Project report on MODLEACH: An Energy Efficient Routing Protocol in Wireless Sensor Networks

1. M.Tech. Project Report
AN ENERGY EFFICIENT ROUTING PROTOCOL
IN WIRELESS SENSOR NETWORKS
Submitted in partial fulfillment of the requirements for the degree of
Master of Technology in Computer Science & Engineering
by
Divya Prabha (1322757)
Under the Supervision of
Mr. Vishal Kumar Arora
PUNJAB TECHNICAL UNIVERSITY
Jalandhar-Kapurthala Highway, Jalandhar
SHAHEED BHAGAT SINGH
STATE TECHNICAL CAMPUS
Moga Road (NH-95), Ferozepur-152004 (PB) INDIA
December 2014

2. CERTIFICATE
I, Divya Prabha (1322757), hereby declare that the work being presented in this project
report on AN ENERGY EFFICIENT ROUTING PROTOCOL IN WIRELESS SENSOR
NETWORKS is an authentic record of my own work carried out by me during my course
under the supervision of Mr. Vishal Kumar Arora. This is submitted to the Department
of CSE at Shaheed Bhagat Singh State Technical Campus, Ferozepur (affiliated to Punjab
Technical University, Jalandhar) as partial fulfillment of requirements for award of the degree
of Master of Technology in Computer Science & Engineering.
Divya Prabha (1322757)
To the best of my knowledge, this project report has not been submitted to Punjab Technical
University, Jalandhar or to any other university or institute for award of any other degree
or diploma. It is further understood that by this certificate, the undersigned do/does not
endorse or approve any statement made, opinion expressed or conclusion drawn therein,
however, approve the report only for the purpose for which it is submitted.
Mr. Vishal Kumar Arora [Supervisor]
The M.Tech. Project of Divya Prabha (1322757) is held at Department of CSE, SBS State
Technical Campus, Ferozepur on ................................................
Supervisor’s Signature Mrs. Daljeet Kaur
Name: ....................................... M.Tech. Coordinator, CSE
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3. ACKNOWLEDGEMENTS
Apart from the efforts of myself, the success of Masters dissertation depends largely on
the encouragement and guidelines of many others. I take this opportunity to express my
gratitude to the people who have been instrumental in the successful completion of this
project. I would like to express the deepest appreciation to my supervisor, Mr. Vishal
Kumar Arora, Assistant Professor, Department of Computer Science & Engineering , SBS
State Technical Campus, Ferozepur (Punjab), India, who has the attitude and the substance
of a genius: he continually and convincingly conveyed a spirit of adventure in regard to
research and scholarship, and an excitement in regard to teaching. Without his guidance
and persistent help this dissertation would not have been possible. I cant say thank you
enough for his tremendous support and help. I feel motivated and encouraged every time I
attend his meeting. Without his encouragement and guidance this project would not have
materialized.
I am becoming increasingly present to the fact that research can indeed be an enjoyable and
rewarding experience, despite the tedium and hardwork involved. This report is truly the
culmination of his support, motivation, generous help and teachings. I can never forget the
cheerful moments of my life when this charismatic personality accepted me as a research
scholar. I must record my sincere gratitude to him for not only the great store-houses of
knowledge he bestowed upon me but also for the chiseling and grooming. I received in large
measure in spheres of academic, professional and personal life. Without his constant chase
and help, this work could not have taken this shape. I am pretty sure that his guidance
would go a step beyond this project report and would be reflected in Doctorate Course and
a couple of more publications of improved quality and of greater rigor and coverage, which
I now look forward to.
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4. iii
Mr. Vishal Kumar Arora’s mature research advice in the very initial stage never let me down
in research throughout the longish period of research. I could learn the technique of orga-
nizing and writing quality research matter only because of his erudite teachings throughout
the project. This in fact has left a permanent impression on my personality and written and
verbal communication. I also express my great admiration and indebtedness for the manner
in which he painstakingly carried out a thorough editing of our papers and the project report,
despite his overwhelming busy schedule and numerous responsibilities.
There are several other persons who made important contributions during this period. The
guidance and support received from all the members who contributed and who are contribut-
ing to this project, was vital for the success of the project. I am grateful for their constant
support and help.
My sincere thanks to Dr. T. S. Sidhu, Principal, SBS State Technical Campus, Ferozepur
(Punjab) and to Mr. Japinder Singh, Head, CSE Department, SBS State Technical
Campus, Ferozepur (Punjab).
I wish to acknowledge the magnificent support I have received from my fellow friends Ms.
Shubhi Bansal, Ms. Reenkamal Gill and Ms. Priya Chawla in the form of useful
discussions throughout this work.
My sincere thanks to my friend Ms. Jaspreet Kaur for clearing my doubts in LaTeX and
making my writing part easier.
Finally, I must thank GOD and my parents Mr. Anil Kumar and Mrs. Pushpa for
giving me the environment to study, people to help, opportunities to encash and potential
to succeed.
Place: SBS STC Ferozepur
Date: December 13, 2014 Divya Prabha

5. ABSTRACT
The popularity of Wireless Sensor Networks have increased tremendously due to the vast
potential of the sensor networks to connect the physical world with the virtual world. Since
these devices rely on battery power and may be placed in hostile environments replacing them
becomes a tedious task. Thus, improving the energy of these networks becomes important.
This project provides methods for clustering and cluster head selection to WSN to improve
energy efficiency. It presents a comparison between the different methods on the basis of
the network lifetime. In this project, we develop and analyze low-energy adaptive clustering
hierarchy(LEACH), a protocol architecture for both homogeneous WSNs and heterogeneous
WSNs that combines the ideas of energy-efficient cluster-based routing and media access
together with data aggregation to achieve good performance in terms of system lifetime,
latency, and application-perceived quality. Further, we modify one of the most prominent
wireless sensor networks routing protocol LEACH as modified LEACH (MODLEACH) by in-
troducing efficient cluster head replacement scheme and dual transmitting power levels. Our
modified LEACH, in comparison with LEACH out performs it using metrics of cluster head
formation, throughput and network life. Finally a brief performance analysis of LEACH and
Modified LEACH (MODLEACH)is undertaken considering metrics of throughput, network
life and cluster head replacements.
Keyword: Wireless Sensor Network, Clustering, Energy Efficiency,LEACH, MODLEACH,
Network Lifetime
Place: Ferozepur Divya Prabha (1322757)
Date: December 13, 2014
iv

