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Leach wireless sensor ntwrk aa1 Leach wireless sensor ntwrk aa1 Document Transcript

  • PROJECT REPORT ON WIRELESS SENSOR NETWORK Submitted By RAMESH VERMA University Roll no-09165001058 ANIL KUMAR University Roll no-16500110066 PRAVIND KUMAR University Roll no-09165001021 B.TECH(Computer Science & Engineering) CALCUTTA INSTITUTE OF ENGINEERING & MANAGEMENT 24/1A , CHANDI GHOSH ROAD, KOLKATA-700040
  • ACKNOWLEDGEMENT The satisfaction that accompanies the successful completion of any task would be incomplete without the mention of people whose ceaseless cooperation made it possible, whose constant guidance and encouragement crown all effort with success. So, I acknowledge all those whose guidance and encouragement has made successful in winding up this. I owe a huge debt of thanks to a large number of people without whom none of this would have been possible. we are grateful to our project guide Mrs. Moumita Mallick for the guidance, inspiration and constructive suggestion that helped us in the preparation of this project. We are also thankful to all our respected faculty members of CSE department for valuable suggestions and enthusiastic interest during the entire process of seminar. I also thank our friends who have helped in successful completion of the project.
  • CALCUTTA INSTITUTE OF ENGINEERING & MANAGEMENT 24/1A ,CHANDI GHOSH ROAD, KOLKATA-700040 CERTIFICATE This is to certify that Ramesh Verma, Pravind Kumar and Anil Kumar students of Calcutta Institute of Engineering and Management 24/1A, Chandi Ghosh Road, Kolkata-700040 Under West Bengal University of Technology have successfully completed a project on “WIRELESS SENSOR NETWORKS” in 8th semester at Department of Computer Science & Engineering in the year 2012-2013. The results embodied in this project report have not been submitted to any other University or Institute for the award of any Degree or Diploma. ………………………………………… ………………………………………… Mr. Abhijeet Mitra Ms. Moumita Mallick (H.O.D.) Computer Science & Engineering Department Computer Science & Engineering Department
  • ABSTRACT Wireless sensor network consists of widely dispersed very small sensors that have limited processing power and energy resources. The development of wireless sensor networks was motivated by military applications such as battlefield surveillance; today such networks are used in many industrial and consumer applications, such as industrial process monitoring and control, machine health monitoring, and so on. It is very important to have an optimal network in order to use its processing power at maximum. This paper is based on the LEACH (Low Energy Adaptive Clustering Hierarchy) which is one of the routing protocol under hierarchical routing topologies in wireless sensor networks. The basic steps of leach protocol along with some of its disadvantages . Finally we have proposed an algorithm to overcome energy problem in sensor nodes. The proposed protocol adds feature to LEACH to reduce consumption of network resource in each rounds.
  • CONTENTS INTRODUCTION NETWORK DESIGN OBJECTIVES ROUTING PROTOCOLS TYPES OF ROUTING PROTOCOL 1. Location Based Protocol 2. Data Centric Based Protocol 3. Hierarchical Based Protocols 4. Mobility Based Protocols 5. Multipath Based Protocols 6. QOS Based protocols LEACH(Low Energy Adaptive Clustering Hierarchical) PROTOCOL 1. Design 2. Set-up phase 3. Steady state phase 4. weakness DECSA(Distance-Energy Cluster Structure Algorithm) 1. Algorithm 2. Initialisation stage 3. Stable working stage CONCLUSION REFERENCES
  • INTRODUCTION Wireless sensor network consist of many widely distributed sensors, which are used to monitor various kinds ambient conditions like temperature , humidity, etc and then transform them into electric signal. A sensor is equipped with a radio transceiver, a small microcontroller, and an energy source, usually a battery. Usually sensors are physically small and expensive. Small sensor are not as reliable as more expensive macrosensors, but small size and small cost of an individual sensor, allow production and deployment in large numbers. A wireless sensor network contains hundreds or thousands of these sensors devices that have that have ability to communicate either directly to the base station or among each other. The nodes in WSNs are usually battery operated sensing devices with limited energy resources and replacing and replenishing the batteries is usually is not an option. The energy efficiency is one of the most designing power efficient protocol is critical for prolonging the lifetime. Usually, sensor nodes are scattered in the sensing field, being the area where we want to monitor some ambient conditions. Sensor nodes have to coordinate among themselves to get information about the physical environment . The information collected by sensor nodes is routed to the base station either directly or through other sensor nodes. The base station is a fixed node or mobile node, which is capable node to connect the sensor node to an infrastructure networks or to the internet where the user can access and process data. The large number of nodes and their random placement in space offers great redundancy in data transmission. Consequently WSN are generally adaptive networks that use data aggregation and hierarchy to reduce energy consumption. WSN creates a local network hierarchy on one or more levels represented by nodes chosen by certain criteria that are aggregating and sending data to a central base station(BS). Communication is mostly from node to BS, the BS sends requests to obtain data from nodes but not the answer of a particular node is important, the area of origin is. All data is aggregated by the cluster-head before reaching the BS.
