Dissertation or Thesis on Efficient Clustering Scheme in Cognitive Radio Wireless Sensor Network

Efﬁcient Clustering Scheme in Cognitive Radio Wireless
Sensor Network
A dissertation submitted in partial fulﬁllment of the requirements
for the degree of
Master of Technology
submitted by
Mohammad Aziz
Roll No. 14MI544
Under the guidance of
Nitin Gupta
Department of Computer Science & Engineering
National Institute of Technology Hamirpur
Hamirpur, India-177005
(May, 2019)

Department of Computer Science & Engineering
National Institute of Technology Hamirpur
Himachal Pradesh, India-177005
Candidate’s Declaration
I hereby state that the work that is accessible in this dissertation, entitled as “Efﬁcient Clus-
tering Scheme in Cognitive Radio Wireless Sensor Network” in partial necessities of the
requirements for the honor of the Degree of Master of Technology and submitted in CSE
Department of NIT Hamirpur is my own legitimate record work carried out during a period
from July 2018 to May 2019 under the supervision of Nitin Gupta, Assistant Professor, CSE
Department, NIT Hamirpur.
The issue presented in this dissertation has not been submitted by me for the award of any
other degree of this or any other Institute/University.
Mohammad Aziz
This is to certify that the above statement made by the candidate is true to the best of our
knowledge and belief.
Nitin Gupta
Date: Assistant Professor
The M.Tech.Viva-Voce examination of Mohammad Aziz, M.Tech. student has been Suc-
cessfully held on ........
Signature of Supervisor Signature of External Examiner
i

ACKNOWLEDGMENTS
I like to thanks Lord for being with me, able to complete the dissertation with success. I
also like to thanks my mentor and guide, Nitin Gupta for remarkable help in this dissertation
process.
The person with the greatest indirect contribution to this work is my mother, Rabiya Kha-
toon, who has taught me love and care about study. I want to thank her, my father, as well as
my brothers , for their constant encouragement.
Then I would like to thank my best friends Jawairiya Afreen, Milindra Pratap Singh, Rahul
Kumar and Pranav Solanki with their valuable suggestions and guidance has been helpful in
various phases of the completition of the dissertation.
(Mohammad Aziz)
ii

ABSTRACT
Cognitive Radio (CR) is a promising answers for spectrum shortage issue. An intellec-
tual radio system is made out of both the primary radios whose radios need not be CR-enable
whereas secondary users with CR-enable radios need not to be licensed. Clustering is a pro-
ductive method to diminish energy consumption. Existing clustering algorithms for wireless
sensor networks (WSN) are not appropriate in cognitive radio network and existing answers
for cognitive radio systems are not reasonable for sensor networks. In this dissertation, an ef-
fective and efficient clustering algorithm for CR based WSN is proposed. Further, Sleep wake
strategies has been used to make strong lifetime of an CRN. Further, K-means clustering and
Affinity Propogation method is combined to choose cluster head.
Simulation results show that the proposed scheme is effective and efficient for generating
lesser number of clusters, in case number of nodes are increased which decreases the overhead
as well as energy consumption required to form clusters.
Keyword Used : Cognitive Radio Network, Clustering, Spectrum sensing data, Primary
user, Secondary user, Primary base station, License band, Channel access, Energy utilization,
Channel allocation.
iii

Table of Contents
Certiﬁcate i
Acknowledgments ii
Abstract iii
List of Figures vi
1 Introduction 1
1.1 Cognitive Radio Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Cognitive cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Cognitive Radio Network Architecture . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Applications of CRN’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 Merits of CRN’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.6 Demerits of CRN’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.7 CRN’s issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.8 Clustering in CRN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.8.1 Types of clustering . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.9 Introduction to K-mean clustering . . . . . . . . . . . . . . . . . . . . . . . . 14
1.9.1 Working of K-mean clustering . . . . . . . . . . . . . . . . . . . . . . 15
1.10 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.11 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.12 Dissertation Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2 Literature review 18
2.1 Efﬁcient clustering Algorithms in CRN’s . . . . . . . . . . . . . . . . . . . . . 18
3 Proposed Work 23
iv

3.1 Preliminaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.1.1 Selection of cluster head . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.1.2 Finding Euclidean distance . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2 Sleep-wake mode strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2.1 Applying Battery state based sleep-wake strategy . . . . . . . . . . . . 27
3.3 Proposed Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.3.1 Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4 Simulation and Results 33
5 Conclusions and Future Work 37
5.1 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
References 38
v

List of Figures
1.1 Process of Cognitive radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Spectrum Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Cognitive cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Architecture of CRN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 Clustering interconnected by gateway nodes . . . . . . . . . . . . . . . . . . . 13
1.6 Inter-cluster connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.7 Distance from 1st node to red cluster . . . . . . . . . . . . . . . . . . . . . . . 15
1.8 An expected cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.9 graph of variation Vs number of cluster . . . . . . . . . . . . . . . . . . . . . 16
3.1 Baddour’s AP approach steps at node u. . . . . . . . . . . . . . . . . . . . . . 26
3.2 Flow diagram of proposed algorithm . . . . . . . . . . . . . . . . . . . . . . . 30
4.1 Number of cluster against number of node . . . . . . . . . . . . . . . . . . . . 33
4.2 Simulation graph of Energy of whole network vs time . . . . . . . . . . . . . . 34
4.3 Energy of a node(First node is working and then sleeping) . . . . . . . . . . . . 35
4.4 Energy of a node(First node is sleeping and then working) . . . . . . . . . . . . 36
vi

Chapter 1
Introduction
Cognitive radio (CR) is a new technique, encountering quick development of wireless sys-
tem because of its capability to tackle considerable issues influencing present-day wireless or
remote systems. The radio range, which is normally restricted, required for the remote commu-
nication systems. Range controllers generally adopt the fixed access approach (FSA) and it is
used to help various administrations and remote applications in non-interfering premises. The
allotted (authorized) users reserve to exploit the designated spectrum and not allow it to use by
the different users, regardless of whether the authorized clients are using it. With the expansion
of wireless services over the few decades, in a few countries, the large part of the accessible
spectrum has completely been allocated, which leads to the shortage issue in the spectrum. To
keep up the attainable improvement of the remote or wireless communication industry, a novel
arrangement should be made to redesign the utilization capability of the radio spectrum.
1.1 Cognitive Radio Network
It can automatically find out the unoccupied channels in the wireless spectrum. The channels
which are not in use in the wireless spectrum are known as white space or white hole. The
CRN is intelligent and dynamically adapts the transmission parameter through the environment
accordingly. It is having the ability to detect whether channels are unused or not and it moves
into vacant channel leaving the used one without interfering other users. It is also having the
capability to do the unutilized spectrum unlicensed and licensed spectrum band. Two kinds of
users that may use spectrum in the CRN namely, Primary user(PU) and secondary user(SU).
PU user have licensed to use the spectrum. A SU is a user who can use spectrum only when the
PU is not using it. When the PU appears again then the SU has to leave that channel. Cognitive
radio allows SUs to use the spectrum without harmful interference with PUs. Figure 1.1 shows
1

