International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com Volume 2, Issue 4, April 2013 ISSN 2319 - 4847 Distributed Data Aggregation Based Energy Efficient Cluster Algorithm for Heterogeneous Wireless Sensor Network C.Divya1, N.Krishnan2 and P.Krishnapriya3 1 Assistant Professor, Center for Information Technology and Engineering, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, India 2 Professor and Head, Center for Information Technology and Engineering, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, India 3 PG Scholar, Center for Information Technology and Engineering, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, India ABSTRACT WSNs are highly affected by the energy dissipation of the nodes. The sensor nodes are usually used to collect and report application-specific data to the sensor node, known as a sink node. A primary goal in the design of wireless sensor networks is to extend the network lifetime and to build the energy efficient network. Clustering technique is one of the most efficient techniques which provide the energy conservation in wireless sensor networks. This paper analyzes the performance of (DDAEEC) Distributed Data aggregation energy efficient clustering protocol. DDAEEC allows more number of data’s to be sent from the cluster head to the base station within a particular time interval. It mainly performs the time reduction of data transmission over the network, thereby increasing the energy efficiency of the network. Keywords: Heterogeneous environment, Energy-efficiency, Data Aggregation, Network Lifetime, Delay minimization. 1. Introduction Wireless sensor network composed of hundreds or thousands of low power devices known as nodes which sense the physical environment in terms of sound, temperature, vibration, pressure, etc. Homogeneous and heterogeneous are the two types of nodes in WSN. Based on this concept, we classify whether they operate in flat topology or hierarchal topology. Flat topology is treated as same nodes, hierarchal topology forms different types of nodes which are grouped together called as clustering [1] [2]. WSN involves so many clustering techniques such as LEACH [3], [8], PEGASIS [15], HEED [4], TEEN [14], EESR [12], Directed Diffusion and SEP for increasing the energy consumption [13] of the sensor network and its lifetime. This clustering technique can be used for grouping the sensor nodes. After grouping the nodes, choose the cluster head among the cluster members. This cluster head provides data communication between sensor nodes and it performs data aggregation also. Wireless sensor network supports the heterogeneous networks efficiently then homogeneous networks. The Heterogeneous networks [6], [11] perform environmental watching and sensor nodes watch a multiplicity of objects. DEEC [4], [9] is the cluster based algorithm which selects the cluster head on the basis of probability of ratio of residual energy and the average energy of the network. The heterogeneous network [6] clustering algorithm in the DEEC extends the lifetime of the network. Distributed Data Aggregation Energy Efficient Clustering protocol also fit for the multilevel heterogeneous networks. Each node in the sensor network transmits sensing data to the base station through a cluster-head. The cluster-heads, which are chosen by certain clustering algorithms, aggregate the data of their cluster members and send it to the base station, from where the end-users can access the data. DDAEEC algorithm allows a more number of data to send from cluster head to base station in a particular time interval. Thus the time delay to reach the cluster head was minimized and thereby increasing the energy efficiency of the network. Applications of sensor networks are Disaster Relief, Military, Habitat Monitoring, Health Care, Emergency Rescue operation, Environmental monitoring, Home networks, tracking, area monitoring, traffic controlling etc. Volume 2, Issue 4, April 2013 Page 126 International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com Volume 2, Issue 4, April 2013 ISSN 2319 - 4847 The structure of the paper is organized as follows. Section 1 describes an overview of routing protocols for wireless sensor network; Section 2 describes the details of DDAEEC algorithm; section 3 shows the simulation results followed by the conclusion of the work. 2. OVERVIEW OF ROUTING PROTOCOLS LEACH [3], [8] (Low Energy Adaptive Clustering Hierarchy) is a hierarchical routing protocol which uses the random rotation of the nodes, the cluster-heads to evenly distribute energy consumption in the network. This protocol mainly works on homogeneous network. In LEACH protocol the nodes in a sensor network are arranged in a small cluster and choose one of the node as cluster head among cluster members. CH selected by random, aggregates the data collected by the nodes and leads to a limit the traffic generated in the network. LEACH uses TDMA communication protocol to decrease interference between the clusters. HEED [4] (Hybrid Energy-Efficient Distributed clustering), Four primary goals are in this clustering algorithm: extending network lifetime, eliminating the clustering process within a number of iterations, minimizing control overhead, producing well-distributed cluster heads and compact clusters. These algorithms are used to form the nodes into clusters then choose Cluster head by considering the communication distance and the remaining energy. It does not require special node capabilities such as location awareness. The advantages of HEED are it does not make assumptions about node distribution, and operates correctly even when nodes are not synchronized. TEEN [14] is a cluster based hierarchical routing protocol and it is based on LEACH. Using this protocol the data can be sensed continuously but transmission of data is not done frequently. TEEN uses LEACH’s approach to form clusters. Hard threshold (HT) and soft threshold (ST) are two types of threshold mode used in this algorithm. In HT mode the sensed attribute will be within the range of interest in order to send the data. In ST mode any changes in the value of the sensed attribute will be transmitted. The nodes sense their environment frequently then store the sensed value for transmission. If it satisfies the below conditions then only the node transmits the sensed value: a. If sensed value greater than the hard threshold (HT). b. If sensed value is not hard threshold and greater than or equal to soft threshold (ST). In TEEN, cluster head always waits for their time slot for data transmission. Suppose node has no data then time slot may be wasted. PEGASIS [15] is a chain-based power efficient protocol performance based on LEACH protocol. All the nodes have information about all other nodes and each node has the ability of transmitting data to the base station directly. Nodes have global knowledge of the network; chain can be construed by greedy algorithms. Each node transmits and receives data from the closest node of its neighbors. In each round, the node is chosen randomly (leader) from the chain. The aggregated data are sent to the BS using leader. This algorithm eliminates the overhead of the dynamic cluster information and it reduces the number of transmissions. Directed diffusion [17], [18] is a data-centric (DC) and application-aware protocol in which data generated by sensor nodes is known as attribute-value pairs. In the DC protocol, the data coming from different sources are combined and thus eliminating redundancy, reduce the number of transmissions, saving energy and extending network lifetime. In directed diffusion, a base station diffuses a query towards nodes in the concerned region. The query or interest is diffused through the network. Each sensor receives the interest and sets up a gradient toward the sensor nodes. The intermediate nodes may aggregate their data depending on the attribute-value pairs thus reducing the communication cost. This algorithm saves energy by selecting the optimal path and processing data in the network. DEEC [4] (Distributed Energy Efficient Cluster) is used in heterogeneous wireless sensor network. After placing the nodes, nodes are clustered based on the average energy of the network and the ratio between the residual energy of each node, the cluster heads are elected. After that sensed data must be transmitted and received between base station and cluster head. It increases the energy efficiency of network and extend lifetime also. In multi-level heterogeneous networks [5], the clustering algorithm should consider the discrepancy of the initial energy. In the heterogeneous network, the reference value of each node should be different to the initial energy. In the Leach-Heterogeneous system, the energy efficient and life time is increased near to 60% than Leach homogeneous Volume 2, Issue 4, April 2013 Page 127 International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com Volume 2, Issue 4, April 2013 ISSN 2319 - 4847 system; Leach-heterogeneous system considerably reduces dissipation which increases the total lifetime of wireless sensor networks. Compared to above clustering techniques this paper proposes a DDAEEC algorithm to save energy consumption and to extend the lifetime. Placing an N number of nodes in the network and then grouping node is known as clustering. Mainly Clustering techniques can be used to increase the energy efficiency of the network in order to minimize time delay in for communication between the nodes. Then select CH among cluster members, cluster head act as a local base station. Considered here, each node transmits sensing data to the base station through a cluster-head. CH aggregates the data of their cluster members and sends it to the base station, from where the end-users can access the data. 2. DISTRIBUTED DATA AGGREGATION ENERGY EFFICIENT CLUSTER PROTOCOL This work proposes and evaluates a new distributed data aggregation energy-efficient cluster algorithm for heterogeneous wireless sensor network. Here, all the nodes use the initial and residual energy level to define the cluster heads. It does not require any global knowledge of energy at every election round. This DDAEEC algorithm allows a more number of data to send from cluster head to a base station in a certain time interval. Thus the time delay to reach the base station was minimized and in order to increase the energy efficiency of the network. DDAEEC algorithm involves the following steps, 1. Placing sensor nodes in the network. 