  • NETWORK DESIGN OBJECTIVES Most sensor networks are application specific and have different application requirements. Thus, all or part of the following main design objectives is considered in the design of sensor networks: Small node size: Since sensor nodes are usually deployed in a harsh or hostile environment in large numbers, reducing node size can facilitate node deployment. It will also reduce the power consumption and cost of sensor nodes. Low node cost: Since sensor nodes are usually deployed in a harsh or hostile environment in large numbers and cannot be reused, reducing cost of sensor nodes is important and will result into the cost reduction of whole network. Low power consumption: Since sensor nodes are powered by battery and it is often very difficult or even impossible to charge or recharge their batteries, it is crucial to reduce the power consumption of sensor nodes so that the lifetime of the sensor nodes, as well as the whole network is prolonged. Scalability: Since the number sensor nodes in sensor networks are in the order of tens, hundreds, or thousands, network protocols designed for sensor networks should be scalable to different network sizes. Reliability: Network protocols designed for sensor networks must provide error control and correction mechanisms to ensure reliable data delivery over noisy, error-prone, and time-varying wireless channels. Self-configurability: In sensor networks, once deployed, sensor nodes should be able to autonomously organize themselves into a communication network and reconfigure their connectivity in the event of topology changes and node failures. Adaptability: In sensor networks, a node may fail, join, or move, which would result in changes in node density and network topology. Thus, network protocols designed for sensor networks should be adaptive to such density and topology changes. Channel utilization: Since sensor networks have limited bandwidth resources, communication protocols designed for sensor networks should efficiently make use of the bandwidth to improve channel utilization. Fault tolerance: Sensor nodes are prone to failures due to harsh deployment environments and unattended operations. Thus, sensor nodes should be fault tolerant and have the abilities of self testing, self-calibrating, self-repairing, and self-recovering.
  • Security: A sensor network should introduce effective security mechanisms to prevent the data information in the network or a sensor node from unauthorized access or malicious attacks. TYPES OF ROUTING PROTOCOLS CATEGORY PROTOCOLS Location-based Protocols MECN, SMECN, GAF, GEAR, Span, TBF,BVGF, GeRaF Data-centric protocols SPIN, Directed Diffusion, Rumor Routing, COUGAR,ACQUIRE, EAD, Information-Directed Routing, Gradient-Based Routing, Energy- aware Routing, Information-Directed Routing, Quorum-Based Information Dissemination, Home Agent Based Information Dissemination Hierarchical based protocols LEACH, PEGASIS, HEED, TEEN, APTEEN Mobility-based protocols SEAD, TTDD, Joint Mobility and Routing, Data MULES, Dynamic Proxy Tree-Base Data Dissemination Multipath-based protocols Sensor-Disjoint Multipath, Braided Multipath, N-to-1Multipath Discovery Heterogeneity-based protocols IDSQ, CADR, CHR QOS-based protocols SAR, SPEED, Energy-aware routing LOCATION -BASED PROTOCOLS In location-based protocols, sensor nodes are addressed by means of their locations. Location information for sensor nodes is required for sensor networks by most of the routing protocols to calculate the distance between two particular nodes so that energy consumption can be estimated. We present a sample of location-aware routing protocols proposed for WSNs. Data centric based protocols Data -centric protocols differ from traditional address-centric protocols in the manner that the data is sent from source sensors to the sink. In address-centric protocols, each source sensor that has the appropriate data responds by sending its data to the sink independently of all other sensors. However, in data-centric protocols, when the source sensors send their data to the sink, intermediate
  • sensors can perform some form of aggregation on the data originating from multiple source sensors and send the aggregated data toward the sink. This process can result in energy savings because of less transmission required to send the data from the sources to the sink. Hierarchical Protocols Hierarchical or cluster-based routing, originally proposed in wireless networks, are well-known techniques with special advantages related to scalability and efficient communication. It is based on clustering of sensor nodes. Clustering is an energy-efficient communication protocol that can be used by the sensors to report their sensed data to the sink. In this section, we describe a sample of layered protocols in which a network is composed of several clumps (or clusters) of sensors. Each clump is managed by a special node, called cluster head, which is responsible for coordinating the data transmission activities of all sensors in its clump. Multipath-based Protocols In this routing protocols we use multiple paths rather than a single path in order to enhance the network performance. The fault tolerance (resilience) of a protocol can be resolved here. There is always an alternate path exists between a source and a destination when the primary path fails. This can be increased by maintaining multiple paths between the source and the destination at the expense of an increased energy consumption and traffic generation. These alternate paths are kept alive by sending periodic messages. Hence, network reliability can be increased at the expense of increased overhead of maintaining the alternate paths. Heterogeneity-based ProtocolsIn heterogeneity sensor network architecture, there are two types of sensors namely line-powered sensors which have no energy constraint, and the battery-powered sensors having limited lifetime, and hence should use their available energy efficiently by minimizing their potential of data communication and computation. . QoS-based routing : In QoS-based routing protocols, the network has to balance between energy consumption and data quality. In particular, the network has to satisfy certain QoS metrics, e.g., delay, energy, bandwidth, etc. when delivering data to the BS.
