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Cluster based routing technique is most popular routing technique in Wireless Sensor Networks (WSNs). Due to varying need of WSN applications efficient energy utilization in routing protocols is still a potential area of research. In this research work we introduced a new energy efficient cluster based routing technique. In this technique we tried to overcome the problem of coverage hole and energy hole. In our technique we controlled these problems by introducing density controlled uniform distribution of nodes and fixing optimum number of Cluster Heads (CHs) in each round. Finally we verified our technique by experimental results of MAT-LAB simulations.Index Terms-energy, efficient, routing, WSN, static, clustering, hole. BACKGROUNDLots of research has been done to control energy utilization in the network layer of WSN. Clustering technique got great attention in resolving energy utilization issue. In clustering technique, data is first gathered and then forwarded to Base Station (BS). A uniform distribution of nodes and optimum number of CHs in each round helps to control load distribution in clustering technique which, ultimately utilizes energy efficiently.As a second step controlling the number of clusters formed during network operation enhances the network stability and lifetime. A network is said to be stable if difference between first node died time and last node died time is minimum [1]. Optimum number of CHs not only control load distribution but also uses energy efficiently.One of the problem in clustering technique is the creation of energy holes. In random distribution of nodes CHs which are overloaded cause the creation of energy holes. In multihop data forwarding technique, nodes near the BS consume large energy. These area of nodes are also called hotspots [1]. Energy depletes quickly in the hotspot areas of network.W.R. Hienzelman, A.P. Chandrakasan and H. Balakrishnan proposed LEACH [2]; one of the first clustering routing protocol for WSNs. According to LEACH algorithm, selection of CH for current round is probabilistic. Therefore, in this approach, of CH selection CHs formed are not uniformly distributed, which may cause existence of disconnected nodes.LEACH-Centralized (LEACH-C) is an extension of LEACH which is proposed by Balakrishnan, Chandrakasan and Heinzelman [3]. The plus point of this algorithm is that, BS makes sure that node with less energy does not become CH. However in large scale network, nodes far away from BS are unable to send their status to BS.Multihop-LEACH protocol is proposed by Nauman Israr and Irfan Awan [4]. Multihop-LEACH has mainly two modes of operations, i.e., multihop inter-cluster operation and multihop-intra cluster operation. In the leading operation nodes sense the environment and send their data to CH, this data is received by BS through a chain of CHs, while the lagging operation is performed in time out period. However, in both modes of operations CH is selected randomly. This agreement does not guaranty full area coverage of the entire network...

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Wireless Sensor Networks (WSNs) consist of numerous sensors which send sensed data to base station. Energy conservation is an important issue for sensor nodes as they have limited power. Many routing protocols have been proposed earlier for energy efficiency of both homogeneous and heterogeneous environments. We can prolong our stability and network lifetime by reducing our energy consumption. In this research paper, we propose a protocol designed for the characteristics of a reactive homogeneous WSNs, HEER (Hybrid Energy Efficient Reactive) protocol. In HEER, Cluster Head(CH) selection is based on the ratio of residual energy of node and average energy of network. Moreover, to conserve more energy, we introduce Hard Threshold (HT) and Soft Threshold (ST). Finally, simulations show that our protocol has not only prolonged the network lifetime but also significantly increased stability period.

Abstract-This I. BACKGROUNDIn Direct Transmission [1], each node in the sensor network communicates directly to BS. In the aforementioned protocol, farthest nodes die faster than the nearest nodes. In Minimum transmission energy [2] routing protocol each node transmits to its nearest node so the nearest nodes die at a faster rate because they receive data from the farther nodes. In the current body of research going in the field of WSNs clustering based protocols have attain significant attraction. In clustering based routing protocols the sensor nodes form clusters. In these clusters, one node is selected as CH. The nodes sense data and send to their respective CHs which aggregate and fuse the data, thus saving the energy as global communication is reduced due to local compression.Once the CH receives data from its nodes it aggregates and fuses the data into a small set and sends to BS. Unbalanced energy consumption among the sensor nodes may cause network partition and node failures where transmission from some sensors to the sink node becomes blocked. Therefore, construction of a stable backbone is one of the challenges in sensor network applications.LEACH [3] proposes a clustering based routing protocol for homogenous networks in which a node becomes CH by a probabilistic equation and forms a cluster of those nodes which receive strong signal to noise ratio from it. The nodes sense the environment and send data to CH where it is aggregated and finally send to BS. In LEACH there is a localized coordination amongst the nodes for cluster set up and locally compress the data to reduce global communication. CHs in LEACH are rotated randomly. Heterogeneous networks are more stable and beneficiary than homogenous networks. A number of protocols like SEP, DEEC and Threshold Distributed Energy-Efficient Clustering protocol (T-DEEC) have been proposed for WSNs. SEP [4] has two level of heterogeneity. In DEEC [5], CH selection is based on the ratio of residual energy and average energy of the network. The high energy nodes have more chances to become CH. In this way the energy is evenly distributed in the network. These routing protocols have some limitation due to their design and performance. II. THE ACH SCHEME A. Optimal Number Of CHsThe optimal probability of a node to take part in election for selection of CHs is a function of the spatial density when the nodes are uniformly distributed over the sensors' field. When the total energy consumption is minimum and energy consumption is well distributed over all sensors, the clustering is then called optimal clustering. The energy model we use for our simulation effect the optimal number of CHs. We use similar energy model as proposed in LEACH, SEP and DEEC. We have been giving particular attention to distribution of CHs in network so as energy in the network. Once nodes are deployed in region of interest the nodes locally coordinate for cluster set up and operation. Each node decides whether to become a CH or not. The node generates a random number and compares it with...

