ENERGY EFFICIENT MULTI LEVEL AND DISTANCE

CLUSTERING MECHANISM FOR WIRELESS SENSOR

Submitted in partial fulfillment of the requirement s for the degree of DOCTOR OF

Supervisor-I Dr. Shafiullah K

Supervisor-II Dr. Bilal Shams

Institute of Information TechnologyKohat University of Science & Technology, Kohat

ENERGY EFFICIENT MULTI LEVEL AND DISTANCE

CLUSTERING MECHANISM FOR WIRELESS SENSOR

NETWORKS

Submitted in partial fulfillment of the requirement s for the degree of DOCTOR OF PHILOSOPHY IN COMPUTER SCIENCE

by

AMJAD MEHMOOD

CS420112001

Dr. Shafiullah Khan Institute of information Technology KUST, Kohat

Dr. Bilal Shams Institute of information Technology KUST, Kohat

Institute of Information Technology Kohat University of Science & Technology, Kohat-2600,

Pakhtunkhwa, Pakistan August, 2014

ENERGY EFFICIENT MULTI LEVEL AND DISTANCE AWARE

CLUSTERING MECHANISM FOR WIRELESS SENSOR

Submitted in partial fulfillment of the requirement s for the degree of COMPUTER SCIENCE

Institute of information Technology .............. Signature

Institute of information Technology ............... Signature

2600, Khyber-

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CERTIFICATION FROM THE SUPERVISORS

This thesis entitled ENERGY EFFICIENT MULTI LEVEL AND DISTANCE

AWARE CLUSTERING MECHANISM FOR WIRELESS SENSOR

NETWORKS submitted by MR. AMJAD MEHMOOD to the Kohat University of

Science &Technology for the award of DOCTOR OF PHILOSOPHY IN

COMPUTER SCIENCE presents bonafide research work carried out under our

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Dr. Shafiullah Khan

Dr. Bilal Shams

Institute of IT, KUST

Institute of IT, KUST

iii

CERTIFICATION FROM THE EXAMINERS

This thesis entitled ENERGY EFFICIENT MULTI LEVEL AND DISTANCE

AWARE CLUSTERING MECHANISM FOR WIRELESS SENSOR NETWORKS

presents a bonafide record of original research work carried out by AMJAD ME-

HMOOD in partial fulfillment of the degree of DOCTOR OF PHILOSOPHY IN

COMPUTER SCIENCE, Kohat University of Science & Technology, Kohat. We find

the work satisfactory for the award of the degree if other requirements are met. The

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iv

ACKNOWLEDGMENT

The success and final outcome of this research required a lot of guidance and assistance

from many people and I am extremely fortunate to have got this all along the completion

of my research work. Whatever I have done is only due to such guidance and assistance

and I would not forget to thank them.

I respect and thank Dr. Shafi Ullah Khan, for giving me an opportunity to do the research

work in WSNs and providing me all support and guidance which made me complete the

research on time. I am extremely grateful to him for providing such a nice support and

guidance though he had busy schedule managing the office affairs.

I heartily thank our internal research supervisor, Dr. Bilal Shams, Director, Institute of

Information Technology, for his guidance and suggestions throughout my research work.

I owe my profound gratitude to Prof. Dr. Jaime LIoret, who took keen interest in my

research work and guided me all along, till the completion by providing all the necessary

information for developing a good system.

I would not forget to remember Mr. Abdur Rehman, Mr. Roman, Dr. Jawad Ashraf, Dr.

and Dr. Asad Habib, of Institute of Information Technology for their unlisted

encouragement and more over for their timely support and guidance till the completion of

my research work.

I am thankful to and fortunate enough to get constant encouragement, support and

guidance from all teaching staffs of Institute of IT which helped me in successfully

completing my research work. Also, I would like to extend our sincere regards to all the

non-teaching staff of my Institute for their support.

Amjad Mehmood.

v

No man succeeds without a good woman behind him. Wife or mother, if it is both, he is twice blessed indeed.

Dedicated to my mother and wife

vi

By Amjad Mehmood Institute of Information Technology, KUST, Kohat, Khyber PakhtunKhwa, Pakistan

Summary

PhD Thesis (2014)

vii

The latest progresses and the amalgamation of micro electro-mechanical systems

technology, integrated circuit technologies, nanotechnology and microprocessor

hardware, wireless communication, ad-hoc networking, distributed signal processing, and

embedded systems have made the notion of Wireless Sensor Networks (WSNs). It

enables the administrator to examine and act in response to a phenomenon in appropriate

surroundings. The WSNs consist of large number of small, low-cost, multi-functional

machines known as sensor nodes that have the capability to sense, process and

communicate with each other. The comfort of installation, economical cost, multi-

functional, and ad-hoc character has illustrated WSN an interesting option for many

applications, such as health-care applications, environmental monitoring, transportation,

military practices, weather forecasting, safe-keeping applications, fire detection, real time

tracking, and so on. WSNs have some constraints such as memory, bandwidth, hardware,

and computation. The plan of this study is to recognize the limitations of WSN and

investigate their unplanned act of routing protocols. We propose Energy-Efficient Multi-

level and Distance-Aware Clustering (EEMDC) mechanism for WSNs. In this

mechanism the network area is divided into three logical layers with respect to the BS.

The logical partition of the network area helps to bridge the problem of distributing

workload among clusters in the network. Similarly, in order to enhance the performance

of the protocol, it selects the Cluster Head (CH) by acquiring the average residual energy

divided by average hop-count values of the nodes. It derives combined data to BS by

practicing minimum CHs as relay nodes.

In order to demonstrate the overall network lifetime, an experiential inspection has been

conducted in OMNET++. It is an object oriented modular discrete event based simulator

viii

having Castalia-3.2 as plug-in for WSN and Body Area Network (BAN). We simulated

different routing protocols, taking into consideration their challenges and the results are

shown. Different results show that EEMDC is more energy-efficient as compared to

other existing conventional protocols, such as Minimum Transmission Energy (MTE),

Direct, Low Energy Adaptive Clustering Hierarchy (LEACH), Low Energy Adaptive

Clustering Hierarchy-Centralized (LEACH-C), A Hybrid, Energy-Efficient, Distributed

Clustering (HEED), and Dynamic Clustering and Distance Aware Routing Protocol

(DDAR).

ix

Contents

PhD Thesis (2014) By Amjad Mehmood Institute of Information Technology, KUST, Kohat, Khyber PakhtunKhwa, Pakistan

x

ACKNOWLEDGMENT ....................................................................................................................... IV

SUMMARY ............................................................................................................................................ VI

CONTENTS ............................................................................................................................................ IX

LIST OF FIGURES .............................................................................................................................. XII

LIST OF TABLES .............................................................................................................................. XIV

LIST OF ACRONYMS ........................................................................................................................ XV

CHAPTER # 01

INTRODUCTION

1.1 WIRELESS SENSOR NETWORKS .............................................................................................................. 1 1.2 RESEARCH OBJECTIVES ......................................................................................................................... 4 1.3 OVERVIEW OF THE RESEARCH ............................................................................................................... 4 1.4 PROBLEM STATEMENT ........................................................................................................................... 6 1.5 ORGANIZATION OF THESIS ..................................................................................................................... 8

CHAPTER # 02

LITERATURE REVIEW

2.1 INTRODUCTION ...................................................................................................................................... 9 2.1.1 Applications of WSN .................................................................................................................... 14

2.2 WSNS ROUTING CHALLENGES COMPARED WITH OTHER WIRELESS NETWORK .................................. 16 2.3 ROUTING PROTOCOLS CLASSIFICATION ............................................................................................... 18