  • LEACH(Low Energy Adaptive Clustering Hierarchy) Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol for sensor networks is proposed by W. R.Heinzelman et.al which minimizes energy dissipation in sensor networks. It is very famous hierarchical routing algorithms for sensor networks which make clusters of the sensor nodes based on the received signal strength. The 5% of the total number of nodes becomes the cluster head which act as router to the sink. Energy consumption is less as transmission will only be done by cluster head. Design: LEACH organizes nodes into clusters with one node from each cluster serving as a cluster-head (CH) shown in figure . It randomly selects some predetermined number of nodes as cluster heads. Cluster heads then advertise themselves and other nodes join one of those cluster heads whose signal they found strongest(i.e. the CH which is nearest to them) . Operation: LEACH operation is broken into rounds, with each round having a set-up phase and a steady state phase. Set-up phase: During this phase, each node decides whether or not to become a cluster head (CH) for the current round. This decision is based on choosing a random number between 0 and 1, if number is less than a threshold T(s), the node become a cluster head for the current round. The threshold is defined as follows [1]: T(s) =p/1-p(r mod (1/p)) if s €G Where p is the desired percentage of cluster heads (e.g.0.05), r is = the current round, and G is the set of nodes that have not been cluster heads in the last 1/p rounds. The cluster head node sets up a TDMA schedule and transmits this schedule to all the nodes in its cluster, completing the setup phase which is then followed by a steady-state operation.
  • Flow chart of the Set-up phase of the LEACH Protocol Steady-state phase: each cluster-head waits to receive data from all nodes in its cluster and then sends the aggregated or compressed result back to a BS.
  • Weaknesses: Clustering is a good approach which, if implemented properly, can lead to energy efficient networking in WSNs. Despite the significant overall energy savings, however, the assumptions made by the protocol raise a number of issues as : LEACH assumes that all nodes can communicate with each other and are able to reach the sink (therefore, it is only suitable for small size networks), LEACH assumes that all nodes have data to send and so assign a time slot for a node even though some nodes might not have data to transmit, LEACH assumes that all nearby nodes have correlated data which is not always true, LEACH requires that all nodes are continuously listening ( this is not realistic in a random distribution of the sensor nodes, for example, where cluster-heads would be located at the edge of the network), there is no mechanism to ensure that the elected cluster heads will be uniformly distributed over the network (hence, there is the possibility that all cluster heads will be concentrated in one part of the network), periodic dynamic clustering carries significant overhead which may off-set energy gains derived by the clustering option. RELATED WORK In this research, we assume that set of sensor nodes are randomly deployed in the square field to continuously monitor the phenomenon under inspection. We know that in LEACH algorithm, each node randomly decides to become a cluster head(CH).Once a node decides to become a cluster head ,it aggregates the data received from various nodes inside the cluster and send it to the base station. However, completely independent random cluster head select can't guarantee the number and the distribution of cluster head in each round. It may selects a node which is far away from base station and has low residual energy to become the cluster head, which will cause the uneven energy loss of nodes in the network and form monitoring blind spot, even will influence the whole performance of the network. In order to improve this kind of situation, different from LEACH, in this paper, we will use a three level hierarchy structure network model, which divides the nodes into four categories: Base Station(BS) , Base Station Cluster head(BCH), ordinary cluster head node (CH), and common sensor node (SN). Following figure shows the network model of DECSA algorithm.
  • Figure. Three level hierarchy structure network model of DECSA DECSA Algorithm In this section, we describe our proposed clustering algorithm DECSA(Distance-Energy Cluster Structure Algorithm). DECSA is a distributed competitive unequal clustering algorithm, it considers both the distance and residual energy information of nodes. Similar to that of LEACH, DECSA protocol continues by round and each round can be divided into initialization stage and stable working stage. In order to minimize energy consumption, the stable working stage should be greatly longer than the initialization stage. Initialization stage In the initialization stage, cluster head is elected and TDMA time slots are distributed to ordinary member nodes by the cluster head. Within a given time slot, ordinary member nodes are joined an appropriate cluster. The process of cluster head select consists of following 2 parts: election of ordinary cluster head node (CH) and election of Base Station Cluster head (BCH).In the part of election CH, the main difference between LEACH and DECAS in this part is DECSA employs both residual energy and distance parameter. First, each sensor node generates a random number between 0 and 1.If the random number for a particular node is smaller than the predefined threshold T, then that sensor node becomes the first round cluster-head, we call it false-cluster- head there. And then all the nodes in the cluster are respectively calculate their k(i), and compared it with their current false-cluster-head. If it is greater than the false-cluster-head’s k(i), then announced that he become the CH of this cluster. If it is smaller, then the false –cluster- head become the CH. Thus, the election of cluster head considers both the nodes’ energy consumption and the communication between the network, comparing the difference of k(i), let the high residual energy, high efficiency of communication node has the bigger probability to be elected as CH, it will prolong the lifetime of the network.
