Proceedings of International Conference on Developments in Engineering Research
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Survey on Wireless Sensor Networks Routing Protocols Based on Energy Efficiency Ms. S.NIVEDITHA1, Ms.M.USHA2 1 2
M.E., Department of Computer Science and Engineering, Velammal Engineering College, Chennai.
Assistant Professor, Department of Computer Science and Engineering, Velammal Engineering College, Chennai. unique.nive@gmail.com, umahalingam@gmail.com
Abstract-Energy consumption and balancing has always been a hot research topic in wireless sensor networks, in this survey, some of the hierarchical routing protocols(LEACH, HEED,PEGASIS, TBC, TREEPSI) with high energy efficient were examined based on some strategies such as data aggregation and clustering, routing and dynamic node allocation methods in the clustering environment. The routing protocols are compared with each other based on these strategies and based on the network life time definitions. Simulation results show which protocol has better prolonging lifetime than other traditional protocols by reducing the energy consumption and load balancing.
energy efficiency and prolong network lifetime in large scale WSN environment. The hierarchical routing protocol imply cluster based organization of the sensor node in order to perform data fusion and aggregation which leads to energy saving. In hierarchical network structure each cluster has a leader, which is called the cluster head (CH) which perform the data aggregation and data transmission to the base station by direct or intermediate communication with other CH nodes.
Key words: Load balancing, Data aggregation, clustering routing protocol.
I.
INTRODUCTION
Wireless sensor networks periodically collects the information of the interested unmanned monitoring area independently through deploying a large number of wireless sensor nodes and send the data to the remote base station.Wirelesssensornodesare deployedrandomlyand denselyina targetregion,especiallywherethephysicalenvironmentissohars hthatthesensor counterpartscannotbe deployed.Afterdeployment,thenetworkcannotworkproperlyun lessthereissufficientbatterypower. Wireless sensor nodes have so many important applications, including military application, disaster prediction and environment monitoring. The military application is performed in the rough environments where the sensor parts cannot deploy due to the energy consumption. Clusteringis very effectivetechnique.Itcan greatly contribute to overall system scalability, lifetime, and energy efficiencyinwirelesssensornetworks(WSNs).Grouping sensor nodes into cluster to satisfy the scalability and achieve high
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Energyconsumption ofanodeisduetouseful, wastefuloperations.The usefuloperationsincludestransmittingorreceivingdatamessag es,andprocessingrequests.Thewastefulconsumption includesconstructingroutingtree,overhearing, retransmittin gb e ca u s e ofharshenvironment, dealingwithredundantover- head messages,andidlelisteningto the media.Each node sends information directly to the base station to full fill the basic task of the sensor nodes. If the base station is located far away from the target area, the sensor nodes will die quickly due to much energy consumption. The distance is also very important factor and the direct transmission leads to the unbalanced energy consumption.
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In general WSN produce large amount of data so if data fusion could be used, the through put could be reduced. Data fusion reduces the redundant data by combining the redundant data to reduce the transmission by suppression, min, maxand average functions. Substantial energy can be saved through the data aggregation this technique has used to achieve energy efficiency and traffic optimization in a number of routing protocols. The data fusion or data aggregation assume that the length of message transmitted by each relay node should be constant. That is each transmits the same volume of data.
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WSN is classified into three categories based on the structure: Flat, hierarchical, and location based routing.
The distance between the nodes to BS leads to two extreme cases 1.
2.
The length of message transmitted by the parent node not only depends on the own length also depends on the length of the message received from its child nodes. The relay node should transmit the length of the message which is the sum of its own sensed data and the received data
Network lifetime has two different definitions: [1] 1. 2.
The time from the start of the operation to death of the first node. The time from the start of the operation to death of the last node
Energy aware protocols and data gathering protocols offering high scalability. A common solution for the balancing energy consumption among all the network nodes, is to periodically re-elect new CH in each cluster. The remainder of the paper is presented as follow:Section IIdiscuss the literature survey. Finally, Section III concludes the paper. II. LITERATURE SURVEY A routingprotocol specifies the routers communicate with each other, and selects the routes between any two nodes on a computer network. Routing algorithms determine the specific choice of route. Each router has knowledge of networks attached to it directly. A routing protocol shares this information first among immediate neighbors, and then throughout the network. Routing strategy is generally based on the following criteria 1.
2. 3.
