The Study of the Energy Efficient Protocols (MODLEACH, SEP and DEEC)

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1 ISSN: The Study of the Energy Efficient Protocols (MODLEACH, SEP and DEEC) Tenzin Jinpa USICT,GGSIP University Abstract The wireless sensor network are the major part of our daily life but due to its limited size and space faces some grave issues. This Paper focuses on the key issue of the wireless sensor network i.e. Energy which defines the life time of the network. The three protocols we discuss here are the energy efficient wireless sensor network protocols. IndexTerms-WSN(Wireless sensor network),sep,deec and ModLeach I. INTRODUCTION The wireless sensor network is the emerging technology in the era of the network and communication with diverse applications. The wireless sensor network consist of large chunk of nodes.the nodes are divided into number of cluster and each cluster having the cluster head and other nodes are transmitting the packets to the cluster head. The cluster head will in turn send the packets to the base stations. Each of the wireless sensor network has few parameters like energy usage,node aggregation,cluster head selection etc. The purpose of this paper is look into the efficiency of the few wireless sensor network protocol regarding the energy consumption. MODLEACH, SEP and DEEC protocols are consider to be an energy efficient clustering based hierarchical routing protocol for the wireless sensor network. THE wireless sensor network faces some grave issue like (i)energy consumption of the node(ii)cluster formation(iii)overhead time for cluster head formation (iv)security. We have develop many protocol to address these issues though a unified protocol for WSN is yet to born. This paper focus on one of the primary problem that a wireless sensor network faces i.e. ENERGY CONSUMPTION. The energy consumption will have a great impact on the performance of the WSN as it not only define the life time of the node but also effect the frequency the cluster formation Dr. B.V.R Reddy Professor, USICT,GGSIP University bvrreddy64@yahoo.co.in and resources spent on the cluster head formation. The LEACH protocol stand for Low Energy Adaptive Clustering Hierarchy [1] is TDMA based MAC protocol with the idea of low energy consumption to maintain cluster and extending the life of the WSN. The MOD LEACH is Modified Low Energy Adaptive Clustering Hierarchy which is a variant of Leach while having the efficient head replacement scheme and dual transmission power level which will help in the energy conservation of the wireless sensor network. The SEP protocol is a Stable Election Protocol [2] which is a cluster heterogeneous routing protocol. The SEP protocol is a two level heterogeneous protocol as it has two set of nodes i.e. Advance nodes (nodes with high energy) and the Normal nodes(nodes with low energy) the SEP will ensure that the Advance nodes will become cluster head more frequently than the normal nodes this will help to extends the Stable period of the WSN. The DEEC protocol is a Distributed Energy Efficient Clustering [3] protocol which is an distributed based energy efficient protocol for the heterogeneous wireless sensor network.it is also based on the basic Leach protocol but the Cluster head selection method here is different as the cluster head are selected based probability based ration between the residual energy of each node and the average energy of the system. The DEEC upholds the distributed property while it can be implemented on the multi-level heterogeneous wireless sensor network. These routing protocols will be analysis for the energy consumption and the effect on the wireless sensor network. Thus an efficient wireless sensor network routing protocol has a low overhead of routing and batter mechanism for data aggregation to increase the output while maintaining the lowest possible energy consumption of the nodes. The paper is divided into five sections. First section:- will discuss about the various work done in the WSN protocol filed related to the energy 32