  • K(i)=En(i)/d0(i) Where k(i)is the threshold of elect CH , En(i) is the residual energy of node i, d0(i) is the average distance between node i with all other nodes in the same cluster. After the election of cluster-head, in the part of election base-station-cluster- head, we use threshold TBCH to select which CH will become the BCH. We select those CH whose TBCH (i) are larger than the predefined threshold TBCH0 as the base-station cluster-head( BCH). The rest of the cluster heads as ordinary cluster head nodes CH. We define TBCH(i) as follow: TBCH(I)=(En(i)/E0)+(En(i)/d(i)) where En(i) is the current residual energy of node i, E0 is the initial energy of node in the network, d(i) is the distance between node i with base station. Stable working stage In the stable working stage, base station broadcasts the message to the entire network. After received the messages, according to the different value of TBCH (i) , base-station-cluster-head select the maximum TBCH cluster-head as its next hop ,and the rest hop can be selected in the same manner until all of the cluster head nodes are connected ,forming a complete communication path. In order to reduce the direct communication between the base station and the cluster-head which is far away from the base station and has low residual energy. Common nodes (SN) in the cluster will transmit data packet to their closest cluster-head, then cluster-head will collect and fusion those data and transmit them to the base-station cluster- head, rather than transmit them to the base station directly. And then, base-station-cluster-head will communicate with the base station. Avoiding the narrowness of the election of base-station cluster head, balance the consumption of energy and data transmission, the value of threshold TBCH0 should be dynamic changed according to the real-time network’s state, thus could guarantee the base-station-cluster head of the whole network be elected is the most appropriate. The value of TBCH0 should between the average TBCH and the maximum TBCH in network .Of course, the difference of the TBCH0 threshold will cause different influence the performance of the network directly.
  • The graph below shows the comparison of DEGSC and LEACH Residual energy relationship of nodes between DECSA and LEACH Above figure shows the residual energy consumption of nodes between DECSA and LEACH. It clearly depicts that DECSA has a better performance than LEACH in terms of energy consumption. The number of remain alive node in LEACH algorithm is far more less than the number in DECSA algorithm, it reduces about 40% of the energy consumption. CONCLUSION In this paper, we proposed a cluster routing algorithm DECSA considering both the distance and residual energy of nodes, improved the process of cluster head election and the process of data transmission of network. This makes the node with more residual energy and has high polymerization degree in the network has greater probability to become cluster heads. In the stable working stage, it reduces the adverse effect on the energy consumption of the cluster head, resulting from the non-uniform distribution of nodes in network and avoids the direct communication between the base station and the cluster head, which may has low energy and far away from base station. The results of simulation indicate that the improved algorithm effectively balances the energy consumption, prolongs 31% of the lifetime, reduces 40% of the energy consumption and has a better performance than the original LEACH protocol.
  • REFERENCES: [1] Hierarchical Cluster-based Routing in Wireless Sensor Networks Sajid Hussain and Abdul W. Matin Jodrey School of Computer Science, Acadia University Wolfville, Nova Scotia, Canada{Sajid.Hussain, 073720m}@acadiau.ca [2] An Enhanced Cluster Based Routing Algorithm for Wireless Sensor Networks Uk-Pyo Han*, Sang-Eon Park**, Seung-Nam Kim*, Young-Jun Chung* * Computer Science Department, Kangwon National University, Chunchon, Korea **Computer Science Department, California State Polytechnic University, Pomona, USA {mania2k, colors95, ychung}@mail.kangwon.ac.kr, sangeonpark@csupomona.edu [3] Delay Tolerant Cluster Based Routing For Wireless Sensor Networks Saranya. N1 and Mr. S.V. Manisekaran2 M. Tech -IT , Anna University of Technology, Coimbatore, saranit45@gmail.com Assistant Professor-IT, Anna University of Technology, Coimbatore, svmanisekaran@yahoo.co.in [4] JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 26, 2159-2171 (2010) 2159 An Energy-Aware, Cluster-Based Routing Algorithm for Wireless Sensor Networks JYH-HUEI CHANG Department of Computer Science National Chiao Tung University Hsinchu, 300 Taiwan