2.3.1 Structure Base Routing Protocols ................................................................................................ 21 2.3.2 Protocol Operation based Classification..................................................................................... 31 2.3.3 Sensor Node architecture based Classification ........................................................................... 39 2.3.4 Packet’s Destination based Classification................................................................................... 40 2.3.5 Source -Destination Recovery based classification ..................................................................... 43 2.3.6 Cooperative Routing .................................................................................................................... 44 2.3.7 Protocol’s initialization point based classification ..................................................................... 44 2.3.8 Epidemic behavior based Classification ...................................................................................... 45 2.3.9 Application based routing protocols Classification ..................................................................... 46 2.3.10 K. Sha et al. based Classification .............................................................................................. 46 2.3.11 M. Perillo et al. based Classification......................................................................................... 46 2.3.12 State based Classification .......................................................................................................... 47 2.3.13 Energy-Efficient Routing Protocols based Classification .......................................................... 48

2.4 DISTINCTIVENESS OF CLUSTER BASED ROUTING PROTOCOLS .............................................................. 61 2. 5 ROUTING CHALLENGES AND DESIGN ISSUES ...................................................................................... 61

2.5.1 Node Placement ........................................................................................................................... 62 2.5.2 Energy Utilization without Losing Precision ............................................................................... 62 2.5.3 Data Reporting Model ................................................................................................................. 63 2.5.4 Node/Link Heterogeneity: ............................................................................................................ 63 2.5.5 Fault Tolerance ........................................................................................................................... 64 2.5.6 Scalability .................................................................................................................................... 64 2.5.7 Network Dynamics ....................................................................................................................... 65 2.5.8 Transmission Media .................................................................................................................... 65 2.5.9 Connectivity ................................................................................................................................. 65 2.5.10 Coverage .................................................................................................................................... 66 2.5.11 Data Aggregation ...................................................................................................................... 66 2.5.12 Quality of Service (QoS) ............................................................................................................ 66 2.5.13 Network Cost ............................................................................................................................. 67

2.6 COMPARATIVE ANALYSIS .................................................................................................................... 67

xi

CHAPTER # 03

ENERGY-EFFICIENT MULTI-LEVEL AND DISTANCE-AWARE CLUSTERING MECHANISM FOR WSNS

3.1 INTRODUCTION ............................................................................................................................... 85 3.2 EEMDC OPERATION ....................................................................................................................... 87

3.2.1 DATA TRANSMISSION FROM CLUSTER HEAD TO THE BASE STATION ............................ 93 3.2.2 FLOWCHART OF THE EEMDC OPERATION .......................................................................... 93

3.3 SIMULATION RESULTS .................................................................................................................. 99 3.3.1 Network and Radio Model ........................................................................................................... 99 3.3.2 Simulation Model ....................................................................................................................... 101 3.3.3 Performance Evaluation ............................................................................................................ 102

3.4 CONCLUSION...................................................................................................................................... 120

CHAPTER # 04

CONCLUSIONS AND FUTURE WORK

4.1 CONCLUSIONS .................................................................................................................................... 122 4.2 FUTURE WORK .................................................................................................................................. 125

BIBLIOGRAPHY ........................................................................................................................... 126

xii

List of Figures

Figure 1.1. Workflow of wireless sensor network ........................................................................................... 1

Figure 1.2. Cluster based strategy for WSNs .................................................................................................. 3

Figure 1.3. A round in cluster based protocols ................................................................................................ 4

Figure 2.1.Sensor node components .............................................................................................................. 10

Figure 2.2. Routing protocols in WSNs ........................................................................................................ 21

Figure 2.3. Single-hop and multi-hop connections to the sink ...................................................................... 24

Figure 2.4. Categorization of different characteristics of clustering in WSNs .............................................. 30

Figure2.5. Directed diffusion scenario .......................................................................................................... 33

Figure 2.6. Directed diffusion: (a) interest propagation, (b) initial gradients set up, and (c) data delivery. .. 34

Figure 2.7. Query plan at a bellwether node: The bellwether node acquires all the understandings,

determines the average and if it is more preponderant than a threshold throw it to the BS........................... 35

Figure 2.8. Categorization of routing protocols ............................................................................................ 40

Figure 2.9. Percentage of number of nodes death vs. number of rounds in the area of 50m*50m ................ 70

Figure 2.10. Percentage of nodes death vs number of rounds in the area of 100m* 100m .......................... 71

Figure 2.11. Number of rounds over number of nodes alive ......................................................................... 73

Figure 2.12 (a) . Number of rounds against number of data messages received ........................................... 74

Figure 2.12 (b). Average energy dissipation against number of data messages received .............................. 75

Figure 2.13. Average energy dissipation over varying network areas ........................................................... 77

Figure 2.14. Number of nodes alive as a function of network area ............................................................... 78

Figure 2.15. First node death over the simulation time [seconds] ................................................................. 79

Figure 2.16. Total 100 nodes: half node die (HND) over the simulation time [seconds] .............................. 80

Figure 2.17. Total 100 nodes: last node die (LND) over simulation time [seconds] ..................................... 81

Figure 2.18. Energy consumed by nodes over simulation time [seconds] ..................................................... 82

Figure 2.19. Number of nodes alive over simulation time [seconds] ............................................................ 83

Figure 2.20. Energy utilized by nodes over simulation time [seconds] ......................................................... 84

Figure 3.1. LEACH protocol's round details (Adv CH: Advertisement advertise by CH, TDMA Sch:

TDMA Schedule) .......................................................................................................................................... 86

Figure 3.2. Message flow in a cluster (FLC) ................................................................................................. 91

Figure 3.3. EMCDR protocol's logical division in levels (TLC, SLC, FLC) ................................................ 92

Figure 3.4. Flowchart of EMCDR working ................................................................................................... 95

Figure 3.5. Calculate hop-count and cluster level ......................................................................................... 96

Figure 3.6. Sending data to the BS considering minimum hop ..................................................................... 97

Figure 3.7. EEMDC’s algorithm: process of clustering in WSNs ................................................................. 99

Figure 3.8. Total 100 nodes: first node die (FND) over simulation time [seconds] .................................... 105

Figure 3.9. Total 200 nodes: first node die (FND) over simulation time [seconds] .................................... 105

xiii

Figure 3.10. Total 100 nodes half node die (HND) over simulation time [seconds] .................................. 106

Figure 3.11. Total 200 nodes half node die (HND) over simulation time [seconds] .................................. 107

Figure 3.12. Total 100 nodes: last node die (LND) over simulation time [seconds] .................................. 108

Figure 3.13. Total 200 nodes: last node die (LND) over simulation time [seconds] ................................... 109

Figure 3.14. Energy consumed by nodes over simulation time [seconds] .................................................. 110

Figure 3.15. Number of nodes alive over simulation time [seconds] ......................................................... 111

Figure 3.16. Percentage of node death vs number of rounds in the area of 50m* 50m .............................. 113

Figure 3.17. Percentage of node death vs number of rounds in the area of 100m* 100m .......................... 114

Figure 3.18. Number of rounds over a number of nodes alive .................................................................... 115

Figure 3.19 (a). Number of rounds over a number of data messages received ............................................ 116

Figure 3.19 (b). Number of rounds over number of data messages received .............................................. 117

Figure 3.20. Network Area over number of nodes alive ............................................................................. 118

Figure 3.21. Network area over average energy dissipation ........................................................................ 120

xiv

LIST OF TABLES

Table 2.1. Applications of WSNs .................................................................................................................. 16

Table 2.2. Routing protocols classification ................................................................................................... 21

Table 2.3. Hierarchical vs. flat topologies routing ........................................................................................ 25

Table 2.4: Energy consumption by nodes as either useful or wasteful source .............................................. 48

Table 2.5. Summary of the most important features of the routing protocols included in this section ......... 60

Table 2.6. Simulation parameters for Figure 2.11 and Figure 2.12 ............................................................... 68

Table 2.7. Percentage of node death over network area of 50m *50m and 100m*100m .............................. 69