Figure 1.1: Process of Cognitive radio
the process of cognitive radio.
A specific sets of functions to be implemented by cognitive radio include geographic lo-
cation with respect to the other radiating transmitter, recognize and authorize its user. It has
to sense all the wireless devices which is in the neighbourhood and adjust both the power and
modulation characteristics.
Allocated range or spectrum portions are not utilized all the time by their holders, which
makes range gaps . A spectrum gap, likewise called void area or white space, is a frequency
band doled out to a PU, however it isn’t being utilized at a specific time and at a specific
location as given in the Fig 1.2 [1]. In this manner, the radio spectrum is wastefully exploited.
Along these lines, the shortage and exploitation of the spectrum management require a dire
intercession to upgrade the radio spectrum get to and accomplish high network execution.
2

Figure 1.2: Spectrum Holes
1.2 Cognitive cycle
As outlined in Figure 1.3 [2], a cognitive radio system plays out a 3-process cycle: sensing,
deciding, and acting. The first process is critical since it is where the estimations are taken
and the spectrum detection is performed. Due to multipath blurring, shadowing, or changing
channel conditions, vulnerability influences this first process. In the perception procedure,
estimations taken by the SUs are also dubious. In the next process, secondary users makes
a decision dependent on what has already been observed using their knowledge basis, which
may have been affected by the vulnerability in the detected estimations, prompting the wrong
decisions. In the last process, vulnerability spreads over the cognitive radio cycle, and some of
the time the wrong actions are made. Along these lines, vulnerability proliferation impacts all
the radio spectrum processes, which degrades the intellectual radio presentation.Consequently,
it is important to address these vulnerability issues in the cognitive radio cycle by detecting the
spectrum accurately, making the right choice, and making the correct action.
3

Figure 1.3: Cognitive cycle
1.3 Cognitive Radio Network Architecture
The present wireless network environment appoints the quality of being diverse of both com-
munication technologies and spectrum policy. Therefore, it clearly states that the CR network
architecture can be critical for the evolving communication procedures.
In the figure 1.5 [3] there are sections on the architecture of the CRN, it can be split into two
sections, the first section can be cognitive system and the second section is primary system. The
cognitive network is not having any right or license to use the desired spectrum band. However,
the main system is also stated as primary system, it is accurate and licensed towards using the
desired spectrum band.
In this work, in the geographical areas it has been expected that the main operators have
being coexisting with the other users. There are independent bodies to control and monitor
PUs and SUs. PUs are being contolled by PUBS which is a fixed base station for primary units.
Similarly SUs too has a contolling body known as SUBS i.e the base station for secondary
units.
The fundamental elements of the unlicensed network and primary networks are stated be-
low:
a) Main user: In the firm desired spectrum bands before the main users use it, it must be
licensed. Having to accesses could be constrained depending on the base-station and
must not be influenced on other individuals activities especially those users who are not
4

Figure 1.4: Architecture of CRN
approved.
b) Primary Base-Station: The main base station has a secure framework, it has organized
sections and those sections have spectrum licensed. The main base station has not got
any cognitive radio or the ability of spectrum division to those who use cognitive radio.
It might be important for the main base station to have two radios, the two radios are
inheritance and cognitive radio. Convention for the main system, so that the individuals
who are using the cognitive radio can have accesses.
c) Cognitive Radio Users: This is when the users cannot use the spectrum licensed be-
cause they have no right to use it. Therefore, the spectrum can be opened if it is used in a
resourceful way. The cognitive radio users capacities include the spectrum choice, spec-
5

trums identifying, cognitive radio MAC/ finding the direction, transportation/ settlement
and spectrum handoff. The cognitive radio user must have the abilities to connect with
the base station and the cognitive radio users.
d) Cognitive Radio Base Station: Cognitive radio base station is firmly based around sec-
tions with cognitive radio capabilities. Cognitive radio base station provides single hop
association with cognitive radio users that done have spectrum license. It is shown in fig-
ure 3 that cognitive radio users can do two things, the first thing they can do is to connect
or contact with each other in many different ways. The second thing they can do is get
accesses to the base station.
e) CRN Access: Cognitive radio users can have their own cognitive radio-station official
and unlicensed spectrum bands. In the CRN all the assistance happens inside, their aver-
age accesses is combined with autonomous of the primary network.
f) Cognitive Radio Ad Hoc Access: Cognitive radio clients can connect with one another
through ad hoc connections by being authorized and unlicensed spectrum bands. Simi-
larly, cognitive radio clients could get their personal average accesses innovation.
g) Primary Network Access: If the primary base system is permitted the cognitive radio
client can get to the primary base station through the authorized band. There could be
like different accesses categories, cognitive radio clients must be able to strengthen the
average accesses innovation of the primary system. Furthermore, primary base station
must strengthen the cognitive radio capacities.
1.4 Applications of CRN’s
CRN’s application is having large range of application domain. CRN node can be implemented
any where in place of wireless sensor network. There are some example where CRN’s node
implemented like surveillance machine, intelligent roads, medical, security, object tracking,
actuation, facility management, telemetries,preventive maintenance, and monitor of indoor and
outdoor environment. The following are given some important areas where CRN’s node can be
implemented with example.
6

