A Survey on Sensor Networks

Hussein AlzoubiHussein_alzoubi@hotmail.com

Rami AlnamnehRamir11@yahoo.com

Outline

Introduction Communication architecture Protocol stack Conclusion

Introduction

Sensor Networks…low-cost, rapid deployment, self-organizing, and fault tolerance.

Application areas: heath, military, and home. Large number of sensor nodes that are densely

deployed. Nodes use their processing abilities to locally carry

out simple computations and transmit the required and partially processed data.

Ad hoc networks are not suitable for the sensor networks because of their unique features and application requirements.

Communication Architecture

Internet and Satellite

Sink

Task managernode

User

Sensor nodesSensor field

A

B

CDE

Design Factors Fault Tolerance

the ability to sustain sensor network functionalities without any interruption due to sensor node failures because of lack of power, physical damage, or environmental interference.

Scalabilitythe density of sensor nodes can range from few sensor nodes to few hundred sensor nodes in a region.

Production Coststhe cost of sensor node should be much less than $1 in order for the sensor network to be feasible

Hardware Constraints

Power Unit Powergenerator

Location finding system Mobilizer

TransceiverSensor ADC

SensingUnit

ProcessingUnit

Processor

Storage

Continue.. Design Factors

Sensor Network Topology- Predeployment and deployment phase- Post-deployment phase- Redeployment of additional nodes phase

Environmentcan work in different environments.

Transmission Medialinks between nodes can be formed by radio, infrared, or optical media.

Power Consumptionbattery lifetimedesign of power-aware protocols and algorithmsPower consumption: sensing, communication, and data processing

Continue.. Design Factors

Protocol Stack

Application layer

Transport layer

Network layer

Data link layer

Physical layer

Pow

er managem

ent plane

Mobility m

anagem

ent pla

ne

Task m

anagement plane

The Physical Layer

Frequency selection. Carrier frequency generation. Signal detection. Modulation

Binary and M-ary modulation schemesthe binary modulation scheme is more energy-efficient

Low transmission power and simple transceiver circuitry make Ultra wideband (UWB) an attractive candidate.

The Data Link Layer

Multiplexing of data streams. Data frame detection. Medium access and error control. Ensures reliable point-to-point and

point-to-multipoint connections in a communication network.

Medium Access Control Must achieve two goals

- the creation of the network infrastructure- share communication resources between sensor nodes fairly and efficiently.

Can’t be adopted into sensor networks, because- there is no central controlling agent like the base station.- power efficiency directly influences network lifetime in sensor network.

Continue.. The Data Link Layer

Some of the proposed MAC protocols

MAC protocol Power conservation

SMACS and EAR Random wakeup during setup and turning off while idle

Hybrid TDMA/FDMA Hardware-based approach for system energy minimization

CSMA-based Constant listening time for energy efficiency

Continue.. The Data Link Layer

Power saving modes of operationTurning the transceiver off during idling may not

always be efficient due to energy spent in turning it back on each time.

Error controlTwo modes of error control:

- Forward Error Correction, decoding complexities.-Automatic Repeat Request (ARQ), additional retransmission energy cost and overhead.

Best solutions: simple error control codes with low-complexity encoding and decoding

Continue.. The Data Link Layer

Network LayerTask: energy efficient routes

Sink

A (PA=2)

B (PA=2)

C (PA=2) T

D (PA=3)

E (PA=1)

F (PA=4)

α

1=1

α

α

α

αα

α

α

α

α 5=2

3=2

4=2

2=16=2

7=1

8=2

9=2

Route 1: Sink-A-B-T, total PA=4, total α = 3 Route 2: Sink-A-B-C-T, total PA=6, total α = 6Route 3: Sink-D-T, total PA=3, total α = 4Route 4: Sink-E-F-T, total PA=5, total α = 6

Approaches:• Minimum PA route: route 4• Minimum Energy (ME) route: route 1• Minimum hop (MH) route: route 3• Maximum minimum PA node route: route 3

Data Aggregation, data fusion

AB C

DE

FG

Sink

Continue.. Network Layer

Routing techniques

Floodingeach node receiving a data or management packet repeats it by broadcasting.

Gossipingsend the incoming packets to a randomly selected neighbor.

Continue.. Network Layer

Sensor Protocols for Information via Negotiation (SPIN)

Step 1

ADV

Step 2

REQ

Step 3

DATA

Step 4

ADV REQ

Step 5 Step 6

DATA

Continue.. Network Layer

Sequential Assignment Routing (SAR) Creates multiple trees where the root of each tree is a one-hop neighbor from the sink.

Low-Energy Adaptive Clustering Hierarchy (LEACH)Forms clusters to minimize energy dissipation.

Directed diffusionSets up gradients for data to flow from source to sink during interest dissemination.

Continue.. Network Layer

Transport Layer

Transport layer protocols are still unexplored: they may be purely UDP-type protocols, because each sensor node has limited memory and power.

The Application Layer Sensor Management Protocol (SMP)

makes the hardware and software of the lower layers transparent to the sensor network management applications. System administrators interact with sensor networks using SMP.

Task Assignment And Data Advertisement Protocol (TADAP)provides the user software with efficient interfaces for interest dissemination.

Sensor Query and Data Dissemination Protocol (SQDDP)provides user applications with interfaces to issue queries, respond to queries and collect incoming replies.

Conclusion

The flexibility, fault tolerance, high sensing fidelity, low cost, and rapid deployment characteristics ofsensor networks create new and exciting application areas for remote sensing.

Questions?

Thank you!