REPORT Biswajit

8/10/2019 REPORT Biswajit

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WIRELESS SENSOR NETWORK

By

Biswajit NayakRegd. No-10IT61B06

School of Information Technology

Indian Institute Of Technology,Kharagpur.

Sept-2011


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CERTIFICATE

This is to certify that the seminar entitled Wireless Sensor Networks submitted by

Biswajit Nayak( Regd.No-10IT61B06 ) ,towards the partial fulfillment of the requirement for the

degree of Master in Technology in Information and Communication Technology of Indian

Institute of Technology ,Kharagpur is the record of work carried out by him under my

supervision and guidance .In my opinion ,the submitted work has reached a level required for

being accepted for examination. The result embodied in this seminar, to the best of my

knowledge, havent been submitted to any other university or institution for award of any degree

or diploma.

Prof. Indranil Sen Gupta Prof. Partha Sarathi DayDepartment of Computer Science & Engg. Department of Computer Science & Engg.

Indian Institute of Technology Kharagpur. Indian Institute of Technology Kharagpur.


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ACKNOWLEDGEMENT

It is matter of great pleasure for me to submit this seminar report on Wireless Sensor

Network, as a part of curriculum for award of Master in Technology with specialization inInformation and Communication Technology (ICT)degree of Indian Institute of Technology,

Kharagpur (IIT KGP).

I am thankful to my seminar guide Prof. Indranil Sen Gupta, Professor in Computer Sc. &

Engg and Prof. Partha Sarathi Day,Professor in Computer Sc. & Engg. Department for hisconstant encouragement and able guidance.

I am also thankful to Prof. D Mukhopadhyay, Assistant Professor in Computer Science &

Engineering, Prof. P. P. Das, Professor, Professor in Computer Sc. & Engg & Prof. K. S. RaoAssistant Professor, Information Technology, for their valuable support. My thanks are also due

to Prof. S Misra, Assistant Professor in Information Technology and Prof. R Mall, Professor

in Computer Science & Engineering, for their support and suggestions.

I take this opportunity to express my deep sense of gratitude towards those, who have helped us

in various ways, for preparing my seminar.

At the last but not least, I am thankful to my parent, who had encouraged & inspired me with

their blessings.

Biswajit NayakMTech (ICT)

Regd.No -10IT61B06


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ABSTRACT

Wireless sensor networks are attracting increased interest for a wide collection of applications,

such as environmental monitoring, vehicle tracking, health monitoring etc. However, developing

sensor network application is notoriously difficult, due to extreme resource limitations of nodes,

the unreliability of radio communication, and the necessity of low power operation. Our goal is

to simplify application design by providing a set of development primitives for sensor networks

that abstract the details of low-level communication, data sharing ,and collective operations

.Through advanced different networking protocols, these devices form a sea of connectivity that

extends the reach of cyberspace out into the physical world. This report gives a brief description

of its architecture, routing protocol,standardization,different metrics to measure efficiency and its

important component like Microcontroller, Transceiver, External Memory; Power Source

(batteries).The unique characteristics include limited power usage, ability to with stand harsh

environmental conditions, ability to cope with node failures, dynamic network topology, etc. The

various factors influencing, sensor networks are also covered. This report also gives brief

description regarding security. The hardware design, software design and architecture forms an

essential part of the report.


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Wireless Sensor Network Content

[Biswajit Nayak, MTech (ICT), IITKgp][Regd.No10IT61B06] Page 1

CONTENT

Page. No

1. Introduction 02

2.

History of Wireless Sensor Network (WSN) 03

3. Characteristics 04

4. Hardware Component 05

5. Hardware Design 06

6. Software Component 08

7. Software Design 09

8. Wireless Sensor Network Architecture 10

8.1Client 10

8.2Server 10

8.3Sensor MOTES 11

8.4Networking Topologies 11

9. Routing Protocols in WSNs 12

10.Security in Wireless Sensor Network 16

10.1 Security Threats in WSN 16

10.2 Countermeasure 17

11.System Evaluation Metrics 17

12.Standardization 18

13.Wireless Sensor Network Applications 19

14.Pros and Cons of Wireless Sensor Network 20

15.Future Scope 20

16.

Conclusion 2117.Bibliography 22


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Wireless Sensor Network Introduction


1. Introduction

A wireless sensor network (WSN) is a wireless network consisting of spatially dispersed anddedicated autonomous devices that use sensors to monitor physical or environmental conditions.

A usual WSN system is formed by combining these autonomous devices, or nodes with routers

and a gateway[9][10].

The dispersed measurement nodes communicate wirelessly to a central gateway, which providesa connection to the wired world where you can collect, process, analyze, and present your

measurement data. You can use routers to gain an additional communication link between end

nodes and the gateway for extend distance and reliability in a wireless sensor network, [10][11].The wireless sensor is networked and scaleable, require very little power. It is also smart and

software programmable, and also capable of fast data acquisition, reliable and accurate over the

long term, but costs little to purchase and install, and requires nearly zero maintenance.

(Figure 1.1: Block diagram of Wireless Sensor Network)

Wireless Sensor Network is different from traditional network.

Wireless Sensor Network is a Single-purpose design means serving one specificapplication where as traditional network general-purpose design means serving manyapplications.

Energy is the main constraint in the design of all node and network components inwireless sensor network where as intraditional network typical primary design concerns are network performance and

latencies, energy is not a primary concern.

Sensor networks often operate in environments with harsh conditions where as intraditional network devices and networks operate in controlled and mild environments.