6. ABBREVIATIONS
Abbreviations Description
ADV Advertisement
BS Base Station
CDMA Code Division Multiple Access
CH Cluster Head
C-Leach Centralized Low-energy Adaptive Clustering Hierarchy
CM Cluster Member
CSMA Carrier Sense Multiple Access
GPS Global Positioning System
I-Leach Improved Low-energy Adaptive Clustering Hierarchy
LEACH Low-energy Adaptive Clustering Hierarchy
Leach-A Advanced Low Energy Adaptive Clustering Hierarchy
Leach-B Balanced Low Energy Adaptive Clustering Hierarchy
Leach-F Fixed no. of clusters Low Energy Adaptive Clustering Hierarchy
Leach-L Energy Balanced Low Energy Adaptive Clustering Hierarchy
Leach-S Solar aware Low energy adaptive clustering hierarchy
MAC Media Access Control
M-Leach Multi-level Low-energy Adaptive Clustering Hierarchy
QoS Quality of Service
v

7. vi
Abbreviations Description
REQ Request
TDM Time Division Multiplexing
TDMA Time Division Multiple Access
TTL Time To Live
TL-Leach Two-level Low-energy Adaptive Clustering Hierarchy
V-Leach Vice Cluster-Head Low-energy Adaptive Clustering Hierarchy
WSNs Wireless Sensor Networks

8. LIST OF FIGURES
1.1 Wireless Sensor Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Block diagram of Sensor Node . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 A Base Station Node . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Radio Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Classification of routing in WSNs . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Clustering in LEACH Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Flow chart of the Set-up phase of the LEACH protocol . . . . . . . . . . . . . 10
2.3 Flow chart of the Steady phase of the LEACH protocol . . . . . . . . . . . . 11
4.1 Simulation Scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1 Homogeneous WSN vs Heterogeneous WSN . . . . . . . . . . . . . . . . . . . 24
5.2 No. of allive nodes in Homogeneous LEACH . . . . . . . . . . . . . . . . . . . 25
5.3 No. of allive nodes in Heterogeneous LEACH . . . . . . . . . . . . . . . . . . 25
5.4 No. of allive nodes in MODLEACH . . . . . . . . . . . . . . . . . . . . . . . 26
5.5 No. of dead nodes in Homogeneous LEACH . . . . . . . . . . . . . . . . . . . 26
5.6 No. of dead nodes in Hetrogeneous LEACH . . . . . . . . . . . . . . . . . . . 27
5.7 No. of dead nodes in MODLEACH . . . . . . . . . . . . . . . . . . . . . . . . 27
5.8 No. of Packets Transmitted to Base Station in Homogeneous LEACH . . . . 28
5.9 No. of Packets Transmitted to Base Station in Heterogeneous LEACH . . . . 29
5.10 No. of Packets Transmitted to Base Station in MODLEACH . . . . . . . . . 29
5.11 No. of Packets Transmitted to Cluster Head in Homogeneous LEACH . . . . 30
5.12 No. of Packets Transmitted to Cluster Head in Heterogeneous LEACH . . . . 30
5.13 No. of Packets Transmitted to Cluster Head in MODLEACH . . . . . . . . . 31
5.14 Comparison, Percentage of Dead Nodes of Network with number of rounds . 32
5.15 Network Lifetime on the basis of Initial Energy in Homogeneous LEACH . . 33
vii

9. viii
5.16 Network Lifetime on the basis of Initial Energy in Heterogeneous LEACH . . 33
5.17 Network Lifetime on the basis of Initial Energy in MODLEACH . . . . . . . 34

10. LIST OF TABLES
4.1 Network Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.1 Comparision of dead nodes percentage . . . . . . . . . . . . . . . . . . . . . . 31
5.2 Comparision with different no. of nodes . . . . . . . . . . . . . . . . . . . . . 32
5.3 Homogeneous Leach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.4 Heterogeneous Leach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.5 MODLEACH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
ix

11. CONTENTS
CERTIFICATE i
ACKNOWLEDGEMENTS ii
ABSTRACT iv
ABBREVIATIONS v
LIST OF FIGURES vii
LIST OF TABLES ix
CONTENTS x
1 INTRODUCTION 1
1.1 Wireless sensor network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Sensor nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1.2 Base Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.3 Radio Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Energy-efficient Routing Algorithms . . . . . . . . . . . . . . . . . . . . . . . 4
1.2.1 Data centric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2.2 Hierarchical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.3 Location Based . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 LITERATURE SURVEY 8
2.1 LEACH ALGORITHM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 ASSUMPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4 ALGORITHM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.5 VARIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
x

12. xi
2.5.1 LEACH-B (Balanced Low Energy Adaptive Clustering Hierarchy) . . 12
2.5.2 LEACH-C (Centralized Low Energy Adaptive Clustering Hierarchy) . 13
2.5.3 LEACH-E (Energy Low Energy Adaptive Clustering Hierarchy) . . . 13
2.5.4 I-LEACH (Improved Low Energy Adaptive Clustering Hierarchy) . . . 13
2.5.5 MULTIHOP LEACH . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.5.6 TL-LEACH (Two-Level Low Energy Adaptive Clustering Hierarchy) . 14
2.5.7 LEACH-M (Mobile Low Energy Adaptive Clustering Hierarchy) . . . 14
3 PROJECT WORK 15
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2 MODLEACH: PROPOSED SCHEME . . . . . . . . . . . . . . . . . . . . . . 16
3.3 Modified Protocol Functioning . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4 SIMULATION 19
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.2 MATLAB Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.4 Proposed work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.5 Network Scenario Assumptions and Parameters . . . . . . . . . . . . . . . . . 21
5 RESULTS AND DISCUSSIONS 23
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.2 Experiments and Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.2.1 Homogeneous vs Heterogeneous Network . . . . . . . . . . . . . . . . . 24
5.2.2 Number of Allive Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.2.3 Number of Dead Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.2.4 Number of Packets Transmitted to Base Station . . . . . . . . . . . . 28
5.2.5 Number of Packets Transmitted to Cluster Head . . . . . . . . . . . . 28
5.2.6 Percentage of Dead Nodes . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.2.7 Comparison among different protocols and Different amount of Initial
Energy for the sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.4 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
REFERENCES 36