Table 3.1. Clustering protocols categorization parameters............................................................................ 86

Table 3.2. Notation used in the equations ................................................................................................... 101

Table 3.3. Network model parameters......................................................................................................... 102

Table 3.4. Percentage of node death over a network area of 50m *50m and 100m*100m ......................... 112

xv

List of Acronyms

Wireless Sensor Networks WSNs Energy Efficient Multi Level and Distance Aware Clustering EEMDC Base Station BS Cluster Head CH Analog-to-Digital Converter ADC Quality of Service QoS Global Position System GPS Medium Access Control MAC Time Division Multiple Access TDMA Mobile Ad hoc Network MANET Sensor Protocols for Information via Negotiation SPIN Directed Diffusion DD Rumor Routing RR Stream Enable Routing SER Gradient Based Routing GBR Threshold Sensitive Energy Efficient Sensor Network Protocol TEEN Adaptive Periodic APTEEN Constrained Anisotropic Diffusion Routing CADR Low-Energy Adaptive Cluster Hierarchy LEACH Leach-Centralized LEACH-C Small Mecn SMECN Geography Adaptive Fidelity GAF Self-Organization SOP Hierarchical Periodic Event-Driven and Query-Based HPEQ Power Efficient Gathering in Sensor Information System PEGASIS Hierarchical PEGASIS H-PEGASIS Hierarchical Energy Aware Protocol for Routing and Aggregation in Sensor Networks

HEAP

Simple Hierarchical Routing Protocol SHRP Minimum Energy Communication Network MECN Small MECN SMECN Geographic and Energy Aware Routing GEAR Stateless Protocol for Real-Time Communication in Sensor Network SPEED Stateless Non-Deterministic Geographic Forwarding SNGF Single Winner Algorithm SWE Multi Winner Algorithm MWE Sensor Nodes SN Distance Source Routing DSR Destination-Sequenced Distance Vector Routing DSDV Ad hoc on Demand Distance Vector Routing AODV Greedy/ Geographic Forwarding GF Face Routing FR Attributes A Soft Threshold ST Hard Threshold HT Court Time CT Heterogeneous Heed H-HEED Reactive Energy Decision Routing Protocol REDRP Scaling Hierarchical Power-Efficient Routing SHPER Simple Energy-Efficient Routing SEER Balance Energy-Aware Routing BEAR Dynamic Clustering And Distance Aware Routing Protocol DDAR First Node Death FND

xvi

Last Node Death LND Half of The Nodes Alive HNA Minimum Transmission Energy MTS Distance-Energy Cluster Structure Algorithm DECSA Hierarchical Routing Protocol HRP Low Energy And Adaptive Clustering Hierarchy LEACH Partition Based Leach pLEACH Power Efficient And Adaptive Clustering Hierarchical PEACH Hybrid Energy Efficient Distributed HEED Energy Efficient Heterogeneous Clustered Scheme For Wireless Sensor Networks

EEHC

Tree-Base Clustering Protocol CBT Energy Efficient Clustering Scheme EECS Dynamic Clustering And Distance Aware Routing Protocol DDAR First Level Clusters FLC Second Level Clusters SLC Third Level Clusters TLC Average Hop-count Value AvgHcv Node’s Energy NdeEnergy Single Hop, Multi Hop SH ,MH Cluster Member CM Average Residual Energy AvgRE

INTRODUCTION

PhD Thesis (2014)

By Amjad Mehmood Institute of Information Technology, KUST, Kohat, Khyber PakhtunKhwa, Pakistan

1

1

1.1 Wireless Sensor Networks

Due to recent advancements in electronic circuitry, WSNs have achieved great interest of

academia and industries. They are deployed in harsh and unattainable environments. A

WSN is made up of large number of sensing devices called nodes, which are associated

wirelessly. Each node in a network consists of short memory, low Central Processing

Unit (CPU) power, limited battery, and transceiver device for sending and receiving data.

Its size and cost depends upon the application. In a sensor network, all the nodes work in

such a manner to get information from the physical environment, process it, and send the

information to the Base Station (BS) for making the decisions [1] as shown in figure 1.1.

The research community has proposed different types of routing protocols to decrease the

energy dissipation, and hence increases the battery life of the network. Intended for

Figure 1.1. Workflow of wireless sensor network

Sensor Nodes

Sensor field

BS

Internet and Satellite

2

energy efficiency among the nodes in WSNs, researchers proposed different types of

techniques such as tree, chain, grid, density, model, and minimum transmission.

However, it has been observed that cluster based protocols are more energy efficient as

compared to the mentioned techniques [3]. Cluster is defined as the collected works of

nodes into groups. In cluster based methodology, there are three main entities such as

CH, members, and BS. The CH collects data from the members. CHs then send the data

for decision making to BS as shown in figure 1.2.

The disadvantages of cluster based routing protocols are as follow:

There is a need to deploy an optimal number of CHs, otherwise, these protocols act same

as flat based protocols.

Division of nodes into clusters creates latency or delay in the network so it could affect

the throughput of the network.

Overlapping among the clusters should be minimized otherwise, it could also affect the

overall lifetime due to traffic congestion.

Nomination of the CHs could also affect the lifetime if we select the node having

minimum energy in cluster, it will get down sooner.

Clusters near BS consume more energy than the clusters far away, so they should

properly be managed to balance the workload among the clusters.

The size of the clusters does matter in energy consumption.

Intra and inter-clusters distances should also be regarded to save the rate of energy

consumption.

Cluster based routing protocols

disadvantages.

Cluster based routing

setup and steady phase

(i) Setup phase

It is further

(a) CH selection

(b) Formation

Cluster based routing protocols could be more energy efficient if we address its

Cluster based routing protocol work in rounds. Each round consists of two phases

phases.

phase

further subdivided into

election

ormation of cluster

Member of Cluster

Base Station(BS)

Figure 1.2. Cluster based strategy for WSNs

3

more energy efficient if we address its

work in rounds. Each round consists of two phases, i.e.

Cluster Head(CH)

Shows flow of data

4

(ii) Steady phase

It is further subdivided into

(a) Aggregation of data

(b) Communication of data

This mechanism is shown in figure 1.3.

1.2 Research Objectives

The main objectives of this work are

• To increase the lifetime of WSNs

• To develop scalable, fault-tolerant, and load-balancing mechanism

• To divide the whole network into multi-levels to avoid the funneling effect

• To increase the throughput and decrease the delay

1.3 Overview of the Research

The research has the following features:

Setup Sate

Steady State

CH Selection Formation of Cluster Aggregation of Data Data

Communication

Round

Figure 1.3. A round in cluster based protocols

Setup phase Stead phase

5

i. Each node in WSNs has limited energy, and usually deployed in harsh

environments. Therefore, their energy can’t be recharged incase of depletion. This

limited energy is used by the nodes for sensing, processing, and communication.

In comparison the communication process consumes more energy than the others.

Therefore, in order to increase the lifespan of network for sending the data from

sensor nodes to BS, energy-efficient routing protocol is highly demanded by the

environment.

ii. In a network some nodes perform more tasks than others which could lead to

deplete their energy earlier. Hence, in order to distribute the workload among the

nodes in the network, load-balancing mechanism is required.

iii. In steady phase, in the multi-hop scenario, the CHs away from BS send their data

using more than one CHs as a relay node. As more CHs are used as relay node, so

it would increase delay as well as minimize the lifetime of the overall network.

Therefore, less numbers of CHs are used as a relay node, in order to maximize the

lifetime and minimize the delay in sending the data from CH to BS.

iv. It is the network of hundreds of thousands of nodes interconnected wirelessly with

each other. So in dense environment more than one node can sense the

phenomenon and send the data to the CHs. As a result, redundant data reaches the

CH, in case CH broadcasts the same data. It causes congestion on the channel,

and wastes the energy of the nodes. In order to fuse the redundant data,

aggregation is performed on the CH, to reduce the congestion and consume less

amount of energy of node which receives it.

