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ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012



 Energy Efficient Multipath Data Fusion Technique for
              Wireless Sensor Networks
                                               Sasikala V1 and C. Chandrasekar2
                                  1
                                      Professor, DRBCCC Hindu College, Chennai, Tamil Nadu
                                                      vsasikalaphd@gmail.com
                                         2
                                           Associate Professor, Dept. of Computer Science,
                                       Periyar University, Salem – 636 011, Tamil Nadu, India.

Abstract—In wireless sensor networks (WSN), data fusion              effectively. [4]
should be energy efficient. But, determining the optimal
number of aggregators in an energy efficient manner is a             B. Existing Data Fusion Techniques in Wireless Sensor
challenging task. Moreover, the existing data fusion                 Networks
techniques mostly use the same path for transmitting                  Witness based data fusion: In the witness based data
aggregated data to the sink which reduces the nodes lifetime.
                                                                     fusion, the data fusion node doesn’t forward its result to the
In this paper, we propose a technique which combines energy
efficiency and multiple path selection for data fusion in WSN.
                                                                     base station but will compute the Message Authentication
The network is partitioned into various clusters and the node        Code (MAC) of the result (they call the MAC a proof). After
with highest residual energy is selected as the cluster head.        receiving this information the data fusion node forwards the
The sink computes multiple paths to each cluster head for            proofs to the base station. The data fusion node has to create
data transmission. The distributed source coding and the             false proofs on the invalid result if the node has to be
lifting scheme wavelet transform are used for compressing            compromised and wanted to send an invalid fusion result to
the data at the CH. During each round of transmission, the           the base station. [5]
path is changed in a round robin manner, to conserve the
                                                                     Dynamic data fusion: In sensor networks, the dynamic
energy. This process is repeated for each cluster. From our
simulation results we show that this data fusion technique           application specified data fusion is supported by an
has less energy consumption with increased packet delivery           architectural framework known as DFuse. The dynamic nature
ratio, when compared with the existing schemes.                      of applications in sensor networks is considered by the
                                                                     advanced fusion applications. This dynamic data fusion
Index Terms— wireless sensor networks (WSN), Data Fusion             bridges an important abstraction gap for developing these
Techniques, distributed source coding (DSC), Modified Unary          applications.
Coding (MUC), Energy Efficient Fusion Techniques.
                                                                      Multi-sensor data fusion: Diverse sensors like temperature,
                                                                     humidity light, and Carbon Monoxide are set in each sensor
                       I. INTRODUCTION                               node. The information about the environmental condition
A. Data Fusion in Wireless Sensor Networks                           can be provided by using more than one sensor. The fuzzy
    In sensor networks, data fusion is an essential service. In      rule based system helps in processing and fusion of these
order to compute useful information, such as average of all          diverse sensor signals. [6]
the sensor readings, the maximum value among the sensor                Single Mobile agent (MA)-based autonomic data fusion:
readings or the number of sensors that detect an event the           Here for autonomic data fusion, only one MA is used. In
data fusion process aggregates the data from independent             small scale WSNs this approach is effective but in the
sensors. [1] By eliminating redundancy and power                     networks comprising hundreds or thousands of sensor nodes
consumption in data fusion, the performance of a network             these solutions doesn’t scale acceptably.
can be increased. This is because the fault-tolerance between        Multiple MA-based autonomic data fusion: In order to
the sensors is ensured and the available communication               fuse the data from WSN sensors, in this approach number of
bandwidth between network components is effectively                  MAs are working parallel. Large scale WSNs also supports
managed. [2]                                                         this fusion technique. The itineraries of individual MAs are
    For the purpose of energy-efficient information flow from        derived using the relatively complex algorithms. [7]
several sensors to a central server or sink, in-network data         Mobile agent based clustering data fusion: In this data
fusion is needed in wireless sensor networks. To effectively         fusion, two cluster head models are used to control the size
fuse the data, the data fusion techniques should be                  of the clusters. All the sensor nodes in the detection region
synchronized at various levels. The credibility of the               are divided into several clusters and the fault nodes are
aggregated report can be increased, by fusing the information        removed through the partial results of data integration. The
from as many sensors as possible. [3] On considering the             mobile agents are used in between the cluster heads for data
measurements of multiple sensors, the system performance             fusion, and the path of the mobile agent is optimized. [8]
can be improved in data fusion which is a widely adopted
signal processing technique. Enabling collaboration among
the sensors improves the system sensing performance
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C. Need for Power Efficient Data Fusion in Wireless Sensor            is changed in a round robin manner, to conserve the energy.
Networks                                                              This process is repeated for each cluster.
 The redundancy among sensed data and the network                       Thus this data fusion technique is energy efficient and
load can be reduced by exploring data correlation and                 involves multiple paths for transmission of data.
employing in-network processing. [9]
  Though the wireless sensor networks have infinite scopes,                               II. RELATED WORK
they have limited node battery lifetime. When there is                    Frank Yeong-Sung Lin et al [14] have proposed this paper
sufficient battery power, the network can be operated after           which considers the energy consumption tradeoffs between
deployment. Once a battery is deployed over an inaccessible           data aggregation and retransmissions in a wireless sensor
area it is impossible to replace the node battery and this            network. By using the existing CSMA/CA (Carrier Sense
problem needs to be considered mainly. [10]                           Multiple Access with Collision Avoidance) MAC protocol,
Failures often occur in wireless sensor networks, since             the retransmission energy consumption function is well
they are not considered for long periods of time in the field.        formulated. This paper proposes a novel non-linear
Sensors running out of energy, ageing or harsh environmental          mathematical formulation, whose function is to minimize the
conditions surrounding them are the reasons for these                 total energy consumption of data transmission subject to
failures. [11]                                                        data aggregation trees and data retransmissions.
 The sensor nodes must rely on small, usually non-                      Rabindra Bista et al [15] have proposed a new energy
renewable batteries, energy efficiency is considered as a most        balanced and efficient approach for data aggregation in
important design concern in sensor networks. Consumption              wireless sensor networks, called Designated Path (DP)
of energy in a sensor node is processed in data acquisition,          scheme. In DP scheme, a set of paths is pre-determined and
processing and communication. The data transmission among             run them in round-robin fashion so that all the nodes can
the sensor nodes is reduced to a minimal level since the              participate in the workload of gathering data form the network
transmit power is governed in many of the applications. [12]          and transferring the data to the sink node. They use Semantic
 Due to limited detection range and reliability of each             Routing Tree (SRT) for disseminating any kind of aggregation
node, we need to make the monitoring range overlap each               query to get aggregated value.
other, so that the accuracy and robustness of the network                 V. Bhoopathy et al [16] have proposed Energy Efficient
can be enhanced. Therefore, the data in the sensor nodes              Secure Data Aggregation Protocol. First the network is