13. CHAPTER 1
INTRODUCTION
In this chapter, we first provide an overview of Wireless Sensor Networks, then we focus on
the Energy-efficient Routing Algorithms. In addition, we describe the components of WSNs
and an energy efficient routing protocol in Wireless Sensor networks.
1.1 Wireless sensor network
A Wireless Sensor Network or WSN is supposed to be made up of a large number of sensors
and at least one base station. The sensors are autonomous small devices with several con-
straints like the battery power, computation capacity, communication range and memory.
They also are supplied with transceivers to gather information from its environment and
pass it on up to a certain base station, where the measured parameters can be stored and
available for the end user.
In most cases, the sensors forming these networks are deployed randomly and left unattended
to and are expected to perform their mission properly and efficiently. As a result of this
random deployment, the WSN has usually varying degrees of node density along its area.
Sensor networks are also energy constrained since the individual sensors, which the network
is formed with, are extremely energy-constrained as well. The communication devices on
these sensors are small and have limited power and range.
Both the probably difference of node density among some regions of the network and the
energy constraint of the sensor nodes cause nodes slowly die making the network less dense.
Also it is quite common to deploy WSNs in harsh environment, what makes many sensors
1

14. CHAPTER 1. INTRODUCTION 2
inoperable or faulty. For that reason, these networks need to be fault-tolerant so that the
need for maintenance is minimized. Typically the network topology is continuously and
dynamically changing, and it is actually not a desired solution to replenish it by infusing
new sensors instead the depleted ones. A real and appropriate solution for this problem is to
implement routing protocols that perform efficiently and utilizing the less amount of energy
as possible for the communication among nodes.
Figure 1.1: Wireless Sensor Network
The WSN consist of two main components:
1. Sensor Nodes, and
2. Base Station (Central Gateway).
1.1.1 Sensor nodes
Sensors nodes are typically built of few sensors and a mote unit as shown in Fig.1.2. A
Sensor is a device which senses the information and pass it on to mote. Sensors are typically
used to measure the changes in physical environmental parameters like temperature, pressure,
humidity, sound, vibration and changes in the health parameter of person e.g. blood pressure
and heartbeat. MEMS based sensor have found good use in sensor nodes. A mote consists of
processor, memory, battery, A/D converter for connecting to a sensor and a radio transceiver
for forming an ad hoc network. A mote and sensor together form a Sensor Node. A sensor
network is a wireless ad-hoc network of sensor nodes. Each sensor node can support a

15. CHAPTER 1. INTRODUCTION 3
multi-hop routing algorithm and function as forwarder for relaying data packets to a base
station.
Figure 1.2: Block diagram of Sensor Node
1.1.2 Base Station
A base station links the sensor network to another network. It consists of a processor,
radio board, antenna and USB interface board. It is preprogrammed with low-power mesh
networking software for communication with wireless sensor nodes. Deployment of the base
station in a wireless sensor network is very important as all the sensor nodes handover their
data to the base station for processing and decision making. Energy conservation, coverage
of sensor nodes and reliability issues are taken care of during deployment of base station in
sensor network. Generally base stations are assumed static in nature but in some scenarios
they are assumed to be mobile to collect the data from sensor nodes.
Figure 1.3: A Base Station Node

16. CHAPTER 1. INTRODUCTION 4
1.1.3 Radio Model
We have assumed the same radio model which has been used in earlier works. For the
radio hardware, the transmitter dissipates energy to run the transmitter radio electronics
and power amplifier, and the receiver dissipates energy to run the receive radio electronics
as shown in Fig.1.4. For the scenarios described in this project work, both the free space (d2
power loss) and the multi path fading (d4 power loss) channel models were used depending
on the distance between the transmitter and the receiver. If the distance is less than a
threshold, the free space (fs) model is used; otherwise, the multi path (mp) model is used.
Figure 1.4: Radio Model
1.2 Energy-efficient Routing Algorithms
Energy efficient routing algorithm can be categorized as follows: data centric routing algo-
rithm, location based routing algorithm and hierarchical routing algorithm . Data centric
routing algorithm uses meta data to find the route from source to destination before any
actual data transmission to eliminate redundant data transmission Location based routing
algorithm requires actual location information for every sensor node. Hierarchical routing
algorithm divides the network into clusters. Cluster head (CH) is elected in each cluster.
CH collects data from its members, aggregates the data and sends to sink. This approach is
energy efficient but relatively complex than other approaches (Akkaya and Younis [2005]).
1.2.1 Data centric
Data centric protocols are query based and they depend on the naming of the desired data,
thus it eliminates much redundant transmissions. The BS sends queries to a certain area
for information and waits for reply from the nodes of that particular region. Since data is
requested through queries, attribute based naming is required to specify the properties of
the data. Depending on the query, sensors collect a particular data from the area of interest

17. CHAPTER 1. INTRODUCTION 5
Figure 1.5: Classification of routing in WSNs
and this particular information is only required to transmit to the BS and thus reducing the
number of transmissions. e.g. SPIN was the first data centric protocol.
1.2.2 Hierarchical
Hierarchical routing is used to perform energy efficient routing, i.e., higher energy nodes
can be used to process and send the information; low energy nodes are used to perform the
sensing in the area of interest. e.g. LEACH, TEEN, APTEEN.
1.2.3 Location Based
Location based routing protocols need some location information of the sensor nodes. Lo-
cation information can be obtained from GPS (Global Positioning System) signals, received
radio signal strength, etc. Using location information, an optimal path can be formed without
using ooding techniques. e.g. Geographic and Energy-Aware Routing(GEAR)
1.3 Motivation
LEACH gives birth to many protocols. The procedures of this protocol are compact and
well coped with homogeneous sensor environment. According to this protocol, for every
round, new cluster head is elected and hence new cluster formation is required. This leads to
unnecessary routing overhead resulting in excessive use of limited energy. If a cluster head
has not utilized much of its energy during previous round, than there is probability that
some low energy node may replace it as a cluster head in next cluster head election process.

