SummaryIn wireless sensor network, a large number of sensor nodes are distributed to cover a certain area. Sensor node is little in size with restricted processing power, memory, and limited battery life. Because of restricted battery power, wireless sensor network needs to broaden the system lifetime by reducing the energy consumption. A clustering-based protocols adapt the use of energy by giving a balance to all nodes to become a cluster head. In this paper, we concentrate on a recent hierarchical routing protocols, which are depending on LEACH protocol to enhance its performance and increase the lifetime of wireless sensor network. So our enhanced protocol called Node Ranked-LEACH is proposed. Our proposed protocol improves the total network lifetime based on node rank algorithm. Node rank algorithm depends on both path cost and number of links between nodes to select the cluster head of each cluster. This enhancement reflects the real weight of specific node to success and can be represented as a cluster head. The proposed algorithm overcomes the random process selection, which leads to unexpected fail for some cluster heads in other LEACH versions, and it gives a good performance in the network lifetime and energy consumption comparing with previous version of LEACH protocols. KEYWORDScluster head selection, clustering-based protocols, LEACH protocols, wireless sensor networks | INTRODUCTIONWireless sensor networks (WSNs) consider a base station (BS) that communicates with countless of wireless sensor nodes by means of a radio channel. Data transmission and reception process are the major operations that consume power in WSN. Elimination of redundant data is important issue in WSN, because multiple nodes may sense the same overlapped area. This action will reduce the overall power consumption and use the bandwidth usage.Routing protocols in WSNs can be divided according to network structure into 3 categories: location based, data centric, and hierarchical protocols. 1,2 Location-based protocol: location information for all nodes is a major cornerstone during data communication. Energy consumption during data transmission depends on the target position distance. Data are sent not only to the target area but also to whole sensors network, which is known as flooding. Residual energy is not considered for each node, so many nodes will run out of energy, which leads at the end to an accumulative data transmission failure. [3][4][5] Data-centric protocol 6 : data transmission from sensor node to the BS through intermediate nodes. The intermediate node may not have interest in the data it receives-it is known as relay node in this case. This process reduces the number of packet sent from source to the sink, which leads to reduce the power consumption.

As expectations for the Internet to support multimedia applicationsgrow, new services need to be deployed. One of them is the group communication service for oneto-many or many-to-many data delivery. After more than a decade of important research and development efforts, the deployment of multicast routing in the Internet is far behind expectations. Therefore, a first motivation for an alternative group communication service is to bypass the lack of native IP multicast routing. Although less efficient and scalable than native multicast routing, such alternative services are generally suitable for the purpose. A second possible motivation is to go beyond the limitations of classic multicast routing for very specific working environments. In this article we identify, classify, and discuss some of these alternative approaches.

In this paper we argue that overlay multicast is an important technology for applications requiring a group communication service. With this approach end-hosts (running the application), dedicated servers and/or border routers automatically self-organize into a distribution topology where data is disseminated. This topology can be composed of both unicast connections and native multicast islands (e.g. within each site). Therefore it offers a group communication service to all hosts, even those located in a site that does not have access to native multicast routing. One of the issues raised is the set up of an efficient and robust overlay topology. In this paper we discuss several possible solutions. We show in particular the benefits of having a centralized approach, of using redundant links and updating the topology based on a host stability criteria.

We study the inipaet of cheating nodes in application-level niulticast overlay trees. We focus on selfish nodes acting independently. cheating ahout their distance measurements during the control phase huilding or maintaining the tree. More precisely, we study, through simulations, the impact of simple cheating strategies in four protocols. representatives of different application-level multicast protoml "faniilies": HBM (a protoeol hased on a centralized approach), TBCP (a distributed, tree fin1 protncnl), NICE (a distrihuted. tree first protocol hased on clustering) and NARADA (a mesh first protocol). We evaluate the impact of cheats on the performance of the overlay trees as perceived hy their nodes and the underlying network.

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