maintains certain redundancy. The redundant information               divided into clusters, each cluster is headed by an aggregator
should be reduced and the energy has to be saved to prolong           and the aggregators are connected to sink either directly or
the network lifetime and so each node transmits its detection         through other aggregators. The aggregator is selected based
data to the sink node in the routing. [8]                             on the nearest distance to a set of sensor nodes and its
 The cost and continual power consumption of sensors                energy level. Separate keys are distributed to the two levels
are high since extra circuits are required in hardware based          i.e., sensor node to the aggregator and aggregator to the
approach in order to detect or frustrate the compromised              sink. Whenever a sensor node wants to send data to another
node. [13]                                                            node; first the sensor node encrypts the data using a key
D. Problem Identification and Solution                                and sends it to the aggregator. For integrity of the data packet,
                                                                      a MAC based authentication code is used.
    In Wireless Sensor Networks (WSN), the data fusion
                                                                           Yuanzhu Peter Chen et al [17] have proposed an Energy-
should be energy efficient. But the existing data fusion
                                                                      Efficient Protocol for Aggregator Selection (EPAS). Then,
techniques mostly use the same path for transmitting
                                                                      they generalize it to an aggregation hierarchy and extend
aggregated data to the sink, which results in reduced lifetime
                                                                      EPAS to a Hierarchical Energy-Efficient Protocol for
of the nodes along the paths. Moreover, determining the
                                                                      Aggregator Selection (hEPAS). They derive the optimal
optimal number of aggregators in an energy efficient manner
                                                                      number of aggregators with generalized compression and
is a challenging task.
                                                                      power consumption models, and present fully distributed
    Here, we propose a technique which combines the energy
                                                                      algorithms for aggregator selection.
efficiency and the multiple path selection for data fusion in
                                                                          M. Umashankar et al [18] have proposed a novel power-
WSN. We assume multiple paths from each cluster to the
                                                                      efficient data fusion assurance scheme using silent negative
sink. Initially, the nodes form a cluster and the number of
                                                                      voting mechanism and data fusion assurance with random
aggregators that minimizes the total energy consumed by
                                                                      key pre-distribution scheme has been proposed. The
transmitting and aggregating data is determined. Each sensor
                                                                      proposed schemes has been compared and evaluated their
selects the closest aggregator as its cluster head. Then the
                                                                      efficiency with a simple MAC based fusion assurance scheme
sensors send packets to their respective aggregator. Each
                                                                      as well as the direct voting based fusion assurance scheme.
aggregator compresses the data it receives from the sensors
                                                                          Huseyin Ozgur Tan et al [22] have proposed localized
of its cluster and finally forwards the data to the sink.
                                                                      power efficient data aggregation protocols (L-PEDAPs) for
    In the initial round, from the aggregators, the aggregated
                                                                      wireless sensor networks. Their protocol is based on
data is transmitted to the sink using one of the established
                                                                      topologies such as local minimum spanning tree (LMST) and
multiple paths. During each round of transmission, the path
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relative neighborhood graph (RNG). Their solution involves              When the energy of the cluster head goes down, the network
route maintenance procedures and it is also adapted to                  performance degrades. In order to balance the network energy
consider the remaining power levels of nodes in order to                consumption, the clustering needs to ensure that energy
increase the network lifetime.                                          dissipation across the network should be balanced and cluster
    D. Kumar et al [23] have proposed a novel Energy Efficient          head should keep on changing.
Clustering and Data Aggregation (EECDA) protocol for the                         The initiator I broadcasts a request message for
heterogeneous WSNs. This protocol includes a novel cluster              energy ( E REQ ) with its own energy level ( RLini )
head election technique and a path would be selected with
maximum sum of energy residues for data transmission instead            information to its surrounding nodes.
of the path with minimum energy consumption.                                    The sensor node S i compares its own energy level
    Hasan Cama et al [24] have proposed energy-efficient
                                                                        ( RLi ) with the initiator.
                                                                                                  .
secure pattern based data aggregation (ESPDA) for wireless
sensor networks. ESPDA prevents the redundant data                              If RLi  RLini , then,
transmission from sensor nodes to cluster-heads. They have                           sends a reply message for energy (EREP).
also presented a security protocol and NOVSF block-hopping                     Else
technique that provides data communication security.
                                                                        waits for cluster head advertisement messages. (CH ADV ) .
    Mohamed Watfa et al [25] have proposed an energy-
efficient approach to query processing by implementing new              The initiator selects the cluster head with maximum residual
optimization techniques applied to in-network aggregation.              energy and the next initiator node is the node having the
They did not concentrate on the data routing strategies and             second maximum residual energy.
loss tolerance mechanism.                                               The initiator node is changed every time when the energy
    Xu Li et al [26] have proposed a novel two-stage delay              level of the node decreases.
model based on IEEE 802.11 CSMA/CA MAC layer. This                      After CH is selected by the initiator, clusters are formed in
model uses hop count to measure end-to-end delay when                   the network.
the network traffic is low, and degree sum along the routing            The nodes in the cluster broadcasts a CHADV to the CH and
path when the traffic is high. They introduced the novel                CH sends it to the sink along with the cluster ID.
concept of DEsired Progress (DEP) for hop selection and                 A join request message JREQ is transmitted by the member
devised a localized delay-bounded and energy-efficient data             node along with CHADV.
aggregation (DEDA) protocol accordingly.                                    The transmission range gets minimized since the initiators
    Siddhartha Chauhan et al [27] have proposed an energy               collect the energy information about the nearest sensors.
efficient data gathering protocol (EEDGP) for wireless sensor           The nodes having energy greater than the energy level of
network. This protocol reduces the transmission of the data             the initiator ensure minimization of E REP message
packets thereby reducing the energy consumption of sensor               transmission.
nodes.                                                                      Once the selected cluster head node receives the J REP
    Mohammad Mostafizur Rahman Mozumdar et al [28] have
                                                                        message from member nodes, it sends a joint reply message
proposed an efficient data aggregation algorithm for
                                                                        JREP back to the nodes. Then the CH transmits data to the
    Cluster-based sensor network. The proposed algorithm
                                                                        sink node.
selects a cluster leader that will perform data aggregation in a
partially connected sensor network. The algorithm reduces
the traffic flow inside the network by adaptively selecting
the shortest route for packet routing to the cluster leader.