a) Health Care: In health care system, for example, telemedicine, wearable body sensors
are being utilized progressively.Various remote sensor nodes are put on patients and get
basic information for remote observing by social insurance providers. Remote BAN-
helped human services frameworks have just been practically speaking in some remote
regions of creating nations, for example, in Nepal and India. Remote BAN for medicinal
services frameworks is appropriate for regions, where the quantity of well being pros
is generally low. Medicinal information is basic, deferral and mistake delicate. In this
way, the constraint of customary WSN, as examined in the past area limits the possibility
of telemedicine. The QoS may not be accomplished at an attractive dimension if the
working range band is packed in helpful ’telemedicine with BAN’. The utilization of
’CR wearable body remote sensors can relieve these issues because of data transmission,
sticking and worldwide operability, henceforth improve unwavering quality. A lot of
research has been done in the territory of WBASN. The necessities of psychological
radio execution in remote therapeutic systems are examined in reference.
b) Public Security and Military Application: Conventional WSNs are utilized in numer-
ous military and open security applications, for example, (a) concoction natural radiolog-
ical and atomic assault location and examination; (b) direction control; (c) assemble the
data of fight harm assessment; (d) war zone reconnaissance; (e) knowledge right hand (f)
focusing on, and so on. In the combat zone or in questioned areas, a foe may send stick-
ing sign to disturb radio correspondence channels. In such circumstances, since CR-WSs
can handoff frequencies over a wide range, CR-WSNs can utilize distinctive recurrence
groups, in this way maintaining a strategic distance from the recurrence band with a
sticking sign. Likewise, some military applications require an enormous transfer speed,
least channel access and correspondence delays . For such applications, CR-WSNs can
be a superior choice.
c) Real-Time Surveillance Applications: Real-time surveillance applications, for exam-
ple, traffic observing, biodiversity mapping, living space checking, natural observing,
ecological conditions checking that influence yields and animals, water system, sub-
merged WSNs, vehicle following, stock following, fiasco help activities, scaffolds or
passage observing, require least channel access and correspondence delay. Some ongo-
7

ing reconnaissance applications are exceptionally delay-touchy and require high unwa-
vering quality. A deferral because of a connection disappointment can likewise happen in
multihop WSNs if the channel condition isn’t great. Then again, WS nodes bounce to an-
other channel in the event that it locate another inactive channel with a superior condition
in CR-WSNs. Channel collection and the utilization of numerous diverts simultaneously
are conceivable in CR-WSNs to expand the channel transfer speed.
d) Diverse Purpose Sensing: Progressively, the utilization of wireless sensors in a simi-
lar region for various targets exists together. In a regular WSN, those wireless sensors
endeavor to get to the divert in non-helpful habits. With the assistance of a productive
medium access control (MAC) convention, CR-WSN may choose various channels for
various applications considering load adjusting and reasonableness.
e) Vehicular Networks and Transportation: The IEEE 1609.4 standard proposes multi-
direct activities in remote access for vehicular environment (WAVE). The WAVE frame-
work works on the 75 MHz range in the 5.9 GHz band with one control channel and
six administration channels. Every single vehicular client should fight for channel ac-
cess and use it to transmit the data in the 5.9 GHz band. Be that as it may, regardless it
experiences range deficiency issues. This range shortage issue and the prerequisites of
subjective radio in WAVE have been examined. Some primer works in CR-empowered
vehicular correspondences have just been done. Vehicular remote sensor systems are
developing as another system worldview for proactively assembling observing data in
urban conditions. CR-WSNs are probably going to be increasingly pertinent in this field.
Despite the fact that this territory still should be analyzed, a few conventions for parkway
security utilizing CR-WSNs have been proposed.
f) Indoor Application and Home Appliances: Numerous potential and developing indoor
applications require a thick WSNs condition to accomplish a sufficient QoS. Regular
WSNs experience critical difficulties in accomplishing solid correspondence since ISM
groups in indoor regions are amazingly packed. A few instances of the indoor uses of
WSNs are keen structures, home observing frameworks, production line computeriza-
tion, individual stimulation, and so on. CR-WSNs can alleviate the difficulties looked by
traditional indoor WSNs applications.
8

g) Intensive-Bandwidth Applications: Interactive media applications, for example, on-
request or live video spilling, sound, and still pictures over asset compelled WSNs, are
incredibly testing a result of their gigantic data transfer capacity necessities. Other WSN
applications, for example, WSNs in an emergency clinic condition, vehicular WSNs,
following, reconnaissance, and so on., have tremendous spatial and fleeting varieties in
information thickness related with the hub thickness. These applications are data trans-
mission hungry, defer unfortunate and bursty in nature. Since in CR-WSN, SUs can get
to different channels at whatever point accessible and vital, CR WSN is truly reasonable
for these sorts of data transfer capacity hungry applications. Rehmani et al. revealed
divert holding in CR-WSNs for such transmission capacity concentrated applications.
1.5 Merits of CRN’s
CRN’s merits or advantages is having large range of domain. Contingent upon the application,
a WSN made out of sensor nodes furnished with cognitive radio [4] may profit by its potential
favorable circumstances:
a) Opportunistic channel usage for bursty traffic: countless sensor hubs recognizing
an event produce bursty traffic and endeavor to gain the channel to send their readings.
This expands the likelihood of collisions and bundle loses, which diminishes the general
communications unwavering quality with excessive power utilization. Crafty access to
numerous multiple channels may reduce these potential difficulties.
b) Adaptability for reducing power consumption: The dynamic nature of the remote
channel causes vitality utilization because of packet loses and retransmissions. cognitive
radio able sensor hubs might most likely adjust to changing channel conditions, which
would build transmission productivity, and thus help diminish control utilized for trans-
mission and reception.
c) Dynamic spectrum access: The current WSN deployments expect a fixed spectrum
portion over very jam-packed unlicensed bands additionally utilized by different gadgets.
Additionally, a spectrum lease for an authorized band intensifies the general arrangement
9

cost. Henceforth, to have the option to participate productively with different kinds of
users, opportunistic spectrum access might be used in WSNs.
d) Energy detection or identification: Implementation effortlessness and computational
complexities low: a vitality sensor can be actualized like a spectrum analyzer by aver-
aging frequency containers of an FFT. Since it is not hard to implement, the ongoing
work on the detection of the essential users has commonly received the energy detector.
vitality detection is the optimum identification if the essential user signal is not known.
e) Feature detection: The principle merits of the component identification is that it can
segregate the commotion energy from the adjusted signal vitality. Moreover, cyclosta-
tionary include identification can identify the signals with low SNR .
f) Cooperative detection: Lower detection affectability prerequisites. Channel hindrances,
for example, shadowing, multipath blurring, building infiltration and multipath blurring
loses high affectability necessities on cognitive radios. The affectability prerequisite can
be definitely diminished by cooperation detection. Improve the deftness of the detection.
One of the greatest difficulties in cognitive radio is the decrease of overall detection time.
Helpful detection can diminish recognition time contrasted with clumsy detection, so it
can improve the dexterity of the identification.
g) Interference-based detection: Interference-based recognition can keep away from the
concealed terminal issue.
1.6 Demerits of CRN’s
The demerits of cogntive radio network is shown in the following:
a) Interference-based detection: Firstly, It’s difficult to gauge interference temperature.
Secondly,during the inerferced based identification, cognitive radio clients can’t recog-
nize real signal from the primary users and clamor or impedance.
b) Cooperation detection: Firstly, cooperation builds the overhead of the cognitive radio
system. Furthermore, cognitive radio clients are generally minimal cost and low power
10

