Wireless Sensor Networks - csit.uob.edu.pkcsit.uob.edu.pk/images/web/staff/lecture/doc-4.2016-9-4.No-4.pdf · Wireless Sensor Network “A wireless sensor network (WSN) is a wireless

Wireless Sensor Networks

Atiq Ahmed

Outline

• Motes & Wireless Sensor Networks

• WSN Applications

9/8/2016 Introduction to WSN 2

Mote

Dig

ita

l I/O

po

rts

Radio Transceiver

An

alo

g I

/O P

ort

s

Microcontroller

A/D

D/A

Sensor

Sensor

• A very low cost low power computer

• Monitors one or more sensors

• A Radio Link to the outside world

• Are the building blocks of Wireless Sensor Networks (WSN)

External Memory

Dig

ita

l I/O

po

rts


Wireless Sensor Network

“A wireless sensor network (WSN) is a wireless network consisting of spatially distributed

autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as environmental conditions, such as

temperature, sound, vibration, pressure, motion or pollutants, at different locations.”

- Wikipedia


Wireless Sensor Network

• WSNs are networks that consists of sensors which

are distributed in an ad hoc manner

• These sensors work with each other to sense some

physical phenomenon and then the information physical phenomenon and then the information

gathered is processed to get relevant results

• WSNs consists of protocols and algorithms with self-

organizing capabilities

Introduction to WSN9/8/2016 5

Wireless Sensor Networks

• Formed by hundreds or thousands of motes that communicate with each other and pass data along from one to data along from one to another

• Research focuses mostly on energy aware computing and distributed computing


WSN node components

• Low-power processor.– Limited processing.

• Memory.– Limited storage.

• Radio.– Low-power.

Sensors

P

O

W– Low-power.

– Low data rate.

– Limited range.

• Sensors.– Scalar sensors: temperature,

light, etc.

– Cameras, microphones.

• Power.

9/8/2016 1-7

Processor

Radio

StorageW

E

R

WSN device schematics

Introduction to WSN

Why Now?

• Use of networked sensors dates back to the

1970s

– Primarily wired and

– “Centralized”– “Centralized”

• Today, enabling technological advances in

VLSI, MEMS1, and wireless communications

– Ubiquitous computing and

– Ubiquitous communications


1Microelectromechanical systems

Vision: Embed the World

•Embed numerous sensing nodes

to monitor and interact with

physical world

•Network these devices so that

they can execute more complex

task


Examples of WSN Platforms

PC-104+

(off-the-shelf)

UCLA TAG

(Girod)UCB Mote

(Pister/Culler)


Example of WSNSource: http://esd.sci.univr.it


Comparison with ad hoc networks

– WSNs mainly use broadcast communication while ad hoc networks use point-to-point communication

– Unlike ad hoc networks, WSNs are limited by sensorslimited power, energy and computational capabilitylimited power, energy and computational capability

– Sensor nodes may not have global ID because of the large amount of overhead and large number of sensors

– The number of nodes is very large

– Being more prone to failure, energy drain


Characteristics of Wireless Sensor

Networks• WSNs mainly consists of sensors which are -

– low power

– limited memory

– energy constrained due to their small size

• Wireless networks can also be deployed in extreme • Wireless networks can also be deployed in extreme environmental conditions and may be prone to enemy attacks

• Although deployed in an ad hoc manner they need to be self organized and self healing and can face constant reconfiguration


Design Challenges

• Heterogeneity

– The devices deployed maybe of various types and need to collaborate with each other

• Distributed Processing• Distributed Processing

– The algorithms need to be centralized as the processing is carried out on different nodes

• Low Bandwidth Communication

– The data should be transferred efficiently between sensors


Continued..

• Large Scale Coordination

– Sensors need to coordinate with each other to produce required results

• Utilization of Sensors• Utilization of Sensors

– Sensors should be utilized in a ways that produce the maximum performance and use less energy

• Real Time Computation

– Computation should be done quickly as new data is always being generated


Operational Challenges of Wireless Sensor

Networks

• Energy Efficiency

• Limited storage and computation

• Low bandwidth and high error rates

• Errors are common• Errors are common

– Wireless communication

– Noisy measurements

– Node failure are expected

• Scalability to a large number of sensor nodes

• Survivability in harsh environments

• Experiments are time- and space-intensive


Enabling Technologies

EmbeddedNetworked

Control system w/

Small form factor Exploit

Embed numerous distributed

devices to monitor and interact

with physical world

Network devices to coordinate and

perform higher-level tasks

Sensing

Small form factor

Untethered nodes

Exploit

collaborative

Sensing, action

Tightly coupled to physical world

Exploit spatially and temporally dense, in situ, sensing and actuation


Applications of Wireless Sensor networks

Applications can be divided in three categories

I. Monitoring of objectsI. Monitoring of objects

II. Monitoring of an area

III. Monitoring of both area and objects


WSN Applications

• Environmental/Habitat monitoring

• Acoustic detection

• Seismic Detection

• Military surveillance • Military surveillance

• Inventory tracking

• Medical monitoring

• Smart spaces

• Process Monitoring


Biomedical / Medical

• Health Monitors

– Glucose

– Heart rate

– Cancer detection

• Chronic Diseases

– Artificial retina

– Cochlear implants

• Hospital Sensors

– Monitor vital signs

– Record anomalies


Military

Remote deployment of sensors for tactical monitoring of enemy

troop movements


Industrial & Commercial

• Numerous industrial and commercial

applications:

– Agricultural Crop Conditions

– Inventory Tracking– Inventory Tracking

– In-Process Parts Tracking

– Automated Problem Reporting

– RFID – Theft Deterrent and Customer Tracing

– Plant Equipment Maintenance Monitoring


Habitat Monitoring on Great Duck IslandSource: http://www.greatduckisland.net/

• Intel Research Laboratory at Berkeley initiated a collaboration with the College of the Atlantic in Bar Harbor and the University of California at Berkeley to deploy wireless sensor networks on Great Duck Island, Maine (in 2002)

• Monitor the microclimates in and around nesting burrows used by the Leach's Storm PetrelPetrel

• Goal : habitat monitoring kit for researchers worldwide


FireBug by UCBSource: D. M. Doolin and N. Sitar. Wireless sensors for wild fire monitoring, Proceedings of SPIE / NDE 2005.