                     III. PROPOSED WORK
A. Cluster Head Selection and Data Transmission
    In this technique, we select the node with highest residual
energy as the cluster head in order to prolong the lifetime of
the network. We randomly consider few nodes as the initiator
nodes (I) to collect the information of the nearest sensor
nodes and to select the cluster heads depending upon the
energy information.
    We assume that in this sensor network, the sink node has
the knowledge about all other node’s location. The sensor
nodes are assumed to be immobile and have limited energy.
    The initiator node (I), determines the CH based upon the
residual energy of the nodes. In a homogeneous network,
cluster head uses more energy than non cluster head nodes.                             Figure 1.      Selection of Cluster Head
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                                                                        supported in LSWT.
                                                                            The individual redundancy can be reduced by the scalar
                                                                        quantization after the LSWT process. The distributed
                                                                        redundancy is reduced when low frequency component of
                                                                        the sensor data is processed by DSC.
                                                                            In the first step, we do the LSWT and it gets repeated by
                                                                        iteration on the S (even part of original data). A multi-level or
                                                                        multi resolution decomposition is created due to this.
                                                                            In the next step, quantization, we reduce the individual
                                                                        redundancy by choosing a scalar quantization in our
                                                                        applications. For data compression combined with WT,
                                                                        quantization is widely studied and successfully implemented.
                                                                        The data values which have higher frequencies are set to
                                                                        zero after the quantization. The individual redundancy can
                                                                        be reduced significantly in the quantization process.
                                                                            The high frequency data sets are encoded using the
         Figure 2.     Data transmission from CH to Sink                Modified Unary Coding (MUC). The nonzero values {Ai}
In figure 1, the Initiator I1, I2, and I3 sends energy request          are only encoded here.
EREQ to all the surrounding nodes. For example, in this figure,          Ai  0 :- encoding with 2  Ai bits 1 plus 10 bits relative
when the node I1 sends E REQ to the nodes, the energy                   position value.
consumption of the nodes is compared with I1. Since node 2               Ai  0 :- encoding with 2 Ai  1 bits 1 and 10 bits relative
has a higher energy level than I1 and so node 2 is selected as          position value.
the cluster head and node 4 which has the next highest energy               H(Y) is a sample value with n bits used for encoding the
level is selected as the next initiator for cluster head selection.     low frequency part when each value is mapped to the source
    Similarly, when the node I2 sends E REQ to the nodes,               codebook ranging from, 0 to2n-1. This is known as base data.
                                                                        The compress process ends and base data is sent to the base
the energy consumption of the nodes is compared with I2.
                                                                        station when the data is collected from the sensor node else
Here, node 9 has the highest energy level and it is selected as
                                                                        it will continue to the next step. The distributed redundancy
the Cluster head and the node 11 which has the next highest
                                                                        is still more reduced by DSC after mapping. Portioning is
energy level is selected as the next initiator for cluster head
                                                                        done in the data set to split it into different cosets as the
selection.
                                                                        correlation of the data from neighbor layers. The fully
    Then when the node I3 sends to the surrounding nodes,
                                                                        compressed data is the original data value which is replaced
the energy consumption of the nodes is compared with I3.
                                                                        with coset index represented by H(X|Y).
Since node 22 has the highest energy level, it is selected as
                                                                            After compressing the data the base station collects these
the cluster head and no other surrounding node has the next
                                                                        data. Decompression of all the data is done when the base
highest energy level other than initiator I3. So, we select
                                                                        station receives the collected data.
node I3 as the next initiator node.
    In figure 2, the data transmission from CH to the sink is           C. Multi path Routing from Cluster Head to Sink
described. After the selection of CH, the clusters are formed.              For data transmission from CHs towards the sink node,
The nodes in the cluster transmit CH ADV with J REQ to the              multiple paths are created in the multi path discovery phase.
CH. The CH then transmits this data to the sink.                        These multi-paths are node disjoint. Due to the utilization of
                                                                        most available network resources, the multi-path routing
B. Data Compression                                                     usually prefers the node disjoint paths and thus they are
    The distributed source coding (DSC) is explained in the             fault tolerant. There is a minimum impact to the diversity of
paper [19].                                                             the routes since when an intermediate node in a set of node
    In WSNs we construct an algorithmic framework which                 disjoint paths is failed, only the path containing that node
supports DSC for high and low frequency signal                          gets affected.
compression. To preprocess the original data for signal                     The path discovery procedure is executed according to
decomposition and noise deduction, we use a lifting scheme              the following phases:
wavelet transform (LSWT) in order to separate the low                       Initialization phase: The information about the neighbors
frequency component from the high frequency component,                  having highest quality data is maintained by each CH since it
and strength the correlation among distributed sensor data.             broadcasts a HELLO message through the clusters. The
Compared to the traditional transforms, LSWT is better                  neighboring table is maintained and updated in this phase.
suitable for WSNs due to the following reasons:                         The knowledge about the list of neighboring nodes of the
1) Efficiency is higher compared to the FFT or DCT.                     cluster head are maintained in the neighboring table. Hop
2) Time domain analysis is supported by transformed data.               count which represents the distance in hops for message
3) Multi-scale analysis and integer to integer mapping are              from its originator is present in the HELLO message.
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Primary path discovery phase: The information on                      D. Combined Algorithm
computing the cost function for CHs neighboring nodes is                 1. Among the N sensor nodes, randomly consider k
contained in the CH after initialization phase. After the             nodes as the initiator nodes to collect the information.
preferred next hop CH is computed by the sink node an RREQ            2. The initiator I1 selects the cluster head based upon the
message is sent to the most preferred next hop. In the same           energy level information.
way, the preferred next hop CH of the sink computes its most             For each neighbor Ni of I1 , i  1, 2  r
preferred next hop in the source node’s direction. An RREQ
                                                                      If RLi  RLi  RL ini , then,
message is sent to the next hop and the operation continues
until the source node.                                                     S i sends a reply message for energy (EREP).
    Alternative Paths discovery phase: The next most                  Else
preferred neighbor is considered as the alternative path and              waits for cluster head advertisement messages .
the sink sends an alternate RREQ message to that neighbor.            End For
Each node accepts only one RREQ message in order to avoid             3. I1 select the node St as CH1 such that RLt = max{RLi},
having paths with shared nodes. When two or more nodes                4. CH1 broadcast a to Ni
receive one RREQ message, the first RREQ message is only              5. Each node Ni sends request to CH1.
accepted rejecting the remaining messages.                            6. On accepting from the CH, nodes join the cluster.
    For example in this figure 3, we compute multiple paths           7. Each CH send its cluster details to the sink.
from the cluster head to the sink. The source node transmits          8. The sink establishes multiple paths towards each CH and
the data to the cluster head CH4 and the CH4 wants to transmit        designates one path as the primary path.
the data to the sink. So, it computes four paths:                     9. At first cycle R1, sends the sensed data to its CH.
     Path 1: Source-CH4-CH2-Sink                                      10. At CH, The data from its members is compressed using
     Path 2: Source-CH4-CH3-Sink                                      DSC.
     Path 3: Source-CH4-CH3-CH1-Sink                                  11. CH sends the compressed data to the sink, using the
     Path 4: Source-CH4-CH5-CH3-CH1-Sink                              primary path.
    The best path is the path with minimum number of hops.            12. After the sink receives the compressed data, it
    We select the path 1 (CH4-CH2-Sink) for transmission              decompresses all the data.
    When a failure occurs in that primary path the alternative        13. During the next cycle R2, CH chooses the next alternative
path is selected. Path 2 (CH4-CH3-CH1-Sink) is chosen as              path from the multi path set, to transmit the data.
the alternative path for further transmission. The path is            14. If all the alternate paths are used, then in the next cycle,
changed in a round robin manner in order to conserve energy.          again the primary path is selected.