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Wireless Sensor Network History


In wireless sensor network physical access to sensor nodes is often difficult or even

impossible where as in traditional network maintenance and repair are common and

networks are typically easy to access

In wireless sensor network most decisions are made localized without the support of a

central manager where as Obtaining global network knowledge is typically feasible and

centralized management is possible

2. History

In the year of 1978, the Defense Advanced Research Projects Agency (DARPA) organized the

Distributed Sensor Nets Workshop (DAR 1978),focusing on sensor network research challenges

such as networking technologies, signal processing techniques, and distributed algorithms.That isthe reason that the military has been a driving force behind the development of wireless sensor

networks[8].

In the early 1980s DARPA also operated the Distributed Sensor Networks (DSN) program

which was then followed by the Sensor Information Technology (SensIT) program, whichprovided the present sensor networks with new capabilities such as ad hoc networking, dynamic

querying and tasking, reprogramming and multitasking[2][8].

The University of California at Los Angeles along with the Rockwell Science Center proposed

the concept of Wireless Integrated Network Sensors or WINS . One outcome of the WINSproject was the Low Power Wireless Integrated Microsensor (LWIM), produced in 1996 (Bult et

al. 1996). This smart sensing system was based on a CMOS chip, integrating multiple sensors,

interface circuits, digital signal processing circuits, wireless radio, and microcontroller onto a

single chip.

In the year 1999 the University of California at Berkeley focused on the design of extremely

small sensor nodes called motes in the Smart Dust Project(Khan et al. 1999).The main aim of

this project was to demonstrate that a complete sensor system can be integrated into tiny devices,possibly the size of a grain of sand or even a dust particle.

In the year 2000 the Berkeley Wireless Research Center (BWRC) focuses on the development of

low-power sensor devices in the PicoRadio project (Rabaey et al. 2000) , whose power

consumption is so small that they can power themselves from energy sources of the operating

environment, such as solar or vibrational energy.

The MIT AMPS (micro-Adaptive Multidomain Power-aware Sensors) project focuses on low-

power hardware and software components for sensor nodes, which includes the use of

microcontrollers capable of dynamic voltage scaling and techniques to restructure data

processing algorithms to reduce power requirements at the software level (Calhoun et al. 2005).

Due to these previous efforts are mostly determined by academic institutions, over the last

decade a number of profitable efforts have also appeared (many based on some of the academicefforts described above), including companies such as Crossbow (www.xbow.com) ,Sensoria

(www.sensoria.com) , Worldsens (http://worldsens.citi.insa-lyon.fr) , Dust Networks

(http://www.dustnetworks.com) , and Ember Corporation (http://www.ember.com) .


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Wireless Sensor Network Characteristics


Due to the profitable effort of these companies,they provide the opportunity to purchase sensor

devices ready for deployment in various different type of applications along with a variety of

management tools for programming,maintenance, and sensor data visualization[8].

3. CharacteristicsThe general structure of Wireless sensor network consists of a basestation or gateway whichcan communicate with a number of wireless sensors via a radio link. Data is captured at the

wireless sensor node, then compressed, and transmitted to the gateway directly or, if required,

uses other wireless sensor nodes to forward data to the gateway. The transmitted data is thenpassed to the system through the gateway connection.

Sensor nodes are likely as small computers, extremely basic in terms of their interfaces and their

components. They usually consist of a processing unit with limited computational power and

limited memory, sensors, a communication device, and a power source usually in the form of abattery.

The base stations act as a gateway between sensor nodes and the end user and they normallyforward data from the WSN on to a server. Other special components are routers, designed to

compute, calculate and distribute the routing tables[10].

On the basis of functionality of sensor nodes and other element, the major characteristics ofWSN are as following :-

Power consumption constrains for nodes using batteries or energy harvesting

Ability to cope with node failures

Mobility of nodes Dynamic network topology

Communication failures

Heterogeneity of nodes Scalability to large scale of deployment

Ability to withstand harsh environmental conditions

Ease of use Unattended operation.

4. Hardware Component

A Wireless Sensor Network(WSN) consists of spatially distributed sensor nodes and each sensor

node can perform some processing and sensing tasks independently. In addition, sensor nodescommunicate with each other in order to forward their sensed information to a central processingunit or conduct some local coordination such as data fusion[1][2][5]. The sensor node consists of

several hardware components that include an embedded processor, a radio transceiver, internal

and external memories, and one or more sensors, a geopositioning system, a power source[2][1].


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Wireless Sensor Network Hardware Component


( Fig 4.1 Architecture of Sensor Node)

4.1 Embedded ProcessorThe functionality of an embedded processor in a sensor node is to schedule tasks, process data

and control the functionality of other hardware components. There are several types of embeddedprocessors available that can be used in a sensor node include Microcontroller, Digital SignalProcessor (DSP), Field Programmable Gate Array (FPGA) and Application Specific Integrated

Circuit (ASIC). been the most used embedded processor for sensor nodes is the Microcontroller

because of its flexibility to connect to other devices and its cheap price[2]. For example, the mostrecent CC2531 development board provided by Chipcon (acquired by Texas Instruments) uses

8051 microcontroller, and the Mica2 Mote platform provided by Crossbow uses ATMega128L

microcontroller.

4.2 TransceiverThe responsibility of a transceiver is for the wireless communication of a sensor node. There are

different types of wireless transmission media, which includes Radio Frequency (RF), Laser and

Infrared. The most used transmission media to fits to most of WSN applications is the RF basedcommunication. The different operational states of a transceiver are Transmit, Receive, Idle and

Sleep[2]. Mica2 Mote uses two kinds of RF radios one is RFM TR1000 and other one is

Chipcon CC1000. The Mica2 Motes outdoor transmission range of is about 150 meters.

