# Robust Clustering Routing Method for Wireless Sensor Networks Considering the Locust Search Scheme
## 1 Introduction  
Recently, wireless communications have been widely used since they provide a robust and flexible way to transmit information. Wireless communications refer to the association between mobility and connectivity, considering the air as a transmission medium. [1]. Wireless sensor networks represent the most popular technology among the existing wireless schemes. To operate wireless sensor networks, efficient processes from a computational and energetical point of view are required. Under such conditions, communication protocols are methodological structures that allow guaranteeing the efficiency of such processes. A wireless network of sensors involves a set of electromechanical devices distributed within a defined geographical section. These elements can provide important information about the area in which they are distributed. This information is exchanged and transmitted among the sensors of the network by using a certain transmission channel [2]. The performance of wireless sensors depends on battery management. This fact represents the main problem since it determines its energy autonomy. Therefore, it is important to use a base station (BS) to improve information processing through a centralized transmission. In the context of WSNs, the BS is also referred to as the sink or fusion center due to its aggregation capabilities. Cluster-based or hierarchical routing are popular schemes with interesting characteristics such as efficiency and scalability in communications. The generic ideas of hierarchical routing have been integrated with several methodologies to save energy in WSNs. In the structure of a hierarchical method, nodes with high energy are only considered for processing and transmit information [3]. On the other hand, nodes with low energy are used to collect information in regions near the target. Hierarchical routing corresponds to a powerful approach to diminish the energy consumption inside the cluster structure through the aggregation of information. Hierarchical routing methods integrate processes to reduce the size of the transmission packet to the determined sink [4]. Under such conditions, the assignation of nodes with special purposes can significantly increase the lifetime of the network and the scalability of the architecture. Cluster Heads (CHs) are special nodes used as references in cluster-based or hierarchical schemes. Scalability represents an important property in WSNs. This concept is an open problem that has not been resolved in most of the routing methods due to the constraints imposed by the initial assumptions. In a general WSN approach, cluster-based protocols consider a single sink and some cluster heads in order to extend their influence of the covering space [5]. With this architecture, WSNs maintain low scalability producing expensive processes in terms of energy consumption. Incrementing the number of nodes or the influence diameter of the network provokes an energetical overload and a bottleneck in the transmission of the information. An efficient protocol should present mechanisms to save energy in each node. The objective is to increase the frequency of the recharging process from the batteries. This fact is important since the recharging process is usually difficult and even not possible. Under this architecture, software processes inside the nodes distribute the power load among different nodes [6]. Hierarchical routing incorporates two roles in the behavior of each node. The existence of such operation modes allows considerable energy saving. These different transmission modes, as cluster head and general sensor, can be important when this architecture is also implemented in all layers [7]. On the other hand, optimization strategies such as metaheuristic methods refer to optimization methods that can solve complex systems. These algorithms are extracted from the observation of biological or social processes, that according to a determined perspective, can be interpreted as search strategies.