                                                                                          IV. SIMULATION RESULTS
                                                                          Energy Efficient Multipath Data Fusion (EEMD)
                                                                      Technique is evaluated through NS2 [21] simulation. A
                                                                      random network deployed in an area of 500 X 500 m is
                                                                      considered. Initially 100 sensor nodes are placed in square
                                                                      grid area by placing each sensor in a 50x50 grid cell. 10 cluster
                                                                      heads are deployed in the grid region according to our
                                                                      protocol. The sink is assumed to be situated 100 meters away
                                                                      from the above specified area. In the simulation, the channel
                                                                      capacity of mobile hosts is set to the same value: 2 Mbps.
                                                                      The simulated traffic is CBR with UDP source and sink. The
                                                                      number of sources is per cluster is varied fro 1 to 4.
                                                                          Table 1 summarizes the simulation parameters used
                                                                                        TABLE 1: SIMULATION PARAMETERS




                 Figure 3. Multi-path clustering
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A. Performance Metrics                                                 Figure 4 gives the average end-to-end delay when the rate is
    The performance of EEMD technique is compared with                 increased. It shows that our proposed EEMDF protocol has
the compressive data gathering (CDG) technique [20]. The               lower delay when compared to CDG.
performance is evaluated mainly, according to the following                Figure 5 gives the packet delivery ratio when the rate is
metrics.                                                               increased. It shows that our proposed EEMDF protocol
      Average end-to-end delay: The end-to-end-delay is               achieves good delivery ratio when compared to CDG.
         averaged over all surviving data packets from the             Figure 6 gives the energy consumption when the rate is
         sources to the destinations.                                  increased. It shows that our proposed EEMDF protocol
      Average Packet Delivery Ratio: It is the ratio of the           utilizes lower energy when compared to CDG.
         number .of packets received successfully and the              B. Based on Sources
         total number of packets transmitted.                              In our second experiment, we vary the no. of sources per
      Energy: It is the average energy consumed for the               cluster from 1 to 4, keeping the CBR sending rate as 100kb.
         data transmission.
B. Results
A. Based on Rate
    In our initial experiment, we vary the transmission sending
rate as 100,150,200, 250 and 300 Kb for CBR traffic. We keep
4 sources per cluster.




                                                                                         Figure 7. Sources Vs Delay




                    Figure 4. Rate Vs Delay




                                                                                     Figure 8. Sources Vs Delivery Ratio




                Figure 5. Rate Vs Delivery Ratio




                                                                                         Figure 9. Sources Vs Energy
                                                                           Figure 7 gives the average end-to-end delay when the
                                                                       no. of source is increased. It shows that our proposed EEMDF
                                                                       protocol has lower delay when compared to CDG.
                                                                           Figure 8 gives the packet delivery ratio when the no. of
                                                                       source is increased. It shows that our proposed EEMDF
                   Figure 6. Rate Vs Energy                            protocol achieves good delivery ratio when compared to CDG.
                                                                           Figure 9 gives the energy consumption when the no. of
                                                                       source is increased. It shows that our proposed EEMDF
                                                                       protocol utilizes lower energy when compared to CDG.

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                         V. CONCLUSION                                     [11] Maen Takruri, and Subhash Challa “Data Fusion Approach
                                                                           for Error Correction in Wireless Sensor Networks” InTech
     In this paper, we have proposed a technique which                      December 2010.
combines the energy efficiency and the multiple path selection             [12] Leeger Yu and Anthony Ephremides “Enhancing Energy
for data fusion in WSN. We have selected the node with                     Efficiency For Data Fusion In Sensor Networks With A Detection
highest residual energy as the cluster head. Randomly                      Mission” The 11th International Symposium on Wireless Personal
selected initiator nodes collect the information of the nearest            Multimedia Communications (WPMC) 2008.
sensor nodes and select the node with highest energy as the                [13] Hung-Ta Pai, and Yunghsiang S. Han “Power-Efficient Direct-
cluster head. The node with the next higher energy level is                Voting Assurance for Data Fusion in Wireless Sensor Networks”
taken as the initiator. The sink computes multiple paths to                IEEE Transactions On Computers, Vol. 57, No. 2, February 2008.
                                                                           [14] Frank Yeong-Sung Lin, Hong-Hsu Yen, and Shu-Ping Lin “A
each cluster head for data transmission. Each CH uses
                                                                           Novel Energy-Efficient MAC Aware Data Aggregation Routing in
distributed source coding and the lifting scheme wavelet                   Wireless Sensor Networks” Sensors 2009.
transform for compressing the data and after the sink receives             [15] Rabindra Bista and Jae-Woo Chang “Energy-Efficient Data
all the collected data, it will decompress all the data.. Initially        Aggregation for Wireless Sensor Networks” Intech 2010.
the path with minimum number of hops is considered as the                  [16] V. Bhoopathy and R. M. S. Parvathi “Energy Efficient Secure
primary path and the compressed data is transmitted to the                 Data Aggregation Protocol for Wireless Sensor Networks”
sink through this path. During each round of transmission,                 EuroJournals Publishing, Inc. 2011.
the path is changed in a round robin manner, to conserve the               [17] Yuanzhu Peter Chen, Arthur L. Liestman and Jiangchuan Liu
energy. This process is repeated for each cluster. From our                “A Hierarchical Energy-Efficient Framework for Data Aggregation
                                                                           in Wireless Sensor Networks” IEEE 2006.
simulation results we have shown that this data fusion
                                                                           [18] M. Umashankar, and C. Chandrasekar “Energy Efficient
technique has less energy consumption with increased packet                Secured Data Fusion Assurance Mechanism For Wireless Sensor
delivery ratio, when compared with the existing schemes.                   Networks” EuroJournals Publishing, Inc. 2011.
                                                                           [19] Zixiang Xiong, Angelos D. Liveris, and Samuel Cheng
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© 2012 ACEEE                                                          40
DOI: 01.IJNS.03.02.14
ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012


                Sasikala V received the MCA., degree from                               Dr. C. Chandrasekar received his Ph.D.
                University of Madras, Chennai, Tamilnadu,                               degree from Periyar University, Salem, TN,
                the M.Phil., degree in Computer Science from                            India. He has been working as Associate
                Manonmaniam Sundaranar University,                                      Professor at Dept. of Computer Science, Periyar
                Tirunelveli, Tamilnadu. She is pursuing her                             University, Salem – 636 011, Tamil Nadu, India.
                PhD under the guidance of Dr. C. Chandrasekar                           The topic of his doctoral dissertation was “An
                and currently working as Assistant Professor                            Optimization and Seamless Mobility for
                & HOD of Computer Application Department                                Integration of Wireless LAN and Cellular
in DRBCCC Hindu College, Chennai, Tamil Nadu, India.                 Networks”. His research interest includes Wireless networking,
                                                                     Mobile computing, Computer Communication and Networks. He
                                                                     was a Research guide at various universities in India. He has been
                                                                     published more than 50 research papers at various National /
                                                                     International Journals.




