In recent years using wireless sensor networks (WSNs) in applications, such as disaster management and security surveillance have been increased. A lot of sensors in these applications are expected to be remotely deployed in unattended environments autonomously. To support scalability, nodes are often grouped into disjointed and mostly non-overlapping Clusters. Every Cluster has a leader that is known as a Cluster-Head (CH). The CH may be selected by the sensors in the network or pre-assigned by the network designer. These networks require effective communication protocols to be energy efficient and increase network quality. In this paper, a self-organization routing protocol for wireless sensor networks is presented by using hierarchical protocols and considering the position of CHs regarding to each other which is called "Probabilistic Selection of Cluster-Head based on the Nearest possible Distance of Cluster-Head". In addition to increase network lifetime, it causes to increase scalability of the network, optimal use of communication bandwidth and improve some of qualitative parameters of the sensor networks. Proposed method has little overHead control and can find appropriate CHs with local information. In this paper, simulation is done by the NS-2 simulator, and simulation results show this protocol could lead to increase environment monitoring, improve network lifetime, throughput and some qualitative sensor network parameters by improving the Clustering process of all the routing protocol. WSNs that aren’t considered CHs distribution (LEACH protocol here).

A wireless sensor network consists of many inexpensive sensor nodes that can be used to confidently extract data from the environment. Nodes are organized into Clusters and in each Cluster all non-Cluster nodes transmit their data only to the Cluster-Head. The Cluster-Head transmits all received data to the base station. Because of energy limitation in sensor nodes and energy reduction in each data transmission, appropriate Cluster-Head election can significantly reduce energy consumption and enhance the life time of the network. In the proposed algorithm, a modified fuzzy logic approach is presented in order to improve the Cluster-Head election based on four descriptors energy, concentration, centrality, and distance to base station. Cluster-Head is elected by the base station in each round by calculating the chance each node has to elect as a Cluster-Head by considering descriptors. Network life time is evaluated based on first node dies metric, so energy depletion of one node causes the network to die. Simulation shows that the proposed algorithm can effectively increase the network life time. Sensor network is also simulated when sensor nodes move with random velocity in random direction in each round. Simulation shows that network life time is increased by considering this assumption in the proposed algorithm and can develop a better performance.

Wireless sensor network includes hundreds or even thousands of sensor nodes, which are devices with low energy and often impossible to be replaced or recharged. For this reason, efficient use of energy is one of the major challenges in these networks. One way for increasing energy efficiency in such networks is Clustering. Clustering protocols such as LEACH, TEEN, SEP and DEEC randomly select the Cluster Heads for the Clustering process. This causes the Cluster Heads to be close together, decreasing the efficiency of protocols. For this reason, we proposed a new approach called EBDCH. In this method, when Cluster Heads are close together, we distribute them based on the energy situation. The proposed approach runs on the Clustering protocols. The simulation results show that with the implementation of the proposed method, throughput is increased and network lifetime is improved compared to protocols LEACH, DEEC, SEP and EEHC respectively at 26%, 28%, 37% and 36%.

The limited energy supply of wireless sensor networks poses a great challenge for the deployment of wireless sensor nodes. In this paper, a sensor network of nodes with wireless transceiver capabilities and limited energy is considered. Clustering is one of the most efficient techniques to save more energy in these networks. Therefore, the proper selection of the Cluster Heads plays important role to save the energy of sensor nodes for data transmission in the network. In this paper, we propose an energy efficient data transmission by determining the proper Cluster Heads in wireless sensor networks. We also obtain the optimal location of the base station according to the Cluster Heads to prolong the network lifetime. An efficient method is considered based on particle swarm algorithm (PSO) which is a nature inspired swarm intelligence based algorithm, modelled after observing the choreography of a flock of birds, to solve a sensor network optimization problem. In the proposed energy-efficient algorithm, Cluster Heads distance from the base station and their residual energy of the sensors nodes are important parameters for Cluster Head selection and base station localization. The simulation results show that our proposed algorithm improves the network lifetime and also more alive sensors are remained in the wireless network compared to the baseline algorithms in different situations.