gadgets that probably won’t have devoted equipment for cooperation. Therefore informa-
tion and cooperation data must be multiplexed that can cause degradation of throughput
for the cognitive client. In conclusion, helpful identification needs control stations.
c) Feature detection: Feature identification requires long perception time and higher com-
putationally complex. Likewise, feature detection needs the earlier learning of the pri-
mary clients.
d) Energy detection: The presentation of the energy detector is exceedingly helpless to
commotion level vulnerability. The commotion vulnerability causes issues particularly
on account of a straightforward energy detector since it is hard to set the thresholds ap-
propriately without the information of the precise commotion level. Besides, an energy
detector can’t separate between tweaked signals, clamor, and obstruction. The presenta-
tion of an energy detector in shadowing and blurring environments degrades clearly. In
addition, it is difficult to choose the correct threshold for energy recognition.
e) Matched filter detection: It requires an earlier knowledge of each primary client, if this
data isn’t precise, the matched filter performs inadequately.
1.7 CRN’s issues
The primary reason for the CR is to acknowledge dynamic access to the ideal spectrum so
as to have correspondence. While implementation of cognitive radio as a challenging job. A
commonplace cognitive radio situation comprises of SUs that coincide with the PUs. PU has a
need to utilize the spectrum as it has legacy rights for the spectrum get to. SU opportunistically
get to the spectrum when it found that PU isn’t utilizing the spectrum or underlay access to the
range, when both PU and SU coincide, with severe requirement over non-obstruction among
the users. The primary issues of CR are as under.
a) Security Issues: The CRN has some security issues such as Not acceptable interference
to authorized users, Banning the utilization of idle channels for secondary users, Restrict-
ing the utilization of common control channel by for all intents and purposes making a
bottleneck issue, Access to private information, Alteration of data, Injection of wrong
data.
11

b) Sensing Techniques: The interference of secondary users to primary users relies upon
the detecting accuracy of secondary users. If secondary users can detect the channels
with high precision, interference with the primary user’s decreases. Contingent upon the
detecting system, there is a tradeoff between the detecting delay and detecting accuracy.
The system that takes a long detecting time has more accuracy with the expense of delay
and vice versa.
c) Cooperative Sensing: CR remote sensors may experience inaccurate decisions since
radio-wave propagation through the remote channels has an antagonistic factors, for ex-
ample, shadowing, multipath fading, and building penetration. CR remote sensors are
hardware imperatives and can’t detect different channels at the same time. In this manner,
CR remote sensors participate and share their detecting data with each other to improve
the detecting accuracy and performance.
1.8 Clustering in CRN
Clustering is nothing but creating the different groups, that groups contain the similar elements.
Elements in that same group are similar as much as possible. Elements in the different groups
are completely different from the other groups element. Clustering is often referred as unsuper-
vised learning techniques. Example: A group of dinners sitting in a restaurant, suppose there
are two tables in a restaurant t1 and 12. The group of the table sitting on a table t1 might be
related to each other, it may be a group of family members, may be groups of colleagues, etc.
Even the people sitting on t2 connected with each other but only when the people sitting on
table t2. If it compares the people sitting on table t1 with people sitting on table t2 entirely
different. All are not at all related to each other. One more example, when visited a big bazaar,
wallmart or retail store, it is found that similar items are grouped together. It is not like the
items are just placed anywhere or mixed with each other. So it creates a group or cluster of
items to show that it can easily shop and ﬁnds the things. The same varieties of apples are
placed in one place while other varieties of apples are placed other like red and green apples
are placed in different placed. Clustering is used Flickr maps photos uses the cluster to reduce
the number of marks on the map. Amazon uses popular the recommended system which is
using the clustering to show the recommended list of products according to its past purchases
12

history. Netﬂix recommends movies based on watch history. Whatever have watched it will
recommend the similar movies. So generally it can say that Clustering cab used to segment the
customer, market in the marketing. Clustering is also used by social network sites in marketing
new groups based on users data. Clustering can help the business to manage the data better.
Generally, it uses the cluster for image segmentation, grouping webpages, market segmen-
tation, and information retrieval. Cluster are interconnected into an enormous network. A
gateway node is an individual from one cluster that can achieve the individual from other clus-
ters. The interconnection clustering is shown in Fig. 1.6 [5], it can be seen that the clusters
are interconnected in two ways: the two cluster heads is associated with one node gateway or
associated by two nodes gateway if there node is not available is the 1-hop node of two clus-
ter heads. There are different kinds of user cluster: the cluster head, node gateway and node
ordinary as shown in Fig 1.6.
Figure 1.5: Clustering interconnected by gateway nodes
1.8.1 Types of clustering
There are mainly three types of clustering:
a) Exclusive clustering: Exclusive clustering is a hard clustering where the data related to
exclusively one cluster. K-mean clustering is an example of exclusive clustering. If there
are two circles, one is having blue data points and other circle having pink data points.
13

Figure 1.6: Inter-cluster connection
Both these clusters are entirely different from each other. It is not at all related to each
other.
b) Overlapping clustering: Overlapping clustering is a soft cluster where data points be-
long to multiple clusters. An example is fuzzy or c-mean clustering. Some of the blue
data points overlap with the blue data points.
c) Hierarchical clustering: hierarchical clustering depends utilizing these clustering pro-
cedures to ﬁnd a hierarchy of clusters, where this chain of importance takes after a tree
structure, called a dendrogram.
1.9 Introduction to K-mean clustering
K-mean clustering is an algorithm of unsupervised machine learning which is utilized to gen-
erate a normal cluster in unlabelled information. Its main goal is to groups in the data. The
number of groups or clusters is represented by k. The algorithm then runs iteratively to assign
each data points to one of the k groups based on the features that already provided. It is an
iterative calculation that comprises of a cluster task and a centroid development step. If k is the
number of clusters generated and training data(unlabelled data) then the k-Means algorithm can
be characterized to produce k number of the cluster from the information. K-means algorithm
14

can be applied to a numeric or continuous data with a smaller number of dimensions. It can
be applied to any scenario where it has to groups several things from a randomly distributed
collection of things. For eg, document classification where it can create the document and mul-
tiple categories based on tags, topics and contains the documents. K-means algorithm is one of
the highly suitable algorithms for this purpose.
1.9.1 Working of K-mean clustering
Assume that the working of the algorithm for, k=3, here k in k-means is nothing but the total
number of clusters required. So here the total number of cluster is three. It randomly select
the three data points, these three data points are nothing but assuming that centroid of each
cluster. Now measure the distance between the first point and the three clusters so that shows
the distance from point 1 to the red cluster as can see in the below figure 1.8. Next, it shows the
Figure 1.7: Distance from 1st node to red cluster
distance from the first point to the blue cluster and the third figure shows the distance from the
first point to the green cluster. Now assign the first point and add the first point to the nearest
cluster since in this case, the nearest one is red. So the first point will be added to the red
cluster. The next is to calculate the mean for the red cluster including the new point which is
recently added to the cluster. The mean value lies somewhere between the two points within
the red cluster as shown in the figure. Now figure out the second point or which cluster does the
second point belongs to. Use the same procedure have done before but measure the distance
to the red mean. Here different distance from the second point to different red, blue and green
clusters. Once this have done with the measuring assign the second point to the nearest cluster
which is again the red cluster. Next, calculate the mean within the red cluster. It will repeat the
same procedure for other remaining points. This procedure will repeat until it get an original
result as shown in the figure 1.9. Here k is very important. Each time it increase the cluster the
variation decreases. The number of clusters is equal to the number of data points then, in that
15