2 conservation and extension of the network life. Second section:-will discuss about the theoretical background of the three protocols under consideration. Third section:- will be of the implementation and the result from the MATLAB simulation and analysis. The fourth section:-we will draw the conclusion point based on the experimental and theoretical knowledge of the protocols under consideration in a wireless sensor network. The final section :-We have the references that we use for this paper. 2.WSN Protocols related to Energy Efficiency The global communication is on fast track to become a wireless network world with low cost of chips manufacturing while possessing high processing and computing power with a minimum cost per storage capacity rate in the entire digital history. Thus humans had deployed hundreds of these chips but by virtues of its small size, it has limited power supply which need to be consumed very wisely to increase the network life time. Though the internal circuit of the node play a vital role but the routing protocols also play an important roles on energy utilization and bandwidth consumption and security in case of the WSN. The solutions to the problems is that Direct Transmission approach i.e. every node will send its data packets to the cluster head but its impact on the nodes that where at far distance from the cluster head will die quickly than that of the node near the head leaving large area blind to sensors. The MTE(Minimum Transmission Energy)emerge as a solution with the multi-hop data transmission in the WSN. This will give more life time for the nodes far from cluster head but it will reduces the life of the nodes near cluster head due to high data aggregation and processing. To solve the problem Direct Diffusion was introduced that involve the data processing and dissemination[4]. The Eri.ent Al[5] presented energy efficient protocol for WSN that deal with the hierarchal clustering mechanism dealing with asymmetric communication. The Jiang et.al presented a CBRP (clustering based routing protocol) [6]though not very efficient in energy saving but implements hierarchical clustering algorithm. The clustering methods had a proven track record for having energy efficient mechanism. In the cluster based WSN when the nodes were deployed it will form the cluster and nominate a node to be its cluster head which is responsible for the data aggregation and fusion of received data and transmit it to the Base Station(BS).This way resulted in low bandwidth utilization and extension of the network life time[7]. In [8] author a multi-hop i.e. data transmission from one cluster head to another cluster head till it reaches the BS thus enhances the network life. Though a number of the cluster base protocol were developed having a various attributions and enhancement but largely focuses on the mechanism of cluster head selection and optimization of the process. The general purpose of the of these protocols is to reduce the energy consumption and data aggregation like M.Tahir et.al[9] introducing the link quality Metric that divide a network in three parts that conserve the energy while the authors of [10]preserve energy saving in WSN by differentiating idle and operational mode of a sensor node. While the Leach protocol uses the basic clustering for enhancing the network life the MODLEACH on other hand uses the efficient head replacement scheme and dual transmitting power levels for optimize use of power in WSN to achieved the same purpose. The SEP(Stable election protocol) give a weighted probability to each node of becoming a cluster head [11]. Thus in our paper we will study the three well known energy efficient routing protocol for the wireless sensor network i.e. Mod Leach,SEP and DEEC. The Protocols The leach protocol was developed by the Wendi, Anantha and Hari and publish in the proceeding of the 33 rd Hawaii conference on system Science-2000.Since the all of the three (Mod-leach,SEP and DEEC) protocols based on the Leach protocol moreover the basic working of all the three protocol is derived from the leach protocol we will look on the Leach protocol first.subsequently we will discuss how the other three protocol are different from the leach. The leach protocol is a clustering based protocol in which it is assume that the energy is uniformly distributed in all the nodes. The leach will use the dynamic selection of the clustering head with the evenly 33

3 distribution of the energy in nodes such that the data are aggregated in the cluster head while the each node will have the 1/n probability of becoming the head of the cluster where n belongs to the number of the nodes. The leach protocol able to reduce the energy consumption by 8 times compared to the conventional routing protocols and its ability to evenly dissipation of energy increase the life time of the network. In the leach protocol once all nodes are group into cluster head creates the schedule of the nodes This will allow the non-cluster head noes to be turn off while not transmitting the packets.once all the packets from the non-cluster head reached to the cluster head it will do the data aggregation and send the compressed data to the base station since the data transmission between the base station and cluster head is of high energy thus drain off the energy of the cluster head very fast. To solve the problem and maintain the homogeneous energy distribution we will have dynamic cluster head selection method. where we maintain a set C(set of nodes to become the cluster head) at time T1 but at the time t1+1 the number node in set is C-1 which mean a node that had become a cluster-head cannot become the cluster-head till 1/n rounds. As discuss in the [33] the number of the cluster head formation is a priori determine and it depends on numerous factor such as topology and cost ration of computation and communication. If the number of the cluster head formation is less than the say optimal number N then some nodes have to transmit the data far which mean loss of energy while the cluster head number above the N mean long-haul packet transmission. The Advertisement phase Initially when the cluster are formed,each node will decide whether it would like to become a cluster head or not.it also depend on the number cluster head allow as per the priori and the number of times the node had become the cluster head. Those nodes whose energy level in less than the threshold energy will be allowed to become the cluster head.. where p=desired percentage of the cluster head (p=0.5),r=number of the rounds, G =is a set of nodes that are allowed to become cluster head. If the r=0 than every node has a p probability to be a head-node, the nodes which will become the head will not be able to become the cluster head at 1/p rounds.thus at t/p -1 rounds the number of the nodes in G is reduced.after the 1/p round the all nodes once again will be allowed to be a head node of the cluster. The advertisement of the cluster head to the non-cluster head is usually done through the CSAM MAC protocol.all the non-cluster head node need to keep their receiver active during the advertisement phase to receive the Advertisement messages and based on the advertisements messages and the strength of the signal the non-cluster head node will decide on which cluster it will become a member during this round. Cluster set-up phase During this phase the non-cluster head nodes will informed the cluster head that it want to become its member during this round of cluster formation and data transmission. The non-cluster head will use the same CSMA MAC protocol as use by the sink for advertisement. During the cluster setup phase the cluster-head should be keep the receiver active to receive the messages from the other nodes. Schedule Creation Once the cluster-head decide which nodes will be in its cluster,it will decide the transmission period from the node to the cluster head by TDMA method. The cluster-head node will decide the schedule for the transmission from the nodes to head-node. This message will be broadcast to all the other nodes. THE MOD-LEACH PROTOCOL The Mod-leach protocol is an modified version of the leach which introduces the efficient cluster head replacement scheme and the dual transmitting power level. In the leach protocol for every new round we chooses a new cluster head thus resulting in new cluster head formation which will result in the energy loss.also in Leach it is assume that the energy needed in any type of transmission in the network is same which is practically not true thus resulting in the loss of energy.the Mod-Leach checks if a new cluster-head is needed in next round by seeing the 34