6

v. Each node in the network has an equal chance to become the CH of the cluster,

but the decision is made on the basis of residual energy of the nodes.

vi. The distance between the nodes, the CH, and between the CHs and BS is also

considered in order to save the energy of the network. Otherwise it may cause

congestion on the channel which may result in consumption of the energy. Hence

it affects the overall performance of the system.

vii. As the network consists of large numbers of nodes, therefore, keeping the whole

routing table at individual node is difficult, and it also makes use of high

bandwidth during communication. Therefore, clustering technique makes the

routing table localized to the cluster and also makes use of limited bandwidth due

to inter-cluster communication to CHs.

viii. Clustering mechanism helps to achieve scalability factor. It handles large number

of nodes in the network and their associated functions and tasks. Hence it helps to

scale to such a high level to acquire advantage of high density of such network.

ix. Nodes in WSNs are more prone to unexpected failure as compared to other

networks. The clustering mechanism brings the fault tolerance ability to the nodes

in the network, so that they may sustain for longer periods of time.

1.4 Problem Statement

WSNs have several design and implementation challenges, primarily due to insufficient

resources and restricted abilities such as processing, storage, bandwidth, sensing,

communication, and scalability. However, one of the most important constraints in WSNs

is the battery or lifetime of the sensor nodes. The routing protocols are divided into two

7

main categories such as flat, and cluster/hierarchical based protocols. Flat based protocols

have following shortcomings:

• They consume more energy.

• They are less scalable.

• They produce high data transmission, which may result in network congestion.

• They can’t perform load balancing.

Hierarchical or Cluster based protocols have the following shortcomings:

• Clusters near BS consume more energy as compared to cluster away from BS.

• The distances between member nodes and CH and to BS onward also play an

important role in energy dissipation.

• Overlapping of the clusters also affects the lifetime of a network.

• The size of clusters does matter as moving away from BS.

• The number of nodes in a cluster is also one of the concerns of energy

dissipation.

• The CH responsibility on the nodes is one of the factors to consume energy.

• As CHs might have redundant data in their ranges which need to be aggregated,

otherwise consume energy due to propagating of redundant data in the network.

• The CHs Send the data to BS over the CHs as relay nodes in multi-hop

communication could affect the lifetime of the network.

By considering the above mentioned problems of flat and cluster based protocols, it is

desirable to design an energy-efficient routing protocol. Therefore, we proposed EEMDC

routing protocol which is more energy efficient than the existing protocols. It helps

8

reduce the energy consumption by dividing the nodes of the network into many small

segments. Moreover, cluster based protocols constraints are addressed in EEMDC by

organizing clusters in multi-level with respect to BS. This can further enhance the

performance, energy load-balancing, scalability and the network- lifetime of the sensor

nodes in the network.

1.5 Organization of Thesis

The chapter-wise organization of the thesis is as follows:

Chapter 2: discusses the energy efficient communication protocols for WSNs suggested

by the research community.

Chapters 3: gives details of the contributions in regards to energy efficient routing

protocol for wireless sensor networks.

Chapter 4: explains the conclusions drawn out of the thesis and directions for future

work of the research.

LITERATURE REVIEW

PhD Thesis (2014)

2

By Amjad Mehmood Institute of Information Technology, KUST, Kohat, Khyber PakhtunKhwa, Pakistan

9

2.1 Introduction

The distributed nature and dynamic topology of WSNs introduces very special

requirements in routing protocols that should be met. The most important feature of a

routing protocol, in order to be efficient for WSNs, is the energy consumption and the

extension of the network's lifetime. Many routing, power management, and data

dissemination protocols have been specifically designed for WSNs where energy

awareness is an essential design issue. Routing protocols in WSNs might differ

depending on the application and network architecture. Consequently, the WSNs are

usually application specific. The most important are military, environment- monitoring,

agricultural-activities, industry, healthcare, cardiac, weather monitoring, sleep-apnea,

disaster-recovery, temperature, security, sound, and water applications [3]. With the

advancement in the technology, the nodes in the WSNs become more accurate, reliable,

energy efficient, smaller in size, cheaper in cost, and robust. This technology has already

addressed different types of applications from fortification to support. It is cost-effective,

easy to install, changes with industry needs, and its uses are countless. It comprises of

small nodes with inadequate processing, storing, sensing, bandwidth, and energy (or

battery power) for communication. Each sensor device consists of a microcontroller for

processing, one or more flash memories to keep long-lived data and program-code, for

dynamic data it needs RAM, for communication it needs wireless-transceiver, an analog-

to-digital converter (ADC), one or more sensors, power source, and an antenna. Consider

the example of MicaZ mote of Crossbow, it has an Atmel Atega microcontroller, 4KB

RAM , 128KB program flash , 512KB flash memory, IEEE 802.15.4 2.4-GHz transceiver

10

supports 250 KBps maximum, and 50 meters of range, ADC supports 10-bit, and runs

two AA batteries which draw 8 mA in active mode [4].

It has the capability to correspond with each other and drive their info to the sink or put

on the air the data to BS directly. The BS is the place which has no resource constraint

like processing, storing, power supply, and others. Once the data arrives on BS, it moves

the data collected from WSNs to internet, where users take a decision accordingly as

shown in figure 2.1.

Figure 2.1.Sensor node components

Po

we

r Un

it

Se

nso

r A

DC

Processing

Storing

Position Finding System Mobilizer

Tra

nsce

iver

Internet/

Satellite

BS

User

11

They are deployed sparsely or densely to the field depending on application requirements

and environment of deployment field. Moreover, nodes are randomly or deterministically

installed. When the nodes are manually mounted then they are normally sparsely

deployed and work under the attended environments, e.g. bridge monitoring, or fire alarm

system. Since nodes are dropped from an airplane or helicopter in disaster affected areas

and work in unattended manner, they get the updates about the area, and make the rescue

squared more equipped about the situations.

In fact, the nodes in WSN have a number of limitations, but energy or battery life is the

most crucial one. Since, nodes are normally planted in the environments which are

unworkable for the user, i.e. battlefield, military surveillance, and moisture tracking,

therefore, recharge or replace of the battery is impossible. Hence, bring into being a huge

issue for network designers, to develop an energy proficient routing protocol for WSNs.

Additionally, sensor nodes are unable to work properly due to their unreliable and

breakable behavior, in order to fix such problem nodes are densely deployed in the

environment. Therefore, all the algorithms and protocols suggested by research

community are mostly energy efficient to increase the functioning lifetime of the

network.

In the recent past years, a huge number of researches have been done in WSNs, which are

increasing the association, processing, and management of the sensor nodes in the

gathering of data from the environment. Sensor nodes have limited resources. Due to

limitations of the constraints and the installation of a huge number of nodes fabricates a

large number of design, management confronts, and focus to consider the energy

consciousness at all the levels of the protocol stack, e.g. at the network level, it is

12

considered that how energy-efficiently the data would be collected from the sensor motes

and routing to BS, in order to escalate the lifespan of the network.

By taking into account the inherited characteristics of WSNs, there are many types of

routing protocols which have been suggested by the research community. The direction-

finding protocols are categorized into the following three groups:

� Network Structure-wise

� Protocol Operation-wise

� Route Discovery-wise protocols.

The structure-wise category is further divided into the following sub-categories:

� Flat-based

� Hierarchical-based

� Location-based

While routing protocols under the category of protocol operation categorized as the

following:

� Multipath-based

� Query-based

� QoS-based

� Negotiation-based

� Coherent-based

� Negotiation-based.