Figure 1.8: An expected cluster
case, the variation is zero. As the number of clusters increases, the total variation decreases
shown graph in the below figure 1.10 [6].
Figure 1.9: graph of variation Vs number of cluster
The above-given graph shows where on the x-axis is the number of clusters and reduction
in a variation on the y-axis. On the graph, it can be seen that the huge reduction in variance
with k = 3. But after that, there is no such change in variation. This point of change is called
the elbow point and the value of this point is the one which decides the value of k. So in order
to find out the value of k, it needs to find out the elbow from the elbow plot.
1.10 Motivation
Cognitive radios offer the guarantee of being a innovation technology that will empower the
future wireless world. Cognitive radios are completely programmable remote gadgets that can
detect their environment and dynamically adjust their transmission waveform, spectrum use,
channel access method, and networking protocol as required for a good system and application
execution. One of the main issue is that on how to do efficient Clustering in a CRN such that
16

consumption of power is also minimized. In this dissertation work, the main motivation of this
work is to design efficient and less power consumption clustering scheme in a CRNs.
1.11 Problem Statement
Inefficient clustering in CRN may lead to high power consumption and reduction of the lifetime
of nodes in the cognitive radio network. The objective of the proposed work is to design a
clustering algorithm such that a lesser number of the cluster are created while the number of
nodes are increased.
1.12 Dissertation Layout
The dissertation carries five chapters. The following details of each chapter are given in brief:
Chapter 2 : Literature review: The literature review on this work done by various research
studies in energy efficient clustering and sleep-wake strategies in cognitive radio network is
presented in this chapter.
Chapter 3 : Proposed work: In this proposed work, the proposed algorithm of clustering
in CRN using sleep-wakeup strategy has done. It uses AP method, K-mean and sleep and
wakeup strategy for making efficient clustering in CRN in which sleeping node is removed
from CR network, select centroid from active node and then construct efficient cluster.
Chapter 4 : Simulation and results: In this section, simulation and desired result are done.
It contains simulation of proposed algorithm based on clustering in cognitive radio network
using sleep wake strategy on each node to make cluster efficient.
Chapter 5 : Conclusion and future work: In this last chapter, conclusion of all the re-
search work and further research scope are discussed.
17

Chapter 2
Literature review
This section addresses the issues and research done till date in the field of clustering in
the Cognitive radio system. The work by various analysts or scientists is briefly reviewed and
discussed. In the previous years various strategies have been developed and presented in order
to carry out clustering in cognitive radio network. Large part of this section covers the research
done in field of clustering cognitive radio network.
Cognitive radio network being of wireless and intelligent in nature that adapt transmit-
ter parameter through its environment automatically can make cluster using its radio nodes.
Following examined are the researches which are utilized as the referenced inquires for this
dissertation work.
2.1 Efficient clustering Algorithms in CRN’s
In [7]. presented a cluster-based MAC convention known for KoN-MAC for Cognitive radio
WSNs. this approach relies on a clustering plan for Wireless sensor network by Lin and Gerla
[8]. Pritom et al. [9] gave a MAC protocol for cluster-based CR-WSNs, yet its MAC conspire
depends on the Low-Energy Adaptive clustering hierarchy convention, that is uniquely intended
for WSNs.
An epic clustering based detecting (CBSD) in cognitive radio WSNs was brought by Qu et
al. [12]. In the strategy, sensor hubs are clustered into various sets dependent on their likeness
in detecting outcomes. A target work is presented to recognize the ideal cluster number. Sub-
tleties for creation of clusters and CH choice were not provided, and the performance was not
contrasted and extent calculations or approaches.
Rauniyar and Shin [13] presented a clustering plan for collective range detecting relies on
other algorithms [14] [15]. In the plan, a couple of nodes in a cluster can switch back and forth
18

between wake and sleep modes amid the detecting procedure.
An spectrum aware cluster based vitality efficient multimedia directing convention was
presented by Shah et al. [7]. In this convention, SU hubs form a group with a excessive number
of commonly accessible inert channels. The Cluster heads are chosen dependent on energy and
relative spectrum awareness, with the end goal that non contiguous accessible spectrum bands
are bunched and scheduled to give continuous transmission opportunity.
Salim et al. [16] presented clustering with brief support hubs. This plan has a xed cluster
development span. It accept that CMs alter conveyance control dependent on distance to the
CH.
Mustapa et al. [17] presented a vitality efficient spectrum aware fortification learning based
clustering calculation for cognitive radio WSNs. In this approach, a part hub learns the energy
detecting value for adjacent clusters so as to accomplish an ideal solution.
Maknoor and Sahid [18] presented a clustering plan called BECHR for cognitive radio
WSNs. This plan choose a CH dependent on remaining vitality in an repetitive way. It works
like traditional WSN clustering approach however with certain varieties.
Eletreeby et al. presented a spectrum aware clustering convention for cognitive radio WSNs
called CogLEACH [8]. It is an expansion of the LEACH convention and utilizes the number
of empty channels as a weight in the probability for every hub to turn into a CH. This work
assesses CogLEACH in three distinctive models. It expands the throughput and lifetime of the
system, contrasted with the normal LEACH convention that operates in similar settings.
Zhang et al. [19] and Han et al. [20] presented a distributed spectrum aware clustering
for cognitive radio WSNs dependent on group wise obliged agglomerated grouping [21]. The
primary idea is to set every hub as a dissever cluster toward the start and to combine the two
closest clusters throughout every cycle until the group number is decreased to the ideal number.
Amid each repetition, the inter-cluster separations are recomputation. At first, DSAC thinks
about every hub as a CH, and then merges CHs inside every cycle until the number of CHs
achieves the ideal number.
Ozger and Akan [22] and Ozger et al. [15] presented event driven spectrum aware clustering
conventions which creates temporary clusters for every occasion in cognitive radio WSNs.
These conventions decide qualified hubs for clustering on the basis of the nearby location of
hubs between the occasion and the sink. CHs are chosen from among the candidate center
19