2. Grouping the nodes 3. Cluster Head selection, 4. Minimum distance estimation 5. Estimate average energy of node in each round. The first step is placing sensor node in the network in this work, the heterogeneous network model has been assumed which exists practically. Let there are N number of nodes which are distributed randomly within a M M square region. The nodes should have different levels of energy, base station located at the centred of region. The Second step is clustering; that means, the deployed N nodes in the region should be clustered. Clustering means grouping of N nodes, in which each node has different levels of energy in the heterogeneous wireless sensor network. The third step is cluster head creation; Next to select a cluster head, for data communication between sensor nodes and the base station efficiently. It performs data aggregation of their cluster members and sends it to the base station. At the DDAEEC algorithm cluster head are elected by initial energy and residual energy of each node. 2.1. Estimating average energy of networks The average energy E (r ) is used as the reference energy for each node. It is the ideal energy of each node, in such ideal situation, the energy of the network and nodes are uniformly distributed. Estimate the average energy E (r ) of each node in rth round as follows E (r ) 1 E total N * n / r / R (1) Here, R denotes the total rounds of the network lifetime. It means that every node consumes the same amount of energy in each round, which is also the target that energy-efficient algorithms should try to achieve. As a result, the actual energy of each node will fluctuate around the reference energy lEt lERx lEDA * lE d4 , d d0 fs E (l, d) 16 Tx lEt lERx lEDA * lE d , d d0 mp Where Et is the total energy of the network, ERx is the receiver energy, and Efsd4 or Empd16 is the amplified energy that (2) depends on the transmitter amplifier model. EDA is energy of aggregation, for aggregate all sensed data this energy multiplies with energy per bit and energy per area depends on the conditions for increase the energy efficiency of the network. There are two conditions is used to calculate transmitter energy, suppose if the distance less than the initial distance use energy per bit and distance greater than or equal to the initial distance use energy per area Each non- Volume 2, Issue 4, April 2013 Page 128 International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com Volume 2, Issue 4, April 2013 ISSN 2319 - 4847 cluster-head send L bits data to the cluster-hea around. Thus the total energy dissipated in the network during a round is equal to: E round L ( 2 NE elec NE DA kE mp d 16 toBS NE fs d 4 toCH ) (3) Where k is the number of clusters, EDA is the data aggregation cost in the cluster-heads, dtoBS is the average distance between the cluster-head and the base station, and dtoCH is the average distance between the cluster members and the cluster-head. dtoCH M = 2 K dtoBS = 0.765 M 2 By setting the derivative of Eround with respect to k to zero, we have the optimal number of clusters as (4) k opt N 2 Efs m Emp d 16 toBS (5) Substituting Esq. (4) and (5) into Eq. (3), we obtain the energy E round dissipated during a round. 2.2. Minimum distance Estimation This method is used to calculate distance and minimum distance between each node and base station. In order to send the data from cluster head to base station based on this method evaluate energy efficiency of network and delay minimization in a heterogeneous network. E n E * ( LEt LE Rx LE DA * LE mp * ( d 16 )) (6) If the distance less than the initial distance, E n E * ( LEt LE Rx LE DA * LE fs * (d 4 )) (7) Now calculate the minimum distance among the resultant distance. For cluster minimum distance, Check the cluster minimum distance~=0, if so then, If the minimum distance greater than the initial distance (d0), E n E * ( LE t LE Rx LE DA * LE mp * (min_ dis16 )) (8) If the minimum distance less than the initial distance, E n E * ( LE t LE Rx LE DA * LE fs * (min_ dis 4 )) (9) Otherwise, the cluster minimum distance=0, then If the minimum distance greater than the initial distance (d0), En E * ( LEt LERx LEDA * LEmp * (min_ dis16 )) (10) If the minimum distance less than the initial distance E n E * ( LE t LE Rx LE DA * LE fs * (min_ dis 4 )) (11) After select, among the minimum distance then send data from the CH to BS through the selected minimum distance. In DDAEEC algorithm is used to increase the energy efficiency of network and perform