© 2012 ACEEE                                                    41
DOI: 01.IJNS.03.02.14

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Energy Efficient Multipath Data Fusion Technique for Wireless Sensor Networks

  • 1. ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012 Energy Efficient Multipath Data Fusion Technique for Wireless Sensor Networks Sasikala V1 and C. Chandrasekar2 1 Professor, DRBCCC Hindu College, Chennai, Tamil Nadu vsasikalaphd@gmail.com 2 Associate Professor, Dept. of Computer Science, Periyar University, Salem – 636 011, Tamil Nadu, India. Abstract—In wireless sensor networks (WSN), data fusion effectively. [4] should be energy efficient. But, determining the optimal number of aggregators in an energy efficient manner is a B. Existing Data Fusion Techniques in Wireless Sensor challenging task. Moreover, the existing data fusion Networks techniques mostly use the same path for transmitting  Witness based data fusion: In the witness based data aggregated data to the sink which reduces the nodes lifetime. fusion, the data fusion node doesn’t forward its result to the In this paper, we propose a technique which combines energy efficiency and multiple path selection for data fusion in WSN. base station but will compute the Message Authentication The network is partitioned into various clusters and the node Code (MAC) of the result (they call the MAC a proof). After with highest residual energy is selected as the cluster head. receiving this information the data fusion node forwards the The sink computes multiple paths to each cluster head for proofs to the base station. The data fusion node has to create data transmission. The distributed source coding and the false proofs on the invalid result if the node has to be lifting scheme wavelet transform are used for compressing compromised and wanted to send an invalid fusion result to the data at the CH. During each round of transmission, the the base station. [5] path is changed in a round robin manner, to conserve the Dynamic data fusion: In sensor networks, the dynamic energy. This process is repeated for each cluster. From our simulation results we show that this data fusion technique application specified data fusion is supported by an has less energy consumption with increased packet delivery architectural framework known as DFuse. The dynamic nature ratio, when compared with the existing schemes. of applications in sensor networks is considered by the advanced fusion applications. This dynamic data fusion Index Terms— wireless sensor networks (WSN), Data Fusion bridges an important abstraction gap for developing these Techniques, distributed source coding (DSC), Modified Unary applications. Coding (MUC), Energy Efficient Fusion Techniques.  Multi-sensor data fusion: Diverse sensors like temperature, humidity light, and Carbon Monoxide are set in each sensor I. INTRODUCTION node. The information about the environmental condition A. Data Fusion in Wireless Sensor Networks can be provided by using more than one sensor. The fuzzy In sensor networks, data fusion is an essential service. In rule based system helps in processing and fusion of these order to compute useful information, such as average of all diverse sensor signals. [6] the sensor readings, the maximum value among the sensor  Single Mobile agent (MA)-based autonomic data fusion: readings or the number of sensors that detect an event the Here for autonomic data fusion, only one MA is used. In data fusion process aggregates the data from independent small scale WSNs this approach is effective but in the sensors. [1] By eliminating redundancy and power networks comprising hundreds or thousands of sensor nodes consumption in data fusion, the performance of a network these solutions doesn’t scale acceptably. can be increased. This is because the fault-tolerance between Multiple MA-based autonomic data fusion: In order to the sensors is ensured and the available communication fuse the data from WSN sensors, in this approach number of bandwidth between network components is effectively MAs are working parallel. Large scale WSNs also supports managed. [2] this fusion technique. The itineraries of individual MAs are For the purpose of energy-efficient information flow from derived using the relatively complex algorithms. [7] several sensors to a central server or sink, in-network data Mobile agent based clustering data fusion: In this data fusion is needed in wireless sensor networks. To effectively fusion, two cluster head models are used to control the size fuse the data, the data fusion techniques should be of the clusters. All the sensor nodes in the detection region synchronized at various levels. The credibility of the are divided into several clusters and the fault nodes are aggregated report can be increased, by fusing the information removed through the partial results of data integration. The from as many sensors as possible. [3] On considering the mobile agents are used in between the cluster heads for data measurements of multiple sensors, the system performance fusion, and the path of the mobile agent is optimized. [8] can be improved in data fusion which is a widely adopted signal processing technique. Enabling collaboration among the sensors improves the system sensing performance © 2012 ACEEE 34 DOI: 01.IJNS.03.02.14
  • 2. ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012 C. Need for Power Efficient Data Fusion in Wireless Sensor is changed in a round robin manner, to conserve the energy. Networks This process is repeated for each cluster.  The redundancy among sensed data and the network Thus this data fusion technique is energy efficient and load can be reduced by exploring data correlation and involves multiple paths for transmission of data. employing in-network processing. [9]  Though the wireless sensor networks have infinite scopes, II. RELATED WORK they have limited node battery lifetime. When there is Frank Yeong-Sung Lin et al [14] have proposed this paper sufficient battery power, the network can be operated after which considers the energy consumption tradeoffs between deployment. Once a battery is deployed over an inaccessible data aggregation and retransmissions in a wireless sensor area it is impossible to replace the node battery and this network. By using the existing CSMA/CA (Carrier Sense problem needs to be considered mainly. [10] Multiple Access with Collision Avoidance) MAC protocol, Failures often occur in wireless sensor networks, since the retransmission energy consumption function is well they are not considered for long periods of time in the field. formulated. This paper proposes a novel non-linear Sensors running out of energy, ageing or harsh environmental mathematical formulation, whose function is to minimize the conditions surrounding them are the reasons for these total energy consumption of data transmission subject to failures. [11] data aggregation trees and data retransmissions.  