13

In the flat-base routing protocols, each node has the likewise role and responsibility

without any discrimination in acquiring data from the environment, coordinate with each

other, and transferring data to BS. In the cluster based protocols, nodes are collected into

clusters. Each cluster has a CH. Nodes in the cluster, collect data and launch their

information to the CH. CH after getting the data, appends its own data, and throws to BS

straightforwardly (single hop) or using relay CHs (multi hop) in transportation. While in

location-based routing protocol sensor nodes know their position in the network.

Therefore, instead of spreading the data in the entire network they send their data to the

destination directly. The last category of routing protocol is consisting of protocols

supported on the operation that depend upon the procedure used in the protocol. In multi-

path based routing nodes use multiple paths for sending their data which make the system

reliable and increase the performance of the network. In query-based protocol BS sends

query in the network, the node responsible for sensing and gathering data sends the data

to requested station or BS in response to that query. In QoS-based protocols consider

power capability and quality of the figures in the network. In negotiation-based protocols,

nodes focus on restricting the redundant information to transfer from the nodes to their

neighbors or the BS. In the coherent-based protocol nodes collect data and perform

minimum processing over it, and launch their records to aggregator for additional

processing. Whereas, the last category of routing protocols consists of route discovery

which is sub-divided into reactive, proactive, and hybrid schemes. The proactive routing

practices are also termed as table driven protocols. In these procedures paths are

calculated before the communication takes place between nodes and the sink. In the

reactive protocols paths were established at the time of communication. While in case of

14

hybrid protocols paths establishment takes place through the amalgamation of proactive

and reactive protocols. In this document, we explore the recent routing protocols as per

their category, in detail, to clear their understanding which in term open new research

directions in the field.

2.1.1 Applications of WSN

The sensor is the most demanding technology of day to day life, to track the sources and

send their data to the destination, without the need of any administrator. Its uses are

countless however the most significant applications against their fields are demonstrated

in Table 2.1.

Area Applications

Health-Care

Applications

� Examine and take-care of patients [5, 6].

� Health industry could save approximately 25$ billion if WSN is

incorporated in health care systems [7].

� Sensor for blood pressure, oxygen measurement, blood flow,

respiration rate, Pulse oxy-meter, ECG (electrocardiogram) [8].

� Monitor the people's health condition and location [9].

� Health-Gear is Microsoft research product. In the project sensor

nodes are connected to phone via Bluetooth device. It is real time

wearable system for analyzing and monitoring real time

physiological signal [10].

� Mobi-Health is European commission funded project, which is

based on mobile health care. It monitors the patients during health

monitoring using GPRS and UMTS networks [11].

� Artificial Retina [12].

� Vital Sign [13].

15

� Glaucoma Patient [14].

Military

Applications

� Object Tracking [15].

� Military monitoring (MILMON) [16].

� This application informs the commander about the battlefield, and

helps to take the better decision to save their soldiers [17].

It is the application for crucial tasks, such as equipment

management, damage assessment and supply management [18].

� It works in hazardous circumstances specially use in battle [19].

Emergency

Applications

� Disaster Recovery applications named as CodeBlue [20].

� Fire crisis discovery and reply for construction surroundings is a

new application area for the operation of WSNs [21].

� FireGuide [22].

� Fire and water detectors [23].

Agricultural

Applications

� The wireless Vineyard [24, 25] is the Intel’s project in which motes

are planted on vine plants in a vine-yard.

� Use of WSN provides accurate amount of water to agricultural

activities, which consumes 70% of world wide water [26].

� Francois Depienne, is a project for moisture tracking [27].

Environmental

Applications

� Study the animals without alarming them

o Great Duck Island network [28].

o ZebraNet [29].

� Fellow-Me [30].

� WSN based Storm and Weather gathering application [31].

� Examine volcanic and seismic actions [32].

� Security applications [33].

16

Table 2.1. Applications of WSNs

2.2 WSNs Routing Challenges Compared with other Wireless Network

There are number of routing challenges which differentiate WSNs from other wireless

networks e.g. mobile-ad-hoc, or wireless mesh networks due to its characteristics [47].

• It is an overhead to maintain a large number of IP (Internet base protocol scheme) due

to length of sensor nodes in the network.

• It works un-attended while other networks need administrator or the same.

Industrial

Applications

� Place sensors inside the machine and measure the attributes such

as heat and vibrations [34].

� WSNs are used to safe the employee in many industries [35].

� Keep control the industry process and automation [36].

Inventory

Tracking

� Suppliers ensure the safety of gas cylinders [37].

� Inventory management to Storage Silo, named as AnyBridge [38].

� Gas Cylinder Management [39].

� CityNet application to monitor the air quality in Urban Areas [40].

Smart Spaces � Smart-M3 [39] interoperable platform for smart devices [41].

� In Smart homes integrated systems work together and inform

home what they are doing and respond them accordingly [42].

Process

Monitoring

� Business Process Modeling Notation (BPMN) it is the

combination of both engine of business working and WSN [43].

� Graphic Workflow Execution Language for Sensor Network

(GWELS) process model helps to understand the services

oriented programming paradigm for sensor networks, hence

makes easy to develop and integrate with sensor network

applications [44].

17

• In WSN data is more important than who has sent the data( no need of IP)

• Flow of data has always been from the sensor nodes to BS, no other way possible like

peer to peer or multi-cast techniques.

• Sensor nodes unlike the other networks have limited processing, storing, battery,

therefore, need intensive management of the resources

• Nodes remain fixed after deployment, but in some application they are allowed to

move but with very low mobility, while in other network nodes are free to move,

resulting in frequent change in the topologies.

• They are application specific, their requirements of design change to the application.

• Sensor nodes normally read one phenomenon, therefore, redundant information flow

in the network. So such redundancy filtered out in order to better utilize the

bandwidth channel.

• They are normally data-centric networks, in which facts are sensed based on specific

characteristics called as attribute-based addressing.

• Nodes in WSN must know their position because on the basis of position information

is collected. In order to get the position,

• GPS (Global Positioning System) hardware is not a feasible solution in term of cost,

energy, and physical constraints. There are large numbers of GPS free solutions

suggested by the researchers.

• Sensor nodes are deployed once in their whole lifetime.

18

2.3 Routing Protocols Classification

The node-to-node communication between the devices takes place at the network layer.

This means that two systems can communicate with each other through an arbitrary

number of intermediate nodes called hops. Whereas transmission between two neighbors

takes place on data link layer, the routing decision in multi-hop communication is taken

on the network layer. As WSNs is a special branch of infrastructure-less environments,

therefore, it has to take all its decisions by its own. Consequently, each node in the

network could be a source of information or act as a router. Normally the nodes in the

network are the source nodes they collect data from their surroundings and send it to the

sink or BS, and depending on the applications, some acts as router nodes to relay the

information between arbitrary numbers of nodes. This makes simpler routing decisions,

notably.

Since there is a limited amount of energy available to each sensor node in the network,

therefore, MANET protocols can’t be used to address the same problem of the WSNs.

Initially, some researchers applied the MANET protocols to WSNs problems, but due to

the application specific nature of the networks, they were failing to provide better results,

therefore, researchers of WSNs focus develop their own protocols as per the demands of

the application.

There are various types of classification for WSNs routing protocols presented in a

literature.

19

Network Structure based

Classification [48]

i. Flat or Data-Centric based routing

ii. Hierarchical or Cluster-based routing

iii. Location based routing

Protocol Operation based

Classification [49]

i. Multi-Path based routing

ii. Query-based routing

iii. Negotiation-based routing

iv. QoS-based routing

v. Non-Coherent & Coherent data processing based

routing

Sensor Node architecture

based Classification [49]

i. Protocols work on Flat topology( In the network all

nodes are treated equally called as homogeneous)

ii. Protocols work on hierarchical topology (in the

network some nodes have more responsibilities than

the others are called as Heterogeneous)

Packet Destination based

Classification [50]

i. Gossiping and Agent based Unicast Forwarding

ii. Energy-efficient unicast

iii. Broadcast and Multi cast

iv. Geographic routing

v. Mobile nodes

Source -Destination Recovery

based classification [51,48]

i. Proactive

ii. Reactive

iii. Hybrid

Cooperative Routing [52] i. The technique in which sensor nodes send their

data to central node that combines the data to

diminish the energy consumption.