points subject to hub degree, channel openness, and detachment to the sink. Since this is event
driven bunching, the groups are immediately ousted consequent to nishing data transmission.
Thus, it isnt suitable for various circumstances.
Shahh and Aken [23] presented a spectrum aware cluster based directing (SCD) convention
for cognitive radio WSNs. Nodes are grouped depending on their relative range mindfulness
and remaining vitality. The protocol chooses CHs dependent on vitality and relative spectrum
awareness, with the end goal that non-coterminous available spectrum bands are bunched and
scheduled to give nonstop transmission oppurtunities.
Pei et al. [24] presented adaptive clustering for cognitive radio WSNs called low-vitality
versatile uneven clustering chain of command (LEAUCH) for cognitive radio sensor systems.
LEAUCH chooses applicant CH nodes dependent on the number of inert channels and chooses
a CH dependent on separation from the sink. Top void the energy hole among CHs, it utilizes
an uneven-sized clustering strategy.
Park et al. [25] presented a cognitive radio-based information type bunching (CR-HDC)
algorithm for cognitive radio. It utilizes blocking and constrained end probabilities for CH
transmission range and channel inhabitance.
20

Table 2.1: Comparison of already existing clustering plans for cognitive radio WSNs.
approches
of clus-
tering
Aims Metrics
Execution
Improvement
CHySelection
Unique
Node
KoN-
MAK
MAC pro-
tocol
Close to
WSNs
Added chan-
nel load
Elected
Gateway
node
CTSS
Energy
effective
Coop-
erative
duty
Similarity
between
remote
hubs
Energy utiliza-
tion
No CH, but
choses a node
forispectrum
sensing
NA
ECS
Cooperative
spectrum
sensing
Spectrum-
aware
node-
grouping
Energy con-
sumption
(compared
with DEEC
algorithm for
WSNs
Predecided
chance Only
nodes in-
nawake mode
busy in the
cluster-head
chosen way
NA
SKEEM
Cross-layer
routingo-
protocol
maximum
spec-
trum
rank
clusters of op-
timal number
Depend on
maximum
spectrum
energyorank
NA
CENTRE
Effective
energy
Distance
todthe
CH
Grouping
over-
head(compared
withDSAC)
Self declared
Temporary
support
(TS)cnode
EASA-
RLC
Energy efﬁ-
cient PUn-
detection
Optimal
amount
ofvclus-
ters
Cooperative
chance of
detection
Amount of
empty chan-
nels (similar
to HEED)
NA
BECHR
Ranging
detection
NA
Energy con-
sumption
(compared
with LEACH)
Looping
(depend on
energy level)
No, but
every
hubs
have
GPS
Cog-
LEAC-
calcu-
lation
in three
different
close
replica
Amount
of empty
channels
Extension
of
LEACH
Amount of
empty chan-
nels as a
weight in the
chance of
every hubs
becoming an
CH
NA
21

Clustering
Plans
Aims Metrics
Execution
Improvement
CHSelection
Unique
Node
EEC
Efficient
energy
Ideal
amount
of
clusters
NA
Remaining
energy and
amount of
neighbour
hubs
NA
ESEC/
mESEC
Event-
driven
grouping
Ranging
avail-
abilities
Energy con-
sumption
(with a late
cost)
degree of a
node, accessi-
ble channels,
distance to the
destination
NA
LEAUCH
Efficient
energy
Number
of chan-
nels
avail-
able
Uneven-
sized
cluster-
ing
Energy con-
sumption
System load
balance
Amount of op-
timal channels
Distance from
the destination
NA
Virtual
grouping
Control
channel es-
tablishment
MACproce
-dure
Similarit
-ies of
spec-
trum
oppor-
tunities
Geo-
graphic
location
Collision miti-
gationControl
packet delay
rate success
NA NA
SCR Routing
Spectrum
mea-
sure-
ments
remain-
ing
energy
Delay Energy
utilization
mean packet
Rank energy
spectrum
NA
CR-HDC
Efficient
energy
Ideal
trans-
mission
range
for Ge-
ograph-
ical
location
NA
Iterative
(based on the
remaining
energy and
average 1-hop
distance to
every other
hubs)
NA
22

Chapter 3
Proposed Work
Here in this segment first the Affinity propagation method, K-means clustering, and sleep-
wake strategy are discussed briefly and afterward both clustering algorithms are combined to
make an efficient clustering in CRN. The proposed algorithm is well suited for finding or mea-
suring the nodes number and clusters number etc. All radio node sends its information to the
cluster head or pair of radio nodes for exchanging its information.
3.1 Preliminaries
Affinity propagation(AP) is a technique of cluster which is used for finding a good partition
of huge data sets and exemplars(cluster head). The cluster head is a point that shows a similar
characteristics to the data points in its neighborhood. This algorithm takes a set of pair-wise
similarities as an input between exemplar(cluster head) and data points and identifies partitions
iteratively which maximize the addition of similarities between exemplars and data points plus
the addition of exemplar preferences. Here it assume exemplars as a cluster head and data points
as radio nodes. In the affinity propagation algorithm simultaneously assuming in the data sets
all the nodes potential cluster-head and send soft data to all data points(pairs of points) in the
data sets iteratively until get an eligible set of exemplars. Availability and resposibility are the
two soft data exchanged between data nodes.
Responsibility is the messages sent from data point to the exemplar and then it gets to reflect
that how this exemplar is well suited for that data point. Responsibility r(u, v) means messages
are sent from u point to the v candidate exemplar this shows that v is well suited as an exemplar
to the data point u.
r(u, v) = s(u, v) − max
v =v
{a(u, v) + s(u, v )} (3.1.1)
where,
23

• u is the data point;
• v is the exemplar or cluster head;
• v represents other node except cluster head;
• s(u, v) represents similarities between data point u and cluster head v;
• r(u, v) represents resposibility between data point u and cluster head v
• a(u, v) represents the availability between data point u and cluster head v.
Availability is the message sent from candidate exemplar to the data point which show that
it is well suited as a cluster head to that data point. Availability a(u, v) means message is sent
from v exemplar to the u point this shows that cluster head v is well suited for data node u. At
each iteration, the availability and responsibility are updated using the following formula:
a(u, v) = min{0, r(v, v) +
u /∈(u,v)
max(0, r(u , v)} (3.1.2)
Here, s(u, v) are the similarity between data node u and v. The similarity s(u, v) simply
denotes that how cluster head v is well suited for data point u. Similarity s(u, v) is selected is
depend on the requirements of the application and cluster.
For selecting the cluster-head, the number of selected clusters is inﬂuenced by preference
value. If the preference value is small then the clusters number is small and when the preference
data is large then the clusters number generation is more. Wireless network, the number of
cluster formation is smaller using node degree while selecting the cluster head. So in the
afﬁnity propagation based clustering of cognitive radio networks, the degree of node u is a
suitable for the preference value p(u).
p(u) = s(u, u) = αu − max
u∈ℵi
αu (3.1.3)
where,
• p(u) represents the preference value of u;
• αu is the degree of nodes at data point u;
24