4.3 MemoryMemories in the sensor nodes includes both program memory (from which instructions are

executed by the processor), and data memory (for storing raw and processed sensor

measurements and other local information). The quantities of memory and storage on board aWSN device are often limited. It include in-chip flash memory and RAM of a microcontroller

and external flash memory. For example, the ATMega128L microcontroller running on Mica2Mote has 128-Kbyte flash program memory and 4-Kbyte static RAM. Further, a 4-Mbit Atemel

AT45DB041B serial flash chip can provide external memories for Mica and Mica2Motes(Hill,2003)[1][2].

4.4 SensorsDue to limited bandwidth and power , Wireless Sensor Network devices primarily support only

low-data-rate sensing. There are various applications call for multi-modal sensing, as a result

each device may have several sensors on board. The specific sensors are used according to therequirement of the application[1].For example, they may include temperature sensors, light


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Wireless Sensor Network Hardware Design


sensors, humidity sensors, pressure sensors, accelerometers, magnetometers, chemical sensors,

acoustic sensors, or even low-resolution imagers.

4.5 Geopositioning systemIt is important for all sensor measurements to be location stamped In numerous WSN

applications. To obtain positioning you need to pre-configure sensor locations at deployment, but

this may only be possible in limited deployments. Mainly for outdoor operations, when thenetwork is deployed in an ad hoc manner, such information is most easily obtained via satellite-

based GPS[1]. The Global Positioning System (GPS) is a space-based global navigation satellitesystem (GNSS) which provides location and time information in all weather, anywhere on or

near the Earth, where there is an clear line of sight to four or more GPS satellites[10].

4.6 Power SourceIn deployment of the WSN device is likely to be battery powered. power is consumed by

sensing, communication and data processing by a sensor node. . Batteries are the main source of

power supply for sensor nodes. For example, Mica2 Mote runs on 2 AA batteries. While some ofthe nodes may be wired to a continuous power source in some applications, and energy

harvesting techniques may provide a degree of energy renewal in some cases, the finite battery

energy is probable to be the most critical resource bottleneck in most applications[1][2][12].

5. HARDWARE DESIGN

It is a critical process to select components for the sensor motes in the development of Wireless

Sensor Network.Low power and immense functionality are two highest priorities in evaluating

the strength of both the microcontroller and the sensor devices[12]. WISENET is introduced tothe new state-of-the-art Chipcon CC1010 microcontroller with integrated RF transceiver.

It had several features ,such as :-

Optimized 8051-core Active (14.8 mA), Idle (2.9mA) and sleep (0.2mA) power modes

32 kB flash memory

kB+128 bytes SRAM Three channel 10-bit ADC

Four timers / Two PWM's

Fully integrated UHF RF transceiver (433 MHz / 868 MHz nominal) Programmable output power (-20 to 10 dBm) Low current consumption (11.9 mA for RX, 17.0 mA for TX at

0dBm) RSSI output that can be sampled by the on-chip ADC

Optimized 8051-core: The8051 was designed from the perspective of what a microcontroller isand what it has to do. It included in the basic design was 4K of Read Only Program Memory,

128 Bytes of Internal RAM, a USART and 32 I/O Pins[12]. The only major problem with the

8051 architecture is the twelve clock cycles per instruction cycle. This has made the 8051 appearnon-competitive to other microcontrollers which can have as few as one clock cycle per

instruction cycles. But most of the early embedded microcontrollers use processor architecturesthat were taken from eight bit microprocessors.


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WirelessSensorNetwork HardwareDesign


Active (14.8 mA), Idle (2.9mA) and sleep (0.2mA) power modes : For the proper working of

the microcontroller,it requires l4.8 mA to work in active mode,requires 2.9mA in the idle stateand requires 0.2mA in the sleep state[12].

32 kB flash memory : In case of flash memory, a section of memory cells can be erased or

written in a single operation or flash. Flash memory is a variation of EEPROM_(Electrically

Erasable Programmable Read-only Memory).Flash can function at higher effective speeds whenthe systems using it read and write to different locations at the same time in a single operation

where as normal EEPROM only allows one location at a time to be erased or written. All types

of flash memory and EEPROM wear out after a certain number of erase operations. Flashmemory is made in two forms: NOR flash and NAND flash. This makes it suitable for storage of

program code that needs to be infrequently updated, as in digital cameras and PDAs. However its

I/O interface allows only sequential access to data. This makes it suitable for mass-storagedevices such as PC cards and various memory cards, and somewhat less useful for computer

memory.Flash memory is used in digital cellular phones, digital cameras, LAN switches, PC

Cards for notebook computers, digital set-up boxes, embedded controllers, and other devices

[12] [10].

2 kB+128 bytes SRAM : SRAM (static RAM) is random access memory that retains data bits inits memory as long as power is being supplied. It provides faster access to data and is more

expensive than DRAM. SRAM is used as cache memory of computers and also as part of therandom access memory digital-to-analog converter on a video card. SRAM consumes more

energy to retain data over time, but does not require as much energy for the initial storage

operation. To achieve the smallest, lowest cost device, SRAM should be used only whennecessary[3][10][12].

Three channel 10-bit ADC : Four wire SPI interface is used in 10bit Analog to Digital

converter (ADC). The 8515 processor has SPI hardware support built in and this makes it fastwith minimum software overhead. 10 bits is a high resolution. To evade digital noise on the

analog signals, a separate +5V supply (78L05) is added to the ADC and the photodiodes used asinputs. The ground for all of the above was tied into one point where the power came into the

regulator. Minimal usage of bypass capacitors on the ADC inputs we can obtain stable readings

Four timers / Two PWM's : There are two different versions of PWM.The original very

lightweight window manager, and the newer Ion-based PWM2. PWM was the first windowmanager to implement "tabbed frames" or the back then unique feature allowing multiple client

windows to be attached to the same frame. This feature helps keeping windows, especially the

numerous xterms, organized. A look at the screenshots below might clarify the idea. Being alightweight window manager with emphasis on usability, PWM discards some features common

in window managers these days: only window shading in lieu of iconification is supported, there

are no close and other window buttons. PWM does have workspaces, menus and Window Makerdockapp support.

