By Areeba Rao with Dr. Nadeem Javaid COMSATS, Institute of Information Technology, Islamabad, Pakistan AM-DisCNT: Angular Multi-hop DIStance based Circular.
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Slide 1
by Areeba Rao with Dr. Nadeem Javaid COMSATS, Institute of
Information Technology, Islamabad, Pakistan AM-DisCNT: Angular
Multi-hop DIStance based Circular Network Transmission 1
Slide 2
Introduction Wireless Sensor Networks (WSNs): Highly
distributed networks of small, lightweight wireless nodes, Deployed
in large numbers, Monitors the environment or system by measuring
physical parameters such as temperature, pressure, humidity. Node:
sensing + processing + communication 2
Slide 3
Applications of WSNs Constant monitoring & detection of
specific events Military, battlefield surveillance Forest fire
& flood detection Habitat exploration of animals Patient
monitoring Home appliances 3
Slide 4
Design Issues & Challenges Random deployment autonomous
setup & maintenance Infrastructure-less networks distributed
routing Energy, the major constraint trading off network lifetime
for fault tolerance or accuracy of results Hardware energy
efficiency Distributed synchronization Adapting to changes in
connectivity Security 4
Low-Energy Adaptive Clustering Hierarchy (LEACH) Setup phase:
>Each sensor chooses a random number m between 0 and 1 >If m
< T(n) for node n, the node becomes a cluster-head where P : the
desired percentage of cluster heads r : the round number G : the
set of nodes that have not been cluster heads during the last 1 / P
rounds A cluster head advertises its neighbors using a CSMA MAC.
Surrounding nodes decide which cluster to join based on the signal
strength of these messages Cluster heads assign a TDMA schedule for
their members 6
Slide 7
Low-Energy Adaptive Clustering Hierarchy (LEACH) Steady-state
phase: All source nodes send their data to their cluster heads
Cluster heads perform data aggregation/fusion through local
transmission Cluster heads send them back to the BS using a single
direct transmission After a certain period of time, cluster heads
are selected again through the set-up phase 7
Slide 8
SEP Differentiate nodes in terms of their energy
(heterogeneous) Consider two types of nodes w.r.t energy: normal
and advanced nodes where: Energy of advanced nodes > Energy of
normal nodes CH selection probability of advanced nodes is greater
than normal nodes Use same threshold T(s i ) for CH selection as
described by LEACH Each node is elected CH once every 1/P rounds
(epoch length) Epoch of advanced nodes < epoch of normal nodes
8
Slide 9
DEEC Differentiate nodes in terms of their energy
(heterogeneous) Consider multiple energy levels of nodes Use same
threshold T(si) for CH selection as described by LEACH Epoch of
high energy nodes < epoch of low energy nodes 9
Slide 10
DEEC DEEC uses the below probability for CH selection in multi-
level heterogeneous network. DEEC estimate average energy E( r ) of
the network for any round r as: R denotes total rounds of network
lifetime and is estimated as: Etotal is total energy of the network
where E round is energy expenditure during each round. 10
Slide 11
Heterogeneous WSN Model Heterogeneous WSNs contain two, three
or multi types of nodes are termed as two, three and multi level
heterogeneous WSNs respectively. Two level heterogeneous WSNs
contain two energy level of nodes, normal and advanced nodes.
Normal and advance nodes contain Eo and Eo(1 + a) energies
respectively. The total initial energy of the network is the sum of
energies of normal and advanced nodes. The two level heterogeneous
WSNs contain am times more energy as compared to homogeneous WSNs.
11
Slide 12
Heterogeneous WSN Model >Three level heterogeneous WSNs
contain three different energy levels of nodes i.e normal, advanced
and super nodes. >Normal, advance and super nodes contain Eo,
Eo(1 + a) and Eo(1 + b) energies respectively. >The total
initial energy of three level heterogeneous WSN is therefore given
by: >The three level heterogeneous WSNs contain (a + mob) times
more energy as compared to homogeneous WSNs. 12
Slide 13
Heterogeneous WSN Model Multi level heterogeneous WSN is a
network that contains nodes of multiple energy levels. The initial
energy of nodes is distributed over the close set [Eo,Eo(1 +
amax)], where Eo is the lower bound and amax is the upperbound
energy. Initially, node Si is equipped with initial energy of
Eo(1+ai). The total initial energy of multi-level heterogeneous
networks is given by: 13
Slide 14
Radio Dissipation Model The radio energy model describes that l
bit message is transmitted over a distance d, energy expended is
then given by: Eelec is the energy dissipated per bit to run the
transmitter or the receiver circuit. d is the distance between
sender and receiver, fs is free space model and mp is multipath
model is used. Now, total energy dissipated in the network during a
round is given by: Where, K= number of clusters EDA= Data
aggregation cost expended in CH dtoBS= Average distance between the
CH and BS dtoCH= Average distance between the cluster members and
the CH 14
Slide 15
AM-DisCNT All nodes are heterogeneous i.e., they all nodes have
different energy at the start of the network. AM-DisCNT is based on
static clustering. The number of clusters are fixed and the shape
and size of clusters is pre-defined. In proposed protocol, the BS
is at the center of the field, i.e., if the area of the network is
R2. The total area is divided into 9 regions as shown in the
following figure. 15
Slide 16
AM-DisCNT Schematics 16
Slide 17
Inner circle communication The region R1 is closest to the BS
and uses Direct Communication as its routing technique. In Direct
Communication, every node sends its data directly to the BS.