20

Protocol’s initialization point

based classification [48]

ii. Source-initiated (Src-initiated)

iii. Destination-initiated (Dst-initiated)

Epidemic behavior based

Classification [53]

i. Pull-based epidemic algorithm

ii. Push-based epidemic algorithm

iii. Pull-push based epidemic algorithm

Application based routing

protocols Classification [54]

i. Query-based WSN applications

ii. Event-driven based applications

iii. Periodic WSN applications

K. Sha et al based

Classification[55]

i. Greedy geographic Routing

ii. Load-balanced Routing

iii. Energy aware Routing

iv. Fault tolerant Routing

v. Information exploiting Routing

M. Perillo et al based

Classification[56]

i. Resource-Aware Routing

ii. Energy-aware Routing

iii. Fidelity-aware Routing

iv. Data-Centric Routing

v. Geographic Routing

vi. Clustering

State based Classification [57] i. Stateful ad hoc Routing

ii. Stateless Geometric ad hoc Routing

21

Energy-Efficient Routing

Protocols based Classification

[58]

i. Protocols for energy efficiency, which manage the

communication power plane at each node while

maintaining the network connected.

ii. Protocols that take decisions on the bases of

power maximization objectives.

iii. Protocols that take care of network topology by

determining which nodes should take part in the

function and which shouldn’t.

Table 2.2. Routing protocols classification

2.3.1 Structure Base Routing Protocols

It is one of the divisions of routing protocols of WSNs, which is further divided into flat,

hierarchical, and location predicated routing protocols. Under this category, protocols are

quantified with regard to design structure of the network area.

i. Flat or Data Centric based Routing

Figure 2.2. Routing protocols in WSNs

Multi-Path Based Routing

Coherent Based Routing

Routing Protocols in WSN

Negotiation Based Routing

Multi-Path Based Routing

QoS Based Routing

Network Structure

Hierarchical

Base

Flat Based

Location Based

Protocol Operation

Route Discovery

Reactive Protocol

Proactive Protocol

Hybrid Protocols

22

ii. Hierarchical or Cluster based Routing

iii. Location based Routing

i. Flat or Data Centric based Routing

In this type of routing technique, every node has the same responsibility for sending,

receiving, and communicating, and mostly use flooding based technique for transferring

of data. Since flooding includes collapse, which occurs due to duplicate messages being

sent to the same node. In flat based protocols overlapping occurs when two or more

nodes sense the same area, and put on the air their packets to the same neighbor node.

This resource blindness could cause to consume large amount of energy. Similarly, in flat

based network nodes work together to accomplish the job of sensing. As in WSNs have a

sizable voluminous quantity of nodes as compared to other networks, therefore, it is not

feasible to give a unique address to each node. In order to address the problem, data

centric routing is started, in which BS transmits the queries to a specified area in the

network and waits for their acknowledgement. Since the information is being

acknowledged in the course of inquiries, therefore, an attribute supported naming is

necessary to indicate the properties of data. They require no topology organization. The

Flat based protocols are classified as follows:

� Sensor Protocols for Information via Negotiation (SPIN)

� Directed Diffusion, Rumor Routing

� Stream Enable Routing

� Gradient based routing

� Threshold sensitive Energy efficient sensor network protocol (TEEN)

� Adaptive periodic (APTEEN)

23

� Constrained Anisotropic Diffusion Routing (CADR).

ii. Hierarchical or Cluster based Routing

In this brand of protocols nodes are grouped into clusters, in order to address the

problems of scalability and energy efficiency of flat based protocols. Thus, in hierarchical

routing protocols, each node of the cluster communicates with its manager node typically

entitled as CH. Nodes in hierarchical routing protocols have different roles, i.e. CH and

non-CH nodes. The CH nodes have normally supplementary energy, as compared to the

regular sensor nodes. The CH nodes process and send the information to BS, while the

non-CH nodes are used to sense the physical phenomenon in the area. The hierarchical

routing technique is used to develop energy efficient, scalable, and reliable protocols for

WSNs. It is also an efficient way to downsize the energy utilized in the cluster. The

hierarchical protocols help to reduce collision in the wireless channel and make easy the

work cycles of sensor motes, which in turn amplify the overall existence of the network.

The advantage of the clustering protocols is to aid in the improvement of routing

protocols, but it might follow longer routes as compared to the flat based protocols. The

CH in clustering process also performs aggregation on sensor’s collected data, because

data might be coming from the overlapped region, before passing the information to the

sink. The passing of records to BS is performed by the following two ways, i.e. single-

hop or multi-hop. In the single-hop CH passes the statistics to BS directly, while in multi-

hop CH uses relay CHs to convey the facts to BS. Following are examples of routing

protocols, i.e.

� Geography Adaptive Fidelity (GAF)

� Self-Organization (SOP)

24

� Hierarchical Periodic, Event-driven and Query-based (HPEQ)

� Power Efficient Gathering in Sensor Information System (PEGASIS)

� Hierarchical PEGASIS

� Hierarchical Energy Aware Protocol for routing and Aggregation in Sensor

networks (HEAP)

� SPAN, Simple Hierarchical routing protocol (SHRP).

Member of Cluster

Cluster Head(CH)

Sink

Shows flow of data

Figure 2.3. Single-hop and multi-hop connections to the sink

( b ): Multi-Hop ( a ): Single-Hop

25

a) Hierarchical or Cluster based Routing Protocols are classified as follows

In this segment we discuss different features of cluster based routing protocols

Hierarchical Routing Flat Routing Reservation-based scheduling Contention-based scheduling

Collisions avoided Collision over-head in attendance

Reduced duty cycle due to periodic sleeping Changeable duty-cycle by governing

sleep time of nodes Data aggregation by cluster-head Nodes on multi-hop pathway aggregate

in-coming data from the neighbors Uncomplicated but non-optimal routing Routing can be made best possible but

with an added complications. Call for global and local synchronization Without synchronization, Links are

created on the fly Operating cost of cluster formation throughout the network

Routes formed only in areas that have data for communication

Lower latency as multiple hops network formed by CHs always available

Latency in coming around the intermediate nodes and placing up the multipath

Energy dissipation is regular Power dissipation trusts traffic models Energy dissipation cannot be restricted Power dissipation adjusts to traffic

models Fair channel allotment Fairness not certain

Table 2.3. Hierarchical vs flat topologies routing

26

• Cluster Formation Method

The cluster formation method consists centralized, distributed and hybrid. In the

centralized technique, there is a central body which takes the decision of forming clusters

and CHs, in the distributed approach each node runs its own logic to form clusters and

CH, while in hybrid approach combination of both the centralized and distributed

approaches are used to form clusters and CHs.

• Cluster Formation Properties

Clustering process has the following properties for the formation of clusters. These are

the internal features of the cluster’s structure.

• Count Clusters

This feature means to count total number of clusters formed in a round. In some cluster

approaches, selection of CH is done before deployment such formation is called as Fixed

selection, while in others, selection of CH takes place randomly, so it is called as Random

selection of CH.

• Size of Cluster

It represents the length or distance of CH’s members from the CH. In case the distance is

small, it saves energy dissipation and also reduces the load on the CH. In some cases this

distance is fixed, while in others it keeps on changing i.e. variable.

• Density of Cluster

It is described as the proportion of the immense number of nodes in the cluster area and

cluster. The important, confront to diminish the energy burning-up in dense clusters. In

27

case of fixed clustering normally considers a sparse cluster, while in dynamic cluster, the

density of the cluster is variable.