4 ISSN: present cluster-heads energy is within the threshold limit. If the energy is within the threshold limit than there is no need to find the new head thus preventing the cluster head formation. If the energy is not within the critical threshold limit than new cluster-head will be elected by Leach protocol. The Mod-leach beside limiting the cluster formation also have the two level of power to amplify signal according to the nature of the transmission. As energy required for inter cluster or cluster head to base station and that of the intra cluster communication is different thus having the minimum energy transmission for the inter cluster transmission than that of the node to the cluster-head help in saving energy which will extend the life of the network as compare to the leach where energy required for the various transmission is same result in the loss of energy. THE SEP (Stable Election Protocol) The SEP(Stable election protocol )is a heterogeneous wireless sensor network protocol which is an improvement over the LEACH protocol. It will prolonged the stable period (time period before the dead of the first node).in the SEP we will select the cluster head based on the energy remaining in the nodes. Here we will divide the node into two categories the advance nodes(the nodes with high energy) and the normal nodes ( nodes with low energy).the advance nodes has to become the head nodes more often so that the we could maintain the spatial density of network remain same to that of the priori setting of Popt. Thus it will increase the stable period of the network which is very beneficial for many application The SEP will have two formula for probability of the nodes becoming the head one for the advance node and other for the other for the normal nodes. Pnrm= Padv= Where the Popt is the desired cluster head probability, is the normal nodes and m is the advance nodes. Will change the threshold formula that we use for the selection of the cluster head in the network. Thus for the advance node we will have the following threshold :- T(Snrm) Where r is the current round, G is the set of normal nodes that have not become the cluster head during the within last 1/pnrm rounds of nodes. The T(Snrm) is threshold applied to a population of n.(1-m) nodes this will ensure that the every normal nodes become the cluster head at rounds per 1/popt. Like wise the advance nodes threshold as shown below :- will have the T(Sadv) Where G is the set of the advance nodes that have not become the cluster heads within the last rounds of the 1/popt and the it is applied to the n*m(advance) nodes. This will ensure that that the spatial density remain same thus improving the stable period of the network which will help the network to get better result. The major drawback of the SEP protocol is that the cluster head selection between two set of nodes (normal nodes and advance nodes) is not a dynamic which result in the nodes that are far away will die out fast. THE DEEC PROTOCOL The DEEC protocol is a Distributed Energy Efficient Clustering protocol which is an distributed based energy efficient protocol for the heterogeneous wireless sensor network.it is also based on the basic Leach protocol but the Cluster head selection method here is different as the cluster head are selected based probability based ration between the residual energy of each node and the average energy of the system. The DEEC upholds the distributed property while it can be 35

