IMPROVEMENT OF LEACH AND ITS VARIANTS IN WIRELESS SENSOR NETWORK

International Journal of Computer Engineering & Technology (IJCET) Volume 7, Issue 3, May-June 2016, pp. 99 107, Article ID: IJCET_07_03_009 Available online at http://www.iaeme.com/ijcet/issues.asp?jtype=ijcet&vtype=7&itype=3 Journal Impact Factor (2016): 9.3590 (Calculated by GISI) www.jifactor.com ISSN Print: 0976-6367 and ISSN Online: 0976 6375 IAEME Publication IMPROVEMENT OF LEACH AND ITS VARIANTS IN WIRELESS SENSOR NETWORK Chaudhari Komalben Kanjibhai Dept. Computer Engineering, Laljibhai Chaturbhai Institute of Technology, Bhandu-384120, Mahesana, Gujarat, India ABSTRACT Sensor webs consisting of nodes with limited battery power and wireless communications are deployed to collect useful information from the field. Gathering sensed information in an energy efficient manner is critical to operate the sensor network for a long period of time. A data collection problem is defined where, in a round of communication, each sensor node has a packet to be sent to the distant base station. If each node transmits its sensed data directly to the base station then it will deplete its power quickly. Since wireless communications consume significant amounts of battery power, sensor nodes should spend as little energy as possible receiving and transmitting data. It is necessary for communication protocols to maximize nodes' lifetimes, reduce bandwidth consumption by using local collaboration among the nodes, and tolerate node failures. Most of the work in energy efficient data gathering application is motivated by LEACH by allowing rotation of cluster head for load distribution. We have presented several existing methods for energy efficient cluster head selection in wireless sensor network. Our goal is to reducing the amount of cluster head selection and replacement cost and ultimately to extend the lifetime of the entire networks compared with the existing clustering protocols. Key words: Clustering, Energy Efficiency, LEACH, Lifetime, Number of Rounds, WSN Cite this Article: Chaudhari Komalben Kanjibhai, Improvement of LEACH and its Variants In Wireless Sensor Network, International Journal of Computer Engineering and Technology, 7(3), 2016, pp. 99 107. http://www.iaeme.com/ijcet/issues.asp?jtype=ijcet&vtype=7&itype=3 http://www.iaeme.com/ijcet/index.asp 99 editor@iaeme.com

Chaudhari Komalben Kanjibhai 1. INTRODUCTION Wireless sensor network is differ from other ad hoc networks likes mobile ad hoc network and vehicular ad hoc network in the sense that they are resource limited, they are prone to failure, their topology often changes, they use broadcast medium instead of point to point, they are densely deployed etc. Wireless sensor networks are made up of a large number of inexpensive devices. Sensor nodes are tiny devices that comprises of battery, tiny processor, analog to digital converter and radio transceiver. WSN consist of several nodes. Each node has computation capability like sensing, control function and transmission/receiving. Every node sends their sensed data to sink or Base Station (BS) using wireless communication. Sink receives sensed data; aggregate that data and takes decision about action for particular application. So there are various application based on WSN like disaster management, animal tracking and monitoring, volcano monitoring etc. In these kind of application, sensor has require energy for various operation; but at such place battery cannot be recharged or replace; so taking care of energy consumption is issue now a days [16]. In an efficient wireless sensor network, we need efficient routing protocol that has low routing overhead and well organized data aggregation mechanisms to increase good put of network and to save limited power of sensor node To solve problems of energy consumption hierarchical routing (clustering) is best approach. In this approach cluster has been formed; each cluster has several nodes and one cluster head. Every node sends their sensed data to CH; CH aggregates that data and sends data to sink. This paper introduces various clustering protocols. In this paper we clearly explain our work. In section II various protocol based on clustering presented, in section III proposed protocol enlightened, in section IV results were generated and analysed and in section V conclusion for proposed protocol. 2. REVIEW OF LITERATURE LEACH Protocol In past year many protocols developed for Clustering some of important are as follows: Low Energy Adaptive Clustering Hierarchy (LEACH) was proposed by [1] W. Heinzelman. It was first clustering approach introduce for WSN. It is for homogeneous and dense sensor network. It is TDMA based MAC protocol integrated with clustering and uses simple routing. It is working in 2 phase. 1) Set up phase: Each node generates random number between 0 and 1. Node elected as CH by calculating threshold using as in (1), T (n) = p/ (1- p (r % (1/p))) if n belongs to G (1) If (random number < T (n)) Current node becomes Cluster Head Else Current node becomes Cluster Member (normal node). p = probability to become CH, r = round number, n = number of nodes G= set of nodes which not become CH for last 1/p round. Elected CH broadcast advertisement packet for nodes to join cluster. According to receive signal strength nodes send joining packet to particular CH. CH send TDMA schedule to nodes which want to join that particular cluster. 2) Steady state phase: nodes transmit sensed data to CH in their time slot according to TDMA schedule; CH http://www.iaeme.com/ijcet/index.asp 100 editor@iaeme.com