The sensor nodes must rely on small, usually non- Rabindra Bista et al [15] have proposed a new energy renewable batteries, energy efficiency is considered as a most balanced and efficient approach for data aggregation in important design concern in sensor networks. Consumption wireless sensor networks, called Designated Path (DP) of energy in a sensor node is processed in data acquisition, scheme. In DP scheme, a set of paths is pre-determined and processing and communication. The data transmission among run them in round-robin fashion so that all the nodes can the sensor nodes is reduced to a minimal level since the participate in the workload of gathering data form the network transmit power is governed in many of the applications. [12] and transferring the data to the sink node. They use Semantic  Due to limited detection range and reliability of each Routing Tree (SRT) for disseminating any kind of aggregation node, we need to make the monitoring range overlap each query to get aggregated value. other, so that the accuracy and robustness of the network V. Bhoopathy et al [16] have proposed Energy Efficient can be enhanced. Therefore, the data in the sensor nodes Secure Data Aggregation Protocol. First the network is maintains certain redundancy. The redundant information divided into clusters, each cluster is headed by an aggregator should be reduced and the energy has to be saved to prolong and the aggregators are connected to sink either directly or the network lifetime and so each node transmits its detection through other aggregators. The aggregator is selected based data to the sink node in the routing. [8] on the nearest distance to a set of sensor nodes and its  The cost and continual power consumption of sensors energy level. Separate keys are distributed to the two levels are high since extra circuits are required in hardware based i.e., sensor node to the aggregator and aggregator to the approach in order to detect or frustrate the compromised sink. Whenever a sensor node wants to send data to another node. [13] node; first the sensor node encrypts the data using a key D. Problem Identification and Solution and sends it to the aggregator. For integrity of the data packet, a MAC based authentication code is used. In Wireless Sensor Networks (WSN), the data fusion Yuanzhu Peter Chen et al [17] have proposed an Energy- should be energy efficient. But the existing data fusion Efficient Protocol for Aggregator Selection (EPAS). Then, techniques mostly use the same path for transmitting they generalize it to an aggregation hierarchy and extend aggregated data to the sink, which results in reduced lifetime EPAS to a Hierarchical Energy-Efficient Protocol for of the nodes along the paths. Moreover, determining the Aggregator Selection (hEPAS). They derive the optimal optimal number of aggregators in an energy efficient manner number of aggregators with generalized compression and is a challenging task. power consumption models, and present fully distributed Here, we propose a technique which combines the energy algorithms for aggregator selection. efficiency and the multiple path selection for data fusion in M. Umashankar et al [18] have proposed a novel power- WSN. We assume multiple paths from each cluster to the efficient data fusion assurance scheme using silent negative sink. Initially, the nodes form a cluster and the number of voting mechanism and data fusion assurance with random aggregators that minimizes the total energy consumed by key pre-distribution scheme has been proposed. The transmitting and aggregating data is determined. Each sensor proposed schemes has been compared and evaluated their selects the closest aggregator as its cluster head. Then the efficiency with a simple MAC based fusion assurance scheme sensors send packets to their respective aggregator. Each as well as the direct voting based fusion assurance scheme. aggregator compresses the data it receives from the sensors Huseyin Ozgur Tan et al [22] have proposed localized of its cluster and finally forwards the data to the sink. power efficient data aggregation protocols (L-PEDAPs) for In the initial round, from the aggregators, the aggregated wireless sensor networks. Their protocol is based on data is transmitted to the sink using one of the established topologies such as local minimum spanning tree (LMST) and multiple paths. During each round of transmission, the path © 2012 ACEEE 35 DOI: 01.IJNS.03.02.14
  • 3. ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012 relative neighborhood graph (RNG). Their solution involves When the energy of the cluster head goes down, the network route maintenance procedures and it is also adapted to performance degrades. In order to balance the network energy consider the remaining power levels of nodes in order to consumption, the clustering needs to ensure that energy increase the network lifetime. dissipation across the network should be balanced and cluster D. Kumar et al [23] have proposed a novel Energy Efficient head should keep on changing. Clustering and Data Aggregation (EECDA) protocol for the  The initiator I broadcasts a request message for heterogeneous WSNs. This protocol includes a novel cluster energy ( E REQ ) with its own energy level ( RLini ) head election technique and a path would be selected with maximum sum of energy residues for data transmission instead information to its surrounding nodes. of the path with minimum energy consumption.  The sensor node S i compares its own energy level Hasan Cama et al [24] have proposed energy-efficient ( RLi ) with the initiator. . secure pattern based data aggregation (ESPDA) for wireless sensor networks. ESPDA prevents the redundant data  If RLi  RLini , then, transmission from sensor nodes to cluster-heads. They have sends a reply message for energy (EREP). also presented a security protocol and NOVSF block-hopping Else technique that provides data communication security. waits for cluster head advertisement messages. (CH ADV ) . Mohamed Watfa et al [25] have proposed an energy- efficient approach to query processing by implementing new The initiator selects the cluster head with maximum residual optimization techniques applied to in-network aggregation. energy and the next initiator node is the node having the They did not concentrate on the data routing strategies and second maximum residual energy. loss tolerance mechanism. The initiator node is changed every time when the energy Xu Li et al [26] have proposed a novel two-stage delay level of the node decreases. model based on IEEE 802.11 CSMA/CA MAC layer. This After CH is selected by the initiator, clusters are formed in model uses hop count to measure end-to-end delay when the network. the network traffic is low, and degree sum along the routing The nodes in the cluster broadcasts a CHADV to the CH and path when the traffic is high. They introduced the novel CH sends it to the sink along with the cluster ID. concept of DEsired Progress (DEP) for hop selection and A join request message JREQ is transmitted by the member devised a localized delay-bounded and energy-efficient data node along with CHADV. aggregation (DEDA) protocol accordingly. The transmission range gets minimized since the initiators Siddhartha Chauhan et al [27] have proposed an energy collect the energy information about the nearest sensors. efficient data gathering protocol (EEDGP) for wireless sensor The nodes having energy greater than the energy level of network. This protocol reduces the transmission of the data the initiator ensure minimization of E REP message packets thereby reducing the energy consumption of sensor transmission. nodes. Once the selected cluster head node receives the J REP Mohammad Mostafizur Rahman Mozumdar et al [28] have message from member nodes, it sends a joint reply message proposed an efficient data aggregation algorithm for JREP back to the nodes. Then the CH transmits data to the Cluster-based sensor network. The proposed algorithm sink node. selects a cluster leader that will perform data aggregation in a partially connected sensor network. The algorithm reduces the traffic flow inside the network by adaptively selecting the shortest route for packet routing to the cluster leader. III. PROPOSED WORK A. Cluster Head Selection and Data Transmission In this technique, we select the node with highest residual energy as the cluster head in order to prolong the lifetime of the network. We randomly consider few nodes as the initiator nodes (I) to collect the information of the nearest sensor nodes and to select the cluster heads depending upon the energy information. We assume that in this sensor network, the sink node has the knowledge about all other node’s location. The sensor nodes are assumed to be immobile and have limited energy. The initiator node (I), determines the CH based upon the residual energy of the nodes. In a homogeneous network, cluster head uses more energy than non cluster head nodes. Figure 1. Selection of Cluster Head © 2012 ACEEE 36 DOI: 01.IJNS.03.02.14