Fully integrated UHF RF transceiver (433 MHz / 868 MHz nominal) : The wireless

transceiver contains at least two physical links, each with its own transmitter-receiver circuit inaddition to digital and analog signal processing circuits to communicate with other wireless units

using Orthogonal Frequency-Division Multiplexing (OFDM) protocol. The design approaches

deal with the issues of noise interference between analog and digital subsystems, noise

interference between two links on the same chip, and high-frequency self-test, measurement offuntional parameters (SNR, jitter, etc.), and interface between on-chip test facilities and external

low-cost testers.


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Wireless Sensor Network Software Component


6. Software Components

The software component plays major role in the development of wireless sensor network. The

development of wireless sensor network composed of three custom software components ,suchas :-

The Web program

WiseDB Tiny OS

6.1 The Web ProgramWeb program was written in PHP and make use of the Chart-Director charting software. The

web application queried MySQL database for the data, then we use a Chart-Director to generate

a graph of that data.

6.2 WiseDBWiseDB is the custom software component that interfaced with the gateway via a serial link to

and with the SQL database via a TCP/IP link. WiseDB was written in C++ and utilized two

open-source APIs (application programming interface).WiseDB collects the data captured bysensor nodes of sensor mots network and passed through gateway and accessed by using SQL

server applications. This is the way that ,the WiseDB interacted with the rest of the system in thewireless sensor network[12].

6.3 TinyOSThe one of the most important custom software component is the TinyOS .TinyOS is anoperating system specifically designed to address the needs of wireless sensor networks. It is

based on an event driven execution engine that simultaneously provides efficiency and fine-

grained concurrency. As you know, TinyOS is a real-time operating system designed for use insensor network applications where low-power, limited resources and hard real-time constraints

are critical parameters[10][12].

7. Software Design

You should have four commercial off the shelf applications installed on the server , that worked

together to create the Data Analysis portion of the Server component.

Web-Server(Apache)

PHP MySQL Database

Chart-Director

Apache is a standard web-server, which makes a web document available on the Internet. The

Apache http server is a powerful, flexible, implements the latest protocols is highly configurable

and extensible with third-party modules can be customized by writing 'modules' using theApache module API provides full source code and comes with an unrestrictive license runs on

Windows NT/9x, Netware 5.x and above, OS/2, and most versions of Unix, as well as several

other operating systems is actively being developed encourages user feedback through new

ideas, bug reports and patches implements many frequently requested features, including:

DBM databases for authentication Customized responses to errors and problems


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Wireless Sensor Network Software Design


Multiple Directorylndex directives

Unlimited flexible URL rewriting and aliasing

Content negotiation Virtual Hosts

Configurable Reliable Piped Logs

PHP is a web programming language, which is used to design web pages and allows dynamic web pages.

It is also designed to be used along with a database and included many built-in functions for interfacing

with MySQL database.

MySQLis primarily an relational database management system and therefore ships with no GUItools to administer MySQL databases or manage data contained within.MySQLis a database thatcan contain any type of data and is accessed through a TCP/IP (Internet) call. MySQL is a popular

choice of database for use in web applications.

ChartDirectoris a powerful charting component for creating professional and clickable chartsfor web and windows applications. Itis a program that generates a graph from raw data. It is availablein many languages such as PHP, ASP, C++, and others[10][12]. It includes several features, Such as:-

Fast and Efficient

Multi-threaded architecture specially designed for the demandingrequirements of server side usage.

Flexible

Object oriented API allows you to control and customize chart details,

enabling you to design the charts you want.

Comprehensive Chart Styles

Pie, bar, line, spline, step line, trend line, curve-fitting, inter-line coloring,

area, scatter, bubble, box-whisker, HLOC, candlestick, simple gantt, radar,polar. XY axis swapping (rotated charts) and 3D effects.

Layer ArchitectureSynchronized chart layers allow chart styles to overlay for arbitrary combo

chart and special effects. For example, box-whisker layers can be used to adderror symbols to any XY chart styles, and scatter layers can be used to

highlight data points with custom symbols.CDML

The innovative Chart Director Mark Up Language (CDML) technology

allows rich formatting of text with embedding icons and images. CDML is

supported in all ChartDirector text positions, including chart titles, legendkeys, axis labels, data labels, etc.

Advance color system

In additional to ARGB colors (true color with alpha transparency), all objectsin ChartDirector can be painted using "magic colors" - colors that depend on

position. Generates image maps to support tool tips and other mouseinteractions. Ideal for "drill-down" capabilities. Tool tips are customizable and

can include custom text or data. Image maps are "open-ended" and can

include user-defined regions, such as for company logos, icons and buttons.


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Wireless Sensor Network WSN Architecture


8. Wireless Sensor Network Architecture

The entire system can be described as consist as two subsystems depending upon the operation

performed by the entire system(Figure 8.1),such as :-

Data Analysis

Data Acquisition

Data Analysis subsystem is software-only . It relied on existing Internet and web (HTTP)infrastructure to ensure communications between the Client and Server components. The main

use of this subsystem was to selectively present the gathered environmental data to the end userin a graphical manner.

Data Acquisition subsystem is used to collect and store environmental data for later processing

by the Data Analysis subsystem. This subsystem is consists of PC , embedded system software

and also embedded system hardware. In the other word you can say ,it is composed of both theServer and Sensor Mote Network components.

(Figure. 8.1 Wireless Sensor Network Architecture)

8.1 ClientThe Client component is external to the development of wireless sensor network.That means,any computer with a web browser and Internet access could be a Client. It served only as a user

interface to the Data Analysis subsystem (Figure 6.1).