• Count Messages

It counts the total number of messages interchanged during the selection of CH. In case of

more messages exchanged, it consumes more energy. In most of the non-probabilistic

approaches, exchange of messages is required for the selection of CH, and in probabilistic

techniques there is no message exchange.

• Stability

If the members of a cluster don’t remain fixed, then that cluster is called as adaptive

cluster, otherwise it is called as fixed. The fixed Count of Clusters increases the stability

of a WSN.

• Intra cluster communication

It means the communication which is performed in a cluster. It could be single or multi-

hop. In Single-hop also called as Direct Link nodes send their data directly to CH, while

in multi-hop nodes in a cluster uses relay nodes to send their data to CH see figure 2.6.

• Inter cluster communication

It indicates the communication between the CH/nodes and BS. If a CH doesn’t have the

range to send the data to BS, then the cluster strategies make sure through intermediate

condition to route the data to BS.

28

• CH- Potentials

The CH potentials in cluster strategies affect the system performance in-succession of

stability and lifetime of WSN. The following are some characteristics on the basis of

which CH strategies are differentiated.

• Node Type

There are different types of nodes some are defined as CH before their deployment

because they have more energy at the beginning than the member nodes in a cluster,

while other CHs have the same energy as member nodes in a cluster.

• CH Mobility

Some CHs are Mobile while others are Stationary. The Mobile CH changes its location

where there is a need to balance the workload, and hence helps to achieve the best

performance. In case of Static CH which remains in its place once deployed, so the

workload is divided among all the members of the CH, in order to achieve the

performance.

• Role of CH

Role defines the operations performed by CHs. So CH performs aggregation, collection

of data from its members, and it also relays the information to BS.

• CH Selection

CH selection can be before, or after deployment of the nodes of WSNs [8].

29

• Probabilistic Based

CH is selected on the basis of probabilistic based techniques. In this technique each node

has predefined probabilistic approach to determine the initial CHs.

• Non-Probabilistic Based

In the non-probabilistic based technique decision of the CH selection is supported on

outstanding power, degree and connectivity of the nodes in a cluster, Location based,

Position based Neighbor nodes, etc.

• Formation of Cluster

The formation of CH takes place such that CH broadcasts the packet to their neighbors,

which comes under its radio range. After receiving the packet nodes acknowledge to the

CH, and hence cluster is formed. In case of single hop nodes forward their data to the CH

directly, although in multi-hop nodes transmit through neighbor nodes. In the figure 3

cluster based protocols parameters have been classified.

30

iii. Location Oriented Routing

Geographic or location-base routing protocols exercise the location information of the

sensor nodes to spread the information to the destination rather than the complete

network. Nodes establish their locality using localization schemes and algorithms, i.e.

localization techniques. Therefore nodes are connected using geographic information

instead of topological connectivity knowledge to formulate promoting decisions. In the

unicast position supported protocols sender nodes not only have the information of their

own, but the information of the destination nodes as well. It obtains the information

either through questioning e.g. flooding, an inquiry to the destination to send its position

or a location agent service that plans the node’s identity into their locations. Although in

multicast location based or broadcast guided routing protocols, the matching packet is

Non-Probabilistic Based

Non-Probabilistic Based

Cluster Formation Properties

CH- Potentials CH Selection

Formation of Cluster Cluster Formation

Properties CH- Potentials CH Selection

Formation of Cluster

Count Clusters

Size of Cluster

Density of Cluster

Count Messages

Stability

Intra cluster communication

Inter cluster

Node Type

CH Mobility

Role of CH

Cluster Formation

Method

Distribute

Centralized

Hybrid

Probabilistic Based Single-hop

Multi-hop ingle-hop

Characteristics of Clustering

Figure 2.4. Categorization of different characteristics of clustering in WSNs

31

disseminated to various targets. Moreover, multicast protocols have the benefit that they

have the knowledge of the sites of the motes which therefore minimize the consumption

of resource by dropping redundant links. In most location based protocols the location

message is exercised to determine the space linking the nodes to deduce the power

utilization. Since nodes are spatially organized in an area, and have no such scheme of

addressing like IP in regular networks. So the data are transmitted to all the motes that

stay alive in a specific geographic area. This approach, of access is called as geo-casting,

i.e. to diffuse query to certain region instead of flooding the whole network. This

technique saves both the energy as well as bandwidth of the channel which increase the

overall performance of the network. Once the packet arrives at the target, it could either

be disseminated to all the sensor nodes within the region which is called as multi-cast, or

transmits the packet to at least one node in the network, which is also called as any-cast.

As compared to other routing protocols, location based protocols want only the

geographic awareness and therefore not necessary to hold the routing table information

and also do not require to set up the back-to-back paths connecting senders and receivers,

hence avoid the requirement of administering message. Illustrations of location supported

routing procedures are Geographic Adaptive Fidelity (GAF), Minimum Energy

Communication Network (MECN), Geographic and Energy Aware Routing (GEAR), and

Small MECN (SMECN).

2.3.2 Protocol Operation based Classification

It’s also an important component of routing protocols of WSNs. In the following group

of routing protocols are measured with respect to the operation of routing protocols and

they are categorized as follows [6].

32

i. Multi-Path based routing

ii. Query-based routing

iii. Negotiation-based routing

iv. QoS-based routing

v. Non-Coherent & Coherent data processing based routing

i. Multi-path based Routing

Multipath routing protocols are most widely used protocols to address the limitations of

the networks. They can also enhance the performance demand of certain applications.

However, on one hand it improves the performance while on the other hand it might

adversely affect the performance of certain application of WSNs. Since sending of

duplicate copies of the same message increase the reliability, but also affect the network

performance as well due to the reason of traffic overhead. Therefore, choosing the

appropriate protocol is depending upon the nature of the applications. The most important

multi-path routing protocol is Directed Diffusion.

• Directed Diffusion

It follows a data-centric approach. Data in such routing protocols are indicated as an

attribute-value tuple. Once the data are generated by the nodes, it is requested through an

attribute-value tuple identified by the application. The BS infuses a notice to the network

[33]. The node updates its interior awareness with the notice acknowledged from the

messages.

The node also has cache to store the most recent messages. The data rate is also

determined through this layout. On

replication path to the source of the progenitor of the interest.

This path is described as gradient and it facilitates to describe the data rate, and running

out time. Moreover, nodes allow their sensors

establish multiple gradients to

optimum gradient is performed by considering affirmative and negative fortifications.

This procedure works with two kinds

Exploratory gradients perform path repair and setup, whereas information gradients are

exercised to transmit actual information.

Figure2.5. Directed diffusion scenario

The node also has cache to store the most recent messages. The data rate is also

determined through this layout. On getting the communication, the nodes construct the

replication path to the source of the progenitor of the interest.

This path is described as gradient and it facilitates to describe the data rate, and running

out time. Moreover, nodes allow their sensors to receive the planned records. The nodes

blish multiple gradients to BS on receiving the interest message. The selection of the

optimum gradient is performed by considering affirmative and negative fortifications.

This procedure works with two kinds of inclines: exploratory, and statistics gradients.

Exploratory gradients perform path repair and setup, whereas information gradients are

exercised to transmit actual information.

33

The node also has cache to store the most recent messages. The data rate is also

getting the communication, the nodes construct the

This path is described as gradient and it facilitates to describe the data rate, and running-

to receive the planned records. The nodes

BS on receiving the interest message. The selection of the

optimum gradient is performed by considering affirmative and negative fortifications.

of inclines: exploratory, and statistics gradients.

Exploratory gradients perform path repair and setup, whereas information gradients are

34

(a) (b) (c)

ii. Query Based

Query supported routing protocols are recipient-commenced. The recipient node spreads

a query for the data in the network and a node containing the information that equivalents

the query, sends the matched data back to the query requester. The queries are usually

defined in high-level and natural languages.