  • 4. ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012 supported in LSWT. The individual redundancy can be reduced by the scalar quantization after the LSWT process. The distributed redundancy is reduced when low frequency component of the sensor data is processed by DSC. In the first step, we do the LSWT and it gets repeated by iteration on the S (even part of original data). A multi-level or multi resolution decomposition is created due to this. In the next step, quantization, we reduce the individual redundancy by choosing a scalar quantization in our applications. For data compression combined with WT, quantization is widely studied and successfully implemented. The data values which have higher frequencies are set to zero after the quantization. The individual redundancy can be reduced significantly in the quantization process. The high frequency data sets are encoded using the Figure 2. Data transmission from CH to Sink Modified Unary Coding (MUC). The nonzero values {Ai} In figure 1, the Initiator I1, I2, and I3 sends energy request are only encoded here. EREQ to all the surrounding nodes. For example, in this figure, Ai  0 :- encoding with 2  Ai bits 1 plus 10 bits relative when the node I1 sends E REQ to the nodes, the energy position value. consumption of the nodes is compared with I1. Since node 2 Ai  0 :- encoding with 2 Ai  1 bits 1 and 10 bits relative has a higher energy level than I1 and so node 2 is selected as position value. the cluster head and node 4 which has the next highest energy H(Y) is a sample value with n bits used for encoding the level is selected as the next initiator for cluster head selection. low frequency part when each value is mapped to the source Similarly, when the node I2 sends E REQ to the nodes, codebook ranging from, 0 to2n-1. This is known as base data. The compress process ends and base data is sent to the base the energy consumption of the nodes is compared with I2. station when the data is collected from the sensor node else Here, node 9 has the highest energy level and it is selected as it will continue to the next step. The distributed redundancy the Cluster head and the node 11 which has the next highest is still more reduced by DSC after mapping. Portioning is energy level is selected as the next initiator for cluster head done in the data set to split it into different cosets as the selection. correlation of the data from neighbor layers. The fully Then when the node I3 sends to the surrounding nodes, compressed data is the original data value which is replaced the energy consumption of the nodes is compared with I3. with coset index represented by H(X|Y). Since node 22 has the highest energy level, it is selected as After compressing the data the base station collects these the cluster head and no other surrounding node has the next data. Decompression of all the data is done when the base highest energy level other than initiator I3. So, we select station receives the collected data. node I3 as the next initiator node. In figure 2, the data transmission from CH to the sink is C. Multi path Routing from Cluster Head to Sink described. After the selection of CH, the clusters are formed. For data transmission from CHs towards the sink node, The nodes in the cluster transmit CH ADV with J REQ to the multiple paths are created in the multi path discovery phase. CH. The CH then transmits this data to the sink. These multi-paths are node disjoint. Due to the utilization of most available network resources, the multi-path routing B. Data Compression usually prefers the node disjoint paths and thus they are The distributed source coding (DSC) is explained in the fault tolerant. There is a minimum impact to the diversity of paper [19]. the routes since when an intermediate node in a set of node In WSNs we construct an algorithmic framework which disjoint paths is failed, only the path containing that node supports DSC for high and low frequency signal gets affected. compression. To preprocess the original data for signal The path discovery procedure is executed according to decomposition and noise deduction, we use a lifting scheme the following phases: wavelet transform (LSWT) in order to separate the low Initialization phase: The information about the neighbors frequency component from the high frequency component, having highest quality data is maintained by each CH since it and strength the correlation among distributed sensor data. broadcasts a HELLO message through the clusters. The Compared to the traditional transforms, LSWT is better neighboring table is maintained and updated in this phase. suitable for WSNs due to the following reasons: The knowledge about the list of neighboring nodes of the 1) Efficiency is higher compared to the FFT or DCT. cluster head are maintained in the neighboring table. Hop 2) Time domain analysis is supported by transformed data. count which represents the distance in hops for message 3) Multi-scale analysis and integer to integer mapping are from its originator is present in the HELLO message. © 2012 ACEEE 37 DOI: 01.IJNS.03.02.14
  • 5. ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012 Primary path discovery phase: The information on D. Combined Algorithm computing the cost function for CHs neighboring nodes is 1. Among the N sensor nodes, randomly consider k contained in the CH after initialization phase. After the nodes as the initiator nodes to collect the information. preferred next hop CH is computed by the sink node an RREQ 2. The initiator I1 selects the cluster head based upon the message is sent to the most preferred next hop. In the same energy level information. way, the preferred next hop CH of the sink computes its most For each neighbor Ni of I1 , i  1, 2  r preferred next hop in the source node’s direction. An RREQ If RLi  RLi  RL ini , then, message is sent to the next hop and the operation continues until the source node. S i sends a reply message for energy (EREP). Alternative Paths discovery phase: The next most Else preferred neighbor is considered as the alternative path and waits for cluster head advertisement messages . the sink sends an alternate RREQ message to that neighbor. End For Each node accepts only one RREQ message in order to avoid 3. I1 select the node St as CH1 such that RLt = max{RLi}, having paths with shared nodes. When two or more nodes 4. CH1 broadcast a to Ni receive one RREQ message, the first RREQ message is only 5. Each node Ni sends request to CH1. accepted rejecting the remaining messages. 6. On accepting from the CH, nodes join the cluster. For example in this figure 3, we compute multiple paths 7. Each CH send its cluster details to the sink. from the cluster head to the sink. The source node transmits 8. The sink establishes multiple paths towards each CH and the data to the cluster head CH4 and the CH4 wants to transmit designates one path as the primary path. the data to the sink. So, it computes four paths: 9. At first cycle R1, sends the sensed data to its CH. Path 1: Source-CH4-CH2-Sink 10. At CH, The data from its members is compressed using Path 2: Source-CH4-CH3-Sink DSC. Path 3: Source-CH4-CH3-CH1-Sink 11. CH sends the compressed data to the sink, using the Path 4: Source-CH4-CH5-CH3-CH1-Sink primary path. The best path is the path with minimum number of hops. 12. After the sink receives the compressed data, it We select the path 1 (CH4-CH2-Sink) for transmission decompresses all the data. When a failure occurs in that primary path the alternative 13. During the next cycle R2, CH chooses the next alternative path is selected. Path 2 (CH4-CH3-CH1-Sink) is chosen as path from the multi path set, to transmit the data. the alternative path for further transmission. The path is 14. If all the alternate paths are used, then in the next cycle, changed in a round robin manner in order to conserve energy. again the primary path is selected. IV. SIMULATION RESULTS Energy Efficient Multipath Data Fusion (EEMD) Technique is evaluated through NS2 [21] simulation. A random network deployed in an area of 500 X 500 m is considered. Initially 100 sensor nodes are placed in square grid area by placing each sensor in a 50x50 grid cell. 10 cluster heads are deployed in the grid region according to our protocol. The sink is assumed to be situated 100 meters away from the above specified area. In the simulation, the channel capacity of mobile hosts is set to the same value: 2 Mbps. The simulated traffic is CBR with UDP source and sink. The number of sources is per cluster is varied fro 1 to 4. Table 1 summarizes the simulation parameters used TABLE 1: SIMULATION PARAMETERS Figure 3. Multi-path clustering © 2012 ACEEE 38 DOI: 01.IJNS.03.02.14