18. CHAPTER 1. INTRODUCTION 6
There is a need to limit change of cluster heads at every round considering residual energy
of existing cluster head. Hence an efficient cluster head replacement algorithm is required to
conserve energy. In clustering protocols as LEACH, nodes use same amplification energy to
transmit data regardless of distance between transmitter and receiver. To preserve energy,
there should also be a transmission mechanism that specify required amplification energy
for communicating with cluster head or base station. For example, transmitting a packet to
cluster head with same amplification power level as required by a node located at farthest
end of network to base station results in wastage of energy. One solution can be having
global knowledge of network and than nodes decide how much they need to amplify signal.
Locating and calculating distances with in full network topology needs lot of routing and so,
this approach do not work for saving energy. To solve above mentioned problems, we propose
two mechanisms. i.e. efficient cluster head replacement and dual transmitting power levels.
1.4 Objectives
To develop modified leach, our primary objectives of this project work are summarized as
follows:
1. Develop a simulated environment of WSN having configurable parameters.
2. To study previous routing protocols and their features.
3. Investigation in Energy efficient routing algorithm with an application of optimizing
WSN.
4. To create modified Leach(MODLEACH) from Leach on MATLAB for optimizing its
various parameters.
5. To conduct a comparative performance evaluation for network lifetime, dead Nodes,
alive Nodes, packets send to base station, packets send to cluster head and throughput.
1.5 Methodology
To achieve aforesaid objectives, the following phases has been adopted:
1. Initial Phase: A detailed literature survey is done from eminent journals like IEEE,
Elsevier and Springer, etc. This will provide the basic and conceptual knowledge of
the domain.

19. CHAPTER 1. INTRODUCTION 7
2. Implementation Phase: A MATLAB programming environment is used for develop-
ment of algorithms for energy efficient routing in WSN. LEACH is supposed to be one
of the most significant algorithm proposed in WSN routing. The same will be again
implemented here in both homogeneous WSNs and heterogeneous WSNs. LEACH pro-
tocol is re-investigated in this project. To explore LEACH and MODLEACH routing
protocols in WSN.
3. Testing Phase: A comparative analysis for various network parameters are then
conducted.

20. CHAPTER 2
LITERATURE SURVEY
The needed detailed literature survey, to get preliminary knowledge and search scope of inves-
tigation, to implement Low energy adaptive clustering hierarchy, is explained in this chap-
ter.This Report presents investigational studies in several energy efficient routing algorithms
and its general purpose. This Chapter contains the overview of Leach and its variants.
2.1 LEACH ALGORITHM
W.Heinzelman, introduced a hierarchical clustering algorithm for sensor networks,called Low
Energy Adaptive Clustering Hierarchy (LEACH). LEACH arranges the nodes in the network
into small clusters and chooses one of them as the cluster-head. Node first senses its target
and then sends the relevant information to its cluster-head. Then the cluster head aggregates
and compresses the information received from all the nodes and sends it to the base station.
The nodes chosen as the cluster head drain out more energy as compared to the other nodes
as it is required to send data to the base station which may be far located. Hence LEACH
uses random rotation of the nodes required to be the cluster-heads to evenly distribute energy
consumption in the network. After a number of simulations by the author, it was found that
only 5 percent of the total number of nodes needs to act as the cluster-heads. TDMA/CDMA
MAC is used to reduce inter-cluster and intra-cluster collisions. This protocol is used were
a constant monitoring by the sensor nodes are required as data collection is centralized (at
the base station) and is performed periodically.
8

21. CHAPTER 2. LITERATURE SURVEY 9
Figure 2.1: Clustering in LEACH Protocol
2.2 OPERATION
LEACH operations can be divided into two phases:-
1. Setup phase
2. Steady phase
In the setup phase, the clusters are formed and a cluster-head is chosen for each cluster.
While in the steady phase, data is sensed and sent to the central base station. The steady
phase is longer than the setup phase. This is done in order to minimize the overhead cost.
1. Setup phase :- During the setup phase, a predetermined fraction of nodes, p, choose
themselves as cluster-heads. This is done according to a threshold value, T(n). The
threshold value depends upon the desired percentage to become a cluster-head- p, the
current round r, and the set of nodes that have not become the cluster-head in the last
1/p rounds, which is denoted by G. The formulae is as follows :
T(n) = p/1-p[r mod(1/p)] if n E G
T(n) = 0 otherwise
Every node wanting to be the cluster-head chooses a value, between 0 and 1. If this
random number is less than the threshold value, T(n), then the node becomes the
cluster-head for the current round. Then each elected CH broadcasts an advertisement
message to the rest of the nodes in the network to invite them to join their clusters.
Based upon the strength of the advertisement signal, the non-cluster head nodes decide

22. CHAPTER 2. LITERATURE SURVEY 10
to join the clusters. The non-cluster head nodes then informs their respective cluster-
heads that they will be under their cluster by sending an acknowledgement message.
After receiving the acknowledgement message, depending upon the number of nodes
under their cluster and the type of information required by the system (in which the
WSN is setup), the cluster-heads creates a TDMA schedule and assigns each node a
time slot in which it can transmit the sensed data. The TDMA schedule is broadcasted
to all the cluster-members. If the size of any cluster becomes too large, the cluster-
head may choose another cluster- head for its cluster. The cluster-head chosen for the
current round cannot again become the cluster-head until all the other nodes in the
network haven’t become the cluster-head.
Figure 2.2: Flow chart of the Set-up phase of the LEACH protocol
2. Steady phase :- During the steady phase, the sensor nodes i.e. the non-cluster head
nodes starts sensing data and sends it to their cluster-head according to the TDMA
schedule. The cluster-head node, after receiving data from all the member nodes,
aggregates it and then sends it to the base-station.
After a certain time, which is determined a priori, the network again goes back into
the setup phase and new cluster-heads are chosen. Each cluster communicates using
different CDMA codes in order to reduce interference from nodes belonging to other
clusters.

