state-of-the-art in sensor networks research ian f. akyildiz broadband & wireless networking...

STATE-OF-THE-ART IN SENSOR STATE-OF-THE-ART IN SENSOR

NETWORKS RESEARCH NETWORKS RESEARCH

Ian F. AkyildizIan F. Akyildiz

Broadband & Wireless Networking LaboratoryBroadband & Wireless Networking Laboratory

School of Electrical and Computer EngineeringSchool of Electrical and Computer Engineering

Georgia Institute of TechnologyGeorgia Institute of Technology

Tel: 404-894-5141; Fax: 404-894-7883 Tel: 404-894-5141; Fax: 404-894-7883

Email: [email protected]: [email protected]

Web: http://www.ece.gatech.edu/research/labs/bwnWeb: http://www.ece.gatech.edu/research/labs/bwn

NeXtworking’03 June 23-25,2003, Chania, Crete, GreeceThe First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN

NETWORKING2Akyildi

z

Internet, Internet, Satellite, Satellite, etcetc

Sink

Sink

TaskManager

SENSOR NETWORKSSENSOR NETWORKS

Several Several thousand nodesthousand nodes

Nodes are tens Nodes are tens of feet of each of feet of each otherother

Densities as high Densities as high as 20 nodes/m3as 20 nodes/m3

•I.F.Akyildiz, W.Su, Y. Sankarasubramaniam, E. Cayirci, I.F.Akyildiz, W.Su, Y. Sankarasubramaniam, E. Cayirci, ““Wireless Sensor Networks: A Survey”, Wireless Sensor Networks: A Survey”, Computer Networks (Elsevier) JournalComputer Networks (Elsevier) Journal, March 2002., March 2002.


NETWORKING3Akyildi

z

A Sensor NodeA Sensor Node

Power UnitPower Unit Power GeneratorPower Generator

Sensor ADCSensor ADCProcessorProcessor

MemoryMemoryTransceiverTransceiver

Location Finding SystemLocation Finding System MobilizerMobilizer

SENSOR NODE SENSOR NODE HARDWAREHARDWARE

SmallSmall Low powerLow power Low bit rateLow bit rate High density High density Low cost Low cost

(dispensable(dispensable))

AutonomousAutonomous AdaptiveAdaptive


NETWORKING4Akyildi

z

Sensor Networks Sensor Networks Communication ArchitectureCommunication Architecture

Application LayerApplication Layer

Transport LayerTransport Layer

Network LayerNetwork Layer

Data Link LayerData Link Layer

Physical LayerPhysical Layer

Pow

er M

anagem

ent

Pow

er M

anagem

ent

Pla

ne

Pla

ne

Mobility

Managem

ent

Mobility

Managem

ent

Pla

ne

Pla

ne

Task M

anagem

ent P

lane

Task M

anagem

ent P

lane

Used by sink and all sensor nodesUsed by sink and all sensor nodes Combines power and routing awarenessCombines power and routing awareness Integrates data with networking protocolsIntegrates data with networking protocols Communicates power efficiently throughCommunicates power efficiently through wireless medium andwireless medium and Promotes cooperative effortsPromotes cooperative efforts


NETWORKING5Akyildi

z

WHY CAN’T AD-HOC NETWORK WHY CAN’T AD-HOC NETWORK PROTOCOLS BE USED HERE?PROTOCOLS BE USED HERE?

Number of sensor nodes can be several Number of sensor nodes can be several orders of magnitude higherorders of magnitude higher

Sensor nodes are Sensor nodes are densely deployeddensely deployed and and are are prone to failuresprone to failures

The topology of a sensor network The topology of a sensor network changes very frequently due to changes very frequently due to node node mobility and node failuremobility and node failure

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

May not have global ID like IP address.May not have global ID like IP address. Need tight integration with sensing tasks.Need tight integration with sensing tasks.


NETWORKING6Akyildi

z

SENSOR NETWORK SENSOR NETWORK APPLICATIONSAPPLICATIONS

Military, Environmental, Health, Home, Space Military, Environmental, Health, Home, Space Exploration, Chemical Processing, Disaster Relief…. Exploration, Chemical Processing, Disaster Relief….