8.2 ServerThe Server plays a significant role between the Data Acquisition and Data Analysissubsystems.In case of Data Analysis ,in this side, an web (HTTP) server hosting a web


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Wireless Sensor Network WSN Architecture


application. When a page request came in, the web server executes the web application, which

retrieved data from the database, processes it, and returns a web page that is transmitted to theClient through the web server.In case of Data Acquisition system, there is a daemon (WiseDB)

running to provide the fascility to establish the communication with the Sensor Mote Network.

This daemon collects raw data packets from the Sensor Mote Network. Then these packets are

then processed and then convert the raw data into meaningful environmental data.Then thisprocessed data is then inserted into the database. Thus the database is the link between the Data

Analysis and Data Acquisition subsystems.

8.3 Sensor MotesThe main focus of wireless sensor network is the development of the Sensor Mote Network

component . Wireless Sensor Networks are collections of motes. Motes are the individual

computers that work together to form networks. It is the component responsible for collectingand transmitting raw environmental data to the Server. The requirements for motes are extensive.

They must be small, energy efficient, multifunctional, and wireless.

The component consists of two parts. Such as:-

The sensor mote

The gateway mote

The sensor mote is developed to collect and transmit raw environmental data. When not doingthis, it went into a low-power idle mode to conserve energy. It also have some other feature

involved adhoc networking and may be for multi-hop routing;

The second part of the Sensor Mote Network is the gateway mote .The gateway mote is

responsible for serving as the liaison between the Server and the Sensor Mote Network andtransport all the data packets to WiseDB. It is possible to implement both sensor and gateway

motes on the same hardware PCB and with the same software .

8.4 Networking Topologies

You need to coordinate the WSN gateway, end nodes, and router nodes . For which you can useseveral network topologies. You can use Router nodes in two different ways ,one way Routernodes are similar to end nodes as they can acquire measurement data, in other way you also can

use them to pass along measurement data from other nodes.

Star Topology :The most basic topology is the star topology, in which each node is directly

connected with the gateway(Figure 8.2). This topology is simple but restricts the overall distancethat your network can achieve[9][11].

(Figure 8.2 Star Topology)

Cluster or Tree Topology : You can implement a cluster, or tree, topology to increase the

distance a network can cover. This is a more complex structure and in this each node still

maintains a single communication path to the gateway but can use other nodes to route its dataalong that path(Figure 8.3). This topology suffers from a problem that if a router node goes


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WirelessSensorNetwork RoutingProtocol


down, all the nodes that depend on that router node also lose their communication paths to the

gateway.

(Figure 8.3 Cluster / Tree Topology)

Mesh Network Topology :The mesh network topology eliminates the issue evolved during theCluster / Tree Topology by using redundant communication paths to increase system reliability.In a mesh network, nodes maintain multiple communication paths back to the gateway, hence if

one router node goes down, the network automatically reroutes the data through a different path

(Figure 8.4). The mesh topology is very reliable but from an increase in network latency as datamust make multiple hops before arriving at the gateway[2][9][11].

(Figure 8.4 Mesh Topology)

9. Routing Protocols in WSNsOn the basis of network structure routing in WSNs can be divided into three different categories,

those are, flat-based Routing, hierarchical based routing, and location-based routing depending

on the network structure (Figure 9.1).

In flat-based routing, all nodes are typically assigned equal roles or functionality. In hierarchical-based routing, however, nodes will play different roles in the network.In location-based routing,

sensor nodes' positions are exploited to route data in the network[1][6][7].


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(Figure 9.1 Types of Routing Protocol)

Flat Network Routing Protocol :This category of routing protocols are the multihop flat

routing protocols. Here, each node typically plays the same role and sensor nodes collaborate

together to perform the sensing task. Due to the large number of such type of nodes, it is notfeasible to assign a global identifer to each node[7].

There are various types of flat networking routing protocols ,those are- Sensor Protocols for

Information via Negotiation (SPIN), Directed Diffusion, Rumor Routing, Gradient-Based

Routing (GBR) , Minimum Cost Forwarding Algorithm (MCFA) , COUGAR , ACtiveQUery forwarding In sensoR nEtworks (ACQUIRE), Energy Aware Routing( EAR)[1][6][7].

(Figure 9.2 Different Flat Network Routing Protocols)

Hierarchical Networking Routing Protocol: Hierarchical initially proposed in wireline

networks, are well-known techniques with special advantages related to scalability and efficient

communication. As such, the concept of hierarchical routing is also utilized to perform energy-efficient routing in WSNs. In a hierarchical architecture, higher energy nodes used to process and

send the information while low energy nodes can be used to perform the sensing in the closenessof the target. This indicates that creation of clusters and assigning special tasks to cluster heads

can significantly contribute to overall system scalability, lifetime, and energy efficiency. In case

of hierarchical routing, it is an efficient way to lower energy consumption within a cluster and by

performing data aggregation and fusion in order to decrease the number of transmitted messagesto the Base Station.


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It is mainly two-layer routing. One layer is used to select cluster heads and the other layer is used

for routing. However, the majority techniques in this kind are not about routing, rather on "whoand when to send or process/aggregate" the information, channel allocation etc., which can be

orthogonal to the multihop routing function.

There are various types of hierarchical routing protocols available,those are -Low Energy

Adaptive Clustering Hierarchy (LEACH), Threshold-sensitive Energy Efficient sensor Networkprotocol(TEEN), and Adaptive Periodic Threshold-sensitive Energy Efficient sensor Network

protocol( APTEEN), Power-Efficient Gathering in Sensor Information Systems (PEGASIS) ,

Small Minimum Energy Communication Network (MECN) , Self Organizing Protocol (SOP),

Hierarchical Power-aware Routing (HPAR):, Virtual Grid Architecture routing (VGA), Sensoraggregate, Two-Tier Data Dissemination (TTDD)[1][6][7].