23. CHAPTER 2. LITERATURE SURVEY 11
Figure 2.3: Flow chart of the Steady phase of the LEACH protocol
2.3 ASSUMPTIONS
LEACH protocol takes into a number of assumptions which may create a lot of problems in
the real-time systems. A few of these assumptions are as follows:
• All nodes can transmit with enough power to reach the base station if needed.
• Each node has computational power to support different MAC protocols.
• Nodes always have data to send.
• Nodes located close to each other have correlated data.
• All nodes begin with the same amount of energy capacity in each election round,
assuming that being a CH consumes approximately the same amount of energy for
each node.
2.4 ALGORITHM
The algorithm for the Low Energy Adaptive Clustering Hierarchy (LEACH) implemented is:
Setup phase :

24. CHAPTER 2. LITERATURE SURVEY 12
1. CN=> r
2. If r > T(n) then, CH = CN else, goto step1
3. CH => G : id(CH) , join adv
4. A(i) -> CH(j) : id(A(i)) , id(CH(j)) , join req
5. CH(j)-> A(i) : id(CH(j)) , < t(i) , id(A(i)) >
Steady phase :
1. A(i) -> CH(j) : id(A(i)) , id(CH(j)) , info
2. CH -> BS : id(CH) , id(BS) , aggr info
The various symbols used here are :
CN : candidate node to become the cluster head.
r : randomvariable(0 > r > 1)
T(n) : threshold value
CH : cluster head
G : all nodes in the network
id : identification number
join adv : advertisement to join the cluster
A : normal node
Join adv : request to join the cluster
t : time-slot to send the sensed data
=> : broadcast
->: unicast
2.5 VARIATIONS
2.5.1 LEACH-B (Balanced Low Energy Adaptive Clustering Hierarchy)
Leach-B uses the decentralized algorithms of cluster formation where each sensor node only
knows about its own position and the final receiver and does not know about the position
of all the sensor nodes. Leach-B involves the following techniques. Cluster head selection
algorithm, Cluster formation and data transmission with multiple access. By evaluating the
energy dissipated in the path between final receiver and itself, each of the sensor node chooses
its cluster head. Efficiency of Leach-B is better than Leach (Pantazis et al. [2013]).

25. CHAPTER 2. LITERATURE SURVEY 13
2.5.2 LEACH-C (Centralized Low Energy Adaptive Clustering Hierarchy)
It involves a centralized clustering algorithm. The steady state will remains the same whereas
the setup phase contains each node sending information about the current location and also
the energy level to the base station .The base station thus by utilizing the global information
of the network produce better clusters that requires the less energy for data transmission..It
needs GPS or the other location tracking method. The base station then broadcasts the
information to all nodes in the network (Muruganathan et al. [2005]).
2.5.3 LEACH-E (Energy Low Energy Adaptive Clustering Hierarchy)
LEACH-E is the enhancement of LEACH. It involves a cluster head selection algorithm which
have non-uniform starting energy level among the sensors having global information about
the other sensors. In order to minimize the total energy consumption .the required number
of cluster heads has to scale as the square root of the total number of sensor nodes and this
can be determined by Leach-E (Chaurasiya et al. [2011]).
2.5.4 I-LEACH (Improved Low Energy Adaptive Clustering Hierarchy)
IMPROVED-LEACH protocol is defined as an improvement over the LEACH protocol. The
only difference is in the CH selection procedure. At first round, a CH is to be chosen, all
the nodes have same probability to be CH. After first round, nodes energy is also considered
in CH selection(Beiranvand et al. [2013]). In this Literature Review, an energy proposed
algorithm saves a significant portion of inner network communications energy.To do this, the
proposed routing algorithm selects sensor nodes by considering the following factors:-
1. higher residual energy
2. more neighbors
3. lower distance from the Base Station (BS) as Cluster Head (CH)
2.5.5 MULTIHOP LEACH
The distance between the cluster head and the base station is increased enormously when the
network diameter is increased beyond a certain level in which the scenario is not suitable for
Leach routing protocol. The energy efficiency of the protocol can be increased by using multi-
hop communication within the cluster. Multihop-Leach is a complete distributed clustering
based routing protocol. The multihop approach is utilized inside the cluster and outside the
cluster (Xiangning and Yulin [2007]).

26. CHAPTER 2. LITERATURE SURVEY 14
2.5.6 TL-LEACH (Two-Level Low Energy Adaptive Clustering Hierarchy)
Two-Level Hierarchy LEACH (TL-LEACH) is extension to the LEACH algorithm. It has
two levels of cluster heads (primary and secondary) instead of a single one. Here, the pri-
mary cluster head in each cluster communicates with the secondaries, and the corresponding
secondaries in turn communicate with the nodes in their sub-cluster. Data fusion can also
be performed here as in LEACH. In addition to it, communication within a cluster is still
scheduled using TDMA time-slots. The organization of a round will consist of first select-
ing the primary and secondary cluster heads using the same mechanism as LEACH, with
the a priori probability of being elevated to a primary cluster head less than that of a sec-
ondary node (Jindal and Gupta [2013]). Communication of data from source node to sink is
achieved in two steps: Secondary nodes collect data from nodes in their respective clusters.
Data fusion can be performed at this level. Primary nodes collect data from their respective
secondary clusters. Data-fusion can also be implemented at the primary cluster head level.
The two-level structure of TLLEACH reduces the amount of nodes that need to transmit to
the base station, effectively reducing the total energy usage (Loscri et al. [2005]).
2.5.7 LEACH-M (Mobile Low Energy Adaptive Clustering Hierarchy)
In LEACH-Mobile (LEACH-M) routing protocol cluster formation and CH selection mecha-
nism is same as LEACH. It clearly copes with the drawbacks of earlier protocol i.e. support
for mobile sensor nodes further it treats data as vital information. Thus it allocates two
timeslots (TS) for all non-CH nodes and the facility of JOIN-ACK message when they are
in the vicinity of other cluster. If a non-CH node A, does not receive any data request
from CH at its allocated TS then A goes to sleeping mode(saving battery life) and waits
for next frame. Again if A does not gets data request then it sends JOIN-ACK message
to new cluster. However, LEACH-M handles node mobility by assuming that the CHs are
stationary. Hence, LEACH-M is not considered efficient in terms of energy consumptions
and data delivery rate because a large number of packets are lost if the CH keeps moving
before selecting a new CH for the next round (Deng et al. [2011]).