Underwater Wireless Sensor Networks (UWSNs) are an enabling technology for many applications in commercial, military, and scientific domains. In some emergency response applications of UWSN, data dissemination is more important, therefore these applications are handled differently as compared to energy-focused approaches, which is only possible when propagation delay is minimized and packet delivery at surface sinks is assured. Packet delivery underwater is a serious concern because of harsh underwater environments and the dense deployment of nodes, which causes collisions and packet loss. Resultantly, re-transmission causes energy loss and increases end-to-end delay ( D E 2 E ). In this work, we devise a framework for the joint optimization of sink mobility, hold and forward mechanisms, adoptive depth threshold ( d t h ) and data aggregation with pattern matching for reducing nodal propagation delay, maximizing throughput, improving network lifetime, and minimizing energy consumption. To evaluate our technique, we simulate the three-dimensional (3-D) underwater network environment with mobile sink and dense deployments of sensor nodes with varying communication radii. We carry out scalability analysis of the proposed framework in terms of network lifetime, throughput, and packet drop. We also compare our framework to existing techniques, i.e., Mobicast and iAMCTD protocols. We note that adapting varying d t h based on node density in a range of network deployment scenarios results in a reduced number of re-transmissions, good energy conservation, and enhanced throughput. Furthermore, results from extensive simulations show that our proposed framework achieves better performance over existing approaches for real-time delay-intolerant applications.

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From energy conservation perspective in Wireless Sensor Networks (WSNs), clustering of sensor nodes is a challenging task. Clustering technique in routing protocols play a key role to prolong the stability period and lifetime of the network. In this paper, we propose and evaluate a new routing protocol for WSNs. Our protocol; Divide-and-Rule (DR) is based upon static clustering and dynamic Cluster Head (CH) selection technique. This technique selects fixed number of CHs in each round instead of probabilistic selection of CH. Simulation results show that DR protocol outperform its counterpart routing protocols. NCR2, NCR3, etc, as shown in figure 1. Nodes in each region select a CH except the region closest to the BS, that is, region; R1. Nodes whose coordinates lie within the perimeter of R1, communicates directly with BS. Selection of CHs in rest of the regions are based on reference point in each region; reference point is the mid point of each region. Node closest to reference point is selected as CH first, then next closest node and so on till least closest node. In each round only one CH is selected in each region furthermore, we uses multi-hop technique for inter region communication to reduce communication distance. DR scheme has the ability to select CH independent of random number and minimize communication distance to almost less than or equal to reference distance. DR scheme uses hybrid theme of static clustering and dynamic CH selection. This technique divides whole network area into 4(n−1) Corner Regions (CRs) and 4(n−1)+1 Non Corner Regions (NCRs). CHs are selected from NCRs only. Nodes of central region (NCR1) communicates directly with BS while, nodes of CRs associate with adjacent side neighbour CH. DR scheme minimizes communication distance, prolong stability period, enhances network lifetime, and increases throughput. Now a day in many application, it is needed that sensor nodes are location aware. The Localization problem is discussed in [4] and [5]. Location awareness of sensor nodes help in removing coverage holes and movement of new sensor nodes in place of dead nodes. Energy holes in sensor networks also causes depletion of network energy quickly. The analysis and modeling of energy hole of different routing protocols are discussed in [6] and [7].