor networks

Open research issues

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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Communication architecture of sensor networks

Application layer: Management protocol makes the

hardware and software 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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Communication architecture of sensor networks

Sensor management protocol (SMP) Introducing the rules related to data aggregation, attribute-based

naming, 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 of

nodes, and reconfiguring the sensor network Authentication, key distribution, and security in data

communications

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Some Other Interesting Applications

MIT d'Arbeloff Lab – The ring sensor

Monitors the physiological status of the wearer and transmits the information 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

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iButton

A 16mm computer chip armored in a stainless steel can

Up-to-date information can travel with a person or object

Types of i-Button Memory Button Java Powered Cryptographic iButton Thermochron iButton

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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 and PIN 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

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Conclusion

Applications of sensor networks Factors influencing sensor network

design Communication architecture of

sensor networks