27. CHAPTER 3
PROJECT WORK
3.1 Introduction
Manufacturing of cheap wireless sensor nodes having sufficient computation and transmit-
ting/ receiving powers are available now. Hence hundreds of nodes can be deployed in a
network for any required application. These sensor nodes have a limited power which must
be utilized in very precise manner to increase nodes life. No doubt efficient circuit is nec-
essary for efficient use of energy, however, routing protocol running on the network plays a
vital role in bandwidth consumption, security and energy conservations as well (considering
WSNs).
To cop with these constraints, initially direct transmission approach was discussed. In direct
transmission, a node sense data from its environment and transmits it straight to base
station. This method, no doubt, ensures data security however, on the other hand we have
to compromise on nodes life time due to excessive power consumption (if BS is far away).
Hence, using direct transmission technique, nodes that are far away from BS die early as they
require more power to propagate their signal, making a portion of field vacant for sensing.
To solve this problem, minimum transmission energy (MTE) emerged. In this technique,
data is transmitted to base stations via multi hop. This gives birth to almost same problem
we faced in direct transmission. Difference is only this that in minimum transmission energy
algorithm, far away nodes remain alive longer with respect to the nodes nearer to BS. Reason
behind early expiry of nearer nodes is routing of all data traffic to base station. More over,
transmitting bulk of sensed data from each node use much energy. To overcome this problem,
concept of Directed Diffusion was introduced that discuss data processing and dissemination.
15

28. CHAPTER 3. PROJECT WORK 16
According to this mechanism, all participating nodes of network are distributed in 2-hop
cluster. Though this protocol is not much energy efficient for wireless sensor nodes however,
it gives way to hierarchical clustering algorithms (Liu et al. [2011]). Clustering for energy
conservation is proven as efficient mechanism for wireless sensor networks. When a sensor
network is deployed, nodes establish clusters and nominate one node from each cluster as a
cluster head. These cluster head nodes are responsible for receiving data from other nodes
of cluster, do data aggregation/ fusion of received data and transmit it to base station. In
this way, bandwidth consumption and lifetime of network is optimized. They prove that
regardless of transmitting fused data direct from cluster head to base station, if data is
transmitted in multiple hopes i.e. from one cluster head to another and finally to base
station, it would further enhance network life time. Considering cluster based algorithms,
today numerous protocols are developed, each having different attributes and enhancements
mainly in cluster head selection algorithms. Though one thing is common, all protocols focus
on energy conservation and data aggregation (Mahmood et al. [2013]).
In DEEC existing energy in node is election criteria of a node to become a cluster head
(Smaragdakis et al. [2004]). LEACH, TEEN, SEP, DEEC and PEGASIS are prominent
routing techniques for WSNs. Main procedure of electing a cluster head was given by LEACH
and that is further enhanced by SEP and DEEC. TEEN introduces the concept of thresholds
that gives good results in network life time by showing reactive nature. These thresholds can
be implemented in any routing protocol to enhance its performance with respect to utility or
application. Considering LEACH, the algorithm is divided into three parts, i.e. advertising
phase, Cluster Set up phase and Scheduling phase. Based on LEACH, SEP and DEEC,
numerous protocols are proposed which gives a detailed comparison analysis on different
variants of LEACH as A-LEACH, S-LEACH and M-LEACH in terms of energy efficiency
and applications.
3.2 MODLEACH: PROPOSED SCHEME
Our work is based on LEACH protocol that can be extended to improved version of LEACH.
Basically, we introduce two techniques to raise network life time and throughput. To un-
derstand our proposed scheme, we have to understand mechanism given by LEACH. This
protocol changes the cluster head at every round and once a cluster head is formed, it will
not get another chance for next 1/p rounds. For every round, cluster heads are replaced and
whole cluster formation process is undertaken. We, in this work, modify LEACH by intro-
ducing efficient cluster head replacement scheme. It is a threshold in cluster head formation
for very next round. If existing cluster has not spent much energy during its tenure and has
more energy than required threshold, it will remain cluster head for the next round as well.

29. CHAPTER 3. PROJECT WORK 17
This is how, energy wasted in routing packets for new cluster head and cluster formation can
be saved. If cluster head has less energy than required threshold, it will be replaced accord-
ing to LEACH algorithm. Besides limiting energy utilization in cluster formation, we also
introduce two different levels of power to amplify signals according to nature of transmission.
Basically there can be three modes of transmission in a cluster based network (Mahmood
et al. [2013]).
1. Intra Cluster Transmission
2. Inter Cluster Transmission
3. Cluster Head To Base Station Transmission
Intra Cluster Transmission deals with all the communication within a cluster i.e. cluster
members sense data and report sensed data to cluster head. The transmission/ reception
between two cluster heads can be termed as inter cluster transmission while a cluster head
transmitting its data straight to base station lies under the caption of cluster head to base
station transmission.
Minimum amplification energy required for inter cluster or cluster head to BS communication
and amplification energy required for intra cluster communication can not be same. In
LEACH, amplification energy is set same for all kinds of transmissions. Using low energy
level for intra cluster transmissions with respect to cluster head to BS transmission leads in
saving much amount of energy. More over, multi power levels also reduce the packet drop
ratio, collisions and/ or interference for other signals. In this context, we assume that a
cluster at maximum may spread into an area of 10 X 10 m2 in a field of 100 X 100 m2.
Energy that is enough to transmit at far ends of a field of 100 X 100 m2 must be lowered
10 times for intra-cluster transmission. When a node act as a Cluster head, routing protocol
informs it to use high power amplification and in next round, when that node becomes a
cluster member, routing protocol switches it to low level power amplification.
3.3 Modified Protocol Functioning
Therefore, the following modifications have been done in the Low Energy Adaptive Clustering
Hierarchy (LEACH) in order to improve efficiency and enhance network lifetime:
1. For every round, protocol will check if energy of Cluster Head has fallen a defined
threshold than it will undertake CH and cluster formation process. Else same CH will
continue its operations.

30. CHAPTER 3. PROJECT WORK 18
2. This is how much of energy that goes wasted in cluster head formation process can be
saved. Moreover, control overhead is also limitized.
3. In an adaptive clustering hierarchic, there can be three kinds of communications w.r.t
distances.
(a) Inter cluster communication.
(b) Intra cluster communication.
(c) Cluster head to base station/ sink communication.
4. Using equal signal amplification energy for all of above communications is also not
needed. Hence multi power levels are adjusted for all three kinds of communication to
preserve energy.
5. Basically, in MODLEACH, two modifications/ enhancements are made. These en-
hancements are (as discussed earlier):
(a) Efficient cluster head replacement technique
(b) Dual amplification power levels