SENSOR TYPESSENSOR TYPES: Seismic, Low sampling rate magnetic, : Seismic, Low sampling rate magnetic, Thermal, Visual, Infrared, Acoustic, Radar…Thermal, Visual, Infrared, Acoustic, Radar…

SENSOR TASKSSENSOR TASKS: Temperature, Humidity, Vehicular : Temperature, Humidity, Vehicular Movement, Lightning Condition, Pressure, Soil Makeup,Movement, Lightning Condition, Pressure, Soil Makeup, Noise Levels, Presence or Absence of Certain Types of Noise Levels, Presence or Absence of Certain Types of Objects, Mechanical Stress Levels on Attached Objects, Objects, Mechanical Stress Levels on Attached Objects, Current Characteristics Speed, Direction, Size) of Current Characteristics Speed, Direction, Size) of an Object ….an Object ….


NETWORKING7Akyildi

z

TRANSPORT LAYERTRANSPORT LAYERRelated WorkRelated Work

Infrastructure Tradeoffs [1] Infrastructure Tradeoffs [1] RMST [2] RMST [2] PSFQ - Pump Slowly Fetch Quickly [3]PSFQ - Pump Slowly Fetch Quickly [3] MAC Level Reliability [4,5]MAC Level Reliability [4,5]

[1] S. Tilak, N. B. Abu-Ghazaleh and W. Heinzelman, “Infrastructure Tradeoffs for Sensor [1] S. Tilak, N. B. Abu-Ghazaleh and W. Heinzelman, “Infrastructure Tradeoffs for Sensor Networks,” Networks,” In Proc. ACM WSNA’02In Proc. ACM WSNA’02, September 2002., September 2002.[2] F. Stann and J. Heidemann, “RMST: Reliable Data Transport in Sensor Networks,” [2] F. Stann and J. Heidemann, “RMST: Reliable Data Transport in Sensor Networks,” In Proc. IEEE SNPA’03In Proc. IEEE SNPA’03, May 2003., May 2003.[3] C. Y. Wan, A. T. Campbell and L. Krishnamurthy, “PSFQ: A Reliable Transport Protocol for [3] C. Y. Wan, A. T. Campbell and L. Krishnamurthy, “PSFQ: A Reliable Transport Protocol for Wireless Wireless Sensor Networks,” Sensor Networks,” In Proc. ACM WSNA’02In Proc. ACM WSNA’02, September 2002., September 2002.[4] A. Woo and D. Culler, “A Transmission Control Scheme for Media Access in Sensor [4] A. Woo and D. Culler, “A Transmission Control Scheme for Media Access in Sensor Networks”, Networks”, In Proc. ACM MOBICOM’01, In Proc. ACM MOBICOM’01, July 2001.July 2001.

[5] W. Ye, J. Heidemann and D. Estrin, “An Energy-Efficient MAC Protocol for Wireless Sensor [5] W. Ye, J. Heidemann and D. Estrin, “An Energy-Efficient MAC Protocol for Wireless Sensor Networks”, Networks”, In Proc. IEEE INFOCOM’02In Proc. IEEE INFOCOM’02, June 2002., June 2002.


NETWORKING8Akyildi

z

TRANSPORT LAYERTRANSPORT LAYERRelated Work ConclusionsRelated Work Conclusions

Wireless TCP variants NOT suitable !!!Wireless TCP variants NOT suitable !!!– End-to-end semanticsEnd-to-end semantics– Huge buffering requirementsHuge buffering requirements– ACKing is energy drainingACKing is energy draining

Reliable multicast solutions NOT applicableReliable multicast solutions NOT applicable– Multiple-sender single receiver transport Multiple-sender single receiver transport

problems traditionally solved as multiple problems traditionally solved as multiple unicastunicast

Traditional end-to-end guaranteed reliability Traditional end-to-end guaranteed reliability (TCP/Multicast solutions) not appropriate…(TCP/Multicast solutions) not appropriate…

New Reliability Notion is required!!!New Reliability Notion is required!!!


NETWORKING9Akyildi

z

Event Radius Sink

Sensor nodes

Event-to-Sink Event-to-Sink Reliability Reliability Y. Sankarasubramaniam, O. B. Y. Sankarasubramaniam, O. B.

Akan, I. F. Akyildiz, Akan, I. F. Akyildiz, Proc. of ACM MobiHoc’03, Annapolis, Maryland, June 2003Proc. of ACM MobiHoc’03, Annapolis, Maryland, June 2003..