• u represents other node except data point u;
The equation indicates subtraction of the maximum degree value of the neighboring node
of node u from node degree(αu) and in this way, preference value is achieved. It has to be
ensured that the neighboring node degree should not be more than node u.
At the starting, availability is set to zero and both availabilities and responsibilities are
iteratively updated using both the above formulae. The AP algorithm stop maybe after a certain
number of the iterations, after if the exemplar or cluster head is constant for the number of
iterations. Availability and responsibility can be combined and make an accumulated proof to
find cluster head at any point during affinity propagation. If u is a cluster head then equation
3.1.3 must satisfy. To Identify the number of cluster head by affinity propagation algorithm
which is affected by the value of the input of s(u, u) self similarities of data nodes. Here
self-similarity also called preferences, which shows how much well-suited cluster head is for
the data node. High preferences show the good cluster head. The condition of a node u for
becoming cluster head if equation 3.1.3 is satisfied.
a(u, u) + r(u, u) > 0 (3.1.4)
where,
• a(u, u) is availability at u;
• αu is the node degree at dtat point u;
• u represents other node except data point u;
3.1.1 Selection of cluster head
The node u exchanges the data and find out the availability a(u, v) and responsibility r(u, v)
values for every neighbor node v ∈ N, where N is the total number of neighbor nodes. For
becoming a potential cluster head, it is checked whether the node u is eligible or not by using the
equation 3.1.3. If an neighboring node satisfies this then that neighboring node is an potential
cluster head otherwise node u behave as a member node. After node u become a potential
cluster head, it again compares the highest number of degree level with other potential cluster
25

head. If node u contains the highest number of degree level then it becomes a cluster head
otherwise node u behave as a member node. The steps of selecting cluster head is given below
in the ﬁgure 3.1.
Figure 3.1: Baddour’s AP approach steps at node u.
26

3.1.2 Finding Euclidean distance
Euclidean distance is used in K Means calculations. In view of Euclidean distance, every
perception is assigned out to one of the clusters in light of least distance. In K-mean clustering
algorithm, Euclidean distance is calculated between two nodes given in below equation.
Euclidean distance = (u1 − v1)2 + (u2 − v2)2 (3.1.5)
Where, u1, u2 and v1, v2 are the coordinate of the node’s location.
3.2 Sleep-wake mode strategies
Sleep-wake strategy is the process of a node to get into sleep and wake mode. A node gets into
sleep mode or wake mode if the condition is passed [7]. The following ﬁgure 3.1 shows AP
procedure to make cluster head.
3.2.1 Applying Battery state based sleep-wake strategy
In this sleep-wake strategy, the wireless node goes to sleep mode if the battery capacity is less
than the threshold battery capacity. For attaining a node to be an active then battery capacity
must be greater than its threshold [7] [10].
Blow represents threshold battery state when a node goes from active mode to sleep mode,
Bhi represents the threshold battery capacity when nodes go from sleep mode to active mode
[11].
Ps→a(c, q, b, r) =



1, if b/B bhi
0, if b/B < bhi
and
Pa→s(c, q, b, r) =



0, if b/B > blow
1, if b/B < blow
where,
27

• b is an battery state;
• B represents capacity of Battery ;
• bhi is threshold battery capacity when sensor node switches from active to sleep mode;
• bblow is threshold battery capacity when sensor node switches from sleep to active mode;
• c, q, b and r are channel state, number of packets in the queue, battery state and solar
radiation state repectively.
Blow > 0 indicate that the battery capacity never going to down. Here it assumes the value
of blow is 0.05 and bhi is 0.3 where a node goes to sleep. if battery state is less than 0.05 times
total battery capacity and it again on wakeup state when battery state is more than or equal to
0.3 times the total battery capacity.
Average battery capacity is calculated in the following:
b = 1
B
B
b=1( a,c,r,s,x,m π(a, c, r, s, x)) (3.2.1)
where,
• b is the average battery capacity;
• a represents state of batch Markovian arrival process;
• π represents the probability matrix;
• m is mode of the node.
Battery average capacity is proportional to the battery size(i.e., 0≤ b≤ 1)
The probability of sleep and wake-up method for packet blocking are as follows:
Psleep = a,c,r,x π(x, a, c, b, r, m) if m = sleep or b = 0 (3.2.2)
28

If any node goes to sleep mode then this node can not receive any incoming packets. So the
coming packets are not allowed. The probability of packet blocking is Pblock = Psleep
3.3 Proposed Algorithm
The main aim of our proposed algorithm is to create an efficient cluster. In this first, it chooses
the cluster head by using Affinity propagation algorithm. Here cluster head is chosen by calcu-
lating the preference of the node. To calculate preference p(u) of node u, the maximum degree
of a neighboring node is subtracted from the degree of node u given in the equation 3.1.3.
By doing this it gets the cluster head. Now applying this cluster head to the k-mean cluster-
ing algorithm to make an efficient cluster.
3.3.1 Algorithm
In proposed flow diagram, it starts with the total number of radio nodes in the network. In that
network, sleep and wake-up strategies are applied to check whether a certain node is in the
active(wake-up) mode or in the sleep mode. Here it is assured that the capacity of the battery
node should be greater than or equal to threshold value. After selecting a number of active
radio nodes, Cluster head or centroid are chosen by using affinity propagation method. Now
in the next step find out the node distance from the centroid using Euclidean distance formula.
The flow diagram of proposed algorithm is shown in figure 3.2.
Further here it checks if two nodes having its distances are equal then at that situation
nodes is selected which is having a higher degree otherwise minimum distance is selected for
the cluster. Iterate these steps until achieved the same centroid value.
The Pseudo Algorithm for clustering in CRN is given illustrated in Algorithm 1.
29