2.1Hierarchical protocols: Hierarchical routing is a method of routing in networks that is based on hierarchical addressing. It imposes the structure on the network to achieve energy efficiency, stability and scalability. In hierarchical protocols nodes are organized in clusters inwhich a node has some responsible takes the role of cluster head which is responsible for coordinating and message transmitting activities. Clustering reduces the energy consumption to prolongs the life time, can balance the load and increase the scalability. 2.1.1.
LEACH: [2][3]
LEACHisthe most energy efficientclusteringalgorithm forWSNs that forms nodes in clusterbased environment. Based onthe receivedsignal strengthand uses these localclusterheadsasrouters tothe BS.
Achieve minimum cost forwarding, while design of the most data forwarding protocol is based on the optimality. Reducing the minimum number of performed operations Scale to large network size with some constrains
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by choosing the most appropriate cluster head (closest cluster head). In the steady-state phase the cluster heads receive data from the nodes, and transfer the fused data to the base station. And the communication is performed via the TDMA Advantages of LEACH: Data transferto theBSconsumesmoreenergy,all thesensor nodeswithina clustertaketurns withthe transmission by rotatingthe cluster heads. This leadstobalancedenergyconsumption ofallnodes,and hence a longerlifetime ofthe network The basic operations of LEACH was performed in two phases:
Setup phase: Cluster formation. Cluster head was selected and informed to all other nodes. Preparation of transmission schedule. Steady phase: Data fusion. Transmission to destination node
Inthe setup phase, each node n chooses a random number between 0 and 1. If the number is less than a threshold T (n), the node becomes a cluster head for the current round. The threshold is set as:
Disadvantages of LEACH:
T (n) = ___P______ if n belongs to G
1-P *(r mod1/P) Otherwise
0
P = percentage of cluster heads, r = current round
G = set of nodes G is not cluster head in the last 1/P rounds. After the cluster heads are selected, the other nodes organize the local clusters
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It performs most of the communication inside the clusters, and provides scalability. The data fusion leads to a limit on the traffic generated in the network. Single-hop routing from node to cluster head, hence saving energy. It increases network lifetime in three ways: Distributing the role of CH to the other nodes. Aggregating the data by the CHs. TDMA, which, assigned by the CH to its members, puts most of the sensor in sleep mode, in event-based applications. Itincreases the network lifetime and achieve a more than 7-fold reduction in energy dissipation compared to direct communication It is dynamic clustering and well-suited for applications where constant monitoring is needed and data collection occurs periodically to a centralized location.All thesensor nodeswithina clustertaketurns withthe transmission by rotatingthe cluster heads. This leadstobalancedenergy consumption ofallnodes,and hence a longerlifetime ofthe network.
Due to the selection of cluster heads. Because itdon’t consider the energy of the nodes for CH selection. It significantly relies on cluster heads and face robustness issues. Additional overheads due to cluster head changes leads to the energy inefficiency for dynamic clustering in large networks. It has no inter cluster communication, and this needs high transmission power. It selects the CH in random manner it results that the low power node can become a cluster head, it will deplete its energy quickly. And the local cluster head only by distance between themselves and it results the formation of minimum or maximum cluster.
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Proceedings of International Conference on Developments in Engineering Research
assigned to cluster heads among all n nodes, Cprob. Cprob is only used to limit the initial cluster head announcements, and has no direct impact on the final clusters.
Single hop method.
2.1.2.
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HEED: [4]
HEED (Hybrid energy efficient distributed clustering) periodically selects cluster heads according based on the node residual energy and other parameter like proximity to node degree. HEED terminates in O (1) iterations, it incurs low message overhead and achieve uniform cluster head distribution across the network.
Before a node starts executing HEED, itsets its probability of becoming a cluster head, CHprob, as follows:
HEED was designed to select different cluster heads in a field according to the amount of energy that is distributed in relation to a neighboring node
Emax = reference maximum energy which is typically identical for all nodes. The CHprob value of a node, however, is not allowed to fall below a certain threshold pmin. Every node then doubles its CHprob and moved to next step.
The basic operations of HEED protocol was performed by the following steps:
Defining parameters formation. Protocol operation.
used
in
the
cluster
Cluster formation: Cluster head selection is based on the residual energy of each node. The parameters are measuring the residual energy and estimating the intracluster communication cost. The first parameter select initial set of cluster heads, the second parameter performing the cluster power level which increase initial reuse and reserve power for intercluster communication.
CHprob = Cprob * Eresidual / Emax Eresidual = estimated current residual energy in the node.