(Figure 9.3 Different Hierarchical Routing Protocols)

Location Based Routing Protocol: In location based routing protocol, sensor nodes are

addressed by means of their locations. The distance between adjacent nodes can be estimated onthe basis of incoming signal strengths. If a node dont have any activity to perform then location

based schemes demands that nodes should go to sleep so that energy can be saved.More energysavings can be possible if the number of sleeping nodes is more in the network.

There are various types of location based routing protocols available, those are- Geographic

Adaptive Fidelity (GAF), Geographic and Energy Aware Routing(GEAR), SPAN, Most Forward

within Radius (MFR), The Geographic Distance Routing (GEDIR)[1][6][7].

(Figure 9.4 Different Location Based Routing Protocols)


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On the basis of operation, routing protocols can also be classified into different categories, those

are- multipath-based, query-based, negotiation-based, QoS-based, or coherent-based routingtechniques(Figure 9.5)[6][7].

(Figure 9.5 Different Types Protocols on the basis of Operation)

During the research it is observed that there are some protocols that fit under more than onecategory. The table in the Figure 9.6 shows comparison between different routing techniques

according to many metrics and also how different routing protocols fit under different category.

(Figure 9.6 Comparison of Routing Protocol in WSNs)


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Wireless Sensor Network Security


10. Security

Security and privacy issues become more important because wireless sensor networks are usually

used for very critical applications.

10. 1 Security Threats in WSNs

WSN is used in the several critical applications. A WSN consists of several number of tiny andresource-constrained sensor nodes. These sensor nodes are spatially distributed and deployed tocollect security-sensitive information in uncontrollable environment. Sensor nodes rely on

wireless communication to deliver the sensed data to a remote base station. In a basic WSN

scenario, resource constraint, wireless communication, security-sensitive data, uncontrollable

environment, and distributed deployment are all vulnerabilities and these vulnerabilities makeWSNs suffer from number of security threats.There are several number of threats in different

layer of network[2][17].

10.1.1 Physical Layer Threats

In physical layer, there may be several threats to the wireless sensor network, due to the non-

tamper-resistant WSN nodes and the broadcasting nature of wireless transmission. Security

threats to WSN are always more than traditional nework.Types of attacks in the physical layerinclude physical layer jamming and the subversion of a node.

10.1.2 Link Layer Threats

The responsibility of data link layer is multiplexing of data streams, data frame detection,mediumaccess, and error control. Types of attacks can be possible in the data linl layer include

Data link layer jamming; Eavesdropping; Resource exhaustion and traffic analysis of wireless

sensor network.

10.1.3 Network Layer Threats

In the network layer ,threats mostly aim at disturbing data-centric and energy efficient multihop

routing.

Types of attacks and threat can be possible in the network layer include Spoofed, altered, or

replayed routing information; Sybil attack; Selective forwarding; Sinkhole attack; and floodingattack.

10.1.4 Application Layer Threats

Aapplications in the application layar of wireless sensor network (WSN) heavily rely on

localization, time synchronization,and in-network data processing to collaboratively process data.Types of attacks and threat can be possible in the network layer include False data

filtering;Clock un-synchronization; False data injection.

10.2 Countermeasures

The threats in wireless network either violate network secrecy and authentication or violatenetwork availability or violate some other network functionalities.Countermeasures to the threats

in WSNs should fulfill the certain security requirements such as :-

Availability: which ensures that the desired network services are available whenever

required.

Authentication : which ensures that the communication from one node to another

node is genuine.

Confidentiality : which provides the privacy of the wireless communication channels.


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Wireless Sensor Network Evaluation Metric


Integrity : which ensures that the message or the entity under consideration is not

altered.

Non-reputation : which prevents malicious nodes to hide or deny their activities.

Freshness : which implies that the data is recent and ensures that no adversary can

replay old messages.

Survivability : which ensures the acceptable level of network services even in thepresence of node failures and malicious attacks.

Self-security : countermeasures may introduce additional hardware and software

infrastructures into the network, which must themselves be secure enough to

withstand attacks.

Countermeasures should also fulfill appropriate performance requirements according to the

application[2][17].

11. System Evaluation Metrics

The evaluation metrics that will be used to evaluate a wireless sensor network include as

Network Coverage and Cost &Ease of deployment, Security, Lifetime, and Response Time[3][19].

11.1 Network CoverageDeployement of a network over a larger physical area can significantly increase a systems value

to the end user. It is necessary to remember that the coverage of the network is not equal to therange of the wireless communication links being used. To extend the coverage of the network

well beyond the range of the radio technology alone, a technology is used called Multi-hop

communication techniques. It is possible for a user to deploy a small trial network at first andthen can frequently add sense points to gather more and different information. A user must be

sure that the network technology being used is capable of scaling to meet its need. If you will

increase the number of nodes in the system .that will put impact either the lifetime or effectivesample rate. Use of more sensing points will cause more data to be transmitted which will

consume more power of the network.

11.2 Cost &Ease of deploymentEase of deployment is the most important evalution metrics of wireless sensor network. For the

successful deployments of the system, the wireless sensor network must configure itself. It must

be possible for nodes to be placed throughout the environment by an untrained person and havethe system simply work.Ideally, the system would automatically configure itself for any possible

physical node placement. The initial deployment and configuration is only the first step in the

network lifecycle. In the long term, the total cost of ownership for a system may have more to dowith the maintenance cost than the initial deployment cost.It is necessary to go for hardware and

software testing prior to the deployment and also the sensor system must be constructed so that it

is capable of performing continual self-maintenance.