Sensor networks are Sensor networks are event-drivenevent-driven Multiple correlated data flows from event to Multiple correlated data flows from event to

sink sink Goal is to reliably detect/estimate event Goal is to reliably detect/estimate event

features from collective informationfeatures from collective information Necessitates Necessitates event-to-sink collective event-to-sink collective

reliability notionreliability notion


NETWORKING10Akyildi

z

Open Research Open Research IssuesIssues

Extend Extend ESRTESRT to address reliable transport of to address reliable transport of concurrent multiple events concurrent multiple events in the sensor field.in the sensor field.

Explore possible other Explore possible other reliability metricsreliability metrics– Total expected mean square distortionTotal expected mean square distortion– Minimum mean squared error estimation.Minimum mean squared error estimation.

Develop unified transport layer protocols for Develop unified transport layer protocols for sink-to-sensorssink-to-sensors and and bi-directional bi-directional reliable reliable transport in WSNtransport in WSN

Research to Research to integrate WSN domain into NGWI integrate WSN domain into NGWI (Next Generation Wireless Internet)(Next Generation Wireless Internet)– Adaptive Transport Protocols for WSN-Ad Hoc Adaptive Transport Protocols for WSN-Ad Hoc

environmentsenvironments


NETWORKING11Akyildi

z

NETWORK LAYERNETWORK LAYER

Important considerations:Important considerations:

Sensor networks are mostly data Sensor networks are mostly data centriccentric

An ideal sensor network has attribute An ideal sensor network has attribute based addressing and location based addressing and location awarenessawareness

Data aggregation is useful unless it Data aggregation is useful unless it does not hinder collaborative effortdoes not hinder collaborative effort

Power efficiency is always a key factorPower efficiency is always a key factor


NETWORKING12Akyildi

z

NETWORK LAYERNETWORK LAYERRelated WorkRelated Work

Sensor Protocols for Information via Negotiation (SPIN) [1]Sensor Protocols for Information via Negotiation (SPIN) [1] Directed Diffusion [2]Directed Diffusion [2]

[1] W. R. Heinzelman, J. Kulik, and H. Balakrishnan, “Adaptive Protocols for [1] W. R. Heinzelman, J. Kulik, and H. Balakrishnan, “Adaptive Protocols for Information Dissemination in Wireless Sensor Networks,” Information Dissemination in Wireless Sensor Networks,” Proc. of the ACM Proc. of the ACM MobiCom’99MobiCom’99, pp. 174-185, Sept. 1999., pp. 174-185, Sept. 1999.[2] C. Intanagonwiwat, R. Govindan, and D. Estrin, “Directed Diffusion: A [2] C. Intanagonwiwat, R. Govindan, and D. Estrin, “Directed Diffusion: A Scalable and Robust Communication Paradigm for Sensor Networks,” Scalable and Robust Communication Paradigm for Sensor Networks,” Proc.Proc. of the ACM MobiCom’00of the ACM MobiCom’00, pp. 56-67, Sept. 2000., pp. 56-67, Sept. 2000.


NETWORKING13Akyildi

z

Desired Features Desired Features

Periodic update of routes not neededPeriodic update of routes not needed Adaptive to failuresAdaptive to failures Cope with topology changesCope with topology changes No need for routing tablesNo need for routing tables Easy incorporation of new sensor nodesEasy incorporation of new sensor nodes Routes based on QoS requirementsRoutes based on QoS requirements One-to-one, many-to-one, one-to-many, and many-to-One-to-one, many-to-one, one-to-many, and many-to-many many communicationscommunications


NETWORKING14Akyildi

z

Open Research Open Research IssuesIssues

• Store and Forward Technique that combines data fusion and aggregation.

• Routing for Mobile Sensors Investigate multi-hop routing techniques for high mobility environments.

• Priority Routing Design routing techniques that allow different priority of data to be aggregated, fused, and relayed.