17
Slide 18
Outer circle communication Regions R2 to R9, do not use Direct
Communication. They form CHs to send their data to the BS. Each
region except R1 is called a cluster and each cluster has only one
CH for a particular round. Other nodes of regions R2-R9 send their
data to the BS via CH of their region. The CH is chosen on the
basis of maximum energy. It means that in any round the node having
the maximum energy becomes the CH. 18
Slide 19
Outer circle communication The CHs of outer regions send their
data to the nodes of inner circle. The inner circle nodes forward
the received data to BS. 19
Slide 20
Region formation Whole network is divided into nine regions.
First of all, the network is divided into two concentric circles.
20
Slide 21
Region formation Outer circle is further divided into eight
regions. This division is done after every 45 degrees angle.
21
Slide 22
Region formation Each region contains fixed number of nodes. R1
contains 20 nodes, whereas, all of regions contain 10 nodes each.
The BS is located at the center of the field. And the fixed number
of nodes for each region is distributed randomly in that region.
22
Slide 23
Cluster head selection Unlike LEACH and DEEC in which the CHs
are selected on probabilistic basis, our proposed protocol selects
a node as the CH of that region if it has the maximum energy before
the start of that round. All nodes send their data to the CH which
receives the data from all the nodes, aggregates it and sends it to
the BS. When the first round is completed, the amount of energy in
each node would not be the same. This is because the utilization of
energy depends upon the distance between the node/CH which is
transmitting and the CH/sink which is receiving. 23
Slide 24
Simulation Results The performance of AM-DisCNT is calculated
by using MATLAB. The network parameter table is given below;
24
Slide 25
Performance Parameters There are seven performance parameters
1. Alive nodes 2. Packets send to BS 3. Dead nodes 4. Delay 5.
Throughput 6. CHs 7. Confidence interval 25
Slide 26
Confidence Interval The confidence interval is the statistical
estimate that is used to calculate the range of values that is
likely to contain the data of interest. This interval is calculated
using the formulae; The left side of equation gives the lower bound
and right side is used to calculate the upper bound. in the above
equation is given by; Here, N is the number of alive nodes. z is
the averaged value. Xi are the samples of nodes(dead, alive etc).
26
Slide 27
Other Performance Parameters Alive nodes: Nodes that have some
residual energy and they can send their status to CH or BS are
termed as alive nodes. Network throughput: Throughput of the
network is the number of data packets that are send to
base-station. Confidence interval: It is used to indicate the
reliability and authentication of estimated results. Packets
received: Packets received refers to the number of packets received
at the BS. Delay: The time consumed by the packet to reach the
specified destination is termed as delay. 27
Slide 28
Alive Nodes The lifetime of a network depends upon the number
of alive nodes. As long as there is even one alive node in the
network, its lifetime counts. So the lifetime of a network refers
to the time period from the start of the network till the death of
the last node. The following figure shows the Confidence Interval
of alive nodes: 28
Slide 29
Dead Nodes The graph of dead nodes compared with DEEC and LEACH
is as follows; 29
Slide 30
No. of Packets Received The average packets received at the
sink in LEACH are less as compared to our protocol but these are
almost equal to DEEC as shown in figure shown below: 30
Slide 31
Packets sent to BS The average packets sent to the sink in
LEACH and DEEC are less as compared to our protocol as shown in
figure shown below: 31
Slide 32
Packets sent to BS It can be seen that the average packets sent
to the sink in LEACH and DEEC are less as compared to our protocol
as shown in the figure. This is because in LEACH and DEEC on
average, there would be around 10 t CHs (not always exactly 10) in
a round. And we know that the normal nodes do not send their data
directly to the sink. Instead, they send their data to the BS via
the CH. So on an average, there would be around 10 packets sent per
round. Whereas in our Protocol, 20 nodes are present in the region
R1 which is closest to the sink and they send their data directly
to the sink. In all the other 8 regions, 8 nodes would be CHs in
each round. 32
Slide 33
No. of CHs The figure shows that the CHs of LEACH and DEEC are
not fixed rather they vary over the interval. Whereas, the CHs of
AM-DisCNT are fixed upto 2000 th round. 33
Slide 34
Delay Delay of a packet to reach BS is measured and compared
with DEEC and LEACH. The figure shows that the delay of AM- DisCNT
is least. This is because the inner circle uses direct
communication. 34
Slide 35
Conclusion Our proposed technique uses static clustering and
CHs are selected on the basis of the maximum energy of the nodes.
AM-DisCNT is more efficient than LEACH and DEEC in terms of network
lifetime, stability, area coverage, energy efficiency and
throughput. This results in fixed number of CHs in each round as
well as the optimum number of CHs is also maintained. We
implemented Packet Drop Model to make our protocol more practical.
We also implemented Confidence Interval to find the possible
deviation of our graphs from the mean value, where mean value is
calculated by simulating our protocol 5 times and then taking its
mean. This scheme enhances the desired attributes, i.e., minimum
energy consumption, maximum stability period, better lifetime and
throughput allot as compared with LEACH. 35