  • 6. ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012 A. Performance Metrics Figure 4 gives the average end-to-end delay when the rate is The performance of EEMD technique is compared with increased. It shows that our proposed EEMDF protocol has the compressive data gathering (CDG) technique [20]. The lower delay when compared to CDG. performance is evaluated mainly, according to the following Figure 5 gives the packet delivery ratio when the rate is metrics. increased. It shows that our proposed EEMDF protocol  Average end-to-end delay: The end-to-end-delay is achieves good delivery ratio when compared to CDG. averaged over all surviving data packets from the Figure 6 gives the energy consumption when the rate is sources to the destinations. increased. It shows that our proposed EEMDF protocol  Average Packet Delivery Ratio: It is the ratio of the utilizes lower energy when compared to CDG. number .of packets received successfully and the B. Based on Sources total number of packets transmitted. In our second experiment, we vary the no. of sources per  Energy: It is the average energy consumed for the cluster from 1 to 4, keeping the CBR sending rate as 100kb. data transmission. B. Results A. Based on Rate In our initial experiment, we vary the transmission sending rate as 100,150,200, 250 and 300 Kb for CBR traffic. We keep 4 sources per cluster. Figure 7. Sources Vs Delay Figure 4. Rate Vs Delay Figure 8. Sources Vs Delivery Ratio Figure 5. Rate Vs Delivery Ratio Figure 9. Sources Vs Energy Figure 7 gives the average end-to-end delay when the no. of source is increased. It shows that our proposed EEMDF protocol has lower delay when compared to CDG. Figure 8 gives the packet delivery ratio when the no. of source is increased. It shows that our proposed EEMDF Figure 6. Rate Vs Energy protocol achieves good delivery ratio when compared to CDG. Figure 9 gives the energy consumption when the no. of source is increased. It shows that our proposed EEMDF protocol utilizes lower energy when compared to CDG. © 2012 ACEEE 39 DOI: 01.IJNS.03.02.14
  • 7. ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012 V. CONCLUSION [11] Maen Takruri, and Subhash Challa “Data Fusion Approach for Error Correction in Wireless Sensor Networks” InTech In this paper, we have proposed a technique which  December 2010. combines the energy efficiency and the multiple path selection [12] Leeger Yu and Anthony Ephremides “Enhancing Energy for data fusion in WSN. We have selected the node with Efficiency For Data Fusion In Sensor Networks With A Detection highest residual energy as the cluster head. Randomly Mission” The 11th International Symposium on Wireless Personal selected initiator nodes collect the information of the nearest Multimedia Communications (WPMC) 2008. sensor nodes and select the node with highest energy as the [13] Hung-Ta Pai, and Yunghsiang S. Han “Power-Efficient Direct- cluster head. The node with the next higher energy level is Voting Assurance for Data Fusion in Wireless Sensor Networks” taken as the initiator. The sink computes multiple paths to IEEE Transactions On Computers, Vol. 57, No. 2, February 2008. [14] Frank Yeong-Sung Lin, Hong-Hsu Yen, and Shu-Ping Lin “A each cluster head for data transmission. Each CH uses Novel Energy-Efficient MAC Aware Data Aggregation Routing in distributed source coding and the lifting scheme wavelet Wireless Sensor Networks” Sensors 2009. transform for compressing the data and after the sink receives [15] Rabindra Bista and Jae-Woo Chang “Energy-Efficient Data all the collected data, it will decompress all the data.. Initially Aggregation for Wireless Sensor Networks” Intech 2010. the path with minimum number of hops is considered as the [16] V. Bhoopathy and R. M. S. Parvathi “Energy Efficient Secure primary path and the compressed data is transmitted to the Data Aggregation Protocol for Wireless Sensor Networks” sink through this path. During each round of transmission, EuroJournals Publishing, Inc. 2011. the path is changed in a round robin manner, to conserve the [17] Yuanzhu Peter Chen, Arthur L. Liestman and Jiangchuan Liu energy. This process is repeated for each cluster. From our “A Hierarchical Energy-Efficient Framework for Data Aggregation in Wireless Sensor Networks” IEEE 2006. simulation results we have shown that this data fusion [18] M. Umashankar, and C. Chandrasekar “Energy Efficient technique has less energy consumption with increased packet Secured Data Fusion Assurance Mechanism For Wireless Sensor delivery ratio, when compared with the existing schemes. Networks” EuroJournals Publishing, Inc. 2011. [19] Zixiang Xiong, Angelos D. Liveris, and Samuel Cheng REFERENCES “Distributed Source Coding for Sensor Networks” IEEE 2004. [20] Chong Luo, Feng Wu, Jun Sun and Chang Wen Chen, [1] Jungmin So, Jintae Kim, and Indranil Gupta “Cushion: “Compressive data gathering for large scale wireless sensor Autonomically Adaptive Data Fusion in Wireless Sensor Networks” networks” MobiCom’09, September 20–25, 2009, Beijing, China. IEEE 2005. [21] Network Simulator, http://www.isi.edu/nsnam/ns [2] WEILIAN SU, and Theodoros C. Bougiouklis “Data Fusion [22] Hu seyin Ozgur Tan, Ibrahim Korpeoglu, and Ivan Stojmenovic, Algorithms In Cluster-Based Wireless Sensor Networks Using “ Computing Localized Power-Efficient Data Aggregation Trees Fuzzy Logic Theory” Proceed ings Of The 11th WSEAS for Sensor Networks”, IEEE Transactions on parallel and distributed International Conference On Communications, Agios Nikolaos, systems, Vol 22, No 3, 2011. Crete Island, Greece, July 26-28, 2007. [23] D. Kumar, T.C. Aseri, R.B. Patel, “EECDA: Energy Efficient [3] Wei Yuan, Srikanth V. Krishnamurthy, and Satish K. 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  • 8. ACEEE Int. J. on Network Security , Vol. 03, No. 02, April 2012 Sasikala V received the MCA., degree from Dr. C. Chandrasekar received his Ph.D. University of Madras, Chennai, Tamilnadu, degree from Periyar University, Salem, TN, the M.Phil., degree in Computer Science from India. He has been working as Associate Manonmaniam Sundaranar University, Professor at Dept. of Computer Science, Periyar Tirunelveli, Tamilnadu. She is pursuing her University, Salem – 636 011, Tamil Nadu, India. PhD under the guidance of Dr. C. Chandrasekar The topic of his doctoral dissertation was “An and currently working as Assistant Professor Optimization and Seamless Mobility for & HOD of Computer Application Department Integration of Wireless LAN and Cellular in DRBCCC Hindu College, Chennai, Tamil Nadu, India. Networks”. His research interest includes Wireless networking, Mobile computing, Computer Communication and Networks. He was a Research guide at various universities in India. He has been published more than 50 research papers at various National / International Journals. © 2012 ACEEE 41 DOI: 01.IJNS.03.02.14