5 implemented on the multi-level heterogeneous wireless sensor network. As we know in the SEP protocol we have two types of the nodes (normal and advance nodes) which help in selection of the cluster head but it fails in a multi-level heterogeneous network environment so in DEEC uses the probability based ration between the residual energy of the node and the average energy of the system but having a global knowledge of the average energy of the system to each node is difficult so DEEC will assume an ideal value for the network lifetime which is now used to calculate the reference energy that each node should expand during each round.the DEEC got limitation that the advance nodes always get penalize as when the residual energy reduced and become equal to that of the normal nodes. On such circumstances the advance nodes will die fast than the other nodes. We will see the what are the differences that the MODLEACH,SEP and DEEC on four parameter that will be (i)number of the alive (ii)number of the dead nodes (iii)packet to the BS and (iv)cluster formation nodes per round. Based on these result we see try to reason out the differences and which protocol will give us the better result. As from the figure(i) that the number of the alive nodes per rounds of the network show that the as theoretically presumed the DEEC give the best result but the MODLEACH protocol and SEP protocol give almost uniform result though the theoretical understanding of the WSN protocols is that the SEP outperformed the LEACH. This show 3.Simulation Results The setup of the experiment:- In this experiment we will initialize the p opt =0.5 while having 100*100 region where there will be 100 sensor nodes randomly distributed in the system. We also assume that the that the there will be 20% sensor node will be advance nodes (m=0.2) and the advance nodes will have 300% more energy than the normal nodes. Other setting in the The various other parameter is taken as follow:- Parameter E elec Value 50nJ/bits E fs 10pj/bit/m 2 EDA E o 0.5j Number of rounds 2500 K opt 3 p opt 0.1 5nj/bit/packet Network size 100*100 Base station location (50,50) E mp 0.014pj/bit/m 4 Figure (1) number of the Alive nodes per rounds that the modification mode in the leach help in getting batter result.the DEEC which employ the unique head selection method where the cluster head are selected based on t ratio of the residual energy and energy of the system which in turn more number of nodes alive for longer period of the time as shown in the above figure (1). The figure (2) that show the number of the dead nodes per rounds of the protocols,it is important to have low dead nodes per rounds as a dead nodes means loss in the information from that region. Lower the dead nodes per rounds higher the network lifetime of the WSN. It is also important to note that the stability period of the protocols can also analyze from the figure (1 & 2). Figure (2) number of the DEAD nodes per rounds 36

6 The DEEC will have the best result as thought while the but the MODLEACH in this case also give a very good result as the number of the dead nodes is almost similar to that of the SEP protocol but the SEP still do have a minor edge on the MODLEACH as shown from the figure(2).this conclude that the DEEC will have the best stable region while the SEP and MODLEACH will have all most similar stability period. What about the packet transmission to the BS from the cluster head. The figure(3) give us the relative packet transmission rate of the three protocol under consideration. Here we see that the packet transmission rate of SEP is good stable after a point. Figure (3) number of packet to the BS per rounds the cluster stability is moderate for both the protocols(sep and DEEC). 4. Conclusion: We now conclude from studying the three wireless sensor network protocols (MODLEACH, SEP and DEEC ) that:- (i)the simulation result show that the DEEC outperformed the both the SEP and the MODLEACH protocol in every sense. (ii)the modification made on the Leach protocol has no effect on its packet transmission rate as the packet transmission rate of the Mod Leach is lower than the both the SEP and DEEC. While it extends the network life of the Mod Leach protocol. (iii)because of the Modification made on the Leach we have Mod-Leach performance is similar to that of the SEP protocol which is not possible with the basic Leach protocol. (iv)the energy efficiency of the DEEC is higher than other two protocols. The SEP and Mod Leach protocol both have the moderate energy efficiency. The table (1) show the comparison of three WSN protocols for various performance metrics The MODLEACH have a very low packet transmission rate than that of the other two protocol. THE DEEC protocol outperformed the both the SEP and MODLEACH protocols. The modification on the basic Leach protocol has no effect on its transmission rate. Now the cluster formation of the three protocols per round is to be considered for idle situation the cluster formation should optimal and number of the cluster head should be same throughout the network life. The figure(4). Criteri a Type system of Energy Efficiency Stability period Rate of packet transfer Mod- Leach Homogene ous WSN SEP Two level of heterogeneo us WSN DEEC Moderate Moderate High Multilevel heterogene ous WSN Moderate Moderate Highest Low Moderate High Cluster stability Moderate Moderate High Figure (4) Cluster head formation The cluster formation of the DEEC show that the DEEC has the higher cluster formation stability while that of the MODLEACH and the SEP is almost similar but compare to that of the DEEC Network life time Batter than Leach and similar to SEP Moderate Higher network life-time than the Mod-leach and SEP. 37

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