• 3D Routing


NETWORKING15Akyildi

z

MEDIUM ACCESS CONTROL (MAC)MEDIUM ACCESS CONTROL (MAC)Related WorkRelated Work

IEEE 802.11 IEEE 802.11 S-MAC and EAR [1,2] S-MAC and EAR [1,2] Transmission Control Scheme [3]Transmission Control Scheme [3] Distributed Source Coding [4,5] Distributed Source Coding [4,5] Routing and Data Compression [6]Routing and Data Compression [6]

[1] K.Sohrabi et al.,”Protocols for Self-Organization of a Wireless Sensor Network”,[1] K.Sohrabi et al.,”Protocols for Self-Organization of a Wireless Sensor Network”, IEEE Personal Communications,October 2000.IEEE Personal Communications,October 2000.[2] W. Ye, J. Heidemann and D. Estrin, “An Energy Efficient MAC Protocol for Wireless Sensor [2] W. Ye, J. Heidemann and D. Estrin, “An Energy Efficient MAC Protocol for Wireless Sensor Networks,” Networks,” Proc. ACM MOBICOM ’01, Proc. ACM MOBICOM ’01, pp.221 –235, July 2001.pp.221 –235, July 2001.[3] A. Woo and D. Culler, “A Transmission Control Scheme for Media Access in Sensor Networks”, [3] A. Woo and D. Culler, “A Transmission Control Scheme for Media Access in Sensor Networks”,

Proc. ACM MOBICOM’01, Proc. ACM MOBICOM’01, July 2001..July 2001..

[4] S.S. Pradhan, K. Ramchandran, “Distributed Source Coding: Symmetric Rates and Applications in [4] S.S. Pradhan, K. Ramchandran, “Distributed Source Coding: Symmetric Rates and Applications in Sensor Sensor

Networks,” in Networks,” in Proc. Data Compression Conference’00, Proc. Data Compression Conference’00, pp. 363 –373, 2000.pp. 363 –373, 2000.

[5] S.S. Pradhan, J. Kusuma, K. Ramchandran, “Distributed Compression in a Dense Microsensor [5] S.S. Pradhan, J. Kusuma, K. Ramchandran, “Distributed Compression in a Dense Microsensor Network,” Network,”

IEEE Signal Processing Magazine, IEEE Signal Processing Magazine, vol.19, no.2, pp.51 –60, Mar 2002.vol.19, no.2, pp.51 –60, Mar 2002.

[6] A. Scaglione, S.D. Servetto, “On the Interdependence of Routing and Data Compression in Multi-[6] A. Scaglione, S.D. Servetto, “On the Interdependence of Routing and Data Compression in Multi-Hop Hop

Sensor Networks,” Sensor Networks,” Proc. MOBICOM’02, Proc. MOBICOM’02, September 2002. September 2002.


NETWORKING16Akyildi

z

Collaborative MAC ProtocolCollaborative MAC ProtocolM. C. Vuran, Y. Sankarasubramaniam, I.F. Akyildiz, M. C. Vuran, Y. Sankarasubramaniam, I.F. Akyildiz, “Collaborative Medium Access for Wireless Sensor “Collaborative Medium Access for Wireless Sensor Networks”, March 2003.Networks”, March 2003.

Spatial correlationSpatial correlation in in sensor networks is sensor networks is exploited in the MAC layerexploited in the MAC layer

Event MAC (E-MAC)Event MAC (E-MAC) filters filters out correlation whereas out correlation whereas Network MAC (N-MAC) Network MAC (N-MAC) prioritizes the route-thru prioritizes the route-thru packetspackets

Number of transmissions Number of transmissions are reduced instead of are reduced instead of number of transmitted number of transmitted bitsbits


NETWORKING17Akyildi

z

Optimal Packet Size for Wireless Optimal Packet Size for Wireless Sensor NetworksSensor Networks

Y. Sankarasubramaniam, I. F. Akyildiz, S. McLaughlin, Y. Sankarasubramaniam, I. F. Akyildiz, S. McLaughlin, ”Optimal ”Optimal Packet Size Packet Size

for Wireless Sensor Networks”, IEEE SNPA, May 2003.for Wireless Sensor Networks”, IEEE SNPA, May 2003.

Determining the optimal packet size for sensor networks is necessary to Determining the optimal packet size for sensor networks is necessary to operate at high operate at high energy efficienciesenergy efficiencies..

The The multihop wireless channelmultihop wireless channel and and energy consumption characteristicsenergy consumption characteristics are the two most are the two most important factors that influence choice of packet size. important factors that influence choice of packet size.