31. CHAPTER 4
SIMULATION
In this chapter, firstly, MATLAB software used for deploying WSN is presented. Secondly,
simulation of Homogeneous-Leach, Heterogeneous-Leach and Modified-Leach (MODLEACH)
routing protocol for WSNs are discussed in detail.
4.1 Introduction
Today, most of the research is done to develop ultra-low powered WSN which is only possible
only if the overall network lifetime increases, energy consumption decreases and the network
run with high stability and reliability. To achieve this, many algorithms have been imple-
mented. They are called energy-efficient algorithms. These algorithms in their basic form
have already been implemented on various network protocols including LEACH, AODV,
TEEN etc. However, these algorithms need further research for increase in network lifetime,
energy efficiency etc.
4.2 MATLAB Environment
The simulation is carried out using Custom Built Iterative Based Simulator in MATLAB
8.2.0.701 (R2013b) which simulates the sending, receiving, dropping and data forwarding
etc. MATLAB is a high-level technical computing language and interactive environment for
algorithm development, data visualization, data analysis, and numeric computation. Using
19

32. CHAPTER 4. SIMULATION 20
the MATLAB product, technical computing problems can be solved faster than with tradi-
tional programming languages, such as C, C++ and Fortran. It is used in a wide range of
applications, including signal and image processing, communications, control design, test and
measurement, financial modeling and analysis. Add-on toolboxes (collections of special pur-
pose MATLAB functions, available separately) extend the MATLAB environment to solve
particular classes of problems in these application areas. MATLAB provides a number of
features for documentary work. MATLAB code can be integrated with other languages and
applications, and gives out various new algorithms and applications. It’s features include:
1. High-level language for technical computing
2. Development environment for managing code, files, and data
3. Interactive tools for iterative exploration, design, and problem solving
4. Mathematical functions for linear algebra, statistics, Fourier analysis, filtering, opti-
mization, and numerical integration
5. 2-D and 3-D graphics functions for visualizing data
6. Tools for building custom graphical user interface
4.3 Implementation
Simulations are conducted using MATLAB 8.2.0.701 (R2013b) and to get precise plots, confi-
dence interval is taken. Sensor nodes are deployed in random manner and made homogeneous
and heterogeneous WSN using MATLAB. The wireless channel is used because the nodes
deployed in the network are communicating wirelessly based on their distance, transmis-
sion range etc. Simulations show that MODLEACH performs better considering metrics of
throughput, network life time,location of base station and initial energy of sensor nodes.
4.4 Proposed work
The proposed work done in this project is mentioned below in steps:
1. Deploy WSN by initializing the parameters.
2. After deploying the network, it is worth-noting to use the appropriate topology for that
network.

33. CHAPTER 4. SIMULATION 21
3. Selecting the cluster head in the sensor network.
4. Initializing the communication by sending the data packets.
5. Implementing LEACH, a routing protocol used for finding optimal solution in both
Homogeneous and Heterogeneous WSN.
6. Implementing modified Leach (MODLEACH).
7. Evaluating the performance and observing the comparative analysis.
4.5 Network Scenario Assumptions and Parameters
The simulation assumed that there are sensor nodes are randomly and densely scattered in
a two-dimensional square field, and the sensor network has the following properties:
Figure 4.1: Simulation Scenario
1. Sensor nodes are unaware about their locations, non-rechargeable i.e energy constrained,
and always have data to send.
2. There is only one sink in the field, which is deployed randomly.
3. A node is considered to be dead when it is not capable of transmitting data to the sink.
4. It is assumed that the probability of signal collision and interference in the wireless
channel is ignorable and the radio transmitter, radio amplifier and data fusion unit are
the main energy consumers of a sensor node.

34. CHAPTER 4. SIMULATION 22
Parameters Value
Network Area(meter) 100x100
Number of Nodes 100
Location of Sink 50,50
Cluster Radius 30m
Sensing Radius 10m
Initial Energy 0.5 J
ETX 50nJ
ERX 50nJ
Eamp 0.0013pJ/bit/m4
Efs 10pJ/bit/m2
Eda 5nJ/bit/signal
Number of Rounds 6000
Routing Protocol LEACH
Table 4.1: Network Parameters
5. The consumed energy in aggregating Lk bit signals into a single k bit signal.
6. Transmission power varies depending upon the distance between node and receiver.

35. CHAPTER 5
RESULTS AND DISCUSSIONS
As already discussed, energy efficient WSN deployment is not an easy task due to large
number of parameters, i.e., energy parameters and cluster head selection then their data
transmission procedure. MATLAB programming platform is used for coding of LEACH and
MODLEACH. Finally, the comparative performance of all algorithms is explained.
5.1 Introduction
The parameters considered during simulation have their own significance for the better per-
formance of the network. The important definitions in the WSNs related to this project
are:
1. Packet delivery ratio: The ratio of number of packets sent from the source to the
number of packets received at the destination. The greater the value of PDR means
better performance of the protocol.
2. Network Lifetime: The time for the first node or a certain percentage of sensor nodes
to run out of power or it is the time interval from the start of operation (of the sensor
network) until the death of the first alive node.
3. Throughput: Average rate of successful packet delivery. The throughput is the most
important parameter to analyze the performance of the network, to get better through-
put the error should be corrected, instead of retransmitting the packet. If the error is
corrected there is no need of retransmitting the packet. If the retransmission traffic
23

36. CHAPTER 5. RESULTS AND DISCUSSIONS 24
is reduced the congestion will not occur. If there is no congestion there is no packet
loss that is error. If more number of packets in the network the performance of the
network degrades which leads to congestion, which leads to packet loss. If there is an
error correction technique which corrects the error instead of going for retransmission
it improves throughput.
5.2 Experiments and Graphs
5.2.1 Homogeneous vs Heterogeneous Network
Firstly, Homogeneous and Heterogeneous WSN were created and simulations were obtained
for Leach Protocol in both the networks. After considering the assumptions, the simulated
environment execution consists nodes describing their energy level as in the following fig-
ure ’+’ desrcibes the nodes having energy = 1, ’o’ states the energy level 0 in the network.
’x’represents the sink node in the simulated environment.Then to assess the performance of
the protocols, a set of simulation runs were carried out. Further Modified Leach (MOD-
LEACH), a variant of Leach for WSNs was simulated. It represents the improved network
lifetime of WSN. The results and analysis conclude that MODLEACH implemented on MAT-
LAB prolongs the lifetime of the network.
Figure 5.1: Homogeneous WSN vs Heterogeneous WSN
5.2.2 Number of Allive Nodes
In this subsection is shown a comparison of the number of allive nodes in Homogeneous
LEACH, Heterogeneous LEACH and MODLEACH. The evaluated results are shown below:

37. CHAPTER 5. RESULTS AND DISCUSSIONS 25
Figure 5.2: No. of allive nodes in Homogeneous LEACH
Figure 5.3: No. of allive nodes in Heterogeneous LEACH