time reduction of data transmission, parameters are described in Table 1. Volume 2, Issue 4, April 2013 Page 129 International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com Volume 2, Issue 4, April 2013 ISSN 2319 - 4847 Table 1: Parameters Specification Value 10 nJ/bit 25 pJ/bit/m2 0.0020pJ/bit/m4 0.7 J 8 nJ/bit/message Parameter Eelec Ef s Emp E0 EDA d0 80m The above parameters are used in the energy calculations and distance between CH and BS. Table 1 refer from [4]. In our DDAEEC protocol, used to deliver more number of sensing data to base station thereby achieved energy efficiency and reduce data transmission time. 3. SIMULATION RESULTS The performance of DDAEEC protocol using MATLAB is evaluated. Consider a sensor network with R = 50 rounds, assume the base station is in the center of the region. The performance of DDAEEC compared with other protocols. The radio parameters used in our simulations are shown in Table 1. DDAEEC 6000 DDAEEC 5000 y(data) 4000 3000 2000 1000 0 0 5 10 15 20 25 x(time) 30 35 40 45 50 Figure 2: Number of data received in base station for DDAEEC protocol. Figure 2 shows the detailed performance of DDAEEC algorithm, for time duration 50 Sec, around 5000 number of data can be transmitted from cluster head to base station.. leach vs DEEC vs DDAEEC 6000 leach DEEC DDAEE C 5000 y(data) 4000 3000 2000 1000 0 0 5 10 15 20 25 x(time) 30 35 40 45 50 Figure 3: Comparison of LEACH, DEEC, DDAEEC. Figure 3 shows that detail views of the performance of clustering protocol such as LEACH, DEEC and DDAEEC. Comparing to DEEC, DDAEEC algorithm can send 5000 messages at time duration 50 Sec whereas DEEC can send 2500 messages at time duration 50 Sec, LEACH can send 1500 messages at time duration 50sec. This means DDAEEC algorithm performs delay minimization, to reduce time for data transmission over the network. So this algorithm more efficient than DEEC and LEACH. 4. CONCLUSION The proposed DDAEEC protocol can take initial energy and residual energy at the same time and also implement the same procedure for selection of cluster head based on DEEC algorithm. But it compared to DEEC, DDAEEC algorithm send more message at particular time duration. Performance of the algorithm for heterogeneous networks in terms of delay Minimization was performed, that means reducing the time duration for data transmission over the network, thereby increasing the energy efficiency of the network and result was compared with existing protocol LEACH and DEEC, the comparison result shows that the DDAEEC algorithm has 40% increase in message transmission when compared to existing protocols. REFERENCES Volume 2, Issue 4, April 2013 Page 130 International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: editor@ijaiem.org, editorijaiem@gmail.com Volume 2, Issue 4, April 2013 ISSN 2319 - 4847 [1] Ian F. Akyildiz, Weilian Su, Yogesh Sankaraubramaniam, and Erdal Cayirci: A Survey on sensor networks, IEEE Communications Magazine (2002). [2]. Rajashree.V.Biradar , V.C .Patil , Dr. S. R. Sawant , Dr. R. R. 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[12] H. Oh and K. Chae, “An Energy-Efficient Sensor Routing with Low Latency, Scalability in Wireless Sensor Networks,” IEEE International Conference on Multimedia and Ubiquitous Engineering, Seoul, 26-28 April 2007, pp [13] Jamal N. Al-Karaki, Ahmed E. Kamal,‖, Routing Techniques in Wireless Sensor Networks: A Survey‖, IEEE Wireless Communications, Volume: 11, Issue: 6 , 26-28, December 2004. [14]. Manjeswari, A.; Agrawal, D.P. TEEN: A protocol for enhanced efficiency in wireless sensor networks. In Proceedings of 1st International Workshop on Parallel and Distributed Computing Issues in Wireless Networks and Mobile Computing, San Francisco, CA, USA, 2001; p. 189. [15]. Lindsey, S.; Raghavendra, C.S. PEGASIS: Power Efficient gathering in sensor information systems. In Proceedings of IEEE Aerospace Conference, Big Sky, MT, USA, March 2002. Author C.Divya received her M.E degree in Communication systems in the year 2010 from SSN college of Engineering, Anna University, Chennai. She is currently working as Assistant Professor in Centre for Information Technology and Engineering, Manonmaniam Sundaranar University, Tirunelveli, India. Her Research interests are in wireless Sensor Networks and Remote Sensing. She has published several papers related to wireless sensor Networks and its Security. Prof.N.Krishnan is working as Prof. & Head , Centre For Information Technology and Engineering, Manonmaniam Sundaranar University. He did his M.Tech at Cochin University of Science and Technology and obtained Ph.d from Manonmaniam Sundaranar University. He has operated several extra mural research projects funded by DRDO, Govt. of India, CDAC,etc. He has published nearly 100 research papers both in National and International. He has also authored several books on information technology. He has guided nearly 20 ph.d scholars. He is the chair for IEEE Podhigai Subsection. Volume 2, Issue 4, April 2013 Page 131