• Wildfire Instrumentation System Using Networked Sensors

• Allows predictive analysis of evolving fire behavior

• Firebugs: GPS-enabled, wireless thermal sensor motes based on TinyOS that self-organize into networks for collecting real time data in wild fire environments

• Software architecture: Several interacting layers (Sensors, Processing of sensor data, Command center)


Example: Precision Agriculture

• Precision agriculture aims at

making cultural operations

more efficient, while reducing

environmental impact

• Collected information is used

to evaluate optimum sowing

density, estimate fertilizers

and other inputs needs, and

to more accurately predict

crop yields

Introduction to WSN9/8/2016

Source: Aslan, et el. "A framework for use of

wireless sensor networks in forest fire

detection and monitoring." Computers,

Environment and Urban Systems 36.6 (2012):

614-625. 25

Preventive Maintenance on an Oil

• Collaboration of Intel & British Petroleum

• Use of sensor networks to support preventive maintenance on board an oil tanker in the North Sea

• A sensor network deployment onboard • A sensor network deployment onboard the ship

• System gathered data reliably and recovered from errors when they occurred

• The project was recognized by InfoWorld as one of the top 100 IT projects in 2004


• Basically a location-aware mote

• Includes an Ultrasound transmitter and receiver

• Uses the combination of RF and Ultrasound technologies to establish differential time of arrival and hence linear range

estimates

“Cricket” Mote

estimates

• Based on Cricket Indoor Location System developed by MIT


• Organizes the sensor

nodes into clusters

• Each cluster is governed

by a cluster-head

Clustered Architecture

by a cluster-head

• Only heads send

messages to a BS

• Suitable for data fusion

• Self-organizing


Low-Energy Adaptive Clustering Hierarchy

(LEACH)

• Self-organizing and adaptive clustering protocol

• Evenly distributes the energy expenditure among the

sensors

• Performs data aggregation where cluster heads act • Performs data aggregation where cluster heads act

as aggregation points

• Two main phases:

– Setup phase: organizing the clusters

– Steady-state phase: deals with the actual data transfers to

the BS


TinyOS• What is TinyOS?

– open-source operating system

– wireless embedded sensor networks

– component-based architecture

• Developed at UCB in collaboration with Intel Research

• Current Stable Version is 1.1.15• Current Stable Version is 1.1.15

• TinyOS 2.0 (T2) released on 6/11

• Main Ideas –– Low complexity

– Conserve power – sleep as frequently as possible

• Written in nesC – next generation C compiler


Different Targets

mica mica2 mica2dot micaz

telos telosb rene2 pc


Mica2

• Extremely popular mote

• 8-bit AVR Controller

• FSK radio

• Data-logger flash• Data-logger flash


Telosb Motes

• Have USB programming capability

• An IEEE 802.15.4 compliant, high data rate radio with integrated antenna, a low-power MCU with integrated antenna, a low-power MCU

• Also equipped with extended memory and an optional sensor suite


Future of WSNSmart Home / Smart Office

• Sensors controlling

appliances and electrical

devices in the house

• Better lighting and • Better lighting and

heating in office

buildings

• The Pentagon building

has used sensors

extensively


References1. Akyildiz, Ian F., and Mehmet Can Vuran. Wireless sensor networks. Vol. 4. John

Wiley & Sons, 2010.

2. Stankovic, John A. "Wireless Sensor Networks." IEEE Computer 41.10 (2008): 92-95.

3. Yang, Kun. "Wireless sensor networks." Principles, Design and Applications(2014).

4. Ye, Wei, et al. "An energy-efficient MAC protocol for wireless sensor networks." INFOCOM 2002. IEEE. Vol. 3. IEEE, 2002.

5. Patwari, Neal, et al. "Locating the nodes: cooperative localization in wireless sensor networks." IEEE Signal processing magazine 22.4 (2005): 54-69.sensor networks." IEEE Signal processing magazine 22.4 (2005): 54-69.

6. Al-Karaki, et al. "Routing techniques in wireless sensor networks: a survey." IEEE wireless communications 11.6 (2004): 6-28.

7. Pal, Amitangshu. "Localization algorithms in wireless sensor networks: Current approaches and future challenges." Network protocols and algorithms 2.1 (2010): 45-73.

8. Ozturk, Yusuf, et al. "An intelligent home energy management system to improve demand response." IEEE Transactions on Smart Grid 4.2 (2013): 694-701.

9. Dong, Wei, et al. "DPLC: Dynamic packet length control in wireless sensor networks." INFOCOM, 2010 Proceedings IEEE. IEEE, 2010.


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Wireless Sensor Networks - csit.uob.edu.pkcsit.uob.edu.pk/images/web/staff/lecture/doc-4.2016-9-4.No-4.pdf · Wireless Sensor Network “A wireless sensor network (WSN) is a wireless