38. CHAPTER 5. RESULTS AND DISCUSSIONS 26
Figure 5.4: No. of allive nodes in MODLEACH
5.2.3 Number of Dead Nodes
In this subsection the following figure presents a comparison of the rounds achieved by all
the simulated protocols when the all node dies.
Figure 5.5: No. of dead nodes in Homogeneous LEACH

39. CHAPTER 5. RESULTS AND DISCUSSIONS 27
Figure 5.6: No. of dead nodes in Hetrogeneous LEACH
Figure 5.7: No. of dead nodes in MODLEACH

40. CHAPTER 5. RESULTS AND DISCUSSIONS 28
5.2.4 Number of Packets Transmitted to Base Station
Besides network life time, another metric to judge efficiency of a routing protocol is its
throughput. A base station receiving more data packets confirms the efficiency of routing
protocol. Throughput depends on network life time in a sense but not always. Considering
the simulated results as shown in below figure, we deduce that, maximum throughput is
achieved by MODLEACH.
Figure 5.8: No. of Packets Transmitted to Base Station in Homogeneous LEACH
5.2.5 Number of Packets Transmitted to Cluster Head
In this subsection the following figure presents a comparison of the number of packets trans-
mitted to the cluster heads nodes through non-cluster head nodes by all the simulated proto-
cols. When non-cluster head nodes transmit data to the cluster head nodes then the trans-
mission is called intra cluster communication. MODLEACH differs from both homogeneous
leach and heterogeneous leach in the following sense:
5.2.6 Percentage of Dead Nodes
The above table shows the overall comparison between Homogeneous Leach, Heterogeneous
Leach and MODLEACH protocols in number of rounds with percentage of dead nodes and
which is graphically presented below:

41. CHAPTER 5. RESULTS AND DISCUSSIONS 29
Figure 5.9: No. of Packets Transmitted to Base Station in Heterogeneous LEACH
Figure 5.10: No. of Packets Transmitted to Base Station in MODLEACH

42. CHAPTER 5. RESULTS AND DISCUSSIONS 30
Figure 5.11: No. of Packets Transmitted to Cluster Head in Homogeneous LEACH
Figure 5.12: No. of Packets Transmitted to Cluster Head in Heterogeneous LEACH

43. CHAPTER 5. RESULTS AND DISCUSSIONS 31
Figure 5.13: No. of Packets Transmitted to Cluster Head in MODLEACH
Percentage of Dead Nodes Round
homogeneous leach heterogeneous leach Mod leach
1 745 935 1004
20 1091 1142 1132
50 1196 1262 1204
70 1269 1308 1267
90 1373 1622 1409
100 3010 4169 1556
Table 5.1: Comparision of dead nodes percentage
5.2.7 Comparison among different protocols and Different amount of Ini-
tial Energy for the sensors
The following table shows the better comparison of Homogeneous Leach, Heterogeneous
Leach and modified leach (MODLEACH). All the protocols are compared with varying num-
ber of nodes on the basis of Network lifetime, packets transmitted to base station and packets
transmitted to cluster head.
In this subsection the following table presents a comparison of the network lifetime with
different amount of initial energy of sensor nodes by all the simulated protocols. For the first
set of experiments, each node of the homogeneous leach, heterogeneous leach and Mod-leach
begins with only 0.25 J of initial energy and compare the 1st node dead and last node dead
of all protocols and then repeated same simulation for 0.5 J and then 1.0 J of initial energy.

44. CHAPTER 5. RESULTS AND DISCUSSIONS 32
Figure 5.14: Comparison, Percentage of Dead Nodes of Network with number of rounds
Parameters No. of Nodes Network Lifetime Packets to BS Packets to CHs
n=100 756 21 99
Homogeneous n=200 850 34 191
Leach n=300 771 47 289
n=400 736 58 387
n=500 794 71 471
n=100 967 21 99
Heterogeneous n=200 991 31 191
Leach n=300 1008 50 284
n=400 1010 59 377
n=500 1042 73 486
n=100 941 13103 109542
Modified n=200 1003 24980 220546
Leach n=300 1017 37555 331083
n=400 1091 49770 442539
n=500 981 62066 553076
Table 5.2: Comparision with different no. of nodes
Initial Energy (J/Node) Protocol Round
Ist node dies Last node dies
0.25 Homogeneous leach 476 800
0.5 Homogeneous leach 756 1556
1.0 Homogeneous leach 1528 3603
Table 5.3: Homogeneous Leach

45. CHAPTER 5. RESULTS AND DISCUSSIONS 33
Figure 5.15: Network Lifetime on the basis of Initial Energy in Homogeneous LEACH
Initial Energy (J/Node) Protocol Round
Ist node dies Last node dies
0.25 Heterogeneous leach 484 3628
0.5 Heterogeneous leach 935 4169
1.0 Heterogeneous leach 2018 5879
Table 5.4: Heterogeneous Leach
Figure 5.16: Network Lifetime on the basis of Initial Energy in Heterogeneous LEACH
Initial Energy (J/Node) Protocol Round
Ist node dies Last node dies
0.25 MODLEACH 448 778
0.5 MODLEACH 1004 1556
1.0 MODLEACH 2041 3201
Table 5.5: MODLEACH

46. CHAPTER 5. RESULTS AND DISCUSSIONS 34
Figure 5.17: Network Lifetime on the basis of Initial Energy in MODLEACH
5.3 Conclusions
In this project work, we give a brief discussion on emergence of cluster based routing in
wireless sensor networks. We also propose MODLEACH, a new variant of LEACH that can
further be utilized in other clustering routing protocols for better efficiency. MODLEACH
tends to minimize network energy consumption by efficient cluster head replacement after
very first round and dual transmitting power levels for intra cluster and cluster head to
base station communication. In MODLEACH, a cluster head will only be replaced when its
energy falls below certain threshold minimizing routing load of protocol. Hence, cluster head
replacement procedure involves residual energy of cluster head at the start of each round.
5.4 Future Work
1. Implementation of MODLEACH protocol on Heterogeneous wireless sensor networks.
2. Next improvement can be possible by considering sink mobility and to ensure successful
delivery of data.
3. Design of a better routing protocol in case when CH dies before sending the data to
the BS.
4. The future work can include some more level of hierarchy and mobility in the network.

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