Figure 3.2: Flow diagram of proposed algorithm
30

Algorithm 1: Efficient clustering in CRN using sleep-wake strategy
Input: nodes[], bnodes[]
Output: clusters[];
Calculate degree of each nodes and put in degree[];
for i in all nodes do
if b nodes[i] >b thres. then
A[j + +]=i;
end
end
Select cluster head by AP from Anode[]andputeachclusters[]
NonCluster[]=nodes[]-clusters[];
for i in all NonCluster do
min=maximumValue;
selectCluster=NULL;
for j in all clusters do
if middist(i,j)<min then
min=middist(i,j);
selectCluster=j;
else if middist(i,j)==min and degree(j)>degree(selectNode) then
selectCluster=j;
end
put nonCluster[j] in clusters[selectCluster];
end
return cluster[];
The above-proposed algorithm is explained the steps:
a) Step 1: In this proposed algorithm, first, choose only the node which is in wakeup mode.
Take the waking node as an input, a list of node z and it takes centroid or cluster head L
from AP method for which is it has to find out the value of preference of each node to
get centroid.
b) Step 2: Now it find out the Euclidean distance of a node to each centroid and select the
31

centroid which is having a minimum distance from the node and put that node in the
cluster by using euclidean distance shown in the the equation 3.3.1.
Euclidean distance = (u1 − v1)2 + (u2 − v2)2 (3.3.1)
Where (u1, u2) and (v1, v2) are coordinate location of the node.
If two nodes are having same Euclidean distance then it compares the number of degree
of both the nodes. The node is selected which is having the maximum number of node
degree. Otherwise, assign a node to the cluster which is having minimum distance with
the centroid.
Node degree = No. of the associated node (3.3.2)
c) Step 3: For the cluster movement step, the cluster head position is upgraded by moving
cluster head to the mean of the nodes position assign to that cluster.
µv
=
1
| cv | u∈cv
x(u), v ∈ [1, k] (3.3.3)
where |cv| = number of nearest nodes allocated to cluster head v, and µv
is the different
centroid and x(u) is the location of the nearest node.
32

Chapter 4
Simulation and Results
In this segment, the analyze the performance of the algorithm which is proposed and evaluated
with the assistance of computer simulations. The strength and effectiveness of the present
work is analyzed utilizing the simulations using MATLAB. This proposed clustering based
model is compared with other three similar existing clustering model, namely, Cogmesh [5],
SOC approach [12] and cluster based approach [13]. The simulation area is 10 km2
, where
the cognitive nodes are situated arbitrarily in the recreation environment. 10 available channels
and 500 meters communication range for every node are assumed.
Figure 4.1: Number of cluster against number of node
It is shown in the ﬁgure 4.1. that increase in the number of node also lead to increase in the
number of clusters for all the three approaches along with the proposed model.
In our proposed approach, 14 clusters are made in the network of 50 nodes while 13, 12
33

and 10 clusters are made in the same network for SOC approach, cluster based approach and
CogMesh respectively. In the network of 150 nodes, 16 clusters are constructed by proposed
approach while 17, 18 and 32 clusters are contstructed by CogMesh approach, cluster based
approach and Soc approach respectively. On the other hand when the node is 300 in the network
then 19 number of clusters are constructed by proposed approach while 24, 27 and 42 number of
clusters are constructed by Cluster based approach, CogMesh and SOC approach respectively.
It is seen that in SOC approach, as the number of node is increasing, the number of cluster are
also increasing highly compared to the other three approach along with proposed algorithm. It
is seen that less number of cluster are constructed by proposed approach while comparing with
other three approaches. Thus, this proposed model approach is efﬁcient clustering method for
cognitive radio network.
Figure 4.2: Simulation graph of Energy of whole network vs time
Next, energy consumption for the whole network is studied. Explicit states of the simulation
are as per the following: 80 nodes are arbitrarily dissipated in a (150 × 150)2
meter region;
Communication radius of the initial node is 30m and beginning energy held is 100; node energy
utilization in the working state is 1.5 every second and in resting or sleeping state is 0.2 every
second. The energy of the node edge set at 75. At the point when a node’s energy is under 50,
it might be viewed as that it has failed and couldn’t work, so it never again associated with the
working node decision. The relationship between energy utilization and identifying radius is in
34

the following equation 4.0.1.
E = Crs (4.0.1)
• E is the energy utilization;
• C is the energy utilization conversion factor;
• rs is the node detection radius.
The threshold energy setting is prompted the number of excess nodes to lessen in the last
area, yet in the state of the whole system, it makes the circulation of intensity increasingly
normal and adjusted and improves the feasibility of the system. Systems by and large energy
utilization simulation appeared in Figure 4.2.
Figure 4.3: Energy of a node(First node is working and then sleeping)
Bends in the diagram showed the general energy utilization of the system under the condi-
tion that there has energy edge set and has not individually, where the intersection purpose of
two broken lines demonstrated that the system without setting energy limit has developed en-
ergy”empty” at the very point on the grounds that the working nodes energy has been depleted,
and it can not keep on working. The ﬁgure additionally demonstrates that despite the fact that
the number of working nodes increment, the sleeping component with energy limit expanded
the life of whole remote sensor systems.
35

Figure 4.4: Energy of a node(First node is sleeping and then working)
Its entire lifetimecan be separated into two sorts of states:working and resting or sleeping.
Subsequent to setting the energy edge for a single node, simulation examination of these two
states as appeared in Figure 4.3 and Figure 4.4.
Bends in the above figure indicate the same significance as those in Fig.4.2. From the figure
it can be seen that regardless of nodes begin at which sort ofstates, (working orsleeping), subse-
quent to setting theenergy edge, the system re-judgenodes to workor to sleep at the certaintime,
making the node lifetime has been incredibly improved contrasted and the nodes continually
being at work. In this way setting the thresold energy of a node canbe well-balanced the energy
utilization of nodes, and certification the trustworthiness of system inclusion progressively.
36

Chapter 5
Conclusions and Future Work
This dissertation work contributes toward the efficient clustering in a cognitive radio wireless
sensor network and the future directions are also pointed out which can be carried out in order
to improve network performance.
5.1 Conclusions
In the proposed work, the k-mean and affinity propagation methods are used to make more
efficient clustering. This strategy checks whether the node of a network is in sleep mode or
in wake-up mode. Only those nodes in the network which are on wake-up mode are selected,
and non-active nodes or sleeping nodes are removed from the network. The checking of active
mode or sleep mode is done by checking the capacity of the battery of the node. If capacity is
more than or equal to threshold value then that node is on active mode otherwise it is on sleep
mode. Then the K-means clustering algorithm is used for making a cluster. In this, Euclidean
distance is calculated between node and centroid. Simulation results show that proposed work
creates a lesser number of clusters than other works when the number of nodes increases which
reduces the overall overhead of the network.
The scope of future work can be considered in energy utilization in mobile cognitive radio
network using a cluster-based algorithm to deduce the jamming in the network and for the
lifetime of the cognitive radio network network.
37

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