• Cougar

Cougar is a query based protocol. It views the network as a giant distributed system. The

main thought behind this protocol is to utilize informative inquiries in turn to conceptual

inquiry dispensation from the network layer utilities, for instance the choice of

appropriate sensors and so on. It performs in-networking aggregation process on the data

to save more energy. The notion is offered by the supplementary layer that exists

Source

Sink

Sink Sink

Source

Interes

Source

Interes

Figure 2.6. Directed diffusion: (a) interest propagation, (b) initial gradients set up, and (c) data delivery.

35

connecting network and application level. It has incorporated structural design of a sensor

database organization in which nodes elect a chief mote to carry out processing of

aggregation and send the information to BS. The query is generated by BS. The query

specifies the information of data flow and its computation, and throws it to the

appropriate nodes. The incoming inquiry also expresses that how to decide on a manager

for the query.

The structural design presents an estimation capability to each sensor nodes in the

network. This computation awards energy efficiency to the sensor nodes, particularly

when the number of nodes produces and transport information to the chief is gigantic.

Since Cougar offered the solution to query the sensor nodes, which is self-governing of

the network cover, but it had some drawbacks. First, it has brought a query layer on each

sensor which puts additional overhead on the sensor motes in term of liveliness

utilization and storage space. Second, in network processing from numerous nodes have

need of bringing together, i.e. a relay node should remain sooner than transport the

information to the chief node until it receives packet from every arriving source node.

The third is that the chief nodes should be maintained vigorously in order to prohibit

them from stoppage.

Partially Aggregated

Select AVG > threshold

Aggregate Operator (AVG)

Network Interface

Average Value

Figure 2.7. Query plan at a bellwether node: The bellwether node acquires all the understandings, determines the average and if it is more preponderant than a threshold throw it to the BS.

36

iii. Negotiation-based

Negotiation based protocols avoid to transmit redundant data transmission by using high

level of descriptor via negotiation. In these protocols, communication decisions are taken

by considering the number of resources available to them. The motivation behind, the

negotiation based protocols is implosion, overlapping and resource blindness between the

sent data in flooding based protocols. Hence due to specified reasons node could receive

duplicate copies of the matching data. It can also affect the energy that is wasted during

the process of communication and processing of duplicated data. So the main theme

behind negation oriented protocols is that they hold down duplicate information by

carrying-out a sequence of negotiation messages to the nodes before actual data

transmission is taking place. It therefore voids the replica of information from being sent

to the next node or BS.

• Sensor Protocols for Information via Negotiation (SPIN)

This family of adaptive protocols is entitled as Sensor Protocols for Information via

Negotiation (SPIN) and is suggested by Heinemann et al [8]. In those protocols every

node broadcasts their information to another node in the network. Consequently, each

node in network carries all the information. It enables the user to get the requested

information instantly, just by querying any node. Since the nodes are very close to each

other, therefore it is assumed that they usually transfer the data which other nodes might

have, causing the redundancy. In order to avoid redundancy in the SPIN protocol’s

family by performing some sort of negotiation and resource adaptive algorithm

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iv. QoS based Protocols

In this category of routing protocols, the network maintains the balance involving energy

utilization and information excellence. QoS based protocols, particularly ensure the

parameters, i.e. hitch, bandwidth, and energy etc., while transmitting information to BS.

The most important example of a QoS based protocol is Stateless Protocol for Real-Time

Communication in Sensor Network (SPEED).

• SPEED (Stateless Protocol for End-to-End Delay)

This is an instance of QoS based direction-finding protocols. This protocol ensures soft

instantaneous back-to-back communications. Each node in this protocol contains the

information of its neighbors and exercises a geographic front-warding strategy to search

the paths. This protocol further guarantees a certain speed of the packets. So each

application preserves roughly determine back-to-back holdup of the packets by

partitioning the space to BS by the packet speed. Speed protocol avoids the congestion in

the network. It is also interested in providing uniform speed of message release crosswise

the network. So the uninterrupted delay of the packet is dependent upon the distance

between the sender and recipient nodes. Therefore, real time applications approximate

this uninterrupted interruption prior to fashioning access consequences.

In the SPEED rule steering module is entitled as Stateless Non-Deterministic Geographic

forwarding (SNGF) and work through other four components of the network cover up.

The beacon collection gets the aggregation about computing machines and their activity.

Delay estimation is performed on each node by means of reckoning the forgotten time

after it receives the ACK from a neighbor in comeback of a convey information packet.

So SNGF choose those computing devices which athletic contest the cannonball along

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constraint, If not succeeded, the dispatch percentage of the mote is ensured, this is

intended via appearing in the overlook percentage of the neighbors of a mote i.e. the node

that couldn’t supply the preferred momentum.

In this category of routing protocols, the network maintains the steadiness connecting

power utilization and info worth. QoS based protocols particularly ensure bandwidth,

stopping, and energy etc., when transmitting facts to BS. The most important example of

a QoS based protocol is Stateless Protocol for Real-Time Communication in Sensor

Network (SPEED).

v. Coherent Based Protocols

As in WSN nodes bring together information and throw it to their neighbors or to BS.

The most important in WSNs is the data processing of the composed facts. There are two

types of processing, i.e. coherent and non-coherent approaches of facts computing. In

non-coherent type, nodes collect information, and then perform processing on it before

the data is transferred to their neighbors or aggregator where the next processing is done

on the data. While in coherent type, nodes perform minimum processing like time

stamping or suppression and send it to aggregator for processing. In coherent based

routing, nodes save their energy as compared to non-coherent based routing. As there is a

long data stream produced in coherent data, but using efficient path, energy utilization is

attained. As there are long data streams produced in coherent processing, but using

efficient path, energy utilization is attained. The first-class instance of non-coherent

protocol is Single Winner Algorithm (SWE), whereas Multi Winner Algorithm (MWE) ,

a variable of SWE is also a coherent computing protocol.Coherent protocol Single

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Winner Algorithm (SWE), whereas Multi Winner Algorithm (MWE), a variable of SWE

is also a coherent computing protocol.

• Single and Multiple Winner Algorithms

These algorithms have been suggested in favor of coherent and non-coherent practices

respectively. In the Single winner algorithms a particular node as an aggregator node is

selected for complicated computing. The selection of the nodes as an aggregator is based

on computation capability and energy assets. In the SWE ending process the minimum

hop spanning tree covers the whole network. While multi winner processing (MWE), is

an extension of SWE. When all nodes throw their facts to aggregator node, an extensive

amount of power is utilized, because this progression has an elevated cost. In one

direction to address this problem is to play down the number of source nodes that

transmit the information to the aggregator node. Instead of preserving a record of the

most excellent contender node, master aggregator node contains the record of all the

candidate nodes also. At the conclusion of MWE procedure, every sensor node has

smallest amount liveliness paths to all sensor nodes (SN) in the network. Afterward,

SWE is exploited node that gives way smallest amount of energy utilization. Thus that

node provides like a middle node in coherent computing. In general, the MWE

progression has high overhead, lengthy setback, and lesser scalability as compared to

non-coherent based computing networks.

2.3.3 Sensor Node architecture based Classification

On the basis of sensor node architecture the routing protocols are categorized as [49]

i. Protocol works on flat based topology containing homogenous nodes

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ii. Protocol works on the hierarchical topology containing heterogeneous nodes

i. Homogeneous

In this breed of routing protocols the entire nodes keep the identical size, chassis,

configuration, and a method of energy contribution. Similarly, transmission power i.e.

ranges data rates, computing power, security and reliability parameters are all same in all

the nodes. It is further divided into Cluster and Non-Cluster supported. In Cluster carried,

nodes are grouped to form clusters, while in Non-Cluster category, nodes are not

grouped.

ii. Heterogeneous

The routing protocols of this type consist of nodes having unequal size, shape,