11.3 SecurityOne of the most required and important metric is the security. A WSN consists of several

number of tiny and resource-constrained sensor nodes. These sensor nodes are spatiallydistributed and deployed to collect security-sensitive information in uncontrollable environment.

Wireless sensor networks must have the capability of keeping the information private from

eavesdropping.As we consider security oriented applications, data security becomes even more


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Wireless Sensor Network WSN Standardization


significant. The system not only must maintain privacy, it must also have the capability to be

able to authenticate data communication.

11.4 LifetimeLifetime is the most critical part wireless sensor network. Energy supply is the main limiting

factor for the lifetime of a sensor network. Each node must be designed to manage its local

supply of energy in order to maximize total network lifetime. In the majority of applicationscenarios, a majority of the nodes will have to be self powered. This means they will either have

to contain enough stored energy to last for years, or they will have to be able to search energyfrom the environment through several other devices, like solar cells or piezoelectric generators to

increase the lifetime of sensor node. Radio power consumption supply is the important factor for

determining lifetime of a energy supply. In a wireless sensor node the radio consumes a vast

majority of the system energy. So the power consumption need to be reduced to increase thelifetime of sensor node and that is possible through decreasing the transmission output power or

through decreasing the radio duty cycle.

11.5 Response TimeResponse time is also critical performance metric when environmental monitoring is used to

control factory machines and equipment. The industrial process control systems would only bepractical if response time guarantees could be met. Despite low power operation, nodes must becapable of having immediate, high-priority messages communicated across the network as

quickly as possible. Response time can be improved by including nodes that are powered all the

time. These nodes can listen for the alarm messages and forward them down a routing path in thenetwork when necessary but it may reduce the ease of deployment for the system[3][19].

12. Standardization

In the vicinity of WSNs, several standards are presently being developed. The main

standardization bodies are the Institute of Electrical and Electronics Engineers (IEEE),the

Internet Engineering Task Force (IETF), the International Society for Automation (ISA) and theHART Communication Foundation, etc.The above mentioned regularity bodies provide openstandards for low-power wireless sensor devices[2][18].

12.1 IEEE 802.15.4IEEE 802.15.4 is a standard which specifies the physical layer and MAC layer for low-rate

wireless personal area networks. The standard of IEEE 802.15.4 isfoundation for the ZigBee and

Wireless HART specification, each of which further endeavor to offer a complete networking

solution by developing the upper layers which are not enclosed by the standard[2][18].The features of IEEE 802.15.4 are the following (IEEE 802.15 WPAN Task Group 4, n.d.):

Its Data rates are of 250 kbps, 40 kbps, and 20 kbps.

There are two addressing modes; 16-bit short and 64-bit IEEE addressing.

It provides support for critical latency devices, such as joysticks. CSMA-CA channel access.

It facilitates coordinator to establish network automatically It is a fully handshaked protocol for transfer reliability.

It ensures low power consumption.

There are 16 channels in the 2.4GHz ISM band, 10 channels in the 915MHz ISMband and one channel in the 868MHz band.


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Wireless Sensor Network Application


12.2 ZigbeeZigBee is a standard for a set of high level communication protocols based on the IEEE 802.15.4standard for low power and low data rate radio communications. Zigbee is initiated and

monitored by the Zigbee Alliance - a big conglomerate of industry players[2][18]. The few

typical application areas of Zigbee are the following:

It assists in Smart energy monitoring. It is also used in Health care monitoring.

It is functional in Remote control. It is applied in Building automation and home automation.

12.3 WirelessHARTWireless HART is an open-standard wireless mesh network communication protocol designed tomeet the needs for process automation applications. The protocol utilizes IEEE 802.15.4 attuned

DSSS radios and it is operating in the 2.4GHz ISM radio band. On the data link layer, the

protocol uses TDMA technology to mediate and manage communications between devices.The WirelessHART facilitates highly secure communications by using AES-128 block ciphers

with individual Join and Session Keys and Data-Link level Network Key.WirelessHART

supports the standard HART Application Layer and is compatible with existing HART tools,applications and system integration technology.The additional features of wirelessHARTinclude reliability and scalability. We can add new devices for further enhancement of the

network and for its communication reliability[2][18].

13. Applications

Military application was the original motivation behind the research into WSNs .At the later

period of time costs for sensor nodes and communication networks have been reduced and thusthe application area has also increased.

13.1Military surveillance and target tracking

Wireless sensor networks originated mainly in military-related research in the year 1978.Unattended sensor networks can be rapidly deployed for surveillance and used to provide

battlefield intelligence regarding the location, numbers, movement, and identity of troops and

vehicles, and for detection of chemical, biological, and nuclear weapons. Faster development ofwireless sensor networks has been provided though several programs funded by the US Defense

Advanced Research Projects Agency (DARPA), through a program known as Sensor

Information Technology (SensIT) which provides the present sensor networks with new capabilitiessuch as ad hoc networking, dynamic querying and tasking, reprogramming and multitasking[1][2].

13.2 Environmental MonitoringEnvironmental monitoring can be used for animal tracking, forest surveillance,flood detection,

and weather forecasting. It is a natural candidate for applying WSNs because the variables that is

considered to be temperature, are usually distributed over a large region[2].13.3 Health MonitoringWireless sensor network is a major application in health sector.WSNs can be embedded into a

hospital building to track and monitor patients and all medical resources. There are various

kinds of sensors which can measure blood pressure, body temperature and electrocardiograph(ECG). A special kind of sensor network called a body sensor network (BSN) formed When the

sensors are worn or implanted for healthcare purposes. BSN is a rich interdisciplinary area which

reforms the healthcare system by allowing inexpensive, continuous and ambulatory health


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Wireless Sensor Network Pros and Cons/Future work


monitoring with real-time updates of medical records via the Internet. Now a days a specialized

BSN sensor node and BSN Development Kit are available for use in health monitoring system[2][10].