In HEED energy consumption it extends the lifetime of all the nodes, which adds to the stability of the neighbor set. Nodes automatically update their neighbor sets by periodically sending and receiving heartbeat messages. If a node elected as a cluster head, it sends an announcement message cluster_head_msg(Node ID, selection status, cost), where the selection status is set to tentative_CH if CHprob<1, or final_CH, if it’s CHprob = 1. A node considers itself “covered” if it is heard from either a tentative_CH. If a node completes HEED execution without selecting a cluster head that it considers itself uncovered, and announces itself to be a cluster head. Advantages:
Protocol operation: At each node, the clustering process requires a number of iterations, which was referred as Niter. Every step takes time tc to receive messages from any neighbor within the cluster range. An initial percentage was
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HEED distribution of energy extends the lifetime of the nodes within the network thus stabilizing the neighboring node.
Does not require special node capabilities, such as location-awareness
Does not make assumptions about node distribution
Operates correctly even when nodes are not synchronized.
The advantages of HEED are that nodes only require local (neighborhood) information to form the clusters
The algorithm guarantees that every sensors is part of just one cluster, and the cluster heads are welldistributed.
Disadvantages:
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The random selection of the cluster heads, may cause higher communication overhead for:
The ordinary member nodes in communicating with their corresponding cluster head
Cluster heads in establishing the communication among them, orBetween a cluster head and a base station
The periodic cluster head rotation or election needs extra energy to rebuild clusters
In HEED Multi level hierarchy cannot be achieved. Recursive applications cannot be applied. 2.1.3.
PEGASIS: [5]
PEGASIS (Power-Efficient Gathering in Sensor Information Systems), is an optimal. In PEGASIS, each nodes communicates only with the close neighbor and transmits the information to the base station, it reduces the amount of energy spent per round. It distributes the energy load evenly among the sensor nodes in the network. The sensor nodes are randomly placed in the play field. The nodes are organized to form a chain, which was accomplished by the sensor nodes using a greedy algorithm starting from some node. On the other hand the BS can compute this chain and broadcast it to all the sensor nodes. Construction of the chain starts with the farthest node from the BS. The nodes farther from the BS have close neighbors, as in the greedy algorithm the neighbor distances will increase gradually. When a node dies, the chain will be reconstructed and the threshold can be changed to determine to elect leaders. In it (i mod N) th node is chosen to be a leader.
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Data gathering in each round each node receives data from neighbor, fuses with its own data, and transmits to the other node in chain.The leader was selected in each round of communication in a random manner and random position on the chain, because of the death of nodes at random locations. Token passing approach initiated by the leader to start the data transmission from the ends of the chain. It performs data fusion at every node except the end nodes in the chain. Each node will fuse its neighbor’s data with its own to generate a single packet of the same length and then transmit that to its other neighbor (if it has two neighbors). Advantages of PEGASIS are 1. 2. 3. 4.
Local gathering distance is less than LEACH The amount of data for the leader to receive Limiting the number of transmissions and receives among all nodes. It eliminates the overhead of dynamic cluster formation, minimizing the distance non leader-nodes must transmit.
Disadvantages: Whenevera node dies the whole chain has to be reconstructed and the scalability is also an important issue in PEGASIS. 2.1.4.
Tree Based Clustering: [6]
Tree-Based Clustering (TBC) is also have cluster based environment and each cluster has a cluster-head (CH).
Tree configuration:The cluster construct a routing tree
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where the cluster-head acts as a root. All sensor in a routing tree sends data to a single collection point know as root.
In GSTEB (General self-organized tree based energy balancing routing protocol) the basic tree construction and communication operation is similar to the TCB.
All the nodes arelocation-aware. The distance between the node and the root is for determining its level in the cluster. The nearest node is elected asitsparentnode.
In each round BS assigns a root node and broadcasts its ID and its coordinates to all sensor nodes. And data aggregation takes place.GSTEB changes the root and reconstruct the routing tree with short delay and low energy consumption by this betterbalancedloadis achieved.
Data transmission: Data transmission performed simultaneously. Data is gathered and each node fuses the received data and transmits it to its parent. InTBC each node holds the information of its neighbors. Fast data collection is main advantage in TBC 2.1.4.1. TREEPSI:[7] In TREEPSI sensor nodes are deployed randomly node i (ith node) is placed at a random location. Compute the path by BS and broadcast the path information to other nodes. After the construction of the tree it collects information from the field. TREEPSI is a tree based multi-hop routing protocol to construct a hierarchical path of the nodes. In this nodes will fuse the received data with their own data and forward the resultant data to their parent. It will repeat this process till all the data are received by the root node. The data are collected at the root and at last root takes responsibility to transmit the datatotheBS.Afterthedeathofnode, anewtreepathisconstructed. Sothe overhead per communication round is less as compared to the energy spent in the data collection phase.