Improvement of LEACH and its Variants In Wireless Sensor Network aggregates that data and transmit to sink. In every round, this 2 phase are worked and new CHs were elected. LEACH-B Protocol LEACH-B is a balanced LEACH. In which proposes an enhanced version of LEACH. It finds the number of cluster heads which are near optimal. In LEACH-B, there is a second stage for selecting cluster head. The second stage considers the residual energy of candidate nodes to become the cluster head. This protocol can save energy consumption by ensuring that the clusters are balanced. The optimal number of cluster heads chosen is between 3 percentages to 5 percentage. Figure 1 LEACH-B Protocol Balanced LEACH guarantees the optimal number of cluster head. Network lifetime increases significantly compared to LEACH. In LEACH-B, we introduce another competition for cluster-heads after the first selection of the cluster heads according to a random number as in LEACH to maintain the constant cluster heads number of n p Where p is the desired percentage of cluster heads and n is the number of total nodes. The first-selected number and the residual energy of cluster heads can be learned by every node through the CHs' advertisement messages. We should consider two different situations because of the uncertain number of cluster heads created by LEACH algorithm. If the number of cluster heads is less thann p, some nodes should be elected from the normal nodes into the cluster heads set. We set a timer for every normal nodes. When the timer expires, and if the number is less thann p, the normal node with short time interval broadcast a CHs advertisement message (ADV_CH) to announce its CH status by using a non-persistent carrier-sense multiple access (CSMA) MAC protocol. http://www.iaeme.com/ijcet/index.asp 101 editor@iaeme.com

Chaudhari Komalben Kanjibhai The value of time interval is set as t =k/e (2) Where k is the factor, E is the residual energy of each node. So the more energy the node has, the shorter the time interval is generated, thus it has more probability to become a cluster head. If the number of cluster heads is more thann p, we can eliminate some low energy cluster head to modify the number of cluster number to n p. The cluster heads sort their residual energy by descend, if one cluster head s energy is ranked behind n p, it is changed to normal node of course, this algorithm is still a distributed algorithm, that is, nodes make autonomous decisions without any centralized control. Furthermore, this new protocol achieves the improvement of the balance of energy consumption. Figure 2 shows the flow chart of the second selection of cluster head. Improvement over LEACH Two phase of selection for cluster he Consider residual energy of nodes. Optimal number of cluster head. Drawback Extra overhead of electing cluster head Each time new cluster head selection in LEACH-B Protocol. 3. PROPOSED APPROACH In most of the energy efficient routing protocols, nodes selected as cluster heads must broadcast to member nodes of the clusters to which they belong that they have become cluster heads. As the frequency of rounding and of cluster head replacement increases, energy consumption increases due to message transmission for broadcasting Our goal is to reducing the amount of cluster head selection and replacement cost and ultimately to extend the lifetime of the entire networks compared with the existing clustering protocols. Cluster head does not directly sends data to the base station. But it sends the data to the next cluster head that is near by the base station and finally data reaches to the base station. (Multi-hop Approach). Select cluster head having highest remaining energy. Replace the cluster head based on the threshold value of residual energy on the sensor nodes. If the energy value of a cluster head is higher than threshold value, then no need to replace the cluster head. The steps in order to setup clusters and then to elect cluster heads are the following: 1. Initially all nodes send their energy level to their neighbors, and ultimately the data reaches to the base station. Base station has the global knowledge of the network. The base station selects cluster head whose energy level is above the threshold. 2. 5% of the total no. of nodes are assigned to be cluster head. The BS broadcasts the unique IDs of the newly selected cluster heads, and their cluster members and the nodes use this information to form and enter a cluster. http://www.iaeme.com/ijcet/index.asp 102 editor@iaeme.com

Improvement of LEACH and its Variants In Wireless Sensor Network 3. Each cluster head creates a TDMA schedule and broadcast this schedule to all other nodes in its cluster. The node sends data within its allocated time. Figure 2 Proposed Methodology 4. Each cluster head aggregate the data and finally data reaches to the base station. A round of data transmission has been completed. If the energy value of a cluster head is higher than threshold value, then cluster head is not replaced. The threshold value for the energy is calculated as per following equation: Updated Threshold = Old Threshold (0.15 * Old Threshold) After completion of second round, node whose energy value greater or equal to 85% becomes Cluster Head. The main features of our proposed method are as follow: Reduce the energy consumption Reduce cluster head selection and replacement cost. http://www.iaeme.com/ijcet/index.asp 103 editor@iaeme.com