13.4 Traffic ControlTraffic control is another area where wireless sensor network plays a major role. Wireless sensor

networks have been used for vehicle traffic monitoring and control for some time. There areeither overhead or buried sensors used to detect vehicles and to control the traffic lights.WSNs

will completely change the landscape of traffic monitoring and control by installing cheap sensornodes in the car, at the parking lots, along the roadside. Streetline, Inc. is a company which uses

sensor network technology to help drivers find unoccupied parking places and avoid traffic

jams[1][2][10].

13.5 Industrial SensingSensor nodes can be deeply embedded into machines and there is no infrastructure ,WSNs make

it economically feasible to monitor the health of machines and to ensure safe operation. Agingpipelines and tanks have become a major problem in the oil and gas industry. Monitoring

corrosion using manual processes is extremely costly, time consuming,and unreliable.A network

of wireless corrosion sensors can be economically deployed to reliably identify issues beforethey become catastrophic failures.

13.6 Infrastructure SecurityWSNs can be used for infrastructure security and counterterrorism applications. Security is the

major aspect of wireless sensor network. Critical buildings and facilities such as power plants,

airports, and military bases have to be protected from attacks. Networks of video, acoustic, andother sensors can be deployed around these facilities[1][10]

14. Pros and Cons of Wireless Sensor Networking

There are several advantages of wireless sensor networking as they can store a limited source of

energy, they have no hassle of cables and have mobility. The major advantage is that it can workefficiently under the harsh conditions, and it has deployment up to large scale etc. Same time italso has some disadvantages which really take the moral of this technology down as they have

very insufficient speed of communication, it is to disturb the propagation of waves and hack your

networking and the major disadvantage of wireless sensor networking is it is too costly to use.

15. Future Work

As the wireless sensor network is under research, there are a number of improvements we can

think of.

We can think of expanding the sensor mote network by adding more motes. This would

allow the development and testing of advanced network-layer functions, such as multi-hop routing.

We can think of alternative energy sources to extend mote battery life. Which may

includes solar cells and rechargeable batteries, these systems could provide a long term,maintenance free, wireless monitoring solution.


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Wireless Sensor Network Conclusion


16. Conclusions

Wireless sensor networks must be designed to meet a number of challenging requirements

including extended lifetime in the face of energy constraints, robustness, scalability, andautonomous operation.

Wireless sensor networks are getting smaller and faster, increasing their potential applications incommercial, industrial, and residential environments.

However, the limit of applications depends only upon the sensors used and the interpretation of

the data obtained. As the technology improves and new low-power digital sensors become morereadily available, motes will increase functionality without increasing power consumption and

will expand the wireless sensing market.

17. Bibliography

1. Networking Wireless Sensorsby Bhaskar Krishnamachari ,2005.

2.

Wireless Sensor Networks - An Introductionby QinghuaWang and Ilangko Balasingham.3. System Architecture for Wireless Sensor Networks by Jason Lester Hill, University of

California, Berkeley ,2003.

4. A Survey of Wireless Sensor Networks Technology by I. Khemapech, I. Duncan and A.Miller ,School of Computer Science , University of St Andrews ,North Haugh, St Andrews.

5. Data Fusion Improves the Coverage of Wireless Sensor Networks by Guoliang Xing1; Rui

Tan2; Benyuan Liu3; Jianping Wang2;Xiaohua Jia2; Chih-Wei Yi4, 1Department ofComputer Science & Engineering, Michigan State University,USA.

6. Routing Protocols in Wireless Sensor Networks A Survey Shio Kumar Singh 1, M P Singh

2, and D K Singh 3.7. Routing Techniques in Wireless Sensor Networks: A Survey,Jamal N. Al-Karaki Ahmed E.

Kamal Dept. of Electrical and Computer Engineering Iowa State University, Ames, Iowa50011.

8. Fundamentals of Wireless Sensor Networks: Theory and Practice, Waltenegus Dargie and

Christian Poellabauer 2010 John Wiley & Sons, Ltd.

9. ftp.ni.com/pub/devzone/pdf/tut_7142.pdf10.Wikipedia

11.Zone.ni.com/devzone/cda/tut/p/id/8707

12.WISENET, SNGCE kolenchery, Dept. ofCSE.

13.Chipcon ,SmartRF CC1010 Datasheet (rev. 1.3) 2004-12-1714.A Survey of Wireless Sensor Networks Technology I. Khemapech, I. Duncan and A. Miller

School of Computer Science University of St Andrews North Haugh, St Andrews.

15.

A survey on routing protocols for wireless sensor networks Kemal Akkaya *, MohamedYounis ,Department of Computer Science and Electrical Engineering, University of

Maryland, Baltimore County, Baltimore.

16.A Hierarchical Routing Protocol for Survivability in Wireless Sensor Network(WSN),Mohammad S. Al-Fares1, student Member , IEEE, Zhili Sun2, Member, IEEE, Haitham

Cruick shank3, Member, IEEE,IMECS 2009, March 18 - 20, 2009, Hong Kong.

17.Wireless Sensor Network Security Analysis by Hemanta Kumar Kalita1 and Avijit Kar2,Department of Computer Engineering, Jadavpur University, Kolkata, India.


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WirelessSensorNetwork Bibliography

18.Standards-Based Wireless Sensor Networking Protocols for Spaceflight Applications byRaymond S. Wagner, Ph.D, NASA Johnson Space Center.

19.Wireless Sensor Network by priyal shah, Dept.CSE.Ahmadbad, Oct 2010.

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