The operation of GSTEB is divided into Initial Phase 1. 2. 3. 4.
Tree ConstructingPhase Self-OrganizedDataCollecting Transmitting Phase Information Exchanging Phase.
EL(i)=[residual
energy(i)/constant
reflect the
minimum energy unit] GSTEBoutperformsLEACH, PEGASIS, TREEPSI [9]andTBC.Because GSTEBisaselforganizedprotocol,itonlyconsumesasmallamountof energy ineach round tochangethetopographyforthepurposeofbalancingt heenergyconsumption.Alltheleafnodescantransmit datainthesameTDMAtimeslotsothatthetransmitting delay isshort.Whenlifetimeisdefinedasthetimefromthestar tofthe networkoperationto thedeath of thefirstnode in the network.
Two schemes: 1.
2.
After root initiate data gathering process by sending a small control packet to the children nodes using standard tree traversal algorithm.it will consume some negligible amount of energy but with little more delay. All the leaf nodes send sensed information to their parent. The parent nodes fuse the received data with their own data and forward the resultant data to their parent until data are received by the root node. It has less delay, but needs to introduce some multiplexing scheme to avoid collision.
This path is used for several rounds until node i dies. After the death of node i, a new tree path is constructed with node i+1 as the root. The simulation results shows that TREEPSI outperforms all the existing protocols in terms of energy efficiency. 2.1.5.
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GSTEB: [1]
Advantages of GSTEB:
Load balancing Self-organizing More efficient than other routing protocols.
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GSTEB prolongs the life time by balancing the load.
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GSTEB
389
677
REFERENCES: [1] Zhao Han, Jie Wu, Liefeng Liu, Jie Zhang and kaiyunTian “A General self-organized tree based energy balance routing protocol for wireless sensor networks”., vol.61 , 0018-9499, 2014
III. Conclusions: In this survey paper, routing protocols are compared based on the network life time and data aggregation and the load balancing criteria. Then the new GSTEB protocol’s simulations show that GSTEB outperforms LEACH, PEGASIS, TREEPSI and TBC. Because GSTEB is a selforganized protocol, it only consumes a small energy and it balancing the energy consumption and it have short transmission. GSTEB prolongs the lifetime by 100% to 300% compared with PEGASIS [1]. GSTEBprolongsthelifetimeofthenetworkbymorethan100% compared with HEED. TABLE 1:
LEACH
ROUND TAKEN TO A NODE DIE 118
ROUND TAKEN TO ALL NODES DEAD 248
PEGASIS
246
568
TREEPSI
267
611
TBC
328
629
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[3] “An Integrative Comparison of Energy Efficient Routing Protocols in Wireless Sensor Network” ,Ali Norouzi1, Abdul Halim Zaim2 1Department of Computer Engineering, Istanbul University (Avcilar), Istanbul, Turkey 2Department of Computer Engineering, Istanbul Commerce University (Eminonu), Istanbul, Turkey Email: norouzi@cscrs.itu.edu.tr, azaim@iticu.edu.tr Received December 8, 2011; revised January 11, 2012; accepted January 30, 2012 [4] “HEED: A Hybrid, Energy-Efficient, Distributed Clustering Approach for Ad Hoc Sensor Networks”, OssamaYounis, Student Member, IEEE, and Sonia Fahmy, Member, IEEE, IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 3, NO. 4, OCTOBER-DECEMBER 2004 [5] “PEGASIS: Power efficient gathering in sensor information system” Stephanie Lindsey and Cauligi S. Raghavendra,”IEEE AC paper #242 , updated Sept. 29,2001. 0-7803-7231- 2002 IEEE.
NETWORK LIFE TIME
PROTOCOL
[2] Ankit Solanki,prof.niten b. patel “LEACH-SCH: An innovative routing protocol for wireless sensor network” 4th icccnt-2013
[6]O.durmazincel, a.ghosh,b.krishnamachari and k.chintalapudi “Fast data collection in tree based wireless sensor networks” ieeecs,comsoc. [7] “TREEPSI: TRee based Energy Efficient Protocol for Sensor Information”SiddharthaSankarSatapathy, NityanandaSarmaTezpur University, Napaam-784028, 2006 IEEE
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