Chaudhari Komalben Kanjibhai 4. SIMULATION SCENARIO Table I Simulation parameter Simulation Tool MATLAB Area 100*100 m 2 No. of Nodes 100 Initial energy of nodes 0.5 J Energy required in sending or receiving 1 bit 50 nj/bit Data Aggregation Energy(EDA) 5 nj/bit/signal Energy consumed in amplifier(eamp) 10 pj/bit/m 2 Base Station Location (50,50) Above Table shows simulation Parameters. Our aim is to prolong network life time. Network life time: Network life time depends on the number of dying nodes. We have measured no. of rounds for LEACH and LEACH B. We have measured no. of rounds for the proposed method. Simulation Results The simulation by MATLAB shows that the improved protocol has balanced the system energy consumption and has better performance of prolonging the network lifetime than LEACH-B protocol. The network performance is measured by its life time. As shown in the figure, nodes in LEACH-B protocol shows that all nodes die after about 1521 rounds. While proposed approach figure shows that all node dies after 1905 rounds. Figure 3 Died nodes after 1521 rounds for LEACH-B Figure 4 Died nodes after 1905 rounds for Proposed Approach http://www.iaeme.com/ijcet/index.asp 104 editor@iaeme.com

Improvement of LEACH and its Variants In Wireless Sensor Network Figure 5 Number of alive nodes between LEACH-B and proposed method Above Figure shows the system lifetime using the LEACH B algorithm and proposed method. It shows the number of alive nodes per rounds of LEACH-B and proposed method. Figure 6 Number of dead nodes between LEACH-B and proposed method Above Figure 6 shows the number of died nodes per rounds of LEACH-B and proposed method. Comparison between LEACH, LEACH-B and proposed method Table 4.2 Comparison between LEACH, LEACH-B and proposed method Energy (J/node) Protocol Number of rounds when last node dies 0.5 LEACH 1312 0.5 LEACH-B 1521 0.5 Proposed method 1905 http://www.iaeme.com/ijcet/index.asp 105 editor@iaeme.com

Chaudhari Komalben Kanjibhai 5. CONCLUSION Energy Efficiency for prolonging the WSN has received much focused attention. We have proposed a simple threshold based cluster head selection method in which we reduce the amount of cluster head selection and replacement cost and ultimately to extend the lifetime of the entire networks. This enhanced algorithm has overcome the shortcoming of the original protocol by taking the threshold value of nodes and minimize the cluster head selection process. 6. FUTURE WORK In future, we consider more parameters to increase the network life time like as distance between cluster head to BS and or node to Cluster Head, packet delivery ratio and network life time etc. ACKNOWLEDGMENT I would like to thank my parents, my guides Prof. S. V. Patel and all staff members of LCIT, Bhandu for guidance throughout work period. REFERENCES [1] W. Heinzelman, A. Chandrakasan and H. Balakrishnan, Energy-Efficient Communication Protocol for Wireless Micro sensor Networks, Proceedings of the 33rd Hawaii International Conference on System Sciences (HICSS 00), January 2000. [2] Wendi B. Heinzelman, Anantha P. Chandrakasan, HariBalakrishnan; An Application-Specific Protocol Architecture for Wireless Microsensor Networks; IEEE Transactions On Wireless Communications, 1(4), October 2002. [3] SonaliSenBaidya, AbhishekBaidya, Energy Conservation in a Wireless Sensor Network by an Efficient Routing Mechanism, IEEE International Conference on Communication, Information & Communication Technology, Jan. 16 17, 2015. [4] Nikunj K. Pandya, H.J. Kathiriya, N.H. Kathiriya, A.D. Pandya, Design and Simulation of Enhanced MODLEACH for Wireless Sensor Network, IEEE International Conference on Computing, Communication & Automation, 2015. [5] Wendi B. Heinzelman, Application-Specific Protocol Architectures For WSN Submitted To The Department of Electrical Engineering and Computer Science In Partial Fulfilment of The Requirements For The Degree of Doctor of Philosophy At The Massachusetts Institute Of Technology June 2000, pp. 154. [6] K.Ramesh, Dr.K.Somasundaram, A Comparative Study of Clusterhead Selection Algorithms In Wireless Sensor Networks, International Journal of Computer Science & Engineering Survey (IJCSES) 2(4), November 2011, pp. 12. [7] Mu Tong, Minghao Tang LEACH-B:An Improved LEACH Protocol for Wireless Sensor Network, In IEEE International conference on Wireless Communications, 2010 [8] J.Gnanambigai, Dr.N.Rengarajan, K.Anbukkarasi Leach and Its Descendant Protocols: A Survey, International Journal of Communication and Computer Technologies, September 2012, pp. 7. [9] S. Lindsey, And C.S. Raghavendra, PEGASIS: Power-efficient gathering in sensor information systems, In IEEE Aerospace Conference Proceedings, 2002, 3(9) 16, pp. 1125 1130. http://www.iaeme.com/ijcet/index.asp 106 editor@iaeme.com

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