Payload (Payload (<=73<=73))Header (Header (22)) Trailer (FEC) (Trailer (FEC) (>=3>=3))


NETWORKING18Akyildi

z

PHYSICAL LAYERPHYSICAL LAYER(Some Facts)(Some Facts)

Low-lying antennae and near-ground channels result in Low-lying antennae and near-ground channels result in fourth fourth power decay of signal intensity with distancepower decay of signal intensity with distance

Transmit power can be reduced by increasing node Transmit power can be reduced by increasing node densitydensity

Multi-hop communication can also mitigate some signal Multi-hop communication can also mitigate some signal propagation effectspropagation effects

M-ary modulation reduces transmit on-time but requires M-ary modulation reduces transmit on-time but requires greater output power to achieve same BER as binary greater output power to achieve same BER as binary modulation modulation


NETWORKING19Akyildi

z

SYNCHRONIZATIONSYNCHRONIZATIONRelated WorkRelated Work

Post-Facto Synchronization [1]Post-Facto Synchronization [1]

Reference-BroadcastReference-Broadcast Synchronization (RBS) [2]Synchronization (RBS) [2] [1][1] J. Elson and D. Estrin, “Time Synchronization for Wireless Sensor Networks,” J. Elson and D. Estrin, “Time Synchronization for Wireless Sensor Networks,”

Proceedings of the 15th International Parallel and Distributed Processing Symposium Proceedings of the 15th International Parallel and Distributed Processing Symposium (IPDPS-01)(IPDPS-01), IEEE Computer Society, April 2001., IEEE Computer Society, April 2001.[2] J. Elson, L. Girod, and D. Estrin, “Fine-Grained Network Time Synchronization using [2] J. Elson, L. Girod, and D. Estrin, “Fine-Grained Network Time Synchronization using Reference Broadcasts,”Reference Broadcasts,” Proceedings of the Fifth Symposium on Operating Proceedings of the Fifth Symposium on Operating Systems Design and Implementation (OSDI 2002)Systems Design and Implementation (OSDI 2002), December 2002., December 2002.


NETWORKING20Akyildi

z

PERCEPTIVE LOCALIZATIONPERCEPTIVE LOCALIZATION Related WorkRelated Work

N. Patwari et. al., “Relative Location Estimation in Wireless Sensor Networks,” N. Patwari et. al., “Relative Location Estimation in Wireless Sensor Networks,” IEEE Transactions on IEEE Transactions on Signal ProcessingSignal Processing, August 2003., August 2003.

- Mathematical analysis of sensor location accuracy based on fixed base-stations capable of - Mathematical analysis of sensor location accuracy based on fixed base-stations capable of peer- to-peer time-of-arrival or received signal strength measurementspeer- to-peer time-of-arrival or received signal strength measurements

R. Moses et.al., “A Self-Localization Method for Wireless Sensor Networks,”R. Moses et.al., “A Self-Localization Method for Wireless Sensor Networks,” Eurasia Journal on Eurasia Journal on Applied Signal ProcessingApplied Signal Processing, No. 4, pp. 348-358, 2003., No. 4, pp. 348-358, 2003. - A self-location method that uses base-stations with known positions as references - A self-location method that uses base-stations with known positions as references

A. Savvides et.al., “Dynamic Fine-Grained Localization in Ad-Hoc Networks of Sensors,”A. Savvides et.al., “Dynamic Fine-Grained Localization in Ad-Hoc Networks of Sensors,” Proc. Of ACM MobiCom’01Proc. Of ACM MobiCom’01, pp. 166-179, 2001., pp. 166-179, 2001. - Use fixed-base stations for fine-grained location- Use fixed-base stations for fine-grained location

OPEN RESEARCH ISSUE: Non Fixed Base-Station based Techniques: Enable location of sensor nodes without the need for location beacons


NETWORKING21Akyildi

z

Some ApplicationsSome Applications

• MAN for Meteorological Observations• SpINet for Mars Surface• Airport Security Sensors/Actors• Sensor Wars• Wide Area Multi-campus Sensor Network


NETWORKING22Akyildi

z

Basic Research Basic Research NeedsNeeds

• An Analytical Framework for Sensor Networks• More theoretical investigations of the Protocol developments• Realistic Demos• Integration with other network paradigms• ….

state-of-the-art in sensor networks research ian f. akyildiz broadband & wireless networking...

Documents

nodes nodes

sensor nodes n

memory sensor nodes

failures sensor nodes

node failure sensor

wireless sensor networks

exchanges trends

nsfusa workshop