sensor networks a survey

Wireless Sensor Networks: A Survey

I. F. Akyildiz, W. Su, Y. Sankarasubramaniam and E. Cayirci

Presented by Yuyan Xue11-30-2005

2

Outline

Introduction Applications of sensor networks Factors influencing sensor network

design Communication architecture of

sensor networks Conclusion

3

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

4

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.

5

Applications of Sensor networks

6

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

7


Environmental applications Forest fire detection Biocomplexity mapping of the enviro

nment Flood detection Precision agriculture

8


Health applications Tele-monitoring of human

physiological data Tracking and monitoring patients

and doctors inside a hospital Drug administration in hospitals

9


Home and other commercial applications

Home automation and Smart environment Interactive museums Managing inventory control Vehicle tracking and detection Detecting and monitoring car thefts

10

Factors Influencing Sensor Network Design

11

Factors influencing sensor network design

12


Fault Tolerance Scalability Hardware Constrains Sensor Network Topology Environment Transmission Media Power Consumption

13


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.

14


Scalability

Scalability measures the density of the sensor nodes.

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

15


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.

16


Hardware constraints

17


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

phase

18


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.

19


Transmission media In a multihop sensor network, communicati

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

Radio infrared optical media

20


Power Consumption

Sensing Communication Data processing

21

Communication architecture of sensor

networks

22

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.

23


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.

24

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)

25


Open research issues Modulation schemes Strategies to overcome signal propag

ation effects Hardware design: transceiver

26


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

27


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)

28


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

29


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.

30


Error Control Error control modes in Communication Networks (addi

tional 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.

31


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

32


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.

33


•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

34


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 ”

35


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

36


Several Network Layer Schemes for Sensor Networks

37


Open research issues New protocols need to be developed to address hi

gher topology changes and higher scalability. New internetworking schemes should be develope

d to allow easy communication between the sensor networks and external networks.

38


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.

39


Open research issues Because acknowledgments are too costl

y, new schemes that split the end-to-end communication probably at the sinks may be needed.

40


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)

41


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

43

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 se

nsor It can detect 400 species of gases a

nd transmit a signal indicating the level to a central control station

44

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

45

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

46

iBadge - UCLA Investigate behavior of

children/patient Features:

Speech recording / replaying Position detection Direction detection /

estimation(compass) Weather data: Temperature, Humidity,

Pressure, Light

47

iBadge - UCLA

48

Conclusion

Applications of sensor networks Factors influencing sensor network

design Communication architecture of

sensor networks

sensor networks a survey

Technology