The most important challenge in wireless sensor NETWORKs is to extend the NETWORK lifetime, which is directly related to the energy consumption. CLUSTERING is one of the well-known energy-saving solutions in WSNs. To put this in perspective, the most studies repeated cluster head selection methods for CLUSTERING in each round, which increases the number of sent and received messages. what's more, inappropriate cluster head selection and unbalanced clusters have increased energy dissipation. To create balanced clusters and reduce energy consumption, we used a centralized NETWORK and relay nodes, respectively. Besides, we applied a metaheuristic algorithm to select the optimal cluster heads because classical methods are easily trapped in local minimum. In this paper, the Grey Wolf Optimizer(GWO), which is a simple and flexible algorithm that is capable of balancing the two phases of exploration and exploitation is used. To prolong the NETWORK lifetime and reduce energy consumption in cluster head nodes, we proposed a centralized multiple CLUSTERING based on GWO that uses both energy and distance in cluster head selection. This research is compared with classical and metaheuristic algorithms in three scenarios based on the criteria of "NETWORK Lifetime", "Number of dead nodes in each round" and "Total Remaining Energy(TRE) in the cluster head and relay nodes. The simulation results show that our research performs better than other methods. In addition, to analyze the scalability, it has been evaluated in terms of "number of nodes", "NETWORK dimensions" and "BS location". Regarding to the results, by rising 2 and 5 times of these conditions, the NETWORK performance is increased by 1. 5 and 2 times, respectively.

Mobile Ad Hoc NETWORK (MANET) is a special and attractive type of new wireless NETWORKs. It is an autonomous system that can dynamically be set up anywhere and anytime without using any pre-existing NETWORK infrastructure and its mobile hosts are free to move randomly. Host mobility in MANET causes failure of wireless links between nodes and breaks all the routes that use these links.Consequently, route reconstructions are needed, which is one of the most crucial issues for this type of wireless NETWORKs. There are two common solutions to this problem which increase the route reliability (lifetime) in MANETs; increasing the reliability of the links by using more reliable links and multipath route discovery. In this paper, both these schemes are used to develop a reliable unicast routing protocol for MANETs. As the first step, an efficient cross layer link reliability metric is proposed for reliable link selection.Reliable routing protocols for MANETs use many link reliability metrics for finding reliable links; four of the most commonly used are: Link Expiration Time, Probabilistic Link Reliable Time, Link Packet Error Rate and Link Received Signal Strength. The cross layer metric combines the aforementioned metrics by means of a weight function. The value of the weighting factors of this function are determined by the Response Surface Methodology. Next a reliable position based CLUSTERING routing protocol is designed. In this protocol the mobile nodes form disjoint sets of clusters, and for increasing the stability of these clusters, the aforementioned cross layer link reliability metric is used for cluster formation. A route is constructed and represented by a sequence of clusters and more reliable links are selected for data transfer inside and between the clusters. Because of the multiple links which usually exist between the clusters, multipath route scheme is used in this routing protocol in addition to the reliable link selection. Simulation results show that by using this protocol the lowest number of route reconstructions is achieved in comparison with the other related protocols.